NEWS
author ballarin
Wed Jun 01 12:30:49 2005 +0200 (2005-06-01)
changeset 16168 adb83939177f
parent 16151 cf7f146086bc
child 16181 22324687e2d2
permissions -rw-r--r--
Locales: new element constrains, parameter renaming with syntax,
experimental command instantiate withdrawn.
     1 Isabelle NEWS -- history user-relevant changes
     2 ==============================================
     3 
     4 New in this Isabelle release
     5 ----------------------------
     6 
     7 *** General ***
     8 
     9 * Theory headers: the new header syntax for Isar theories is
    10 
    11   theory <name>
    12   imports <theory1> ... <theoryn>
    13   begin
    14 
    15   optionally also with a "files" section. The syntax
    16 
    17   theory <name> = <theory1> + ... + <theoryn>:
    18 
    19   will still be supported for some time but will eventually disappear.
    20   The syntax of old-style theories has not changed.
    21 
    22 * Theory loader: parent theories can now also be referred to via
    23   relative and absolute paths.
    24 
    25 * Provers/quasi.ML: new transitivity reasoners for transitivity only
    26   and quasi orders.
    27 
    28 * Provers/trancl.ML: new transitivity reasoner for transitive and
    29   reflexive-transitive closure of relations.
    30 
    31 * Provers/blast.ML: new reference depth_limit to make blast's depth
    32   limit (previously hard-coded with a value of 20) user-definable.
    33 
    34 * Provers: new version of the subst method, for single-step rewriting: it now
    35   works in bound variable contexts. New is subst (asm), for rewriting an
    36   assumption. Thanks to Lucas Dixon! INCOMPATIBILITY: may rewrite a different
    37   subterm than the original subst method, which is still available under the
    38   name simplesubst.
    39 
    40 * Pure: thin_tac now works even if the assumption being deleted contains !! or ==>. 
    41   More generally, erule now works even if the major premise of the elimination rule
    42   contains !! or ==>.
    43 
    44 * Pure: considerably improved version of 'constdefs' command.  Now
    45   performs automatic type-inference of declared constants; additional
    46   support for local structure declarations (cf. locales and HOL
    47   records), see also isar-ref manual.  Potential INCOMPATIBILITY: need
    48   to observe strictly sequential dependencies of definitions within a
    49   single 'constdefs' section; moreover, the declared name needs to be
    50   an identifier.  If all fails, consider to fall back on 'consts' and
    51   'defs' separately.
    52 
    53 * Pure: improved indexed syntax and implicit structures.  First of
    54   all, indexed syntax provides a notational device for subscripted
    55   application, using the new syntax \<^bsub>term\<^esub> for arbitrary
    56   expressions.  Secondly, in a local context with structure
    57   declarations, number indexes \<^sub>n or the empty index (default
    58   number 1) refer to a certain fixed variable implicitly; option
    59   show_structs controls printing of implicit structures.  Typical
    60   applications of these concepts involve record types and locales.
    61 
    62 * Pure: clear separation of logical types and nonterminals, where the
    63   latter may only occur in 'syntax' specifications or type
    64   abbreviations.  Before that distinction was only partially
    65   implemented via type class "logic" vs. "{}".  Potential
    66   INCOMPATIBILITY in rare cases of improper use of 'types'/'consts'
    67   instead of 'nonterminals'/'syntax'.  Some very exotic syntax
    68   specifications may require further adaption (e.g. Cube/Base.thy).
    69 
    70 * Pure: removed obsolete type class "logic", use the top sort {}
    71   instead.  Note that non-logical types should be declared as
    72   'nonterminals' rather than 'types'.  INCOMPATIBILITY for new
    73   object-logic specifications.
    74 
    75 * Pure: command 'no_syntax' removes grammar declarations (and
    76   translations) resulting from the given syntax specification, which
    77   is interpreted in the same manner as for the 'syntax' command.
    78 
    79 * Pure: print_tac now outputs the goal through the trace channel.
    80 
    81 * Pure: reference NameSpace.unique_names included.  If true the
    82   (shortest) namespace-prefix is printed to disambiguate conflicts (as
    83   yet). If false the first entry wins (as during parsing). Default
    84   value is true.
    85 
    86 * Pure: tuned internal renaming of symbolic identifiers -- attach
    87   primes instead of base 26 numbers.
    88 
    89 * Pure: new flag show_question_marks controls printing of leading
    90   question marks in schematic variable names.
    91 
    92 * Pure: new version of thms_containing that searches for a list of
    93   criteria instead of a list of constants. Known criteria are: intro,
    94   elim, dest, name:string, simp:term, and any term. Criteria can be 
    95   preceded by '-' to select theorems that do not match. Intro, elim, 
    96   dest select theorems that match the current goal, name:s selects
    97   theorems whose fully qualified name contain s, and simp:term selects
    98   all simplification rules whose lhs match term.  Any other term is 
    99   interpreted as pattern and selects all theorems matching the
   100   pattern. Available in ProofGeneral under 'ProofGeneral -> Find
   101   Theorems' or C-c C-f.
   102 
   103   Example: C-c C-f (100) "(_::nat) + _ + _" intro -name:"HOL."
   104 
   105   prints the last 100 theorems matching the pattern "(_::nat) + _ + _",
   106   matching the current goal as introduction rule and not having "HOL." 
   107   in their name (i.e. not being defined in theory HOL).
   108 
   109 * Pure/Syntax: In schematic variable names, *any* symbol following
   110   \<^isub> or \<^isup> is now treated as part of the base name.  For
   111   example, the following works without printing of ugly ".0" indexes:
   112 
   113     lemma "x\<^isub>1 = x\<^isub>2 ==> x\<^isub>2 = x\<^isub>1"
   114       by simp
   115 
   116 * Pure/Syntax: inner syntax includes (*(*nested*) comments*).
   117 
   118 * Pure/Syntax: pretty pinter now supports unbreakable blocks,
   119   specified in mixfix annotations as "(00...)".
   120 
   121 * Pure/Syntax: 'advanced' translation functions (parse_translation
   122   etc.) may depend on the signature of the theory context being
   123   presently used for parsing/printing, see also isar-ref manual.
   124 
   125 * Pure/Simplifier: you can control the depth to which conditional rewriting
   126   is traced via the PG menu Isabelle -> Settings -> Trace Simp Depth Limit.
