NEWS
author ballarin
Mon Apr 18 09:25:23 2005 +0200 (2005-04-18)
changeset 15763 b901a127ac73
parent 15744 daa84ebbdf94
child 15776 e2f45df0696f
permissions -rw-r--r--
Interpretation supports statically scoped attributes; documentation.
     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   For details, see the Isar Reference manual.
   167 
   168 * Locales: proper static binding of attribute syntax -- i.e. types /
   169   terms / facts mentioned as arguments are always those of the locale
   170   definition context, independently of the context of later
   171   invocations.  Moreover, locale operations (renaming and type / term
   172   instantiation) are applied to attribute arguments as expected.
   173 
   174   INCOMPATIBILITY of the ML interface: always pass Attrib.src instead
   175   of actual attributes; rare situations may require Attrib.attribute
   176   to embed those attributes into Attrib.src that lack concrete syntax.
   177 
   178   Attribute implementations need to cooperate properly with the static
   179   binding mechanism.  Basic parsers Args.XXX_typ/term/prop and
   180   Attrib.XXX_thm etc. already do the right thing without further
   181   intervention.  Only unusual applications -- such as "where" or "of"
   182   (cf. src/Pure/Isar/attrib.ML), which process arguments depending
   183   both on the context and the facts involved -- may have to assign
   184   parsed values to argument tokens explicitly.
   185 
   186 * Attributes 'induct' and 'cases': type or set names may now be
   187   locally fixed variables as well.
   188 
   189 * Isar: new syntax 'name(i-j, i-, i, ...)' for referring to specific
   190   selections of theorems in named facts via indices.
   191 
   192 
   193 *** Document preparation ***
   194 
   195 * New antiquotations @{lhs thm} and @{rhs thm} printing the lhs/rhs of
   196   definitions, equations, inequations etc.
   197 
   198 * Antiquotations now provide the option 'locale=NAME' to specify an
   199   alternative context used for evaluating and printing the subsequent
   200   argument, as in @{thm [locale=LC] fold_commute}, for example.
   201 
   202 * Commands 'display_drafts' and 'print_drafts' perform simple output
   203   of raw sources.  Only those symbols that do not require additional
   204   LaTeX packages (depending on comments in isabellesym.sty) are
   205   displayed properly, everything else is left verbatim.  We use
   206   isatool display and isatool print as front ends; these are subject
   207   to the DVI/PDF_VIEWER and PRINT_COMMAND settings, respectively.
   208 
   209 * Proof scripts as well as some other commands such as ML or
   210   parse/print_translation can now be hidden in the document.  Hiding
   211   is enabled by default, and can be disabled either via the option '-H
   212   false' of isatool usedir or by resetting the reference variable
   213   IsarOutput.hide_commands. Additional commands to be hidden may be
   214   declared using IsarOutput.add_hidden_commands.
   215 
   216 
   217 *** HOL ***
   218 
   219 * Datatype induction via method `induct' now preserves the name of the
   220   induction variable. For example, when proving P(xs::'a list) by induction
   221   on xs, the induction step is now P(xs) ==> P(a#xs) rather than
   222   P(list) ==> P(a#list) as previously.
   223 
   224 * HOL/record: reimplementation of records. Improved scalability for
   225   records with many fields, avoiding performance problems for type
   226   inference. Records are no longer composed of nested field types, but
   227   of nested extension types. Therefore the record type only grows
   228   linear in the number of extensions and not in the number of fields.
   229   The top-level (users) view on records is preserved.  Potential
   230   INCOMPATIBILITY only in strange cases, where the theory depends on
   231   the old record representation. The type generated for a record is
   232   called <record_name>_ext_type.
   233 
   234 * HOL/record: Reference record_quick_and_dirty_sensitive can be
   235   enabled to skip the proofs triggered by a record definition or a
   236   simproc (if quick_and_dirty is enabled). Definitions of large
   237   records can take quite long.
   238 
   239 * HOL/record: "record_upd_simproc" for simplification of multiple
   240   record updates enabled by default.  Moreover, trivial updates are
   241   also removed: r(|x := x r|) = r.  INCOMPATIBILITY: old proofs break
   242   occasionally, since simplification is more powerful by default.
   243 
   244 * HOL: symbolic syntax of Hilbert Choice Operator is now as follows:
   245 
   246   syntax (epsilon)
   247     "_Eps" :: "[pttrn, bool] => 'a"    ("(3\<some>_./ _)" [0, 10] 10)
   248 
   249   The symbol \<some> is displayed as the alternative epsilon of LaTeX
   250   and x-symbol; use option '-m epsilon' to get it actually printed.
   251   Moreover, the mathematically important symbolic identifier
   252   \<epsilon> becomes available as variable, constant etc.
   253 
   254 * HOL: "x > y" abbreviates "y < x" and "x >= y" abbreviates "y <= x".
   255   Similarly for all quantifiers: "ALL x > y" etc.
   256   The x-symbol for >= is \<ge>.
   257 
   258 * HOL/Set: "{x:A. P}" abbreviates "{x. x:A & P}"
   259            (and similarly for "\<in>" instead of ":")
   260 
   261 * HOL/SetInterval: The syntax for open intervals has changed:
   262 
   263   Old         New
   264   {..n(}   -> {..<n}
   265   {)n..}   -> {n<..}
   266   {m..n(}  -> {m..<n}
   267   {)m..n}  -> {m<..n}
   268   {)m..n(} -> {m<..<n}
   269 
   270   The old syntax is still supported but will disappear in the future.
   271   For conversion use the following emacs search and replace patterns:
   272 
   273   {)\([^\.]*\)\.\.  ->  {\1<\.\.}
   274   \.\.\([^(}]*\)(}  ->  \.\.<\1}
   275 
   276   They are not perfect but work quite well.
   277 
   278 * HOL: The syntax for 'setsum', summation over finite sets, has changed:
   279 
   280   The syntax for 'setsum (%x. e) A' used to be '\<Sum>x:A. e'
   281   and is now either 'SUM x:A. e' or '\<Sum>x\<in>A. e'.
   282 
   283   There is new syntax for summation over finite sets:
   284 
   285   '\<Sum>x | P. e'    is the same as  'setsum (%x. e) {x. P}'
   286   '\<Sum>x=a..b. e'   is the same as  'setsum (%x. e) {a..b}'
   287   '\<Sum>x=a..<b. e'  is the same as  'setsum (%x. e) {a..<b}'
   288   '\<Sum>x<k. e'      is the same as  'setsum (%x. e) {..<k}'
   289 
   290   Function 'Summation' over nat is gone, its syntax '\<Sum>i<k. e'
   291   now translates into 'setsum' as above.
   292 
   293 * HOL: Finite set induction: In Isar proofs, the insert case is now
   294   "case (insert x F)" instead of the old counterintuitive "case (insert F x)".
   295 
   296 * HOL/Simplifier:
   297 
   298   - Is now set up to reason about transitivity chains involving "trancl"
   299   (r^+) and "rtrancl" (r^*) by setting up tactics provided by
   300   Provers/trancl.ML as additional solvers.  INCOMPATIBILITY: old proofs break
   301   occasionally as simplification may now solve more goals than previously.
   302 
   303   - Converts x <= y into x = y if assumption y <= x is present.  Works for
   304   all partial orders (class "order"), in particular numbers and sets. For
   305   linear orders (e.g. numbers) it treats ~ x < y just like y <= x.
   306 
   307   - Simproc for "let x = a in f x"
   308   If a is a free or bound variable or a constant then the let is unfolded.
   309   Otherwise first a is simplified to a', and then f a' is simplified to
   310   g. If possible we abstract a' from g arriving at "let x = a' in g' x",
   311   otherwise we unfold the let and arrive at g. The simproc can be 
   312   enabled/disabled by the reference use_let_simproc. Potential
   313   INCOMPATIBILITY since simplification is more powerful by default.
   314  
   315 
   316 *** HOLCF ***
   317 
   318 * HOLCF: discontinued special version of 'constdefs' (which used to
   319   support continuous functions) in favor of the general Pure one with
   320   full type-inference.
   321 
   322 
   323 *** ZF ***
   324 
   325 * ZF/ex/{Group,Ring}: examples in abstract algebra, including the
   326   First Isomorphism Theorem (on quotienting by the kernel of a
   327   homomorphism).
   328 
   329 * ZF/Simplifier: install second copy of type solver that actually
   330   makes use of TC rules declared to Isar proof contexts (or locales);
   331   the old version is still required for ML proof scripts.
   332 
   333 
   334 *** System ***
   335 
   336 * HOL: isatool dimacs2hol converts files in DIMACS CNF format
   337   (containing Boolean satisfiability problems) into Isabelle/HOL
   338   theories.
   339 
   340 * isatool usedir: option -f allows specification of the ML file to be
   341   used by Isabelle; default is ROOT.ML.
   342 
   343 * ISABELLE_DOC_FORMAT setting specifies preferred document format (for
   344   isatool doc, isatool mkdir, display_drafts etc.).
   345 
   346 
   347 *** ML ***
   348 
   349 * Pure: output via the Isabelle channels of writeln/warning/error
   350   etc. is now passed through Output.output, with a hook for arbitrary
   351   transformations depending on the print_mode (cf. Output.add_mode --
   352   the first active mode that provides a output function wins).
   353   Already formatted output may be embedded into further text via
   354   Output.raw; the result of Pretty.string_of/str_of and derived
   355   functions (string_of_term/cterm/thm etc.) is already marked raw to
   356   accommodate easy composition of diagnostic messages etc.
   357   Programmers rarely need to care about Output.output or Output.raw at
   358   all, with some notable exceptions: Output.output is required when
   359   bypassing the standard channels (writeln etc.), or in token
   360   translations to produce properly formatted results; Output.raw is
   361   required when capturing already output material that will eventually
   362   be presented to the user a second time.  For the default print mode,
   363   both Output.output and Output.raw have no effect.
   364 
   365 * Provers: Simplifier and Classical Reasoner now support proof context
   366   dependent plug-ins (simprocs, solvers, wrappers etc.).  These extra
   367   components are stored in the theory and patched into the
   368   simpset/claset when used in an Isar proof context.  Context
   369   dependent components are maintained by the following theory
   370   operations:
   371 
   372     Simplifier.add_context_simprocs
   373     Simplifier.del_context_simprocs
   374     Simplifier.set_context_subgoaler
   375     Simplifier.reset_context_subgoaler
   376     Simplifier.add_context_looper
   377     Simplifier.del_context_looper
   378     Simplifier.add_context_unsafe_solver
   379     Simplifier.add_context_safe_solver
   380 
   381     Classical.add_context_safe_wrapper
   382     Classical.del_context_safe_wrapper
   383     Classical.add_context_unsafe_wrapper
   384     Classical.del_context_unsafe_wrapper
   385 
   386   IMPORTANT NOTE: proof tools (methods etc.) need to use
   387   local_simpset_of and local_claset_of to instead of the primitive
   388   Simplifier.get_local_simpset and Classical.get_local_claset,
   389   respectively, in order to see the context dependent fields!
   390 
   391 
   392 
   393 New in Isabelle2004 (April 2004)
   394 --------------------------------
   395 
   396 *** General ***
   397 
   398 * Provers/order.ML:  new efficient reasoner for partial and linear orders.
   399   Replaces linorder.ML.
   400 
   401 * Pure: Greek letters (except small lambda, \<lambda>), as well as Gothic
   402   (\<aa>...\<zz>\<AA>...\<ZZ>), calligraphic (\<A>...\<Z>), and Euler
   403   (\<a>...\<z>), are now considered normal letters, and can therefore
   404   be used anywhere where an ASCII letter (a...zA...Z) has until
   405   now. COMPATIBILITY: This obviously changes the parsing of some
   406   terms, especially where a symbol has been used as a binder, say
   407   '\<Pi>x. ...', which is now a type error since \<Pi>x will be parsed
   408   as an identifier.  Fix it by inserting a space around former
   409   symbols.  Call 'isatool fixgreek' to try to fix parsing errors in
   410   existing theory and ML files.
   411 
   412 * Pure: Macintosh and Windows line-breaks are now allowed in theory files.
   413 
   414 * Pure: single letter sub/superscripts (\<^isub> and \<^isup>) are now
   415   allowed in identifiers. Similar to Greek letters \<^isub> is now considered
   416   a normal (but invisible) letter. For multiple letter subscripts repeat
   417   \<^isub> like this: x\<^isub>1\<^isub>2.
   418 
   419 * Pure: There are now sub-/superscripts that can span more than one
   420   character. Text between \<^bsub> and \<^esub> is set in subscript in
   421   ProofGeneral and LaTeX, text between \<^bsup> and \<^esup> in
   422   superscript. The new control characters are not identifier parts.
   423 
   424 * Pure: Control-symbols of the form \<^raw:...> will literally print the
   425   content of "..." to the latex file instead of \isacntrl... . The "..."
   426   may consist of any printable characters excluding the end bracket >.
   427 
   428 * Pure: Using new Isar command "finalconsts" (or the ML functions
   429   Theory.add_finals or Theory.add_finals_i) it is now possible to
   430   declare constants "final", which prevents their being given a definition
   431   later.  It is useful for constants whose behaviour is fixed axiomatically
   432   rather than definitionally, such as the meta-logic connectives.
   433 
   434 * Pure: 'instance' now handles general arities with general sorts
   435   (i.e. intersections of classes),
   436 
   437 * Presentation: generated HTML now uses a CSS style sheet to make layout
   438   (somewhat) independent of content. It is copied from lib/html/isabelle.css.
   439   It can be changed to alter the colors/layout of generated pages.
   440 
   441 
   442 *** Isar ***
   443 
   444 * Tactic emulation methods rule_tac, erule_tac, drule_tac, frule_tac,
   445   cut_tac, subgoal_tac and thin_tac:
   446   - Now understand static (Isar) contexts.  As a consequence, users of Isar
   447     locales are no longer forced to write Isar proof scripts.
   448     For details see Isar Reference Manual, paragraph 4.3.2: Further tactic
   449     emulations.
   450   - INCOMPATIBILITY: names of variables to be instantiated may no
   451     longer be enclosed in quotes.  Instead, precede variable name with `?'.
   452     This is consistent with the instantiation attribute "where".
   453 
   454 * Attributes "where" and "of":
   455   - Now take type variables of instantiated theorem into account when reading
   456     the instantiation string.  This fixes a bug that caused instantiated
   457     theorems to have too special types in some circumstances.
   458   - "where" permits explicit instantiations of type variables.
   459 
   460 * Calculation commands "moreover" and "also" no longer interfere with
   461   current facts ("this"), admitting arbitrary combinations with "then"
   462   and derived forms.
   463 
   464 * Locales:
   465   - Goal statements involving the context element "includes" no longer
   466     generate theorems with internal delta predicates (those ending on
   467     "_axioms") in the premise.
   468     Resolve particular premise with <locale>.intro to obtain old form.
   469   - Fixed bug in type inference ("unify_frozen") that prevented mix of target
   470     specification and "includes" elements in goal statement.
   471   - Rule sets <locale>.intro and <locale>.axioms no longer declared as
   472     [intro?] and [elim?] (respectively) by default.
   473   - Experimental command for instantiation of locales in proof contexts:
   474         instantiate <label>[<attrs>]: <loc>
   475     Instantiates locale <loc> and adds all its theorems to the current context
   476     taking into account their attributes.  Label and attrs are optional
   477     modifiers, like in theorem declarations.  If present, names of
   478     instantiated theorems are qualified with <label>, and the attributes
   479     <attrs> are applied after any attributes these theorems might have already.
   480       If the locale has assumptions, a chained fact of the form
   481     "<loc> t1 ... tn" is expected from which instantiations of the parameters
   482     are derived.  The command does not support old-style locales declared
   483     with "locale (open)".
   484       A few (very simple) examples can be found in FOL/ex/LocaleInst.thy.
   485 
   486 * HOL: Tactic emulation methods induct_tac and case_tac understand static
   487   (Isar) contexts.
   488 
   489 
   490 *** HOL ***
   491 
   492 * Proof import: new image HOL4 contains the imported library from
   493   the HOL4 system with about 2500 theorems. It is imported by
   494   replaying proof terms produced by HOL4 in Isabelle. The HOL4 image
   495   can be used like any other Isabelle image.  See
   496   HOL/Import/HOL/README for more information.
   497 
   498 * Simplifier:
   499   - Much improved handling of linear and partial orders.