   127 
   128 * Pure/Simplifier: simplification procedures may now take the current
   129   simpset into account (cf. Simplifier.simproc(_i) / mk_simproc
   130   interface), which is very useful for calling the Simplifier
   131   recursively.  Minor INCOMPATIBILITY: the 'prems' argument of
   132   simprocs is gone -- use prems_of_ss on the simpset instead.
   133   Moreover, the low-level mk_simproc no longer applies Logic.varify
   134   internally, to allow for use in a context of fixed variables.
   135 
   136 * Isar debugging: new reference Toplevel.debug; default false.  Set to
   137   make printing of exceptions THM, TERM, TYPE and THEORY more verbose.
   138   
   139 * Locales: modifications regarding "includes"
   140   - "includes" disallowed in declaration of named locales (command "locale").
   141   - Fixed parameter management in theorem generation for goals with "includes".
   142     INCOMPATIBILITY: rarely, the generated theorem statement is different.
   143 
   144 * Locales: new context element "constrains" for adding type constraints
   145   to parameters.
   146 
   147 * Locales: context expressions permit optional syntax redeclaration when
   148   renaming parameters.
   149 
   150 * Locales: new commands for the interpretation of locale expressions
   151   in theories (interpretation) and proof contexts (interpret).  These take an
   152   instantiation of the locale parameters and compute proof obligations from
   153   the instantiated specification.  After the obligations have been discharged,
   154   the instantiated theorems of the locale are added to the theory or proof
   155   context.  Interpretation is smart in that already active interpretations
   156   do not occur in proof obligations, neither are instantiated theorems stored
   157   in duplicate.
   158   Use print_interps to inspect active interpretations of a particular locale.
   159   For details, see the Isar Reference manual.
   160 
   161 * Locales: INCOMPATIBILITY: experimental command "instantiate" has
   162   been withdrawn.  Use "interpret" instead.
   163 
   164 * Locales: proper static binding of attribute syntax -- i.e. types /
   165   terms / facts mentioned as arguments are always those of the locale
   166   definition context, independently of the context of later
   167   invocations.  Moreover, locale operations (renaming and type / term
   168   instantiation) are applied to attribute arguments as expected.
   169 
   170   INCOMPATIBILITY of the ML interface: always pass Attrib.src instead
   171   of actual attributes; rare situations may require Attrib.attribute
   172   to embed those attributes into Attrib.src that lack concrete syntax.
   173 
   174   Attribute implementations need to cooperate properly with the static
   175   binding mechanism.  Basic parsers Args.XXX_typ/term/prop and
   176   Attrib.XXX_thm etc. already do the right thing without further
   177   intervention.  Only unusual applications -- such as "where" or "of"
   178   (cf. src/Pure/Isar/attrib.ML), which process arguments depending
   179   both on the context and the facts involved -- may have to assign
   180   parsed values to argument tokens explicitly.
   181 
   182 * Attributes 'induct' and 'cases': type or set names may now be
   183   locally fixed variables as well.
   184 
   185 * Isar: new syntax 'name(i-j, i-, i, ...)' for referring to specific
   186   selections of theorems in named facts via indices.
   187 
   188 * Pure: reorganized bootstrapping of the Pure theories; CPure is now
   189   derived from Pure, which contains all common declarations already.
   190   Both theories are defined via plain Isabelle/Isar .thy files.
   191   INCOMPATIBILITY: elements of CPure (such as the CPure.intro /
   192   CPure.elim / CPure.dest attributes) now appear in the Pure name
   193   space; use isatool fixcpure to adapt your theory and ML sources.
   194 
   195 * Provers/simplifier.ML has been moved to Pure, where Simplifier.setup
   196   is peformed already.  Object-logics merely need to finish their
   197   initial simpset configuration as before.
   198 
   199 
   200 *** Document preparation ***
   201 
   202 * Several new antiquotation:
   203 
   204   @{term_type term} prints a term with its type annotated;
   205 
   206   @{typeof term} prints the type of a term;
   207 
   208   @{const const} is the same as @{term const}, but checks
   209     that the argument is a known logical constant;
   210 
   211   @{term_style style term} and @{thm_style style thm} print a term or
   212     theorem applying a "style" to it
   213 
   214   Predefined styles are "lhs" and "rhs" printing the lhs/rhs of
   215   definitions, equations, inequations etc. and "conclusion" printing
   216   only the conclusion of a meta-logical statement theorem.  Styles may
   217   be defined via TermStyle.add_style in ML.  See the "LaTeX Sugar"
   218   document for more information.
   219 
   220 * Antiquotations now provide the option 'locale=NAME' to specify an
   221   alternative context used for evaluating and printing the subsequent
   222   argument, as in @{thm [locale=LC] fold_commute}, for example.
   223 
   224 * Commands 'display_drafts' and 'print_drafts' perform simple output
   225   of raw sources.  Only those symbols that do not require additional
   226   LaTeX packages (depending on comments in isabellesym.sty) are
   227   displayed properly, everything else is left verbatim.  We use
   228   isatool display and isatool print as front ends; these are subject
   229   to the DVI/PDF_VIEWER and PRINT_COMMAND settings, respectively.
   230 
   231 * Proof scripts as well as some other commands such as ML or
   232   parse/print_translation can now be hidden in the document.  Hiding
   233   is enabled by default, and can be disabled either via the option '-H
   234   false' of isatool usedir or by resetting the reference variable
   235   IsarOutput.hide_commands. Additional commands to be hidden may be
   236   declared using IsarOutput.add_hidden_commands.
   237 
   238 
   239 *** HOL ***
   240 
   241 * Datatype induction via method `induct' now preserves the name of the
   242   induction variable. For example, when proving P(xs::'a list) by induction
   243   on xs, the induction step is now P(xs) ==> P(a#xs) rather than
   244   P(list) ==> P(a#list) as previously.
   245 
   246 * HOL/record: reimplementation of records. Improved scalability for
   247   records with many fields, avoiding performance problems for type
   248   inference. Records are no longer composed of nested field types, but
   249   of nested extension types. Therefore the record type only grows
   250   linear in the number of extensions and not in the number of fields.
   251   The top-level (users) view on records is preserved.  Potential
   252   INCOMPATIBILITY only in strange cases, where the theory depends on
   253   the old record representation. The type generated for a record is
   254   called <record_name>_ext_type.
   255 
   256 * HOL/record: Reference record_quick_and_dirty_sensitive can be
   257   enabled to skip the proofs triggered by a record definition or a
   258   simproc (if quick_and_dirty is enabled). Definitions of large
   259   records can take quite long.
   260 
   261 * HOL/record: "record_upd_simproc" for simplification of multiple
   262   record updates enabled by default.  Moreover, trivial updates are
   263   also removed: r(|x := x r|) = r.  INCOMPATIBILITY: old proofs break
   264   occasionally, since simplification is more powerful by default.
   265 
   266 * HOL: symbolic syntax of Hilbert Choice Operator is now as follows:
   267 
   268   syntax (epsilon)
   269     "_Eps" :: "[pttrn, bool] => 'a"    ("(3\<some>_./ _)" [0, 10] 10)
   270 
   271   The symbol \<some> is displayed as the alternative epsilon of LaTeX
   272   and x-symbol; use option '-m epsilon' to get it actually printed.
   273   Moreover, the mathematically important symbolic identifier
   274   \<epsilon> becomes available as variable, constant etc.
   275 
   276 * HOL: "x > y" abbreviates "y < x" and "x >= y" abbreviates "y <= x".
   277   Similarly for all quantifiers: "ALL x > y" etc.  The x-symbol for >=
   278   is \<ge>.
   279 
   280 * HOL/Set: "{x:A. P}" abbreviates "{x. x:A & P}" (and similarly for
   281   "\<in>" instead of ":").
   282 
   283 * HOL/SetInterval: The syntax for open intervals has changed:
   284 
   285   Old         New
   286   {..n(}   -> {..<n}
   287   {)n..}   -> {n<..}
   288   {m..n(}  -> {m..<n}
   289   {)m..n}  -> {m<..n}
   290   {)m..n(} -> {m<..<n}
   291 
   292   The old syntax is still supported but will disappear in the future.
   293   For conversion use the following emacs search and replace patterns:
   294 
   295   {)\([^\.]*\)\.\.  ->  {\1<\.\.}
   296   \.\.\([^(}]*\)(}  ->  \.\.<\1}
   297 
   298   They are not perfect but work quite well.
   299 
   300 * HOL: The syntax for 'setsum', summation over finite sets, has changed:
   301 
   302   The syntax for 'setsum (%x. e) A' used to be '\<Sum>x:A. e'
   303   and is now either 'SUM x:A. e' or '\<Sum>x\<in>A. e'.
   304 
   305   There is new syntax for summation over finite sets:
   306 
   307   '\<Sum>x | P. e'    is the same as  'setsum (%x. e) {x. P}'
   308   '\<Sum>x=a..b. e'   is the same as  'setsum (%x. e) {a..b}'
   309   '\<Sum>x=a..<b. e'  is the same as  'setsum (%x. e) {a..<b}'
   310   '\<Sum>x<k. e'      is the same as  'setsum (%x. e) {..<k}'
   311 
   312   Function 'Summation' over nat is gone, its syntax '\<Sum>i<k. e'
   313   now translates into 'setsum' as above.
   314 
   315 * HOL: Finite set induction: In Isar proofs, the insert case is now
   316   "case (insert x F)" instead of the old counterintuitive "case (insert F x)".
   317 
   318 * HOL/Simplifier:
   319 
   320   - Is now set up to reason about transitivity chains involving "trancl"
   321   (r^+) and "rtrancl" (r^*) by setting up tactics provided by
   322   Provers/trancl.ML as additional solvers.  INCOMPATIBILITY: old proofs break
   323   occasionally as simplification may now solve more goals than previously.
   324 
   325   - Converts x <= y into x = y if assumption y <= x is present.  Works for
   326   all partial orders (class "order"), in particular numbers and sets. For
   327   linear orders (e.g. numbers) it treats ~ x < y just like y <= x.
   328 
   329   - Simproc for "let x = a in f x"
   330   If a is a free or bound variable or a constant then the let is unfolded.
   331   Otherwise first a is simplified to a', and then f a' is simplified to
   332   g. If possible we abstract a' from g arriving at "let x = a' in g' x",
   333   otherwise we unfold the let and arrive at g. The simproc can be 
   334   enabled/disabled by the reference use_let_simproc. Potential
   335   INCOMPATIBILITY since simplification is more powerful by default.
   336 
   337 * HOL: The 'refute' command has been extended to support a much larger
   338   fragment of HOL, including axiomatic type classes, constdefs and typedefs,
   339   inductive datatypes and recursion.
   340 
   341 
   342 *** HOLCF ***
   343 
   344 * HOLCF: discontinued special version of 'constdefs' (which used to
   345   support continuous functions) in favor of the general Pure one with
   346   full type-inference.
   347 
   348 
   349 *** ZF ***
   350 
   351 * ZF/ex/{Group,Ring}: examples in abstract algebra, including the
   352   First Isomorphism Theorem (on quotienting by the kernel of a
   353   homomorphism).
   354 
   355 * ZF/Simplifier: install second copy of type solver that actually
   356   makes use of TC rules declared to Isar proof contexts (or locales);
   357   the old version is still required for ML proof scripts.
   358 
   359 
   360 *** System ***
   361 
   362 * Allow symlinks to all proper Isabelle executables (Isabelle,
   363   isabelle, isatool etc.).
   364 
   365 * isabelle-process: Poly/ML no longer needs Perl to run an interactive
   366   session.
   367 
   368 * ISABELLE_DOC_FORMAT setting specifies preferred document format (for
   369   isatool doc, isatool mkdir, display_drafts etc.).
   370 
   371 * isatool usedir: option -f allows specification of the ML file to be
   372   used by Isabelle; default is ROOT.ML.
   373 
   374 * HOL: isatool dimacs2hol converts files in DIMACS CNF format
   375   (containing Boolean satisfiability problems) into Isabelle/HOL
   376   theories.
   377 
   378 
   379 *** ML ***
   380 
   381 * Pure/library.ML no longer defines its own option datatype, but uses
   382   that of the SML basis, which has constructors NONE and SOME instead
   383   of None and Some, as well as exception Option.Option instead of
   384   OPTION.  The functions the, if_none, is_some, is_none have been
   385   adapted accordingly, while Option.map replaces apsome.
   386 
   387 * The exception LIST has been given up in favour of the standard
   388   exceptions Empty and Subscript, as well as Library.UnequalLengths.
   389   Function like Library.hd and Library.tl are superceded by the
   390   standard hd and tl functions etc.