   500     Reasoners for linear and partial orders are set up for type classes
   501     "linorder" and "order" respectively, and are added to the default simpset
   502     as solvers.  This means that the simplifier can build transitivity chains
   503     to solve goals from the assumptions.
   504   - INCOMPATIBILITY: old proofs break occasionally.  Typically, applications
   505     of blast or auto after simplification become unnecessary because the goal
   506     is solved by simplification already.
   507 
   508 * Numerics: new theory Ring_and_Field contains over 250 basic numerical laws,
   509     all proved in axiomatic type classes for semirings, rings and fields.
   510 
   511 * Numerics:
   512   - Numeric types (nat, int, and in HOL-Complex rat, real, complex, etc.) are
   513     now formalized using the Ring_and_Field theory mentioned above.
   514   - INCOMPATIBILITY: simplification and arithmetic behaves somewhat differently
   515     than before, because now they are set up once in a generic manner.
   516   - INCOMPATIBILITY: many type-specific arithmetic laws have gone.
   517     Look for the general versions in Ring_and_Field (and Power if they concern
   518     exponentiation).
   519 
   520 * Type "rat" of the rational numbers is now available in HOL-Complex.
   521 
   522 * Records:
   523   - Record types are now by default printed with their type abbreviation
   524     instead of the list of all field types. This can be configured via
   525     the reference "print_record_type_abbr".
   526   - Simproc "record_upd_simproc" for simplification of multiple updates added
   527     (not enabled by default).
   528   - Simproc "record_ex_sel_eq_simproc" to simplify EX x. sel r = x resp.
   529     EX x. x = sel r to True (not enabled by default).
   530   - Tactic "record_split_simp_tac" to split and simplify records added.
   531 
   532 * 'specification' command added, allowing for definition by
   533   specification.  There is also an 'ax_specification' command that
   534   introduces the new constants axiomatically.
   535 
   536 * arith(_tac) is now able to generate counterexamples for reals as well.
   537 
   538 * HOL-Algebra: new locale "ring" for non-commutative rings.
   539 
   540 * HOL-ex: InductiveInvariant_examples illustrates advanced recursive function
   541   definitions, thanks to Sava Krsti\'{c} and John Matthews.
   542 
   543 * HOL-Matrix: a first theory for matrices in HOL with an application of
   544   matrix theory to linear programming.
   545 
   546 * Unions and Intersections:
   547   The latex output syntax of UN and INT has been changed
   548   from "\Union x \in A. B" to "\Union_{x \in A} B"
   549   i.e. the index formulae has become a subscript.
   550   Similarly for "\Union x. B", and for \Inter instead of \Union.
   551 
   552 * Unions and Intersections over Intervals:
   553   There is new short syntax "UN i<=n. A" for "UN i:{0..n}. A". There is
   554   also an x-symbol version with subscripts "\<Union>\<^bsub>i <= n\<^esub>. A"
   555   like in normal math, and corresponding versions for < and for intersection.
   556 
   557 * HOL/List: Ordering "lexico" is renamed "lenlex" and the standard
   558   lexicographic dictonary ordering has been added as "lexord".
   559 
   560 * ML: the legacy theory structures Int and List have been removed. They had
   561   conflicted with ML Basis Library structures having the same names.
   562 
   563 * 'refute' command added to search for (finite) countermodels.  Only works
   564   for a fragment of HOL.  The installation of an external SAT solver is
   565   highly recommended.  See "HOL/Refute.thy" for details.
   566 
   567 * 'quickcheck' command: Allows to find counterexamples by evaluating
   568   formulae under an assignment of free variables to random values.
   569   In contrast to 'refute', it can deal with inductive datatypes,
   570   but cannot handle quantifiers. See "HOL/ex/Quickcheck_Examples.thy"
   571   for examples.
   572 
   573 
   574 *** HOLCF ***
   575 
   576 * Streams now come with concatenation and are part of the HOLCF image
   577 
   578 
   579 
   580 New in Isabelle2003 (May 2003)
   581 ------------------------------
   582 
   583 *** General ***
   584 
   585 * Provers/simplifier:
   586 
   587   - Completely reimplemented method simp (ML: Asm_full_simp_tac):
   588     Assumptions are now subject to complete mutual simplification,
   589     not just from left to right. The simplifier now preserves
   590     the order of assumptions.
   591 
   592     Potential INCOMPATIBILITY:
   593 
   594     -- simp sometimes diverges where the old version did
   595        not, e.g. invoking simp on the goal
   596 
   597         [| P (f x); y = x; f x = f y |] ==> Q
   598 
   599        now gives rise to the infinite reduction sequence
   600 
   601         P(f x) --(f x = f y)--> P(f y) --(y = x)--> P(f x) --(f x = f y)--> ...
   602 
   603        Using "simp (asm_lr)" (ML: Asm_lr_simp_tac) instead often solves this
   604        kind of problem.
   605 
   606     -- Tactics combining classical reasoner and simplification (such as auto)
   607        are also affected by this change, because many of them rely on
   608        simp. They may sometimes diverge as well or yield a different numbers
   609        of subgoals. Try to use e.g. force, fastsimp, or safe instead of auto
   610        in case of problems. Sometimes subsequent calls to the classical
   611        reasoner will fail because a preceeding call to the simplifier too
   612        eagerly simplified the goal, e.g. deleted redundant premises.
   613 
   614   - The simplifier trace now shows the names of the applied rewrite rules
   615 
   616   - You can limit the number of recursive invocations of the simplifier
   617     during conditional rewriting (where the simplifie tries to solve the
   618     conditions before applying the rewrite rule):
   619     ML "simp_depth_limit := n"
   620     where n is an integer. Thus you can force termination where previously
   621     the simplifier would diverge.
   622 
   623   - Accepts free variables as head terms in congruence rules.  Useful in Isar.
   624 
   625   - No longer aborts on failed congruence proof.  Instead, the
   626     congruence is ignored.
   627 
   628 * Pure: New generic framework for extracting programs from constructive
   629   proofs. See HOL/Extraction.thy for an example instantiation, as well
   630   as HOL/Extraction for some case studies.
   631 
   632 * Pure: The main goal of the proof state is no longer shown by default, only
   633 the subgoals. This behaviour is controlled by a new flag.
   634    PG menu: Isabelle/Isar -> Settings -> Show Main Goal
   635 (ML: Proof.show_main_goal).
   636 
   637 * Pure: You can find all matching introduction rules for subgoal 1, i.e. all
   638 rules whose conclusion matches subgoal 1:
   639       PG menu: Isabelle/Isar -> Show me -> matching rules
   640 The rules are ordered by how closely they match the subgoal.
   641 In particular, rules that solve a subgoal outright are displayed first
   642 (or rather last, the way they are printed).
   643 (ML: ProofGeneral.print_intros())
   644 
   645 * Pure: New flag trace_unify_fail causes unification to print
   646 diagnostic information (PG: in trace buffer) when it fails. This is
   647 useful for figuring out why single step proofs like rule, erule or
   648 assumption failed.
   649 
   650 * Pure: Locale specifications now produce predicate definitions
   651 according to the body of text (covering assumptions modulo local
   652 definitions); predicate "loc_axioms" covers newly introduced text,
   653 while "loc" is cumulative wrt. all included locale expressions; the
   654 latter view is presented only on export into the global theory
   655 context; potential INCOMPATIBILITY, use "(open)" option to fall back
   656 on the old view without predicates;
   657 
   658 * Pure: predefined locales "var" and "struct" are useful for sharing
   659 parameters (as in CASL, for example); just specify something like
   660 ``var x + var y + struct M'' as import;
   661 
   662 * Pure: improved thms_containing: proper indexing of facts instead of
   663 raw theorems; check validity of results wrt. current name space;
   664 include local facts of proof configuration (also covers active
   665 locales), cover fixed variables in index; may use "_" in term
   666 specification; an optional limit for the number of printed facts may
   667 be given (the default is 40);
   668 
   669 * Pure: disallow duplicate fact bindings within new-style theory files
   670 (batch-mode only);
   671 
   672 * Provers: improved induct method: assumptions introduced by case
   673 "foo" are split into "foo.hyps" (from the rule) and "foo.prems" (from
   674 the goal statement); "foo" still refers to all facts collectively;
   675 
   676 * Provers: the function blast.overloaded has been removed: all constants
   677 are regarded as potentially overloaded, which improves robustness in exchange
   678 for slight decrease in efficiency;
   679 
   680 * Provers/linorder: New generic prover for transitivity reasoning over
   681 linear orders.  Note: this prover is not efficient!
   682 
   683 * Isar: preview of problems to finish 'show' now produce an error
   684 rather than just a warning (in interactive mode);
   685 
   686 
   687 *** HOL ***
   688 
   689 * arith(_tac)
   690 
   691  - Produces a counter example if it cannot prove a goal.
   692    Note that the counter example may be spurious if the goal is not a formula
   693    of quantifier-free linear arithmetic.
   694    In ProofGeneral the counter example appears in the trace buffer.
   695 
   696  - Knows about div k and mod k where k is a numeral of type nat or int.
   697 
   698  - Calls full Presburger arithmetic (by Amine Chaieb) if quantifier-free
   699    linear arithmetic fails. This takes account of quantifiers and divisibility.
   700    Presburger arithmetic can also be called explicitly via presburger(_tac).
   701 
   702 * simp's arithmetic capabilities have been enhanced a bit: it now
   703 takes ~= in premises into account (by performing a case split);
   704 
   705 * simp reduces "m*(n div m) + n mod m" to n, even if the two summands
   706 are distributed over a sum of terms;
   707 
   708 * New tactic "trans_tac" and method "trans" instantiate
   709 Provers/linorder.ML for axclasses "order" and "linorder" (predicates
   710 "<=", "<" and "=").
   711 
   712 * function INCOMPATIBILITIES: Pi-sets have been redefined and moved from main
   713 HOL to Library/FuncSet; constant "Fun.op o" is now called "Fun.comp";
   714 
   715 * 'typedef' command has new option "open" to suppress the set
   716 definition;
   717 
   718 * functions Min and Max on finite sets have been introduced (theory
   719 Finite_Set);
   720 
   721 * attribute [symmetric] now works for relations as well; it turns
   722 (x,y) : R^-1 into (y,x) : R, and vice versa;
   723 
   724 * induct over a !!-quantified statement (say !!x1..xn):
   725   each "case" automatically performs "fix x1 .. xn" with exactly those names.
   726 
   727 * Map: `empty' is no longer a constant but a syntactic abbreviation for
   728 %x. None. Warning: empty_def now refers to the previously hidden definition
   729 of the empty set.
   730 
   731 * Algebra: formalization of classical algebra.  Intended as base for
   732 any algebraic development in Isabelle.  Currently covers group theory
   733 (up to Sylow's theorem) and ring theory (Universal Property of
   734 Univariate Polynomials).  Contributions welcome;
   735 
   736 * GroupTheory: deleted, since its material has been moved to Algebra;
   737 
   738 * Complex: new directory of the complex numbers with numeric constants,
   739 nonstandard complex numbers, and some complex analysis, standard and
   740 nonstandard (Jacques Fleuriot);
   741 
   742 * HOL-Complex: new image for analysis, replacing HOL-Real and HOL-Hyperreal;
   743 
   744 * Hyperreal: introduced Gauge integration and hyperreal logarithms (Jacques
   745 Fleuriot);
   746 
   747 * Real/HahnBanach: updated and adapted to locales;
   748 
   749 * NumberTheory: added Gauss's law of quadratic reciprocity (by Avigad,
   750 Gray and Kramer);
   751 
   752 * UNITY: added the Meier-Sanders theory of progress sets;
   753 
   754 * MicroJava: bytecode verifier and lightweight bytecode verifier
   755 as abstract algorithms, instantiated to the JVM;
   756 
   757 * Bali: Java source language formalization. Type system, operational
   758 semantics, axiomatic semantics. Supported language features:
   759 classes, interfaces, objects,virtual methods, static methods,
   760 static/instance fields, arrays, access modifiers, definite
   761 assignment, exceptions.
   762 
   763 
   764 *** ZF ***
   765 
   766 * ZF/Constructible: consistency proof for AC (Gdel's constructible
   767 universe, etc.);
   768 
   769 * Main ZF: virtually all theories converted to new-style format;
   770 
   771 
   772 *** ML ***
   773 
   774 * Pure: Tactic.prove provides sane interface for internal proofs;
   775 omits the infamous "standard" operation, so this is more appropriate
   776 than prove_goalw_cterm in many situations (e.g. in simprocs);
   777 
   778 * Pure: improved error reporting of simprocs;
   779 
   780 * Provers: Simplifier.simproc(_i) provides sane interface for setting
   781 up simprocs;
   782 
   783 
   784 *** Document preparation ***
   785 
   786 * uses \par instead of \\ for line breaks in theory text. This may
   787 shift some page breaks in large documents. To get the old behaviour
   788 use \renewcommand{\isanewline}{\mbox{}\\\mbox{}} in root.tex.
   789 
   790 * minimized dependencies of isabelle.sty and isabellesym.sty on
   791 other packages
   792 
   793 * \<euro> now needs package babel/greek instead of marvosym (which
   794 broke \Rightarrow)
   795 
   796 * normal size for \<zero>...\<nine> (uses \mathbf instead of
   797 textcomp package)
   798 
   799 
   800 
   801 New in Isabelle2002 (March 2002)
   802 --------------------------------
   803 
   804 *** Document preparation ***
   805 
   806 * greatly simplified document preparation setup, including more
   807 graceful interpretation of isatool usedir -i/-d/-D options, and more
   808 instructive isatool mkdir; users should basically be able to get
   809 started with "isatool mkdir HOL Test && isatool make"; alternatively,
   810 users may run a separate document processing stage manually like this:
   811 "isatool usedir -D output HOL Test && isatool document Test/output";
   812 
   813 * theory dependency graph may now be incorporated into documents;
   814 isatool usedir -g true will produce session_graph.eps/.pdf for use
   815 with \includegraphics of LaTeX;
   816 
   817 * proper spacing of consecutive markup elements, especially text
   818 blocks after section headings;
   819 
   820 * support bold style (for single symbols only), input syntax is like
   821 this: "\<^bold>\<alpha>" or "\<^bold>A";
   822 
   823 * \<bullet> is now output as bold \cdot by default, which looks much
   824 better in printed text;
   825 
   826 * added default LaTeX bindings for \<tturnstile> and \<TTurnstile>;
   827 note that these symbols are currently unavailable in Proof General /
   828 X-Symbol; new symbols \<zero>, \<one>, ..., \<nine>, and \<euro>;
   829 
   830 * isatool latex no longer depends on changed TEXINPUTS, instead
   831 isatool document copies the Isabelle style files to the target
   832 location;
   833 
   834 
   835 *** Isar ***
   836 
   837 * Pure/Provers: improved proof by cases and induction;
   838   - 'case' command admits impromptu naming of parameters (such as
   839     "case (Suc n)");
   840   - 'induct' method divinates rule instantiation from the inductive
   841     claim; no longer requires excessive ?P bindings for proper
   842     instantiation of cases;
   843   - 'induct' method properly enumerates all possibilities of set/type
   844     rules; as a consequence facts may be also passed through *type*
   845     rules without further ado;
   846   - 'induct' method now derives symbolic cases from the *rulified*
   847     rule (before it used to rulify cases stemming from the internal
   848     atomized version); this means that the context of a non-atomic
   849     statement becomes is included in the hypothesis, avoiding the
   850     slightly cumbersome show "PROP ?case" form;
   851   - 'induct' may now use elim-style induction rules without chaining
   852     facts, using ``missing'' premises from the goal state; this allows
   853     rules stemming from inductive sets to be applied in unstructured
   854     scripts, while still benefitting from proper handling of non-atomic
   855     statements; NB: major inductive premises need to be put first, all
   856     the rest of the goal is passed through the induction;
   857   - 'induct' proper support for mutual induction involving non-atomic
   858     rule statements (uses the new concept of simultaneous goals, see
   859     below);
   860   - append all possible rule selections, but only use the first
   861     success (no backtracking);
   862   - removed obsolete "(simplified)" and "(stripped)" options of methods;
   863   - undeclared rule case names default to numbers 1, 2, 3, ...;
   864   - added 'print_induct_rules' (covered by help item in recent Proof
   865     General versions);
   866   - moved induct/cases attributes to Pure, methods to Provers;
   867   - generic method setup instantiated for FOL and HOL;
   868 
   869 * Pure: support multiple simultaneous goal statements, for example
   870 "have a: A and b: B" (same for 'theorem' etc.); being a pure
   871 meta-level mechanism, this acts as if several individual goals had
   872 been stated separately; in particular common proof methods need to be
   873 repeated in order to cover all claims; note that a single elimination
   874 step is *not* sufficient to establish the two conjunctions, so this
   875 fails:
   876 
   877   assume "A & B" then have A and B ..   (*".." fails*)
   878 
   879 better use "obtain" in situations as above; alternative refer to
   880 multi-step methods like 'auto', 'simp_all', 'blast+' etc.;
   881 
   882 * Pure: proper integration with ``locales''; unlike the original
   883 version by Florian Kammller, Isar locales package high-level proof
   884 contexts rather than raw logical ones (e.g. we admit to include
   885 attributes everywhere); operations on locales include merge and
   886 rename; support for implicit arguments (``structures''); simultaneous
   887 type-inference over imports and text; see also HOL/ex/Locales.thy for
   888 some examples;
   889 
   890 * Pure: the following commands have been ``localized'', supporting a
   891 target locale specification "(in name)": 'lemma', 'theorem',
   892 'corollary', 'lemmas', 'theorems', 'declare'; the results will be
   893 stored both within the locale and at the theory level (exported and
   894 qualified by the locale name);
   895 
   896 * Pure: theory goals may now be specified in ``long'' form, with
   897 ad-hoc contexts consisting of arbitrary locale elements. for example
   898 ``lemma foo: fixes x assumes "A x" shows "B x"'' (local syntax and
   899 definitions may be given, too); the result is a meta-level rule with
   900 the context elements being discharged in the obvious way;
   901 
   902 * Pure: new proof command 'using' allows to augment currently used
   903 facts after a goal statement ('using' is syntactically analogous to
   904 'apply', but acts on the goal's facts only); this allows chained facts
   905 to be separated into parts given before and after a claim, as in
   906 ``from a and b have C using d and e <proof>'';
   907 
   908 * Pure: renamed "antecedent" case to "rule_context";
   909 
   910 * Pure: new 'judgment' command records explicit information about the
   911 object-logic embedding (used by several tools internally); no longer
   912 use hard-wired "Trueprop";
   913 
   914 * Pure: added 'corollary' command;
   915 
   916 * Pure: fixed 'token_translation' command;
   917 
   918 * Pure: removed obsolete 'exported' attribute;
   919 
   920 * Pure: dummy pattern "_" in is/let is now automatically lifted over
   921 bound variables: "ALL x. P x --> Q x" (is "ALL x. _ --> ?C x")
   922 supersedes more cumbersome ... (is "ALL x. _ x --> ?C x");
   923 
   924 * Pure: method 'atomize' presents local goal premises as object-level
   925 statements (atomic meta-level propositions); setup controlled via
   926 rewrite rules declarations of 'atomize' attribute; example
   927 application: 'induct' method with proper rule statements in improper
   928 proof *scripts*;
   929 
   930 * Pure: emulation of instantiation tactics (rule_tac, cut_tac, etc.)