   391 
   392   A number of basic functions are now no longer exported to the ML
   393   toplevel, as they are variants of standard functions.  The following
   394   suggests how one can translate existing code:
   395 
   396     rev_append xs ys = List.revAppend (xs, ys)
   397     nth_elem (i, xs) = List.nth (xs, i)
   398     last_elem xs = List.last xs
   399     flat xss = List.concat xss
   400     seq fs = app fs
   401     partition P xs = List.partition P xs
   402     filter P xs = List.filter P xs
   403     mapfilter f xs = List.mapPartial f xs
   404 
   405 * Pure: output via the Isabelle channels of writeln/warning/error
   406   etc. is now passed through Output.output, with a hook for arbitrary
   407   transformations depending on the print_mode (cf. Output.add_mode --
   408   the first active mode that provides a output function wins).
   409   Already formatted output may be embedded into further text via
   410   Output.raw; the result of Pretty.string_of/str_of and derived
   411   functions (string_of_term/cterm/thm etc.) is already marked raw to
   412   accommodate easy composition of diagnostic messages etc.
   413   Programmers rarely need to care about Output.output or Output.raw at
   414   all, with some notable exceptions: Output.output is required when
   415   bypassing the standard channels (writeln etc.), or in token
   416   translations to produce properly formatted results; Output.raw is
   417   required when capturing already output material that will eventually
   418   be presented to the user a second time.  For the default print mode,
   419   both Output.output and Output.raw have no effect.
   420 
   421 * Pure: name spaces have been refined, with significant changes of the
   422   internal interfaces -- INCOMPATIBILITY.  Renamed cond_extern(_table)
   423   to extern(_table).  The plain name entry path is superceded by a
   424   general 'naming' context, which also includes the 'policy' to
   425   produce a fully qualified name and external accesses of a fully
   426   qualified name; NameSpace.extend is superceded by context dependent
   427   Sign.declare_name.  Several theory and proof context operations
   428   modify the naming context; especially note Theory.restore_naming and
   429   ProofContext.restore_naming.
   430 
   431 * Pure: cases produced by proof methods specify options, where NONE
   432   means to remove case bindings -- INCOMPATIBILITY in
   433   (RAW_)METHOD_CASES.
   434 
   435 * Provers: Simplifier and Classical Reasoner now support proof context
   436   dependent plug-ins (simprocs, solvers, wrappers etc.).  These extra
   437   components are stored in the theory and patched into the
   438   simpset/claset when used in an Isar proof context.  Context
   439   dependent components are maintained by the following theory
   440   operations:
   441 
   442     Simplifier.add_context_simprocs
   443     Simplifier.del_context_simprocs
   444     Simplifier.set_context_subgoaler
   445     Simplifier.reset_context_subgoaler
   446     Simplifier.add_context_looper
   447     Simplifier.del_context_looper
   448     Simplifier.add_context_unsafe_solver
   449     Simplifier.add_context_safe_solver
   450 
   451     Classical.add_context_safe_wrapper
   452     Classical.del_context_safe_wrapper
   453     Classical.add_context_unsafe_wrapper
   454     Classical.del_context_unsafe_wrapper
   455 
   456   IMPORTANT NOTE: proof tools (methods etc.) need to use
   457   local_simpset_of and local_claset_of to instead of the primitive
   458   Simplifier.get_local_simpset and Classical.get_local_claset,
   459   respectively, in order to see the context dependent fields!
   460 
   461 
   462 
   463 New in Isabelle2004 (April 2004)
   464 --------------------------------
   465 
   466 *** General ***
   467 
   468 * Provers/order.ML:  new efficient reasoner for partial and linear orders.
   469   Replaces linorder.ML.
   470 
   471 * Pure: Greek letters (except small lambda, \<lambda>), as well as Gothic
   472   (\<aa>...\<zz>\<AA>...\<ZZ>), calligraphic (\<A>...\<Z>), and Euler
   473   (\<a>...\<z>), are now considered normal letters, and can therefore
   474   be used anywhere where an ASCII letter (a...zA...Z) has until
   475   now. COMPATIBILITY: This obviously changes the parsing of some
   476   terms, especially where a symbol has been used as a binder, say
   477   '\<Pi>x. ...', which is now a type error since \<Pi>x will be parsed
   478   as an identifier.  Fix it by inserting a space around former
   479   symbols.  Call 'isatool fixgreek' to try to fix parsing errors in
   480   existing theory and ML files.
   481 
   482 * Pure: Macintosh and Windows line-breaks are now allowed in theory files.
   483 
   484 * Pure: single letter sub/superscripts (\<^isub> and \<^isup>) are now
   485   allowed in identifiers. Similar to Greek letters \<^isub> is now considered
   486   a normal (but invisible) letter. For multiple letter subscripts repeat
   487   \<^isub> like this: x\<^isub>1\<^isub>2.
   488 
   489 * Pure: There are now sub-/superscripts that can span more than one
   490   character. Text between \<^bsub> and \<^esub> is set in subscript in
   491   ProofGeneral and LaTeX, text between \<^bsup> and \<^esup> in
   492   superscript. The new control characters are not identifier parts.
   493 
   494 * Pure: Control-symbols of the form \<^raw:...> will literally print the
   495   content of "..." to the latex file instead of \isacntrl... . The "..."
   496   may consist of any printable characters excluding the end bracket >.
   497 
   498 * Pure: Using new Isar command "finalconsts" (or the ML functions
   499   Theory.add_finals or Theory.add_finals_i) it is now possible to
   500   declare constants "final", which prevents their being given a definition
   501   later.  It is useful for constants whose behaviour is fixed axiomatically
   502   rather than definitionally, such as the meta-logic connectives.
   503 
   504 * Pure: 'instance' now handles general arities with general sorts
   505   (i.e. intersections of classes),
   506 
   507 * Presentation: generated HTML now uses a CSS style sheet to make layout
   508   (somewhat) independent of content. It is copied from lib/html/isabelle.css.
   509   It can be changed to alter the colors/layout of generated pages.
   510 
   511 
   512 *** Isar ***
   513 
   514 * Tactic emulation methods rule_tac, erule_tac, drule_tac, frule_tac,
   515   cut_tac, subgoal_tac and thin_tac:
   516   - Now understand static (Isar) contexts.  As a consequence, users of Isar
   517     locales are no longer forced to write Isar proof scripts.
   518     For details see Isar Reference Manual, paragraph 4.3.2: Further tactic
   519     emulations.
   520   - INCOMPATIBILITY: names of variables to be instantiated may no
   521     longer be enclosed in quotes.  Instead, precede variable name with `?'.
   522     This is consistent with the instantiation attribute "where".
   523 
   524 * Attributes "where" and "of":
   525   - Now take type variables of instantiated theorem into account when reading
   526     the instantiation string.  This fixes a bug that caused instantiated
   527     theorems to have too special types in some circumstances.
   528   - "where" permits explicit instantiations of type variables.
   529 
   530 * Calculation commands "moreover" and "also" no longer interfere with
   531   current facts ("this"), admitting arbitrary combinations with "then"
   532   and derived forms.
   533 
   534 * Locales:
   535   - Goal statements involving the context element "includes" no longer
   536     generate theorems with internal delta predicates (those ending on
   537     "_axioms") in the premise.
   538     Resolve particular premise with <locale>.intro to obtain old form.
   539   - Fixed bug in type inference ("unify_frozen") that prevented mix of target
   540     specification and "includes" elements in goal statement.
   541   - Rule sets <locale>.intro and <locale>.axioms no longer declared as
   542     [intro?] and [elim?] (respectively) by default.
   543   - Experimental command for instantiation of locales in proof contexts:
   544         instantiate <label>[<attrs>]: <loc>
   545     Instantiates locale <loc> and adds all its theorems to the current context
   546     taking into account their attributes.  Label and attrs are optional
   547     modifiers, like in theorem declarations.  If present, names of
   548     instantiated theorems are qualified with <label>, and the attributes
   549     <attrs> are applied after any attributes these theorems might have already.
   550       If the locale has assumptions, a chained fact of the form
   551     "<loc> t1 ... tn" is expected from which instantiations of the parameters
   552     are derived.  The command does not support old-style locales declared
   553     with "locale (open)".
   554       A few (very simple) examples can be found in FOL/ex/LocaleInst.thy.
   555 
   556 * HOL: Tactic emulation methods induct_tac and case_tac understand static
   557   (Isar) contexts.
   558 
   559 
   560 *** HOL ***
   561 
   562 * Proof import: new image HOL4 contains the imported library from
   563   the HOL4 system with about 2500 theorems. It is imported by
   564   replaying proof terms produced by HOL4 in Isabelle. The HOL4 image
   565   can be used like any other Isabelle image.  See
   566   HOL/Import/HOL/README for more information.
   567 
   568 * Simplifier:
   569   - Much improved handling of linear and partial orders.
   570     Reasoners for linear and partial orders are set up for type classes
   571     "linorder" and "order" respectively, and are added to the default simpset
   572     as solvers.  This means that the simplifier can build transitivity chains
   573     to solve goals from the assumptions.
   574   - INCOMPATIBILITY: old proofs break occasionally.  Typically, applications
   575     of blast or auto after simplification become unnecessary because the goal
   576     is solved by simplification already.
   577 
   578 * Numerics: new theory Ring_and_Field contains over 250 basic numerical laws,
   579     all proved in axiomatic type classes for semirings, rings and fields.
   580 
   581 * Numerics:
   582   - Numeric types (nat, int, and in HOL-Complex rat, real, complex, etc.) are
   583     now formalized using the Ring_and_Field theory mentioned above.
   584   - INCOMPATIBILITY: simplification and arithmetic behaves somewhat differently
   585     than before, because now they are set up once in a generic manner.
   586   - INCOMPATIBILITY: many type-specific arithmetic laws have gone.
   587     Look for the general versions in Ring_and_Field (and Power if they concern
   588     exponentiation).
   589 
   590 * Type "rat" of the rational numbers is now available in HOL-Complex.
   591 
   592 * Records:
   593   - Record types are now by default printed with their type abbreviation
   594     instead of the list of all field types. This can be configured via
   595     the reference "print_record_type_abbr".
   596   - Simproc "record_upd_simproc" for simplification of multiple updates added
   597     (not enabled by default).
   598   - Simproc "record_ex_sel_eq_simproc" to simplify EX x. sel r = x resp.
   599     EX x. x = sel r to True (not enabled by default).
   600   - Tactic "record_split_simp_tac" to split and simplify records added.
   601 
   602 * 'specification' command added, allowing for definition by
   603   specification.  There is also an 'ax_specification' command that
   604   introduces the new constants axiomatically.
   605 
   606 * arith(_tac) is now able to generate counterexamples for reals as well.
   607 
   608 * HOL-Algebra: new locale "ring" for non-commutative rings.
   609 
   610 * HOL-ex: InductiveInvariant_examples illustrates advanced recursive function
   611   definitions, thanks to Sava Krsti\'{c} and John Matthews.
   612 
   613 * HOL-Matrix: a first theory for matrices in HOL with an application of
   614   matrix theory to linear programming.
   615 
   616 * Unions and Intersections:
   617   The latex output syntax of UN and INT has been changed
   618   from "\Union x \in A. B" to "\Union_{x \in A} B"
   619   i.e. the index formulae has become a subscript.
   620   Similarly for "\Union x. B", and for \Inter instead of \Union.
   621 
   622 * Unions and Intersections over Intervals:
   623   There is new short syntax "UN i<=n. A" for "UN i:{0..n}. A". There is
   624   also an x-symbol version with subscripts "\<Union>\<^bsub>i <= n\<^esub>. A"
   625   like in normal math, and corresponding versions for < and for intersection.
   626 
   627 * HOL/List: Ordering "lexico" is renamed "lenlex" and the standard
   628   lexicographic dictonary ordering has been added as "lexord".
   629 
   630 * ML: the legacy theory structures Int and List have been removed. They had
   631   conflicted with ML Basis Library structures having the same names.
   632 
   633 * 'refute' command added to search for (finite) countermodels.  Only works
   634   for a fragment of HOL.  The installation of an external SAT solver is
   635   highly recommended.  See "HOL/Refute.thy" for details.
   636 
   637 * 'quickcheck' command: Allows to find counterexamples by evaluating
   638   formulae under an assignment of free variables to random values.
   639   In contrast to 'refute', it can deal with inductive datatypes,
   640   but cannot handle quantifiers. See "HOL/ex/Quickcheck_Examples.thy"
   641   for examples.
   642 
   643 
   644 *** HOLCF ***
   645 
   646 * Streams now come with concatenation and are part of the HOLCF image
   647 
   648 
   649 
   650 New in Isabelle2003 (May 2003)
   651 ------------------------------
   652 
   653 *** General ***
   654 
   655 * Provers/simplifier:
   656 
   657   - Completely reimplemented method simp (ML: Asm_full_simp_tac):
   658     Assumptions are now subject to complete mutual simplification,
   659     not just from left to right. The simplifier now preserves
   660     the order of assumptions.