   931 now consider the syntactic context of assumptions, giving a better
   932 chance to get type-inference of the arguments right (this is
   933 especially important for locales);
   934 
   935 * Pure: "sorry" no longer requires quick_and_dirty in interactive
   936 mode;
   937 
   938 * Pure/obtain: the formal conclusion "thesis", being marked as
   939 ``internal'', may no longer be reference directly in the text;
   940 potential INCOMPATIBILITY, may need to use "?thesis" in rare
   941 situations;
   942 
   943 * Pure: generic 'sym' attribute which declares a rule both as pure
   944 'elim?' and for the 'symmetric' operation;
   945 
   946 * Pure: marginal comments ``--'' may now occur just anywhere in the
   947 text; the fixed correlation with particular command syntax has been
   948 discontinued;
   949 
   950 * Pure: new method 'rules' is particularly well-suited for proof
   951 search in intuitionistic logic; a bit slower than 'blast' or 'fast',
   952 but often produces more compact proof terms with less detours;
   953 
   954 * Pure/Provers/classical: simplified integration with pure rule
   955 attributes and methods; the classical "intro?/elim?/dest?"
   956 declarations coincide with the pure ones; the "rule" method no longer
   957 includes classically swapped intros; "intro" and "elim" methods no
   958 longer pick rules from the context; also got rid of ML declarations
   959 AddXIs/AddXEs/AddXDs; all of this has some potential for
   960 INCOMPATIBILITY;
   961 
   962 * Provers/classical: attribute 'swapped' produces classical inversions
   963 of introduction rules;
   964 
   965 * Provers/simplifier: 'simplified' attribute may refer to explicit
   966 rules instead of full simplifier context; 'iff' attribute handles
   967 conditional rules;
   968 
   969 * HOL: 'typedef' now allows alternative names for Rep/Abs morphisms;
   970 
   971 * HOL: 'recdef' now fails on unfinished automated proofs, use
   972 "(permissive)" option to recover old behavior;
   973 
   974 * HOL: 'inductive' no longer features separate (collective) attributes
   975 for 'intros' (was found too confusing);
   976 
   977 * HOL: properly declared induction rules less_induct and
   978 wf_induct_rule;
   979 
   980 
   981 *** HOL ***
   982 
   983 * HOL: moved over to sane numeral syntax; the new policy is as
   984 follows:
   985 
   986   - 0 and 1 are polymorphic constants, which are defined on any
   987   numeric type (nat, int, real etc.);
   988 
   989   - 2, 3, 4, ... and -1, -2, -3, ... are polymorphic numerals, based
   990   binary representation internally;
   991 
   992   - type nat has special constructor Suc, and generally prefers Suc 0
   993   over 1::nat and Suc (Suc 0) over 2::nat;
   994 
   995 This change may cause significant problems of INCOMPATIBILITY; here
   996 are some hints on converting existing sources:
   997 
   998   - due to the new "num" token, "-0" and "-1" etc. are now atomic
   999   entities, so expressions involving "-" (unary or binary minus) need
  1000   to be spaced properly;
  1001 
  1002   - existing occurrences of "1" may need to be constraint "1::nat" or
  1003   even replaced by Suc 0; similar for old "2";
  1004 
  1005   - replace "#nnn" by "nnn", and "#-nnn" by "-nnn";
  1006 
  1007   - remove all special provisions on numerals in proofs;
  1008 
  1009 * HOL: simp rules nat_number expand numerals on nat to Suc/0
  1010 representation (depends on bin_arith_simps in the default context);
  1011 
  1012 * HOL: symbolic syntax for x^2 (numeral 2);
  1013 
  1014 * HOL: the class of all HOL types is now called "type" rather than
  1015 "term"; INCOMPATIBILITY, need to adapt references to this type class
  1016 in axclass/classes, instance/arities, and (usually rare) occurrences
  1017 in typings (of consts etc.); internally the class is called
  1018 "HOL.type", ML programs should refer to HOLogic.typeS;
  1019 
  1020 * HOL/record package improvements:
  1021   - new derived operations "fields" to build a partial record section,
  1022     "extend" to promote a fixed record to a record scheme, and
  1023     "truncate" for the reverse; cf. theorems "xxx.defs", which are *not*
  1024     declared as simp by default;
  1025   - shared operations ("more", "fields", etc.) now need to be always
  1026     qualified) --- potential INCOMPATIBILITY;
  1027   - removed "make_scheme" operations (use "make" with "extend") --
  1028     INCOMPATIBILITY;
  1029   - removed "more" class (simply use "term") -- INCOMPATIBILITY;
  1030   - provides cases/induct rules for use with corresponding Isar
  1031     methods (for concrete records, record schemes, concrete more
  1032     parts, and schematic more parts -- in that order);
  1033   - internal definitions directly based on a light-weight abstract
  1034     theory of product types over typedef rather than datatype;
  1035 
  1036 * HOL: generic code generator for generating executable ML code from
  1037 specifications; specific support for HOL constructs such as inductive
  1038 datatypes and sets, as well as recursive functions; can be invoked
  1039 via 'generate_code' theory section;
  1040 
  1041 * HOL: canonical cases/induct rules for n-tuples (n = 3..7);
  1042 
  1043 * HOL: consolidated and renamed several theories.  In particular:
  1044         Ord.thy has been absorbed into HOL.thy
  1045         String.thy has been absorbed into List.thy
  1046 
  1047 * HOL: concrete setsum syntax "\<Sum>i:A. b" == "setsum (%i. b) A"
  1048 (beware of argument permutation!);
  1049 
  1050 * HOL: linorder_less_split superseded by linorder_cases;
  1051 
  1052 * HOL/List: "nodups" renamed to "distinct";
  1053 
  1054 * HOL: added "The" definite description operator; move Hilbert's "Eps"
  1055 to peripheral theory "Hilbert_Choice"; some INCOMPATIBILITIES:
  1056   - Ex_def has changed, now need to use some_eq_ex
  1057 
  1058 * HOL: made split_all_tac safe; EXISTING PROOFS MAY FAIL OR LOOP, so
  1059 in this (rare) case use:
  1060 
  1061   delSWrapper "split_all_tac"
  1062   addSbefore ("unsafe_split_all_tac", unsafe_split_all_tac)
  1063 
  1064 * HOL: added safe wrapper "split_conv_tac" to claset; EXISTING PROOFS
  1065 MAY FAIL;
  1066 
  1067 * HOL: introduced f^n = f o ... o f; warning: due to the limits of
  1068 Isabelle's type classes, ^ on functions and relations has too general
  1069 a domain, namely ('a * 'b) set and 'a => 'b; this means that it may be
  1070 necessary to attach explicit type constraints;
  1071 
  1072 * HOL/Relation: the prefix name of the infix "O" has been changed from
  1073 "comp" to "rel_comp"; INCOMPATIBILITY: a few theorems have been
  1074 renamed accordingly (eg "compI" -> "rel_compI").
  1075 
  1076 * HOL: syntax translations now work properly with numerals and records
  1077 expressions;
  1078 
  1079 * HOL: bounded abstraction now uses syntax "%" / "\<lambda>" instead
  1080 of "lam" -- INCOMPATIBILITY;
  1081 
  1082 * HOL: got rid of some global declarations (potential INCOMPATIBILITY
  1083 for ML tools): const "()" renamed "Product_Type.Unity", type "unit"
  1084 renamed "Product_Type.unit";
  1085 
  1086 * HOL: renamed rtrancl_into_rtrancl2 to converse_rtrancl_into_rtrancl
  1087 
  1088 * HOL: removed obsolete theorem "optionE" (use "option.exhaust", or
  1089 the "cases" method);
  1090 
  1091 * HOL/GroupTheory: group theory examples including Sylow's theorem (by
  1092 Florian Kammller);
  1093 
  1094 * HOL/IMP: updated and converted to new-style theory format; several
  1095 parts turned into readable document, with proper Isar proof texts and
  1096 some explanations (by Gerwin Klein);
  1097 
  1098 * HOL-Real: added Complex_Numbers (by Gertrud Bauer);
  1099 
  1100 * HOL-Hyperreal is now a logic image;
  1101 
  1102 
  1103 *** HOLCF ***
  1104 
  1105 * Isar: consts/constdefs supports mixfix syntax for continuous
  1106 operations;
  1107 
  1108 * Isar: domain package adapted to new-style theory format, e.g. see
  1109 HOLCF/ex/Dnat.thy;
  1110 
  1111 * theory Lift: proper use of rep_datatype lift instead of ML hacks --
  1112 potential INCOMPATIBILITY; now use plain induct_tac instead of former
  1113 lift.induct_tac, always use UU instead of Undef;
  1114 
  1115 * HOLCF/IMP: updated and converted to new-style theory;
  1116 
  1117 
  1118 *** ZF ***
  1119 
  1120 * Isar: proper integration of logic-specific tools and packages,
  1121 including theory commands '(co)inductive', '(co)datatype',
  1122 'rep_datatype', 'inductive_cases', as well as methods 'ind_cases',
  1123 'induct_tac', 'case_tac', and 'typecheck' (with attribute 'TC');
  1124 
  1125 * theory Main no longer includes AC; for the Axiom of Choice, base
  1126 your theory on Main_ZFC;
  1127 
  1128 * the integer library now covers quotients and remainders, with many
  1129 laws relating division to addition, multiplication, etc.;
  1130 
  1131 * ZF/UNITY: Chandy and Misra's UNITY is now available in ZF, giving a
  1132 typeless version of the formalism;
  1133 
  1134 * ZF/AC, Coind, IMP, Resid: updated and converted to new-style theory
  1135 format;
  1136 
  1137 * ZF/Induct: new directory for examples of inductive definitions,
  1138 including theory Multiset for multiset orderings; converted to
  1139 new-style theory format;
  1140 
  1141 * ZF: many new theorems about lists, ordinals, etc.;
  1142 
  1143 
  1144 *** General ***
  1145 
  1146 * Pure/kernel: meta-level proof terms (by Stefan Berghofer); reference
  1147 variable proof controls level of detail: 0 = no proofs (only oracle
  1148 dependencies), 1 = lemma dependencies, 2 = compact proof terms; see
  1149 also ref manual for further ML interfaces;
  1150 
  1151 * Pure/axclass: removed obsolete ML interface
  1152 goal_subclass/goal_arity;
  1153 
  1154 * Pure/syntax: new token syntax "num" for plain numerals (without "#"
  1155 of "xnum"); potential INCOMPATIBILITY, since -0, -1 etc. are now
  1156 separate tokens, so expressions involving minus need to be spaced
  1157 properly;
  1158 
  1159 * Pure/syntax: support non-oriented infixes, using keyword "infix"
  1160 rather than "infixl" or "infixr";
  1161 
  1162 * Pure/syntax: concrete syntax for dummy type variables admits genuine
  1163 sort constraint specifications in type inference; e.g. "x::_::foo"
  1164 ensures that the type of "x" is of sort "foo" (but not necessarily a
  1165 type variable);
  1166 
  1167 * Pure/syntax: print modes "type_brackets" and "no_type_brackets"
  1168 control output of nested => (types); the default behavior is
  1169 "type_brackets";
  1170 
  1171 * Pure/syntax: builtin parse translation for "_constify" turns valued
  1172 tokens into AST constants;
  1173 
  1174 * Pure/syntax: prefer later declarations of translations and print
  1175 translation functions; potential INCOMPATIBILITY: need to reverse
  1176 multiple declarations for same syntax element constant;
  1177 
  1178 * Pure/show_hyps reset by default (in accordance to existing Isar
  1179 practice);
  1180 
  1181 * Provers/classical: renamed addaltern to addafter, addSaltern to
  1182 addSafter;
  1183 
  1184 * Provers/clasimp: ``iff'' declarations now handle conditional rules
  1185 as well;
  1186 
  1187 * system: tested support for MacOS X; should be able to get Isabelle +
  1188 Proof General to work in a plain Terminal after installing Poly/ML
  1189 (e.g. from the Isabelle distribution area) and GNU bash alone
  1190 (e.g. from http://www.apple.com); full X11, XEmacs and X-Symbol
  1191 support requires further installations, e.g. from
  1192 http://fink.sourceforge.net/);
  1193 
  1194 * system: support Poly/ML 4.1.1 (able to manage larger heaps);
  1195 
  1196 * system: reduced base memory usage by Poly/ML (approx. 20 MB instead
  1197 of 40 MB), cf. ML_OPTIONS;
  1198 
  1199 * system: Proof General keywords specification is now part of the
  1200 Isabelle distribution (see etc/isar-keywords.el);
  1201 
  1202 * system: support for persistent Proof General sessions (refrain from
  1203 outdating all loaded theories on startup); user may create writable
  1204 logic images like this: ``isabelle -q HOL Test'';
  1205 
  1206 * system: smart selection of Isabelle process versus Isabelle
  1207 interface, accommodates case-insensitive file systems (e.g. HFS+); may
  1208 run both "isabelle" and "Isabelle" even if file names are badly
  1209 damaged (executable inspects the case of the first letter of its own
  1210 name); added separate "isabelle-process" and "isabelle-interface";
  1211 
  1212 * system: refrain from any attempt at filtering input streams; no
  1213 longer support ``8bit'' encoding of old isabelle font, instead proper
  1214 iso-latin characters may now be used; the related isatools
  1215 "symbolinput" and "nonascii" have disappeared as well;
  1216 
  1217 * system: removed old "xterm" interface (the print modes "xterm" and
  1218 "xterm_color" are still available for direct use in a suitable
  1219 terminal);
  1220 
  1221 
  1222 
  1223 New in Isabelle99-2 (February 2001)
  1224 -----------------------------------
  1225 
  1226 *** Overview of INCOMPATIBILITIES ***
  1227 
  1228 * HOL: please note that theories in the Library and elsewhere often use the
  1229 new-style (Isar) format; to refer to their theorems in an ML script you must
  1230 bind them to ML identifers by e.g.      val thm_name = thm "thm_name";
  1231 
  1232 * HOL: inductive package no longer splits induction rule aggressively,
  1233 but only as far as specified by the introductions given; the old
  1234 format may be recovered via ML function complete_split_rule or attribute
  1235 'split_rule (complete)';
  1236 
  1237 * HOL: induct renamed to lfp_induct, lfp_Tarski to lfp_unfold,
  1238 gfp_Tarski to gfp_unfold;
  1239 
  1240 * HOL: contrapos, contrapos2 renamed to contrapos_nn, contrapos_pp;
  1241 
  1242 * HOL: infix "dvd" now has priority 50 rather than 70 (because it is a
  1243 relation); infix "^^" has been renamed "``"; infix "``" has been
  1244 renamed "`"; "univalent" has been renamed "single_valued";
  1245 
  1246 * HOL/Real: "rinv" and "hrinv" replaced by overloaded "inverse"
  1247 operation;
  1248 
  1249 * HOLCF: infix "`" has been renamed "$"; the symbol syntax is \<cdot>;
  1250 
  1251 * Isar: 'obtain' no longer declares "that" fact as simp/intro;
  1252 
  1253 * Isar/HOL: method 'induct' now handles non-atomic goals; as a
  1254 consequence, it is no longer monotonic wrt. the local goal context
  1255 (which is now passed through the inductive cases);
  1256 
  1257 * Document preparation: renamed standard symbols \<ll> to \<lless> and
  1258 \<gg> to \<ggreater>;
  1259 
  1260 
  1261 *** Document preparation ***
  1262 
  1263 * \isabellestyle{NAME} selects version of Isabelle output (currently
  1264 available: are "it" for near math-mode best-style output, "sl" for
  1265 slanted text style, and "tt" for plain type-writer; if no
  1266 \isabellestyle command is given, output is according to slanted
  1267 type-writer);
  1268 
  1269 * support sub/super scripts (for single symbols only), input syntax is
  1270 like this: "A\<^sup>*" or "A\<^sup>\<star>";
  1271 
  1272 * some more standard symbols; see Appendix A of the system manual for
  1273 the complete list of symbols defined in isabellesym.sty;
  1274 
  1275 * improved isabelle style files; more abstract symbol implementation
  1276 (should now use \isamath{...} and \isatext{...} in custom symbol
  1277 definitions);
  1278 
  1279 * antiquotation @{goals} and @{subgoals} for output of *dynamic* goals
  1280 state; Note that presentation of goal states does not conform to
  1281 actual human-readable proof documents.  Please do not include goal
  1282 states into document output unless you really know what you are doing!