   661 
   662     Potential INCOMPATIBILITY:
   663 
   664     -- simp sometimes diverges where the old version did
   665        not, e.g. invoking simp on the goal
   666 
   667         [| P (f x); y = x; f x = f y |] ==> Q
   668 
   669        now gives rise to the infinite reduction sequence
   670 
   671         P(f x) --(f x = f y)--> P(f y) --(y = x)--> P(f x) --(f x = f y)--> ...
   672 
   673        Using "simp (asm_lr)" (ML: Asm_lr_simp_tac) instead often solves this
   674        kind of problem.
   675 
   676     -- Tactics combining classical reasoner and simplification (such as auto)
   677        are also affected by this change, because many of them rely on
   678        simp. They may sometimes diverge as well or yield a different numbers
   679        of subgoals. Try to use e.g. force, fastsimp, or safe instead of auto
   680        in case of problems. Sometimes subsequent calls to the classical
   681        reasoner will fail because a preceeding call to the simplifier too
   682        eagerly simplified the goal, e.g. deleted redundant premises.
   683 
   684   - The simplifier trace now shows the names of the applied rewrite rules
   685 
   686   - You can limit the number of recursive invocations of the simplifier
   687     during conditional rewriting (where the simplifie tries to solve the
   688     conditions before applying the rewrite rule):
   689     ML "simp_depth_limit := n"
   690     where n is an integer. Thus you can force termination where previously
   691     the simplifier would diverge.
   692 
   693   - Accepts free variables as head terms in congruence rules.  Useful in Isar.
   694 
   695   - No longer aborts on failed congruence proof.  Instead, the
   696     congruence is ignored.
   697 
   698 * Pure: New generic framework for extracting programs from constructive
   699   proofs. See HOL/Extraction.thy for an example instantiation, as well
   700   as HOL/Extraction for some case studies.
   701 
   702 * Pure: The main goal of the proof state is no longer shown by default, only
   703 the subgoals. This behaviour is controlled by a new flag.
   704    PG menu: Isabelle/Isar -> Settings -> Show Main Goal
   705 (ML: Proof.show_main_goal).
   706 
   707 * Pure: You can find all matching introduction rules for subgoal 1, i.e. all
   708 rules whose conclusion matches subgoal 1:
   709       PG menu: Isabelle/Isar -> Show me -> matching rules
   710 The rules are ordered by how closely they match the subgoal.
   711 In particular, rules that solve a subgoal outright are displayed first
   712 (or rather last, the way they are printed).
   713 (ML: ProofGeneral.print_intros())
   714 
   715 * Pure: New flag trace_unify_fail causes unification to print
   716 diagnostic information (PG: in trace buffer) when it fails. This is
   717 useful for figuring out why single step proofs like rule, erule or
   718 assumption failed.
   719 
   720 * Pure: Locale specifications now produce predicate definitions
   721 according to the body of text (covering assumptions modulo local
   722 definitions); predicate "loc_axioms" covers newly introduced text,
   723 while "loc" is cumulative wrt. all included locale expressions; the
   724 latter view is presented only on export into the global theory
   725 context; potential INCOMPATIBILITY, use "(open)" option to fall back
   726 on the old view without predicates;
   727 
   728 * Pure: predefined locales "var" and "struct" are useful for sharing
   729 parameters (as in CASL, for example); just specify something like
   730 ``var x + var y + struct M'' as import;
   731 
   732 * Pure: improved thms_containing: proper indexing of facts instead of
   733 raw theorems; check validity of results wrt. current name space;
   734 include local facts of proof configuration (also covers active
   735 locales), cover fixed variables in index; may use "_" in term
   736 specification; an optional limit for the number of printed facts may
   737 be given (the default is 40);
   738 
   739 * Pure: disallow duplicate fact bindings within new-style theory files
   740 (batch-mode only);
   741 
   742 * Provers: improved induct method: assumptions introduced by case
   743 "foo" are split into "foo.hyps" (from the rule) and "foo.prems" (from
   744 the goal statement); "foo" still refers to all facts collectively;
   745 
   746 * Provers: the function blast.overloaded has been removed: all constants
   747 are regarded as potentially overloaded, which improves robustness in exchange
   748 for slight decrease in efficiency;
   749 
   750 * Provers/linorder: New generic prover for transitivity reasoning over
   751 linear orders.  Note: this prover is not efficient!
   752 
   753 * Isar: preview of problems to finish 'show' now produce an error
   754 rather than just a warning (in interactive mode);
   755 
   756 
   757 *** HOL ***
   758 
   759 * arith(_tac)
   760 
   761  - Produces a counter example if it cannot prove a goal.
   762    Note that the counter example may be spurious if the goal is not a formula
   763    of quantifier-free linear arithmetic.
   764    In ProofGeneral the counter example appears in the trace buffer.
   765 
   766  - Knows about div k and mod k where k is a numeral of type nat or int.
   767 
   768  - Calls full Presburger arithmetic (by Amine Chaieb) if quantifier-free
   769    linear arithmetic fails. This takes account of quantifiers and divisibility.
   770    Presburger arithmetic can also be called explicitly via presburger(_tac).
   771 
   772 * simp's arithmetic capabilities have been enhanced a bit: it now
   773 takes ~= in premises into account (by performing a case split);
   774 
   775 * simp reduces "m*(n div m) + n mod m" to n, even if the two summands
   776 are distributed over a sum of terms;
   777 
   778 * New tactic "trans_tac" and method "trans" instantiate
   779 Provers/linorder.ML for axclasses "order" and "linorder" (predicates
   780 "<=", "<" and "=").
   781 
   782 * function INCOMPATIBILITIES: Pi-sets have been redefined and moved from main
   783 HOL to Library/FuncSet; constant "Fun.op o" is now called "Fun.comp";
   784 
   785 * 'typedef' command has new option "open" to suppress the set
   786 definition;
   787 
   788 * functions Min and Max on finite sets have been introduced (theory
   789 Finite_Set);
   790 
   791 * attribute [symmetric] now works for relations as well; it turns
   792 (x,y) : R^-1 into (y,x) : R, and vice versa;
   793 
   794 * induct over a !!-quantified statement (say !!x1..xn):
   795   each "case" automatically performs "fix x1 .. xn" with exactly those names.