  1283 
  1284 * proper indentation of antiquoted output with proportional LaTeX
  1285 fonts;
  1286 
  1287 * no_document ML operator temporarily disables LaTeX document
  1288 generation;
  1289 
  1290 * isatool unsymbolize tunes sources for plain ASCII communication;
  1291 
  1292 
  1293 *** Isar ***
  1294 
  1295 * Pure: Isar now suffers initial goal statements to contain unbound
  1296 schematic variables (this does not conform to actual readable proof
  1297 documents, due to unpredictable outcome and non-compositional proof
  1298 checking); users who know what they are doing may use schematic goals
  1299 for Prolog-style synthesis of proven results;
  1300 
  1301 * Pure: assumption method (an implicit finishing) now handles actual
  1302 rules as well;
  1303 
  1304 * Pure: improved 'obtain' --- moved to Pure, insert "that" into
  1305 initial goal, declare "that" only as Pure intro (only for single
  1306 steps); the "that" rule assumption may now be involved in implicit
  1307 finishing, thus ".." becomes a feasible for trivial obtains;
  1308 
  1309 * Pure: default proof step now includes 'intro_classes'; thus trivial
  1310 instance proofs may be performed by "..";
  1311 
  1312 * Pure: ?thesis / ?this / "..." now work for pure meta-level
  1313 statements as well;
  1314 
  1315 * Pure: more robust selection of calculational rules;
  1316 
  1317 * Pure: the builtin notion of 'finished' goal now includes the ==-refl
  1318 rule (as well as the assumption rule);
  1319 
  1320 * Pure: 'thm_deps' command visualizes dependencies of theorems and
  1321 lemmas, using the graph browser tool;
  1322 
  1323 * Pure: predict failure of "show" in interactive mode;
  1324 
  1325 * Pure: 'thms_containing' now takes actual terms as arguments;
  1326 
  1327 * HOL: improved method 'induct' --- now handles non-atomic goals
  1328 (potential INCOMPATIBILITY); tuned error handling;
  1329 
  1330 * HOL: cases and induct rules now provide explicit hints about the
  1331 number of facts to be consumed (0 for "type" and 1 for "set" rules);
  1332 any remaining facts are inserted into the goal verbatim;
  1333 
  1334 * HOL: local contexts (aka cases) may now contain term bindings as
  1335 well; the 'cases' and 'induct' methods new provide a ?case binding for
  1336 the result to be shown in each case;
  1337 
  1338 * HOL: added 'recdef_tc' command;
  1339 
  1340 * isatool convert assists in eliminating legacy ML scripts;
  1341 
  1342 
  1343 *** HOL ***
  1344 
  1345 * HOL/Library: a collection of generic theories to be used together
  1346 with main HOL; the theory loader path already includes this directory
  1347 by default; the following existing theories have been moved here:
  1348 HOL/Induct/Multiset, HOL/Induct/Acc (as Accessible_Part), HOL/While
  1349 (as While_Combinator), HOL/Lex/Prefix (as List_Prefix);
  1350 
  1351 * HOL/Unix: "Some aspects of Unix file-system security", a typical
  1352 modelling and verification task performed in Isabelle/HOL +
  1353 Isabelle/Isar + Isabelle document preparation (by Markus Wenzel).
  1354 
  1355 * HOL/Algebra: special summation operator SUM no longer exists, it has
  1356 been replaced by setsum; infix 'assoc' now has priority 50 (like
  1357 'dvd'); axiom 'one_not_zero' has been moved from axclass 'ring' to
  1358 'domain', this makes the theory consistent with mathematical
  1359 literature;
  1360 
  1361 * HOL basics: added overloaded operations "inverse" and "divide"
  1362 (infix "/"), syntax for generic "abs" operation, generic summation
  1363 operator \<Sum>;
  1364 
  1365 * HOL/typedef: simplified package, provide more useful rules (see also
  1366 HOL/subset.thy);
  1367 
  1368 * HOL/datatype: induction rule for arbitrarily branching datatypes is
  1369 now expressed as a proper nested rule (old-style tactic scripts may
  1370 require atomize_strip_tac to cope with non-atomic premises);
  1371 
  1372 * HOL: renamed theory "Prod" to "Product_Type", renamed "split" rule
  1373 to "split_conv" (old name still available for compatibility);
  1374 
  1375 * HOL: improved concrete syntax for strings (e.g. allows translation
  1376 rules with string literals);
  1377 
  1378 * HOL-Real-Hyperreal: this extends HOL-Real with the hyperreals
  1379  and Fleuriot's mechanization of analysis, including the transcendental
  1380  functions for the reals;
  1381 
  1382 * HOL/Real, HOL/Hyperreal: improved arithmetic simplification;
  1383 
  1384 
  1385 *** CTT ***
  1386 
  1387 * CTT: x-symbol support for Pi, Sigma, -->, : (membership); note that
  1388 "lam" is displayed as TWO lambda-symbols
  1389 
  1390 * CTT: theory Main now available, containing everything (that is, Bool
  1391 and Arith);
  1392 
  1393 
  1394 *** General ***
  1395 
  1396 * Pure: the Simplifier has been implemented properly as a derived rule
  1397 outside of the actual kernel (at last!); the overall performance
  1398 penalty in practical applications is about 50%, while reliability of
  1399 the Isabelle inference kernel has been greatly improved;
  1400 
  1401 * print modes "brackets" and "no_brackets" control output of nested =>
  1402 (types) and ==> (props); the default behaviour is "brackets";
  1403 
  1404 * Provers: fast_tac (and friends) now handle actual object-logic rules
  1405 as assumptions as well;
  1406 
  1407 * system: support Poly/ML 4.0;
  1408 
  1409 * system: isatool install handles KDE version 1 or 2;
  1410 
  1411 
  1412 
  1413 New in Isabelle99-1 (October 2000)
  1414 ----------------------------------
  1415 
  1416 *** Overview of INCOMPATIBILITIES ***
  1417 
  1418 * HOL: simplification of natural numbers is much changed; to partly
  1419 recover the old behaviour (e.g. to prevent n+n rewriting to #2*n)
  1420 issue the following ML commands:
  1421 
  1422   Delsimprocs Nat_Numeral_Simprocs.cancel_numerals;
  1423   Delsimprocs [Nat_Numeral_Simprocs.combine_numerals];
  1424 
  1425 * HOL: simplification no longer dives into case-expressions; this is
  1426 controlled by "t.weak_case_cong" for each datatype t;
  1427 
  1428 * HOL: nat_less_induct renamed to less_induct;
  1429 
  1430 * HOL: systematic renaming of the SOME (Eps) rules, may use isatool
  1431 fixsome to patch .thy and .ML sources automatically;
  1432 
  1433   select_equality  -> some_equality
  1434   select_eq_Ex     -> some_eq_ex
  1435   selectI2EX       -> someI2_ex
  1436   selectI2         -> someI2
  1437   selectI          -> someI
  1438   select1_equality -> some1_equality
  1439   Eps_sym_eq       -> some_sym_eq_trivial
  1440   Eps_eq           -> some_eq_trivial
  1441 
  1442 * HOL: exhaust_tac on datatypes superceded by new generic case_tac;
  1443 
  1444 * HOL: removed obsolete theorem binding expand_if (refer to split_if
  1445 instead);
  1446 
  1447 * HOL: the recursion equations generated by 'recdef' are now called
  1448 f.simps instead of f.rules;
  1449 
  1450 * HOL: qed_spec_mp now also handles bounded ALL as well;
  1451 
  1452 * HOL: 0 is now overloaded, so the type constraint ":: nat" may
  1453 sometimes be needed;
  1454 
  1455 * HOL: the constant for "f``x" is now "image" rather than "op ``";
  1456 
  1457 * HOL: the constant for "f-``x" is now "vimage" rather than "op -``";
  1458 
  1459 * HOL: the disjoint sum is now "<+>" instead of "Plus"; the cartesian
  1460 product is now "<*>" instead of "Times"; the lexicographic product is
  1461 now "<*lex*>" instead of "**";
  1462 
  1463 * HOL: theory Sexp is now in HOL/Induct examples (it used to be part
  1464 of main HOL, but was unused); better use HOL's datatype package;
  1465 
  1466 * HOL: removed "symbols" syntax for constant "override" of theory Map;
  1467 the old syntax may be recovered as follows:
  1468 
  1469   syntax (symbols)
  1470     override  :: "('a ~=> 'b) => ('a ~=> 'b) => ('a ~=> 'b)"
  1471       (infixl "\\<oplus>" 100)
  1472 
  1473 * HOL/Real: "rabs" replaced by overloaded "abs" function;
  1474 
  1475 * HOL/ML: even fewer consts are declared as global (see theories Ord,
  1476 Lfp, Gfp, WF); this only affects ML packages that refer to const names
  1477 internally;
  1478 
  1479 * HOL and ZF: syntax for quotienting wrt an equivalence relation
  1480 changed from A/r to A//r;
  1481 
  1482 * ZF: new treatment of arithmetic (nat & int) may break some old
  1483 proofs;
  1484 
  1485 * Isar: renamed some attributes (RS -> THEN, simplify -> simplified,
  1486 rulify -> rule_format, elimify -> elim_format, ...);
  1487 
  1488 * Isar/Provers: intro/elim/dest attributes changed; renamed
  1489 intro/intro!/intro!! flags to intro!/intro/intro? (in most cases, one
  1490 should have to change intro!! to intro? only); replaced "delrule" by
  1491 "rule del";
  1492 
  1493 * Isar/HOL: renamed "intrs" to "intros" in inductive definitions;
  1494 
  1495 * Provers: strengthened force_tac by using new first_best_tac;
  1496 
  1497 * LaTeX document preparation: several changes of isabelle.sty (see
  1498 lib/texinputs);
  1499 
  1500 
  1501 *** Document preparation ***
  1502 
  1503 * formal comments (text blocks etc.) in new-style theories may now
  1504 contain antiquotations of thm/prop/term/typ/text to be presented
  1505 according to latex print mode; concrete syntax is like this:
  1506 @{term[show_types] "f(x) = a + x"};
  1507 
  1508 * isatool mkdir provides easy setup of Isabelle session directories,
  1509 including proper document sources;
  1510 
  1511 * generated LaTeX sources are now deleted after successful run
  1512 (isatool document -c); may retain a copy somewhere else via -D option
  1513 of isatool usedir;
  1514 
  1515 * isatool usedir -D now lets isatool latex -o sty update the Isabelle
  1516 style files, achieving self-contained LaTeX sources and simplifying
  1517 LaTeX debugging;
  1518 
  1519 * old-style theories now produce (crude) LaTeX output as well;
  1520 
  1521 * browser info session directories are now self-contained (may be put
  1522 on WWW server seperately); improved graphs of nested sessions; removed
  1523 graph for 'all sessions';
  1524 
  1525 * several improvements in isabelle style files; \isabellestyle{it}
  1526 produces fake math mode output; \isamarkupheader is now \section by
  1527 default; see lib/texinputs/isabelle.sty etc.;
  1528 
  1529 
  1530 *** Isar ***
  1531 
  1532 * Isar/Pure: local results and corresponding term bindings are now
  1533 subject to Hindley-Milner polymorphism (similar to ML); this
  1534 accommodates incremental type-inference very nicely;
  1535 
  1536 * Isar/Pure: new derived language element 'obtain' supports
  1537 generalized existence reasoning;
  1538 
  1539 * Isar/Pure: new calculational elements 'moreover' and 'ultimately'
  1540 support accumulation of results, without applying any rules yet;
  1541 useful to collect intermediate results without explicit name
  1542 references, and for use with transitivity rules with more than 2
  1543 premises;
  1544 
  1545 * Isar/Pure: scalable support for case-analysis type proofs: new
  1546 'case' language element refers to local contexts symbolically, as
  1547 produced by certain proof methods; internally, case names are attached
  1548 to theorems as "tags";
  1549 
  1550 * Isar/Pure: theory command 'hide' removes declarations from
  1551 class/type/const name spaces;
  1552 
  1553 * Isar/Pure: theory command 'defs' supports option "(overloaded)" to
  1554 indicate potential overloading;
  1555 
  1556 * Isar/Pure: changed syntax of local blocks from {{ }} to { };
  1557 
  1558 * Isar/Pure: syntax of sorts made 'inner', i.e. have to write
  1559 "{a,b,c}" instead of {a,b,c};
  1560 
  1561 * Isar/Pure now provides its own version of intro/elim/dest
  1562 attributes; useful for building new logics, but beware of confusion
  1563 with the version in Provers/classical;
  1564 
  1565 * Isar/Pure: the local context of (non-atomic) goals is provided via
  1566 case name 'antecedent';
  1567 
  1568 * Isar/Pure: removed obsolete 'transfer' attribute (transfer of thms
  1569 to the current context is now done automatically);
  1570 
  1571 * Isar/Pure: theory command 'method_setup' provides a simple interface
  1572 for definining proof methods in ML;
  1573 
  1574 * Isar/Provers: intro/elim/dest attributes changed; renamed
  1575 intro/intro!/intro!! flags to intro!/intro/intro? (INCOMPATIBILITY, in
  1576 most cases, one should have to change intro!! to intro? only);
  1577 replaced "delrule" by "rule del";
  1578 
  1579 * Isar/Provers: new 'hypsubst' method, plain 'subst' method and
  1580 'symmetric' attribute (the latter supercedes [RS sym]);
  1581 
  1582 * Isar/Provers: splitter support (via 'split' attribute and 'simp'
  1583 method modifier); 'simp' method: 'only:' modifier removes loopers as
  1584 well (including splits);
  1585 
  1586 * Isar/Provers: Simplifier and Classical methods now support all kind
  1587 of modifiers used in the past, including 'cong', 'iff', etc.
  1588 
  1589 * Isar/Provers: added 'fastsimp' and 'clarsimp' methods (combination
  1590 of Simplifier and Classical reasoner);
  1591 
  1592 * Isar/HOL: new proof method 'cases' and improved version of 'induct'
  1593 now support named cases; major packages (inductive, datatype, primrec,
  1594 recdef) support case names and properly name parameters;
  1595 
  1596 * Isar/HOL: new transitivity rules for substitution in inequalities --
  1597 monotonicity conditions are extracted to be proven at end of
  1598 calculations;
  1599 
  1600 * Isar/HOL: removed 'case_split' thm binding, should use 'cases' proof
  1601 method anyway;
  1602 
  1603 * Isar/HOL: removed old expand_if = split_if; theorems if_splits =
  1604 split_if split_if_asm; datatype package provides theorems foo.splits =
  1605 foo.split foo.split_asm for each datatype;
  1606 
  1607 * Isar/HOL: tuned inductive package, rename "intrs" to "intros"
  1608 (potential INCOMPATIBILITY), emulation of mk_cases feature for proof
  1609 scripts: new 'inductive_cases' command and 'ind_cases' method; (Note:
  1610 use "(cases (simplified))" method in proper proof texts);
  1611 
  1612 * Isar/HOL: added global 'arith_split' attribute for 'arith' method;
  1613 
  1614 * Isar: names of theorems etc. may be natural numbers as well;
  1615 
  1616 * Isar: 'pr' command: optional arguments for goals_limit and
  1617 ProofContext.prems_limit; no longer prints theory contexts, but only
  1618 proof states;
  1619 
  1620 * Isar: diagnostic commands 'pr', 'thm', 'prop', 'term', 'typ' admit
  1621 additional print modes to be specified; e.g. "pr(latex)" will print
  1622 proof state according to the Isabelle LaTeX style;
  1623 
  1624 * Isar: improved support for emulating tactic scripts, including proof
  1625 methods 'rule_tac' etc., 'cut_tac', 'thin_tac', 'subgoal_tac',
  1626 'rename_tac', 'rotate_tac', 'tactic', and 'case_tac' / 'induct_tac'
  1627 (for HOL datatypes);
  1628 
  1629 * Isar: simplified (more robust) goal selection of proof methods: 1st
  1630 goal, all goals, or explicit goal specifier (tactic emulation); thus
  1631 'proof method scripts' have to be in depth-first order;
  1632 
  1633 * Isar: tuned 'let' syntax: replaced 'as' keyword by 'and';
  1634 
  1635 * Isar: removed 'help' command, which hasn't been too helpful anyway;
  1636 should instead use individual commands for printing items
  1637 (print_commands, print_methods etc.);
  1638 
  1639 * Isar: added 'nothing' --- the empty list of theorems;
  1640 
  1641 
  1642 *** HOL ***
  1643 
  1644 * HOL/MicroJava: formalization of a fragment of Java, together with a
  1645 corresponding virtual machine and a specification of its bytecode
  1646 verifier and a lightweight bytecode verifier, including proofs of
  1647 type-safety; by Gerwin Klein, Tobias Nipkow, David von Oheimb, and
  1648 Cornelia Pusch (see also the homepage of project Bali at
  1649 http://isabelle.in.tum.de/Bali/);
  1650 
  1651 * HOL/Algebra: new theory of rings and univariate polynomials, by
  1652 Clemens Ballarin;
  1653 
  1654 * HOL/NumberTheory: fundamental Theorem of Arithmetic, Chinese
  1655 Remainder Theorem, Fermat/Euler Theorem, Wilson's Theorem, by Thomas M
  1656 Rasmussen;
  1657 
  1658 * HOL/Lattice: fundamental concepts of lattice theory and order
  1659 structures, including duals, properties of bounds versus algebraic
  1660 laws, lattice operations versus set-theoretic ones, the Knaster-Tarski
  1661 Theorem for complete lattices etc.; may also serve as a demonstration
  1662 for abstract algebraic reasoning using axiomatic type classes, and
  1663 mathematics-style proof in Isabelle/Isar; by Markus Wenzel;
  1664 
  1665 * HOL/Prolog: a (bare-bones) implementation of Lambda-Prolog, by David
  1666 von Oheimb;
  1667 
  1668 * HOL/IMPP: extension of IMP with local variables and mutually
  1669 recursive procedures, by David von Oheimb;
  1670 
  1671 * HOL/Lambda: converted into new-style theory and document;
  1672 
  1673 * HOL/ex/Multiquote: example of multiple nested quotations and
  1674 anti-quotations -- basically a generalized version of de-Bruijn
  1675 representation; very useful in avoiding lifting of operations;
  1676 
  1677 * HOL/record: added general record equality rule to simpset; fixed
  1678 select-update simplification procedure to handle extended records as
  1679 well; admit "r" as field name;
  1680 
  1681 * HOL: 0 is now overloaded over the new sort "zero", allowing its use with
  1682 other numeric types and also as the identity of groups, rings, etc.;
  1683 
  1684 * HOL: new axclass plus_ac0 for addition with the AC-laws and 0 as identity.
  1685 Types nat and int belong to this axclass;
  1686 
  1687 * HOL: greatly improved simplification involving numerals of type nat, int, real:
  1688    (i + #8 + j) = Suc k simplifies to  #7 + (i + j) = k
  1689    i*j + k + j*#3*i     simplifies to  #4*(i*j) + k
  1690   two terms #m*u and #n*u are replaced by #(m+n)*u
  1691     (where #m, #n and u can implicitly be 1; this is simproc combine_numerals)
  1692   and the term/formula #m*u+x ~~ #n*u+y simplifies simplifies to #(m-n)+x ~~ y
  1693     or x ~~ #(n-m)+y, where ~~ is one of = < <= or - (simproc cancel_numerals);
  1694 
  1695 * HOL: meson_tac is available (previously in ex/meson.ML); it is a
  1696 powerful prover for predicate logic but knows nothing of clasets; see
  1697 ex/mesontest.ML and ex/mesontest2.ML for example applications;
  1698 
  1699 * HOL: new version of "case_tac" subsumes both boolean case split and
  1700 "exhaust_tac" on datatypes; INCOMPATIBILITY: exhaust_tac no longer
  1701 exists, may define val exhaust_tac = case_tac for ad-hoc portability;
  1702 
  1703 * HOL: simplification no longer dives into case-expressions: only the
  1704 selector expression is simplified, but not the remaining arms; to
  1705 enable full simplification of case-expressions for datatype t, you may
  1706 remove t.weak_case_cong from the simpset, either globally (Delcongs
  1707 [thm"t.weak_case_cong"];) or locally (delcongs [...]).
  1708 
  1709 * HOL/recdef: the recursion equations generated by 'recdef' for
  1710 function 'f' are now called f.simps instead of f.rules; if all
  1711 termination conditions are proved automatically, these simplification
  1712 rules are added to the simpset, as in primrec; rules may be named
  1713 individually as well, resulting in a separate list of theorems for
  1714 each equation;
  1715 
  1716 * HOL/While is a new theory that provides a while-combinator. It
  1717 permits the definition of tail-recursive functions without the
  1718 provision of a termination measure. The latter is necessary once the
  1719 invariant proof rule for while is applied.
  1720 
  1721 * HOL: new (overloaded) notation for the set of elements below/above
  1722 some element: {..u}, {..u(}, {l..}, {)l..}. See theory SetInterval.
  1723 
  1724 * HOL: theorems impI, allI, ballI bound as "strip";
  1725 
  1726 * HOL: new tactic induct_thm_tac: thm -> string -> int -> tactic
  1727 induct_tac th "x1 ... xn" expects th to have a conclusion of the form
  1728 P v1 ... vn and abbreviates res_inst_tac [("v1","x1"),...,("vn","xn")] th;
  1729 
  1730 * HOL/Real: "rabs" replaced by overloaded "abs" function;
  1731 
  1732 * HOL: theory Sexp now in HOL/Induct examples (it used to be part of
  1733 main HOL, but was unused);
  1734 
  1735 * HOL: fewer consts declared as global (e.g. have to refer to
  1736 "Lfp.lfp" instead of "lfp" internally; affects ML packages only);
  1737 
  1738 * HOL: tuned AST representation of nested pairs, avoiding bogus output
  1739 in case of overlap with user translations (e.g. judgements over
  1740 tuples); (note that the underlying logical represenation is still
  1741 bogus);
  1742 
  1743 
  1744 *** ZF ***
  1745 
  1746 * ZF: simplification automatically cancels common terms in arithmetic
  1747 expressions over nat and int;
  1748 
  1749 * ZF: new treatment of nat to minimize type-checking: all operators
  1750 coerce their operands to a natural number using the function natify,
  1751 making the algebraic laws unconditional;
  1752 
  1753 * ZF: as above, for int: operators coerce their operands to an integer
  1754 using the function intify;
  1755 
  1756 * ZF: the integer library now contains many of the usual laws for the
  1757 orderings, including $<=, and monotonicity laws for $+ and $*;
  1758 
  1759 * ZF: new example ZF/ex/NatSum to demonstrate integer arithmetic
  1760 simplification;
  1761 
  1762 * FOL and ZF: AddIffs now available, giving theorems of the form P<->Q
  1763 to the simplifier and classical reasoner simultaneously;
  1764 
  1765 
  1766 *** General ***
  1767 
  1768 * Provers: blast_tac now handles actual object-logic rules as
  1769 assumptions; note that auto_tac uses blast_tac internally as well;
  1770 
  1771 * Provers: new functions rulify/rulify_no_asm: thm -> thm for turning
  1772 outer -->/All/Ball into ==>/!!; qed_spec_mp now uses rulify_no_asm;
  1773 
  1774 * Provers: delrules now handles destruct rules as well (no longer need
  1775 explicit make_elim);
  1776 
  1777 * Provers: Blast_tac now warns of and ignores "weak elimination rules" e.g.
  1778   [| inj ?f;          ?f ?x = ?f ?y; ?x = ?y ==> ?W |] ==> ?W
  1779 use instead the strong form,
  1780   [| inj ?f; ~ ?W ==> ?f ?x = ?f ?y; ?x = ?y ==> ?W |] ==> ?W
  1781 in HOL, FOL and ZF the function cla_make_elim will create such rules
  1782 from destruct-rules;
  1783 
  1784 * Provers: Simplifier.easy_setup provides a fast path to basic
  1785 Simplifier setup for new object-logics;
  1786 
  1787 * Pure: AST translation rules no longer require constant head on LHS;
  1788 
  1789 * Pure: improved name spaces: ambiguous output is qualified; support
  1790 for hiding of names;
  1791 
  1792 * system: smart setup of canonical ML_HOME, ISABELLE_INTERFACE, and
  1793 XSYMBOL_HOME; no longer need to do manual configuration in most
  1794 situations;
  1795 
  1796 * system: compression of ML heaps images may now be controlled via -c
  1797 option of isabelle and isatool usedir (currently only observed by
  1798 Poly/ML);
  1799 
  1800 * system: isatool installfonts may handle X-Symbol fonts as well (very
  1801 useful for remote X11);
  1802 
  1803 * system: provide TAGS file for Isabelle sources;
  1804 
  1805 * ML: infix 'OF' is a version of 'MRS' with more appropriate argument
  1806 order;
  1807 
  1808 * ML: renamed flags Syntax.trace_norm_ast to Syntax.trace_ast; global
  1809 timing flag supersedes proof_timing and Toplevel.trace;
  1810 
  1811 * ML: new combinators |>> and |>>> for incremental transformations
  1812 with secondary results (e.g. certain theory extensions):
  1813 
  1814 * ML: PureThy.add_defs gets additional argument to indicate potential
  1815 overloading (usually false);
  1816 
  1817 * ML: PureThy.add_thms/add_axioms/add_defs now return theorems as
  1818 results;
  1819 
  1820 
  1821 
  1822 New in Isabelle99 (October 1999)
  1823 --------------------------------
  1824 
  1825 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  1826 
  1827 * HOL: The THEN and ELSE parts of conditional expressions (if P then x else y)
  1828 are no longer simplified.  (This allows the simplifier to unfold recursive
  1829 functional programs.)  To restore the old behaviour, declare
  1830 
  1831     Delcongs [if_weak_cong];
  1832 
  1833 * HOL: Removed the obsolete syntax "Compl A"; use -A for set
  1834 complement;
  1835 
  1836 * HOL: the predicate "inj" is now defined by translation to "inj_on";
  1837 
  1838 * HOL/datatype: mutual_induct_tac no longer exists --
  1839   use induct_tac "x_1 ... x_n" instead of mutual_induct_tac ["x_1", ..., "x_n"]
  1840 
  1841 * HOL/typedef: fixed type inference for representing set; type
  1842 arguments now have to occur explicitly on the rhs as type constraints;
  1843 
  1844 * ZF: The con_defs part of an inductive definition may no longer refer
  1845 to constants declared in the same theory;
  1846 
  1847 * HOL, ZF: the function mk_cases, generated by the inductive
  1848 definition package, has lost an argument.  To simplify its result, it
  1849 uses the default simpset instead of a supplied list of theorems.
  1850 
  1851 * HOL/List: the constructors of type list are now Nil and Cons;
  1852 
  1853 * Simplifier: the type of the infix ML functions
  1854         setSSolver addSSolver setSolver addSolver
  1855 is now  simpset * solver -> simpset  where `solver' is a new abstract type
  1856 for packaging solvers. A solver is created via
  1857         mk_solver: string -> (thm list -> int -> tactic) -> solver
  1858 where the string argument is only a comment.
  1859 
  1860 
  1861 *** Proof tools ***
  1862 
  1863 * Provers/Arith/fast_lin_arith.ML contains a functor for creating a
  1864 decision procedure for linear arithmetic. Currently it is used for
  1865 types `nat', `int', and `real' in HOL (see below); it can, should and
  1866 will be instantiated for other types and logics as well.
  1867 
  1868 * The simplifier now accepts rewrite rules with flexible heads, eg
  1869      hom ?f ==> ?f(?x+?y) = ?f ?x + ?f ?y
  1870   They are applied like any rule with a non-pattern lhs, i.e. by first-order
  1871   matching.