   796 
   797 * Map: `empty' is no longer a constant but a syntactic abbreviation for
   798 %x. None. Warning: empty_def now refers to the previously hidden definition
   799 of the empty set.
   800 
   801 * Algebra: formalization of classical algebra.  Intended as base for
   802 any algebraic development in Isabelle.  Currently covers group theory
   803 (up to Sylow's theorem) and ring theory (Universal Property of
   804 Univariate Polynomials).  Contributions welcome;
   805 
   806 * GroupTheory: deleted, since its material has been moved to Algebra;
   807 
   808 * Complex: new directory of the complex numbers with numeric constants,
   809 nonstandard complex numbers, and some complex analysis, standard and
   810 nonstandard (Jacques Fleuriot);
   811 
   812 * HOL-Complex: new image for analysis, replacing HOL-Real and HOL-Hyperreal;
   813 
   814 * Hyperreal: introduced Gauge integration and hyperreal logarithms (Jacques
   815 Fleuriot);
   816 
   817 * Real/HahnBanach: updated and adapted to locales;
   818 
   819 * NumberTheory: added Gauss's law of quadratic reciprocity (by Avigad,
   820 Gray and Kramer);
   821 
   822 * UNITY: added the Meier-Sanders theory of progress sets;
   823 
   824 * MicroJava: bytecode verifier and lightweight bytecode verifier
   825 as abstract algorithms, instantiated to the JVM;
   826 
   827 * Bali: Java source language formalization. Type system, operational
   828 semantics, axiomatic semantics. Supported language features:
   829 classes, interfaces, objects,virtual methods, static methods,
   830 static/instance fields, arrays, access modifiers, definite
   831 assignment, exceptions.
   832 
   833 
   834 *** ZF ***
   835 
   836 * ZF/Constructible: consistency proof for AC (Gdel's constructible
   837 universe, etc.);
   838 
   839 * Main ZF: virtually all theories converted to new-style format;
   840 
   841 
   842 *** ML ***
   843 
   844 * Pure: Tactic.prove provides sane interface for internal proofs;
   845 omits the infamous "standard" operation, so this is more appropriate
   846 than prove_goalw_cterm in many situations (e.g. in simprocs);
   847 
   848 * Pure: improved error reporting of simprocs;
   849 
   850 * Provers: Simplifier.simproc(_i) provides sane interface for setting
   851 up simprocs;
   852 
   853 
   854 *** Document preparation ***
   855 
   856 * uses \par instead of \\ for line breaks in theory text. This may
   857 shift some page breaks in large documents. To get the old behaviour
   858 use \renewcommand{\isanewline}{\mbox{}\\\mbox{}} in root.tex.
   859 
   860 * minimized dependencies of isabelle.sty and isabellesym.sty on
   861 other packages
   862 
   863 * \<euro> now needs package babel/greek instead of marvosym (which
   864 broke \Rightarrow)
   865 
   866 * normal size for \<zero>...\<nine> (uses \mathbf instead of
   867 textcomp package)
   868 
   869 
   870 
   871 New in Isabelle2002 (March 2002)
   872 --------------------------------
   873 
   874 *** Document preparation ***
   875 
   876 * greatly simplified document preparation setup, including more
   877 graceful interpretation of isatool usedir -i/-d/-D options, and more
   878 instructive isatool mkdir; users should basically be able to get
   879 started with "isatool mkdir HOL Test && isatool make"; alternatively,
   880 users may run a separate document processing stage manually like this:
   881 "isatool usedir -D output HOL Test && isatool document Test/output";
   882 
   883 * theory dependency graph may now be incorporated into documents;
   884 isatool usedir -g true will produce session_graph.eps/.pdf for use
   885 with \includegraphics of LaTeX;
   886 
   887 * proper spacing of consecutive markup elements, especially text
   888 blocks after section headings;
   889 
   890 * support bold style (for single symbols only), input syntax is like
   891 this: "\<^bold>\<alpha>" or "\<^bold>A";
   892 
   893 * \<bullet> is now output as bold \cdot by default, which looks much
   894 better in printed text;
   895 
   896 * added default LaTeX bindings for \<tturnstile> and \<TTurnstile>;
   897 note that these symbols are currently unavailable in Proof General /
   898 X-Symbol; new symbols \<zero>, \<one>, ..., \<nine>, and \<euro>;
   899 
   900 * isatool latex no longer depends on changed TEXINPUTS, instead
   901 isatool document copies the Isabelle style files to the target
   902 location;
   903 
   904 
   905 *** Isar ***
   906 
   907 * Pure/Provers: improved proof by cases and induction;
   908   - 'case' command admits impromptu naming of parameters (such as
   909     "case (Suc n)");
   910   - 'induct' method divinates rule instantiation from the inductive
   911     claim; no longer requires excessive ?P bindings for proper
   912     instantiation of cases;
   913   - 'induct' method properly enumerates all possibilities of set/type
   914     rules; as a consequence facts may be also passed through *type*
   915     rules without further ado;
   916   - 'induct' method now derives symbolic cases from the *rulified*
   917     rule (before it used to rulify cases stemming from the internal
   918     atomized version); this means that the context of a non-atomic
   919     statement becomes is included in the hypothesis, avoiding the
   920     slightly cumbersome show "PROP ?case" form;
   921   - 'induct' may now use elim-style induction rules without chaining
   922     facts, using ``missing'' premises from the goal state; this allows
   923     rules stemming from inductive sets to be applied in unstructured
   924     scripts, while still benefitting from proper handling of non-atomic
   925     statements; NB: major inductive premises need to be put first, all
   926     the rest of the goal is passed through the induction;
   927   - 'induct' proper support for mutual induction involving non-atomic
   928     rule statements (uses the new concept of simultaneous goals, see
   929     below);
   930   - append all possible rule selections, but only use the first
   931     success (no backtracking);
   932   - removed obsolete "(simplified)" and "(stripped)" options of methods;
   933   - undeclared rule case names default to numbers 1, 2, 3, ...;
   934   - added 'print_induct_rules' (covered by help item in recent Proof
   935     General versions);
   936   - moved induct/cases attributes to Pure, methods to Provers;
   937   - generic method setup instantiated for FOL and HOL;
   938 
   939 * Pure: support multiple simultaneous goal statements, for example