  1872 
  1873 
  1874 *** General ***
  1875 
  1876 * New Isabelle/Isar subsystem provides an alternative to traditional
  1877 tactical theorem proving; together with the ProofGeneral/isar user
  1878 interface it offers an interactive environment for developing human
  1879 readable proof documents (Isar == Intelligible semi-automated
  1880 reasoning); for further information see isatool doc isar-ref,
  1881 src/HOL/Isar_examples and http://isabelle.in.tum.de/Isar/
  1882 
  1883 * improved and simplified presentation of theories: better HTML markup
  1884 (including colors), graph views in several sizes; isatool usedir now
  1885 provides a proper interface for user theories (via -P option); actual
  1886 document preparation based on (PDF)LaTeX is available as well (for
  1887 new-style theories only); see isatool doc system for more information;
  1888 
  1889 * native support for Proof General, both for classic Isabelle and
  1890 Isabelle/Isar;
  1891 
  1892 * ML function thm_deps visualizes dependencies of theorems and lemmas,
  1893 using the graph browser tool;
  1894 
  1895 * Isabelle manuals now also available as PDF;
  1896 
  1897 * theory loader rewritten from scratch (may not be fully
  1898 bug-compatible); old loadpath variable has been replaced by show_path,
  1899 add_path, del_path, reset_path functions; new operations such as
  1900 update_thy, touch_thy, remove_thy, use/update_thy_only (see also
  1901 isatool doc ref);
  1902 
  1903 * improved isatool install: option -k creates KDE application icon,
  1904 option -p DIR installs standalone binaries;
  1905 
  1906 * added ML_PLATFORM setting (useful for cross-platform installations);
  1907 more robust handling of platform specific ML images for SML/NJ;
  1908 
  1909 * the settings environment is now statically scoped, i.e. it is never
  1910 created again in sub-processes invoked from isabelle, isatool, or
  1911 Isabelle;
  1912 
  1913 * path element specification '~~' refers to '$ISABELLE_HOME';
  1914 
  1915 * in locales, the "assumes" and "defines" parts may be omitted if
  1916 empty;
  1917 
  1918 * new print_mode "xsymbols" for extended symbol support (e.g. genuine
  1919 long arrows);
  1920 
  1921 * new print_mode "HTML";
  1922 
  1923 * new flag show_tags controls display of tags of theorems (which are
  1924 basically just comments that may be attached by some tools);
  1925 
  1926 * Isamode 2.6 requires patch to accomodate change of Isabelle font
  1927 mode and goal output format:
  1928 
  1929 diff -r Isamode-2.6/elisp/isa-load.el Isamode/elisp/isa-load.el
  1930 244c244
  1931 <       (list (isa-getenv "ISABELLE") "-msymbols" logic-name)
  1932 ---
  1933 >       (list (isa-getenv "ISABELLE") "-misabelle_font" "-msymbols" logic-name)
  1934 diff -r Isabelle-2.6/elisp/isa-proofstate.el Isamode/elisp/isa-proofstate.el
  1935 181c181
  1936 < (defconst proofstate-proofstart-regexp "^Level [0-9]+$"
  1937 ---
  1938 > (defconst proofstate-proofstart-regexp "^Level [0-9]+"
  1939 
  1940 * function bind_thms stores lists of theorems (cf. bind_thm);
  1941 
  1942 * new shorthand tactics ftac, eatac, datac, fatac;
  1943 
  1944 * qed (and friends) now accept "" as result name; in that case the
  1945 theorem is not stored, but proper checks and presentation of the
  1946 result still apply;
  1947 
  1948 * theorem database now also indexes constants "Trueprop", "all",
  1949 "==>", "=="; thus thms_containing, findI etc. may retrieve more rules;
  1950 
  1951 
  1952 *** HOL ***
  1953 
  1954 ** HOL arithmetic **
  1955 
  1956 * There are now decision procedures for linear arithmetic over nat and
  1957 int:
  1958 
  1959 1. arith_tac copes with arbitrary formulae involving `=', `<', `<=',
  1960 `+', `-', `Suc', `min', `max' and numerical constants; other subterms
  1961 are treated as atomic; subformulae not involving type `nat' or `int'
  1962 are ignored; quantified subformulae are ignored unless they are
  1963 positive universal or negative existential. The tactic has to be
  1964 invoked by hand and can be a little bit slow. In particular, the
  1965 running time is exponential in the number of occurrences of `min' and
  1966 `max', and `-' on `nat'.
  1967 
  1968 2. fast_arith_tac is a cut-down version of arith_tac: it only takes
  1969 (negated) (in)equalities among the premises and the conclusion into
  1970 account (i.e. no compound formulae) and does not know about `min' and
  1971 `max', and `-' on `nat'. It is fast and is used automatically by the
  1972 simplifier.
  1973 
  1974 NB: At the moment, these decision procedures do not cope with mixed
  1975 nat/int formulae where the two parts interact, such as `m < n ==>
  1976 int(m) < int(n)'.
  1977 
  1978 * HOL/Numeral provides a generic theory of numerals (encoded
  1979 efficiently as bit strings); setup for types nat/int/real is in place;
  1980 INCOMPATIBILITY: since numeral syntax is now polymorphic, rather than
  1981 int, existing theories and proof scripts may require a few additional
  1982 type constraints;
  1983 
  1984 * integer division and remainder can now be performed on constant
  1985 arguments;
  1986 
  1987 * many properties of integer multiplication, division and remainder
  1988 are now available;
  1989 
  1990 * An interface to the Stanford Validity Checker (SVC) is available through the
  1991 tactic svc_tac.  Propositional tautologies and theorems of linear arithmetic
  1992 are proved automatically.  SVC must be installed separately, and its results
  1993 must be TAKEN ON TRUST (Isabelle does not check the proofs, but tags any
  1994 invocation of the underlying oracle).  For SVC see
  1995   http://verify.stanford.edu/SVC
  1996 
  1997 * IsaMakefile: the HOL-Real target now builds an actual image;
  1998 
  1999 
  2000 ** HOL misc **
  2001 
  2002 * HOL/Real/HahnBanach: the Hahn-Banach theorem for real vector spaces
  2003 (in Isabelle/Isar) -- by Gertrud Bauer;
  2004 
  2005 * HOL/BCV: generic model of bytecode verification, i.e. data-flow
  2006 analysis for assembly languages with subtypes;
  2007 
  2008 * HOL/TLA (Lamport's Temporal Logic of Actions): major reorganization
  2009 -- avoids syntactic ambiguities and treats state, transition, and
  2010 temporal levels more uniformly; introduces INCOMPATIBILITIES due to
  2011 changed syntax and (many) tactics;
  2012 
  2013 * HOL/inductive: Now also handles more general introduction rules such
  2014   as "ALL y. (y, x) : r --> y : acc r ==> x : acc r"; monotonicity
  2015   theorems are now maintained within the theory (maintained via the
  2016   "mono" attribute);
  2017 
  2018 * HOL/datatype: Now also handles arbitrarily branching datatypes
  2019   (using function types) such as
  2020 
  2021   datatype 'a tree = Atom 'a | Branch "nat => 'a tree"
  2022 
  2023 * HOL/record: record_simproc (part of the default simpset) takes care
  2024 of selectors applied to updated records; record_split_tac is no longer
  2025 part of the default claset; update_defs may now be removed from the
  2026 simpset in many cases; COMPATIBILITY: old behavior achieved by
  2027 
  2028   claset_ref () := claset() addSWrapper record_split_wrapper;
  2029   Delsimprocs [record_simproc]
  2030 
  2031 * HOL/typedef: fixed type inference for representing set; type
  2032 arguments now have to occur explicitly on the rhs as type constraints;
  2033 
  2034 * HOL/recdef (TFL): 'congs' syntax now expects comma separated list of theorem
  2035 names rather than an ML expression;
  2036 
  2037 * HOL/defer_recdef (TFL): like recdef but the well-founded relation can be
  2038 supplied later.  Program schemes can be defined, such as
  2039     "While B C s = (if B s then While B C (C s) else s)"
  2040 where the well-founded relation can be chosen after B and C have been given.
  2041 
  2042 * HOL/List: the constructors of type list are now Nil and Cons;
  2043 INCOMPATIBILITY: while [] and infix # syntax is still there, of
  2044 course, ML tools referring to List.list.op # etc. have to be adapted;
  2045 
  2046 * HOL_quantifiers flag superseded by "HOL" print mode, which is
  2047 disabled by default; run isabelle with option -m HOL to get back to
  2048 the original Gordon/HOL-style output;
  2049 
  2050 * HOL/Ord.thy: new bounded quantifier syntax (input only): ALL x<y. P,
  2051 ALL x<=y. P, EX x<y. P, EX x<=y. P;
  2052 
  2053 * HOL basic syntax simplified (more orthogonal): all variants of
  2054 All/Ex now support plain / symbolic / HOL notation; plain syntax for
  2055 Eps operator is provided as well: "SOME x. P[x]";
  2056 
  2057 * HOL/Sum.thy: sum_case has been moved to HOL/Datatype;
  2058 
  2059 * HOL/Univ.thy: infix syntax <*>, <+>, <**>, <+> eliminated and made
  2060 thus available for user theories;
  2061 
  2062 * HOLCF/IOA/Sequents: renamed 'Cons' to 'Consq' to avoid clash with
  2063 HOL/List; hardly an INCOMPATIBILITY since '>>' syntax is used all the
  2064 time;
  2065 
  2066 * HOL: new tactic smp_tac: int -> int -> tactic, which applies spec
  2067 several times and then mp;
  2068 
  2069 
  2070 *** LK ***
  2071 
  2072 * the notation <<...>> is now available as a notation for sequences of
  2073 formulas;
  2074 
  2075 * the simplifier is now installed
  2076 
  2077 * the axiom system has been generalized (thanks to Soren Heilmann)
  2078 
  2079 * the classical reasoner now has a default rule database
  2080 
  2081 
  2082 *** ZF ***
  2083 
  2084 * new primrec section allows primitive recursive functions to be given
  2085 directly (as in HOL) over datatypes and the natural numbers;
  2086 
  2087 * new tactics induct_tac and exhaust_tac for induction (or case
  2088 analysis) over datatypes and the natural numbers;
  2089 
  2090 * the datatype declaration of type T now defines the recursor T_rec;
  2091 
  2092 * simplification automatically does freeness reasoning for datatype
  2093 constructors;
  2094 
  2095 * automatic type-inference, with AddTCs command to insert new
  2096 type-checking rules;
  2097 
  2098 * datatype introduction rules are now added as Safe Introduction rules
  2099 to the claset;
  2100 
  2101 * the syntax "if P then x else y" is now available in addition to
  2102 if(P,x,y);
  2103 
  2104 
  2105 *** Internal programming interfaces ***
  2106 
  2107 * tuned simplifier trace output; new flag debug_simp;
  2108 
  2109 * structures Vartab / Termtab (instances of TableFun) offer efficient
  2110 tables indexed by indexname_ord / term_ord (compatible with aconv);
  2111 
  2112 * AxClass.axclass_tac lost the theory argument;
  2113 
  2114 * tuned current_goals_markers semantics: begin / end goal avoids
  2115 printing empty lines;
  2116 
  2117 * removed prs and prs_fn hook, which was broken because it did not
  2118 include \n in its semantics, forcing writeln to add one
  2119 uncoditionally; replaced prs_fn by writeln_fn; consider std_output:
  2120 string -> unit if you really want to output text without newline;
  2121 
  2122 * Symbol.output subject to print mode; INCOMPATIBILITY: defaults to
  2123 plain output, interface builders may have to enable 'isabelle_font'
  2124 mode to get Isabelle font glyphs as before;
  2125 
  2126 * refined token_translation interface; INCOMPATIBILITY: output length
  2127 now of type real instead of int;
  2128 
  2129 * theory loader actions may be traced via new ThyInfo.add_hook
  2130 interface (see src/Pure/Thy/thy_info.ML); example application: keep
  2131 your own database of information attached to *whole* theories -- as
  2132 opposed to intra-theory data slots offered via TheoryDataFun;
  2133 
  2134 * proper handling of dangling sort hypotheses (at last!);
  2135 Thm.strip_shyps and Drule.strip_shyps_warning take care of removing
  2136 extra sort hypotheses that can be witnessed from the type signature;
  2137 the force_strip_shyps flag is gone, any remaining shyps are simply
  2138 left in the theorem (with a warning issued by strip_shyps_warning);
  2139 
  2140 
  2141 
  2142 New in Isabelle98-1 (October 1998)
  2143 ----------------------------------
  2144 
  2145 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  2146 
  2147 * several changes of automated proof tools;
  2148 
  2149 * HOL: major changes to the inductive and datatype packages, including
  2150 some minor incompatibilities of theory syntax;
  2151 
  2152 * HOL: renamed r^-1 to 'converse' from 'inverse'; 'inj_onto' is now
  2153 called `inj_on';
  2154 
  2155 * HOL: removed duplicate thms in Arith:
  2156   less_imp_add_less  should be replaced by  trans_less_add1
  2157   le_imp_add_le      should be replaced by  trans_le_add1
  2158 
  2159 * HOL: unary minus is now overloaded (new type constraints may be
  2160 required);
  2161 
  2162 * HOL and ZF: unary minus for integers is now #- instead of #~.  In
  2163 ZF, expressions such as n#-1 must be changed to n#- 1, since #-1 is
  2164 now taken as an integer constant.
  2165 
  2166 * Pure: ML function 'theory_of' renamed to 'theory';
  2167 
  2168 
  2169 *** Proof tools ***
  2170 
  2171 * Simplifier:
  2172   1. Asm_full_simp_tac is now more aggressive.
  2173      1. It will sometimes reorient premises if that increases their power to
  2174         simplify.
  2175      2. It does no longer proceed strictly from left to right but may also
  2176         rotate premises to achieve further simplification.
  2177      For compatibility reasons there is now Asm_lr_simp_tac which is like the
  2178      old Asm_full_simp_tac in that it does not rotate premises.
  2179   2. The simplifier now knows a little bit about nat-arithmetic.
  2180 
  2181 * Classical reasoner: wrapper mechanism for the classical reasoner now
  2182 allows for selected deletion of wrappers, by introduction of names for
  2183 wrapper functionals.  This implies that addbefore, addSbefore,
  2184 addaltern, and addSaltern now take a pair (name, tactic) as argument,
  2185 and that adding two tactics with the same name overwrites the first
  2186 one (emitting a warning).
  2187   type wrapper = (int -> tactic) -> (int -> tactic)
  2188   setWrapper, setSWrapper, compWrapper and compSWrapper are replaced by
  2189   addWrapper, addSWrapper: claset * (string * wrapper) -> claset
  2190   delWrapper, delSWrapper: claset *  string            -> claset
  2191   getWrapper is renamed to appWrappers, getSWrapper to appSWrappers;
  2192 
  2193 * Classical reasoner: addbefore/addSbefore now have APPEND/ORELSE
  2194 semantics; addbefore now affects only the unsafe part of step_tac
  2195 etc.; this affects addss/auto_tac/force_tac, so EXISTING PROOFS MAY
  2196 FAIL, but proofs should be fixable easily, e.g. by replacing Auto_tac
  2197 by Force_tac;
  2198 
  2199 * Classical reasoner: setwrapper to setWrapper and compwrapper to
  2200 compWrapper; added safe wrapper (and access functions for it);
  2201 
  2202 * HOL/split_all_tac is now much faster and fails if there is nothing
  2203 to split.  Some EXISTING PROOFS MAY REQUIRE ADAPTION because the order
  2204 and the names of the automatically generated variables have changed.
  2205 split_all_tac has moved within claset() from unsafe wrappers to safe
  2206 wrappers, which means that !!-bound variables are split much more
  2207 aggressively, and safe_tac and clarify_tac now split such variables.
  2208 If this splitting is not appropriate, use delSWrapper "split_all_tac".
  2209 Note: the same holds for record_split_tac, which does the job of
  2210 split_all_tac for record fields.
  2211 
  2212 * HOL/Simplifier: Rewrite rules for case distinctions can now be added
  2213 permanently to the default simpset using Addsplits just like
  2214 Addsimps. They can be removed via Delsplits just like
  2215 Delsimps. Lower-case versions are also available.
  2216 
  2217 * HOL/Simplifier: The rule split_if is now part of the default
  2218 simpset. This means that the simplifier will eliminate all occurrences
  2219 of if-then-else in the conclusion of a goal. To prevent this, you can
  2220 either remove split_if completely from the default simpset by
  2221 `Delsplits [split_if]' or remove it in a specific call of the
  2222 simplifier using `... delsplits [split_if]'.  You can also add/delete
  2223 other case splitting rules to/from the default simpset: every datatype
  2224 generates suitable rules `split_t_case' and `split_t_case_asm' (where
  2225 t is the name of the datatype).
  2226 
  2227 * Classical reasoner / Simplifier combination: new force_tac (and
  2228 derivatives Force_tac, force) combines rewriting and classical
  2229 reasoning (and whatever other tools) similarly to auto_tac, but is
  2230 aimed to solve the given subgoal completely.
  2231 
  2232 
  2233 *** General ***
  2234 
  2235 * new top-level commands `Goal' and `Goalw' that improve upon `goal'
  2236 and `goalw': the theory is no longer needed as an explicit argument -
  2237 the current theory context is used; assumptions are no longer returned
  2238 at the ML-level unless one of them starts with ==> or !!; it is
  2239 recommended to convert to these new commands using isatool fixgoal
  2240 (backup your sources first!);
  2241 
  2242 * new top-level commands 'thm' and 'thms' for retrieving theorems from
  2243 the current theory context, and 'theory' to lookup stored theories;
  2244 
  2245 * new theory section 'locale' for declaring constants, assumptions and
  2246 definitions that have local scope;
  2247 
  2248 * new theory section 'nonterminals' for purely syntactic types;
  2249 
  2250 * new theory section 'setup' for generic ML setup functions
  2251 (e.g. package initialization);
  2252 
  2253 * the distribution now includes Isabelle icons: see
  2254 lib/logo/isabelle-{small,tiny}.xpm;
  2255 
  2256 * isatool install - install binaries with absolute references to
  2257 ISABELLE_HOME/bin;
  2258 
  2259 * isatool logo -- create instances of the Isabelle logo (as EPS);
  2260 
  2261 * print mode 'emacs' reserved for Isamode;
  2262 
  2263 * support multiple print (ast) translations per constant name;
  2264 
  2265 * theorems involving oracles are now printed with a suffixed [!];
  2266 
  2267 
  2268 *** HOL ***
  2269 
  2270 * there is now a tutorial on Isabelle/HOL (do 'isatool doc tutorial');
  2271 
  2272 * HOL/inductive package reorganized and improved: now supports mutual
  2273 definitions such as
  2274 
  2275   inductive EVEN ODD
  2276     intrs
  2277       null "0 : EVEN"
  2278       oddI "n : EVEN ==> Suc n : ODD"
  2279       evenI "n : ODD ==> Suc n : EVEN"
  2280 
  2281 new theorem list "elims" contains an elimination rule for each of the
  2282 recursive sets; inductive definitions now handle disjunctive premises
  2283 correctly (also ZF);
  2284 
  2285 INCOMPATIBILITIES: requires Inductive as an ancestor; component
  2286 "mutual_induct" no longer exists - the induction rule is always
  2287 contained in "induct";
  2288 
  2289 
  2290 * HOL/datatype package re-implemented and greatly improved: now
  2291 supports mutually recursive datatypes such as
  2292 
  2293   datatype
  2294     'a aexp = IF_THEN_ELSE ('a bexp) ('a aexp) ('a aexp)
  2295             | SUM ('a aexp) ('a aexp)
  2296             | DIFF ('a aexp) ('a aexp)
  2297             | NUM 'a
  2298   and
  2299     'a bexp = LESS ('a aexp) ('a aexp)
  2300             | AND ('a bexp) ('a bexp)
  2301             | OR ('a bexp) ('a bexp)
  2302 
  2303 as well as indirectly recursive datatypes such as
  2304 
  2305   datatype
  2306     ('a, 'b) term = Var 'a
  2307                   | App 'b ((('a, 'b) term) list)
  2308 
  2309 The new tactic  mutual_induct_tac [<var_1>, ..., <var_n>] i  performs
  2310 induction on mutually / indirectly recursive datatypes.
  2311 
  2312 Primrec equations are now stored in theory and can be accessed via
  2313 <function_name>.simps.
  2314 
  2315 INCOMPATIBILITIES:
  2316 
  2317   - Theories using datatypes must now have theory Datatype as an
  2318     ancestor.
  2319   - The specific <typename>.induct_tac no longer exists - use the
  2320     generic induct_tac instead.
  2321   - natE has been renamed to nat.exhaust - use exhaust_tac
  2322     instead of res_inst_tac ... natE. Note that the variable
  2323     names in nat.exhaust differ from the names in natE, this
  2324     may cause some "fragile" proofs to fail.
  2325   - The theorems split_<typename>_case and split_<typename>_case_asm
  2326     have been renamed to <typename>.split and <typename>.split_asm.
  2327   - Since default sorts of type variables are now handled correctly,
  2328     some datatype definitions may have to be annotated with explicit
  2329     sort constraints.
  2330   - Primrec definitions no longer require function name and type
  2331     of recursive argument.
  2332 
  2333 Consider using isatool fixdatatype to adapt your theories and proof
  2334 scripts to the new package (backup your sources first!).
  2335 
  2336 
  2337 * HOL/record package: considerably improved implementation; now
  2338 includes concrete syntax for record types, terms, updates; theorems
  2339 for surjective pairing and splitting !!-bound record variables; proof
  2340 support is as follows:
  2341 
  2342   1) standard conversions (selectors or updates applied to record
  2343 constructor terms) are part of the standard simpset;
  2344 
  2345   2) inject equations of the form ((x, y) = (x', y')) == x=x' & y=y' are
  2346 made part of standard simpset and claset via addIffs;
  2347 
  2348   3) a tactic for record field splitting (record_split_tac) is part of
  2349 the standard claset (addSWrapper);
  2350 
  2351 To get a better idea about these rules you may retrieve them via
  2352 something like 'thms "foo.simps"' or 'thms "foo.iffs"', where "foo" is
  2353 the name of your record type.
  2354 
  2355 The split tactic 3) conceptually simplifies by the following rule:
  2356 
  2357   "(!!x. PROP ?P x) == (!!a b. PROP ?P (a, b))"
  2358 
  2359 Thus any record variable that is bound by meta-all will automatically
  2360 blow up into some record constructor term, consequently the
  2361 simplifications of 1), 2) apply.  Thus force_tac, auto_tac etc. shall
  2362 solve record problems automatically.
  2363 
  2364 
  2365 * reorganized the main HOL image: HOL/Integ and String loaded by
  2366 default; theory Main includes everything;
  2367 
  2368 * automatic simplification of integer sums and comparisons, using cancellation;
  2369 
  2370 * added option_map_eq_Some and not_Some_eq to the default simpset and claset;
  2371 
  2372 * added disj_not1 = "(~P | Q) = (P --> Q)" to the default simpset;
  2373 
  2374 * many new identities for unions, intersections, set difference, etc.;
  2375 
  2376 * expand_if, expand_split, expand_sum_case and expand_nat_case are now
  2377 called split_if, split_split, split_sum_case and split_nat_case (to go
  2378 with add/delsplits);
  2379 
  2380 * HOL/Prod introduces simplification procedure unit_eq_proc rewriting
  2381 (?x::unit) = (); this is made part of the default simpset, which COULD
  2382 MAKE EXISTING PROOFS FAIL under rare circumstances (consider
  2383 'Delsimprocs [unit_eq_proc];' as last resort); also note that
  2384 unit_abs_eta_conv is added in order to counter the effect of
  2385 unit_eq_proc on (%u::unit. f u), replacing it by f rather than by
  2386 %u.f();
  2387 
  2388 * HOL/Fun INCOMPATIBILITY: `inj_onto' is now called `inj_on' (which
  2389 makes more sense);
  2390 
  2391 * HOL/Set INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
  2392   It and 'sym RS equals0D' are now in the default  claset, giving automatic
  2393   disjointness reasoning but breaking a few old proofs.
  2394 
  2395 * HOL/Relation INCOMPATIBILITY: renamed the relational operator r^-1
  2396 to 'converse' from 'inverse' (for compatibility with ZF and some
  2397 literature);
  2398 
  2399 * HOL/recdef can now declare non-recursive functions, with {} supplied as
  2400 the well-founded relation;
  2401 
  2402 * HOL/Set INCOMPATIBILITY: the complement of set A is now written -A instead of
  2403     Compl A.  The "Compl" syntax remains available as input syntax for this
  2404     release ONLY.
  2405 
  2406 * HOL/Update: new theory of function updates:
  2407     f(a:=b) == %x. if x=a then b else f x
  2408 may also be iterated as in f(a:=b,c:=d,...);
  2409 
  2410 * HOL/Vimage: new theory for inverse image of a function, syntax f-``B;
  2411 
  2412 * HOL/List:
  2413   - new function list_update written xs[i:=v] that updates the i-th
  2414     list position. May also be iterated as in xs[i:=a,j:=b,...].
  2415   - new function `upt' written [i..j(] which generates the list
  2416     [i,i+1,...,j-1], i.e. the upper bound is excluded. To include the upper
  2417     bound write [i..j], which is a shorthand for [i..j+1(].
  2418   - new lexicographic orderings and corresponding wellfoundedness theorems.
  2419 
  2420 * HOL/Arith:
  2421   - removed 'pred' (predecessor) function;
  2422   - generalized some theorems about n-1;
  2423   - many new laws about "div" and "mod";
  2424   - new laws about greatest common divisors (see theory ex/Primes);
  2425 
  2426 * HOL/Relation: renamed the relational operator r^-1 "converse"
  2427 instead of "inverse";
  2428 
  2429 * HOL/Induct/Multiset: a theory of multisets, including the wellfoundedness
  2430   of the multiset ordering;
  2431 
  2432 * directory HOL/Real: a construction of the reals using Dedekind cuts
  2433   (not included by default);
  2434 
  2435 * directory HOL/UNITY: Chandy and Misra's UNITY formalism;
  2436 
  2437 * directory HOL/Hoare: a new version of Hoare logic which permits many-sorted
  2438   programs, i.e. different program variables may have different types.
  2439 
  2440 * calling (stac rew i) now fails if "rew" has no effect on the goal
  2441   [previously, this check worked only if the rewrite rule was unconditional]
  2442   Now rew can involve either definitions or equalities (either == or =).
  2443 
  2444 
  2445 *** ZF ***
  2446 
  2447 * theory Main includes everything; INCOMPATIBILITY: theory ZF.thy contains
  2448   only the theorems proved on ZF.ML;
  2449 
  2450 * ZF INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
  2451   It and 'sym RS equals0D' are now in the default  claset, giving automatic
  2452   disjointness reasoning but breaking a few old proofs.
  2453 
  2454 * ZF/Update: new theory of function updates
  2455     with default rewrite rule  f(x:=y) ` z = if(z=x, y, f`z)
  2456   may also be iterated as in f(a:=b,c:=d,...);
  2457 
  2458 * in  let x=t in u(x), neither t nor u(x) has to be an FOL term.
  2459 
  2460 * calling (stac rew i) now fails if "rew" has no effect on the goal
  2461   [previously, this check worked only if the rewrite rule was unconditional]
  2462   Now rew can involve either definitions or equalities (either == or =).
  2463 
  2464 * case_tac provided for compatibility with HOL
  2465     (like the old excluded_middle_tac, but with subgoals swapped)
  2466 
  2467 
  2468 *** Internal programming interfaces ***
  2469 
  2470 * Pure: several new basic modules made available for general use, see
  2471 also src/Pure/README;
  2472 
  2473 * improved the theory data mechanism to support encapsulation (data
  2474 kind name replaced by private Object.kind, acting as authorization
  2475 key); new type-safe user interface via functor TheoryDataFun; generic
  2476 print_data function becomes basically useless;
  2477 
  2478 * removed global_names compatibility flag -- all theory declarations
  2479 are qualified by default;
  2480 
  2481 * module Pure/Syntax now offers quote / antiquote translation
  2482 functions (useful for Hoare logic etc. with implicit dependencies);
  2483 see HOL/ex/Antiquote for an example use;
  2484 
  2485 * Simplifier now offers conversions (asm_)(full_)rewrite: simpset ->
  2486 cterm -> thm;
  2487 
  2488 * new tactical CHANGED_GOAL for checking that a tactic modifies a
  2489 subgoal;
  2490 
  2491 * Display.print_goals function moved to Locale.print_goals;
  2492 
  2493 * standard print function for goals supports current_goals_markers
  2494 variable for marking begin of proof, end of proof, start of goal; the
  2495 default is ("", "", ""); setting current_goals_markers := ("<proof>",
  2496 "</proof>", "<goal>") causes SGML like tagged proof state printing,
  2497 for example;
  2498 
  2499 
  2500 
  2501 New in Isabelle98 (January 1998)
  2502 --------------------------------
  2503 
  2504 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  2505 
  2506 * changed lexical syntax of terms / types: dots made part of long
  2507 identifiers, e.g. "%x.x" no longer possible, should be "%x. x";
  2508 
  2509 * simpset (and claset) reference variable replaced by functions
  2510 simpset / simpset_ref;
  2511 
  2512 * no longer supports theory aliases (via merge) and non-trivial
  2513 implicit merge of thms' signatures;
  2514 
  2515 * most internal names of constants changed due to qualified names;
  2516 
  2517 * changed Pure/Sequence interface (see Pure/seq.ML);
  2518 
  2519 
  2520 *** General Changes ***
  2521 
  2522 * hierachically structured name spaces (for consts, types, axms, thms
  2523 etc.); new lexical class 'longid' (e.g. Foo.bar.x) may render much of
  2524 old input syntactically incorrect (e.g. "%x.x"); COMPATIBILITY:
  2525 isatool fixdots ensures space after dots (e.g. "%x. x"); set
  2526 long_names for fully qualified output names; NOTE: ML programs
  2527 (special tactics, packages etc.) referring to internal names may have
  2528 to be adapted to cope with fully qualified names; in case of severe
  2529 backward campatibility problems try setting 'global_names' at compile
  2530 time to have enrything declared within a flat name space; one may also
  2531 fine tune name declarations in theories via the 'global' and 'local'
  2532 section;
  2533 
  2534 * reimplemented the implicit simpset and claset using the new anytype
  2535 data filed in signatures; references simpset:simpset ref etc. are
  2536 replaced by functions simpset:unit->simpset and
  2537 simpset_ref:unit->simpset ref; COMPATIBILITY: use isatool fixclasimp
  2538 to patch your ML files accordingly;
  2539 
  2540 * HTML output now includes theory graph data for display with Java
  2541 applet or isatool browser; data generated automatically via isatool
  2542 usedir (see -i option, ISABELLE_USEDIR_OPTIONS);
  2543 
  2544 * defs may now be conditional; improved rewrite_goals_tac to handle
  2545 conditional equations;
  2546 
  2547 * defs now admits additional type arguments, using TYPE('a) syntax;
  2548 
  2549 * theory aliases via merge (e.g. M=A+B+C) no longer supported, always
  2550 creates a new theory node; implicit merge of thms' signatures is
  2551 restricted to 'trivial' ones; COMPATIBILITY: one may have to use
  2552 transfer:theory->thm->thm in (rare) cases;
  2553 
  2554 * improved handling of draft signatures / theories; draft thms (and
  2555 ctyps, cterms) are automatically promoted to real ones;
  2556 
  2557 * slightly changed interfaces for oracles: admit many per theory, named
  2558 (e.g. oracle foo = mlfun), additional name argument for invoke_oracle;
  2559 
  2560 * print_goals: optional output of const types (set show_consts and
  2561 show_types);
  2562 
  2563 * improved output of warnings (###) and errors (***);
  2564 
  2565 * subgoal_tac displays a warning if the new subgoal has type variables;
  2566 
  2567 * removed old README and Makefiles;
  2568 
  2569 * replaced print_goals_ref hook by print_current_goals_fn and result_error_fn;
  2570 
  2571 * removed obsolete init_pps and init_database;
  2572 
  2573 * deleted the obsolete tactical STATE, which was declared by
  2574     fun STATE tacfun st = tacfun st st;
  2575 
  2576 * cd and use now support path variables, e.g. $ISABELLE_HOME, or ~
  2577 (which abbreviates $HOME);
  2578 
  2579 * changed Pure/Sequence interface (see Pure/seq.ML); COMPATIBILITY:
  2580 use isatool fixseq to adapt your ML programs (this works for fully
  2581 qualified references to the Sequence structure only!);
  2582 
  2583 * use_thy no longer requires writable current directory; it always
  2584 reloads .ML *and* .thy file, if either one is out of date;
  2585 
  2586 
  2587 *** Classical Reasoner ***
  2588 
  2589 * Clarify_tac, clarify_tac, clarify_step_tac, Clarify_step_tac: new
  2590 tactics that use classical reasoning to simplify a subgoal without
  2591 splitting it into several subgoals;
  2592 
  2593 * Safe_tac: like safe_tac but uses the default claset;
  2594 
  2595 
  2596 *** Simplifier ***
  2597 
  2598 * added simplification meta rules:
  2599     (asm_)(full_)simplify: simpset -> thm -> thm;
  2600 
  2601 * simplifier.ML no longer part of Pure -- has to be loaded by object
  2602 logics (again);
  2603 
  2604 * added prems argument to simplification procedures;
  2605 
  2606 * HOL, FOL, ZF: added infix function `addsplits':
  2607   instead of `<simpset> setloop (split_tac <thms>)'
  2608   you can simply write `<simpset> addsplits <thms>'
  2609 
  2610 
  2611 *** Syntax ***
  2612 
  2613 * TYPE('a) syntax for type reflection terms;
  2614 
  2615 * no longer handles consts with name "" -- declare as 'syntax' instead;
  2616 
  2617 * pretty printer: changed order of mixfix annotation preference (again!);
  2618 
  2619 * Pure: fixed idt/idts vs. pttrn/pttrns syntactic categories;
  2620 
  2621 
  2622 *** HOL ***
  2623 
  2624 * HOL: there is a new splitter `split_asm_tac' that can be used e.g.
  2625   with `addloop' of the simplifier to faciliate case splitting in premises.
  2626 
  2627 * HOL/TLA: Stephan Merz's formalization of Lamport's Temporal Logic of Actions;
  2628 
  2629 * HOL/Auth: new protocol proofs including some for the Internet
  2630   protocol TLS;
  2631 
  2632 * HOL/Map: new theory of `maps' a la VDM;
  2633 
  2634 * HOL/simplifier: simplification procedures nat_cancel_sums for
  2635 cancelling out common nat summands from =, <, <= (in)equalities, or
  2636 differences; simplification procedures nat_cancel_factor for
  2637 cancelling common factor from =, <, <= (in)equalities over natural
  2638 sums; nat_cancel contains both kinds of procedures, it is installed by
  2639 default in Arith.thy -- this COULD MAKE EXISTING PROOFS FAIL;
  2640 
  2641 * HOL/simplifier: terms of the form
  2642   `? x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x)'  (or t=x)
  2643   are rewritten to
  2644   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t)',
  2645   and those of the form
  2646   `! x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x) --> R(x)'  (or t=x)
  2647   are rewritten to
  2648   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t) --> R(t)',
  2649 
  2650 * HOL/datatype
  2651   Each datatype `t' now comes with a theorem `split_t_case' of the form
  2652 
  2653   P(t_case f1 ... fn x) =
  2654      ( (!y1 ... ym1. x = C1 y1 ... ym1 --> P(f1 y1 ... ym1)) &
  2655         ...
  2656        (!y1 ... ymn. x = Cn y1 ... ymn --> P(f1 y1 ... ymn))
  2657      )
  2658 
  2659   and a theorem `split_t_case_asm' of the form
  2660 
  2661   P(t_case f1 ... fn x) =
  2662     ~( (? y1 ... ym1. x = C1 y1 ... ym1 & ~P(f1 y1 ... ym1)) |
  2663         ...
  2664        (? y1 ... ymn. x = Cn y1 ... ymn & ~P(f1 y1 ... ymn))
  2665      )
  2666   which can be added to a simpset via `addsplits'. The existing theorems
  2667   expand_list_case and expand_option_case have been renamed to
  2668   split_list_case and split_option_case.
  2669 
  2670 * HOL/Arithmetic:
  2671   - `pred n' is automatically converted to `n-1'.
  2672     Users are strongly encouraged not to use `pred' any longer,
  2673     because it will disappear altogether at some point.
  2674   - Users are strongly encouraged to write "0 < n" rather than
  2675     "n ~= 0". Theorems and proof tools have been modified towards this
  2676     `standard'.
  2677 
  2678 * HOL/Lists:
  2679   the function "set_of_list" has been renamed "set" (and its theorems too);
  2680   the function "nth" now takes its arguments in the reverse order and
  2681   has acquired the infix notation "!" as in "xs!n".
  2682 
  2683 * HOL/Set: UNIV is now a constant and is no longer translated to Compl{};
  2684 
  2685 * HOL/Set: The operator (UN x.B x) now abbreviates (UN x:UNIV. B x) and its
  2686   specialist theorems (like UN1_I) are gone.  Similarly for (INT x.B x);
  2687 
  2688 * HOL/record: extensible records with schematic structural subtyping
  2689 (single inheritance); EXPERIMENTAL version demonstrating the encoding,
  2690 still lacks various theorems and concrete record syntax;
  2691 
  2692 
  2693 *** HOLCF ***
  2694 
  2695 * removed "axioms" and "generated by" sections;
  2696 
  2697 * replaced "ops" section by extended "consts" section, which is capable of
  2698   handling the continuous function space "->" directly;
  2699 
  2700 * domain package:
  2701   . proves theorems immediately and stores them in the theory,
  2702   . creates hierachical name space,
  2703   . now uses normal mixfix annotations (instead of cinfix...),
  2704   . minor changes to some names and values (for consistency),
  2705   . e.g. cases -> casedist, dists_eq -> dist_eqs, [take_lemma] -> take_lemmas,
  2706   . separator between mutual domain defs: changed "," to "and",
  2707   . improved handling of sort constraints;  now they have to
  2708     appear on the left-hand side of the equations only;
  2709 
  2710 * fixed LAM <x,y,zs>.b syntax;
  2711 
  2712 * added extended adm_tac to simplifier in HOLCF -- can now discharge
  2713 adm (%x. P (t x)), where P is chainfinite and t continuous;
  2714 
  2715 
  2716 *** FOL and ZF ***
  2717 
  2718 * FOL: there is a new splitter `split_asm_tac' that can be used e.g.
  2719   with `addloop' of the simplifier to faciliate case splitting in premises.
  2720 
  2721 * qed_spec_mp, qed_goal_spec_mp, qed_goalw_spec_mp are available, as
  2722 in HOL, they strip ALL and --> from proved theorems;
  2723 
  2724 
  2725 
  2726 New in Isabelle94-8 (May 1997)
  2727 ------------------------------
  2728 
  2729 *** General Changes ***
  2730 
  2731 * new utilities to build / run / maintain Isabelle etc. (in parts
  2732 still somewhat experimental); old Makefiles etc. still functional;
  2733 
  2734 * new 'Isabelle System Manual';
  2735 
  2736 * INSTALL text, together with ./configure and ./build scripts;
  2737 
  2738 * reimplemented type inference for greater efficiency, better error
  2739 messages and clean internal interface;
  2740 
  2741 * prlim command for dealing with lots of subgoals (an easier way of
  2742 setting goals_limit);
  2743 
  2744 
  2745 *** Syntax ***
  2746 
  2747 * supports alternative (named) syntax tables (parser and pretty
  2748 printer); internal interface is provided by add_modesyntax(_i);
  2749 
  2750 * Pure, FOL, ZF, HOL, HOLCF now support symbolic input and output; to
  2751 be used in conjunction with the Isabelle symbol font; uses the
  2752 "symbols" syntax table;
  2753 
  2754 * added token_translation interface (may translate name tokens in
  2755 arbitrary ways, dependent on their type (free, bound, tfree, ...) and
  2756 the current print_mode); IMPORTANT: user print translation functions
  2757 are responsible for marking newly introduced bounds
  2758 (Syntax.mark_boundT);
  2759 
  2760 * token translations for modes "xterm" and "xterm_color" that display
  2761 names in bold, underline etc. or colors (which requires a color
  2762 version of xterm);
  2763 
  2764 * infixes may now be declared with names independent of their syntax;
  2765 
  2766 * added typed_print_translation (like print_translation, but may
  2767 access type of constant);
  2768 
  2769 
  2770 *** Classical Reasoner ***
  2771 
  2772 Blast_tac: a new tactic!  It is often more powerful than fast_tac, but has
  2773 some limitations.  Blast_tac...
  2774   + ignores addss, addbefore, addafter; this restriction is intrinsic
  2775   + ignores elimination rules that don't have the correct format
  2776         (the conclusion MUST be a formula variable)
  2777   + ignores types, which can make HOL proofs fail
  2778   + rules must not require higher-order unification, e.g. apply_type in ZF
  2779     [message "Function Var's argument not a bound variable" relates to this]
  2780   + its proof strategy is more general but can actually be slower
  2781 
  2782 * substitution with equality assumptions no longer permutes other
  2783 assumptions;
  2784 
  2785 * minor changes in semantics of addafter (now called addaltern); renamed
  2786 setwrapper to setWrapper and compwrapper to compWrapper; added safe wrapper
  2787 (and access functions for it);
  2788 
  2789 * improved combination of classical reasoner and simplifier:
  2790   + functions for handling clasimpsets
  2791   + improvement of addss: now the simplifier is called _after_ the
  2792     safe steps.
  2793   + safe variant of addss called addSss: uses safe simplifications
  2794     _during_ the safe steps. It is more complete as it allows multiple
  2795     instantiations of unknowns (e.g. with slow_tac).
  2796 
  2797 *** Simplifier ***
  2798 
  2799 * added interface for simplification procedures (functions that
  2800 produce *proven* rewrite rules on the fly, depending on current
  2801 redex);
  2802 
  2803 * ordering on terms as parameter (used for ordered rewriting);
  2804 
  2805 * new functions delcongs, deleqcongs, and Delcongs. richer rep_ss;
  2806 
  2807 * the solver is now split into a safe and an unsafe part.
  2808 This should be invisible for the normal user, except that the
  2809 functions setsolver and addsolver have been renamed to setSolver and
  2810 addSolver; added safe_asm_full_simp_tac;
  2811 
  2812 
  2813 *** HOL ***
  2814 
  2815 * a generic induction tactic `induct_tac' which works for all datatypes and
  2816 also for type `nat';
  2817 
  2818 * a generic case distinction tactic `exhaust_tac' which works for all
  2819 datatypes and also for type `nat';
  2820 
  2821 * each datatype comes with a function `size';
  2822 
  2823 * patterns in case expressions allow tuple patterns as arguments to
  2824 constructors, for example `case x of [] => ... | (x,y,z)#ps => ...';
  2825 
  2826 * primrec now also works with type nat;
  2827 
  2828 * recdef: a new declaration form, allows general recursive functions to be
  2829 defined in theory files.  See HOL/ex/Fib, HOL/ex/Primes, HOL/Subst/Unify.
  2830 
  2831 * the constant for negation has been renamed from "not" to "Not" to
  2832 harmonize with FOL, ZF, LK, etc.;
  2833 
  2834 * HOL/ex/LFilter theory of a corecursive "filter" functional for
  2835 infinite lists;
  2836 
  2837 * HOL/Modelcheck demonstrates invocation of model checker oracle;
  2838 
  2839 * HOL/ex/Ring.thy declares cring_simp, which solves equational
  2840 problems in commutative rings, using axiomatic type classes for + and *;
  2841 
  2842 * more examples in HOL/MiniML and HOL/Auth;
  2843 
  2844 * more default rewrite rules for quantifiers, union/intersection;
  2845 
  2846 * a new constant `arbitrary == @x.False';
  2847 
  2848 * HOLCF/IOA replaces old HOL/IOA;
  2849 
  2850 * HOLCF changes: derived all rules and arities
  2851   + axiomatic type classes instead of classes
  2852   + typedef instead of faking type definitions
  2853   + eliminated the internal constants less_fun, less_cfun, UU_fun, UU_cfun etc.
  2854   + new axclasses cpo, chfin, flat with flat < chfin < pcpo < cpo < po
  2855   + eliminated the types void, one, tr
  2856   + use unit lift and bool lift (with translations) instead of one and tr
  2857   + eliminated blift from Lift3.thy (use Def instead of blift)
  2858   all eliminated rules are derived as theorems --> no visible changes ;
  2859 
  2860 
  2861 *** ZF ***
  2862 
  2863 * ZF now has Fast_tac, Simp_tac and Auto_tac.  Union_iff is a now a default
  2864 rewrite rule; this may affect some proofs.  eq_cs is gone but can be put back
  2865 as ZF_cs addSIs [equalityI];
  2866 
  2867 
  2868 
  2869 New in Isabelle94-7 (November 96)
  2870 ---------------------------------
  2871 
  2872 * allowing negative levels (as offsets) in prlev and choplev;
  2873 
  2874 * super-linear speedup for large simplifications;
  2875 
  2876 * FOL, ZF and HOL now use miniscoping: rewriting pushes
  2877 quantifications in as far as possible (COULD MAKE EXISTING PROOFS
  2878 FAIL); can suppress it using the command Delsimps (ex_simps @
  2879 all_simps); De Morgan laws are also now included, by default;
  2880 
  2881 * improved printing of ==>  :  ~:
  2882 
  2883 * new object-logic "Sequents" adds linear logic, while replacing LK
  2884 and Modal (thanks to Sara Kalvala);
  2885 
  2886 * HOL/Auth: correctness proofs for authentication protocols;
  2887 
  2888 * HOL: new auto_tac combines rewriting and classical reasoning (many
  2889 examples on HOL/Auth);
  2890 
  2891 * HOL: new command AddIffs for declaring theorems of the form P=Q to
  2892 the rewriter and classical reasoner simultaneously;
  2893 
  2894 * function uresult no longer returns theorems in "standard" format;
  2895 regain previous version by: val uresult = standard o uresult;
  2896 
  2897 
  2898 
  2899 New in Isabelle94-6
  2900 -------------------
  2901 
  2902 * oracles -- these establish an interface between Isabelle and trusted
  2903 external reasoners, which may deliver results as theorems;
  2904 
  2905 * proof objects (in particular record all uses of oracles);
  2906 
  2907 * Simp_tac, Fast_tac, etc. that refer to implicit simpset / claset;
  2908 
  2909 * "constdefs" section in theory files;
  2910 
  2911 * "primrec" section (HOL) no longer requires names;
  2912 
  2913 * internal type "tactic" now simply "thm -> thm Sequence.seq";
  2914 
  2915 
  2916 
  2917 New in Isabelle94-5
  2918 -------------------
  2919 
  2920 * reduced space requirements;
  2921 
  2922 * automatic HTML generation from theories;
  2923 
  2924 * theory files no longer require "..." (quotes) around most types;
  2925 
  2926 * new examples, including two proofs of the Church-Rosser theorem;
  2927 
  2928 * non-curried (1994) version of HOL is no longer distributed;
  2929 
  2930 
  2931 
  2932 New in Isabelle94-4
  2933 -------------------
  2934 
  2935 * greatly reduced space requirements;
  2936 
  2937 * theory files (.thy) no longer require \...\ escapes at line breaks;
  2938 
  2939 * searchable theorem database (see the section "Retrieving theorems" on
  2940 page 8 of the Reference Manual);
  2941 
  2942 * new examples, including Grabczewski's monumental case study of the
  2943 Axiom of Choice;
  2944 
  2945 * The previous version of HOL renamed to Old_HOL;
  2946 
  2947 * The new version of HOL (previously called CHOL) uses a curried syntax
  2948 for functions.  Application looks like f a b instead of f(a,b);
  2949 
  2950 * Mutually recursive inductive definitions finally work in HOL;
  2951 
  2952 * In ZF, pattern-matching on tuples is now available in all abstractions and
  2953 translates to the operator "split";
  2954 
  2955 
  2956 
  2957 New in Isabelle94-3
  2958 -------------------
  2959 
  2960 * new infix operator, addss, allowing the classical reasoner to
  2961 perform simplification at each step of its search.  Example:
  2962         fast_tac (cs addss ss)
  2963 
  2964 * a new logic, CHOL, the same as HOL, but with a curried syntax
  2965 for functions.  Application looks like f a b instead of f(a,b).  Also pairs
  2966 look like (a,b) instead of <a,b>;
  2967 
  2968 * PLEASE NOTE: CHOL will eventually replace HOL!
  2969 
  2970 * In CHOL, pattern-matching on tuples is now available in all abstractions.
  2971 It translates to the operator "split".  A new theory of integers is available;
  2972 
  2973 * In ZF, integer numerals now denote two's-complement binary integers.
  2974 Arithmetic operations can be performed by rewriting.  See ZF/ex/Bin.ML;
  2975 
  2976 * Many new examples: I/O automata, Church-Rosser theorem, equivalents
  2977 of the Axiom of Choice;
  2978 
  2979 
  2980 
  2981 New in Isabelle94-2
  2982 -------------------
  2983 
  2984 * Significantly faster resolution;
  2985 
  2986 * the different sections in a .thy file can now be mixed and repeated
  2987 freely;
  2988 
  2989 * Database of theorems for FOL, HOL and ZF.  New
  2990 commands including qed, qed_goal and bind_thm store theorems in the database.
  2991 
  2992 * Simple database queries: return a named theorem (get_thm) or all theorems of
  2993 a given theory (thms_of), or find out what theory a theorem was proved in
  2994 (theory_of_thm);
  2995 
  2996 * Bugs fixed in the inductive definition and datatype packages;
  2997 
  2998 * The classical reasoner provides deepen_tac and depth_tac, making FOL_dup_cs
  2999 and HOL_dup_cs obsolete;
  3000 
  3001 * Syntactic ambiguities caused by the new treatment of syntax in Isabelle94-1
  3002 have been removed;
  3003 
  3004 * Simpler definition of function space in ZF;
  3005 
  3006 * new results about cardinal and ordinal arithmetic in ZF;
  3007 
  3008 * 'subtype' facility in HOL for introducing new types as subsets of existing
  3009 types;
  3010 
  3011 
  3012 $Id$