   940 "have a: A and b: B" (same for 'theorem' etc.); being a pure
   941 meta-level mechanism, this acts as if several individual goals had
   942 been stated separately; in particular common proof methods need to be
   943 repeated in order to cover all claims; note that a single elimination
   944 step is *not* sufficient to establish the two conjunctions, so this
   945 fails:
   946 
   947   assume "A & B" then have A and B ..   (*".." fails*)
   948 
   949 better use "obtain" in situations as above; alternative refer to
   950 multi-step methods like 'auto', 'simp_all', 'blast+' etc.;
   951 
   952 * Pure: proper integration with ``locales''; unlike the original
   953 version by Florian Kammller, Isar locales package high-level proof
   954 contexts rather than raw logical ones (e.g. we admit to include
   955 attributes everywhere); operations on locales include merge and
   956 rename; support for implicit arguments (``structures''); simultaneous
   957 type-inference over imports and text; see also HOL/ex/Locales.thy for
   958 some examples;
   959 
   960 * Pure: the following commands have been ``localized'', supporting a
   961 target locale specification "(in name)": 'lemma', 'theorem',
   962 'corollary', 'lemmas', 'theorems', 'declare'; the results will be
   963 stored both within the locale and at the theory level (exported and
   964 qualified by the locale name);
   965 
   966 * Pure: theory goals may now be specified in ``long'' form, with
   967 ad-hoc contexts consisting of arbitrary locale elements. for example
   968 ``lemma foo: fixes x assumes "A x" shows "B x"'' (local syntax and
   969 definitions may be given, too); the result is a meta-level rule with
   970 the context elements being discharged in the obvious way;
   971 
   972 * Pure: new proof command 'using' allows to augment currently used
   973 facts after a goal statement ('using' is syntactically analogous to
   974 'apply', but acts on the goal's facts only); this allows chained facts
   975 to be separated into parts given before and after a claim, as in
   976 ``from a and b have C using d and e <proof>'';
   977 
   978 * Pure: renamed "antecedent" case to "rule_context";
   979 
   980 * Pure: new 'judgment' command records explicit information about the
   981 object-logic embedding (used by several tools internally); no longer
   982 use hard-wired "Trueprop";
   983 
   984 * Pure: added 'corollary' command;
   985 
   986 * Pure: fixed 'token_translation' command;
   987 
   988 * Pure: removed obsolete 'exported' attribute;
   989 
   990 * Pure: dummy pattern "_" in is/let is now automatically lifted over
   991 bound variables: "ALL x. P x --> Q x" (is "ALL x. _ --> ?C x")
   992 supersedes more cumbersome ... (is "ALL x. _ x --> ?C x");
   993 
   994 * Pure: method 'atomize' presents local goal premises as object-level
   995 statements (atomic meta-level propositions); setup controlled via
   996 rewrite rules declarations of 'atomize' attribute; example
   997 application: 'induct' method with proper rule statements in improper
   998 proof *scripts*;
   999 
  1000 * Pure: emulation of instantiation tactics (rule_tac, cut_tac, etc.)
  1001 now consider the syntactic context of assumptions, giving a better
  1002 chance to get type-inference of the arguments right (this is
  1003 especially important for locales);
  1004 
  1005 * Pure: "sorry" no longer requires quick_and_dirty in interactive
  1006 mode;
  1007 
  1008 * Pure/obtain: the formal conclusion "thesis", being marked as
  1009 ``internal'', may no longer be reference directly in the text;
  1010 potential INCOMPATIBILITY, may need to use "?thesis" in rare
  1011 situations;
  1012 
  1013 * Pure: generic 'sym' attribute which declares a rule both as pure
  1014 'elim?' and for the 'symmetric' operation;
  1015 
  1016 * Pure: marginal comments ``--'' may now occur just anywhere in the
  1017 text; the fixed correlation with particular command syntax has been
  1018 discontinued;
  1019 
  1020 * Pure: new method 'rules' is particularly well-suited for proof
  1021 search in intuitionistic logic; a bit slower than 'blast' or 'fast',
  1022 but often produces more compact proof terms with less detours;
  1023 
  1024 * Pure/Provers/classical: simplified integration with pure rule
  1025 attributes and methods; the classical "intro?/elim?/dest?"
  1026 declarations coincide with the pure ones; the "rule" method no longer
  1027 includes classically swapped intros; "intro" and "elim" methods no
  1028 longer pick rules from the context; also got rid of ML declarations
  1029 AddXIs/AddXEs/AddXDs; all of this has some potential for
  1030 INCOMPATIBILITY;
  1031 
  1032 * Provers/classical: attribute 'swapped' produces classical inversions
  1033 of introduction rules;
  1034 
  1035 * Provers/simplifier: 'simplified' attribute may refer to explicit
  1036 rules instead of full simplifier context; 'iff' attribute handles
  1037 conditional rules;
  1038 
  1039 * HOL: 'typedef' now allows alternative names for Rep/Abs morphisms;
  1040 
  1041 * HOL: 'recdef' now fails on unfinished automated proofs, use
  1042 "(permissive)" option to recover old behavior;
  1043 
  1044 * HOL: 'inductive' no longer features separate (collective) attributes
  1045 for 'intros' (was found too confusing);
  1046 
  1047 * HOL: properly declared induction rules less_induct and
  1048 wf_induct_rule;
  1049 
  1050 
  1051 *** HOL ***
  1052 
  1053 * HOL: moved over to sane numeral syntax; the new policy is as
  1054 follows:
  1055 
  1056   - 0 and 1 are polymorphic constants, which are defined on any
  1057   numeric type (nat, int, real etc.);
  1058 
  1059   - 2, 3, 4, ... and -1, -2, -3, ... are polymorphic numerals, based
  1060   binary representation internally;
  1061 
  1062   - type nat has special constructor Suc, and generally prefers Suc 0
  1063   over 1::nat and Suc (Suc 0) over 2::nat;
  1064 
  1065 This change may cause significant problems of INCOMPATIBILITY; here
  1066 are some hints on converting existing sources:
  1067 
  1068   - due to the new "num" token, "-0" and "-1" etc. are now atomic
  1069   entities, so expressions involving "-" (unary or binary minus) need
  1070   to be spaced properly;
  1071 
  1072   - existing occurrences of "1" may need to be constraint "1::nat" or
  1073   even replaced by Suc 0; similar for old "2";
  1074 
  1075   - replace "#nnn" by "nnn", and "#-nnn" by "-nnn";
  1076 
  1077   - remove all special provisions on numerals in proofs;
  1078 
  1079 * HOL: simp rules nat_number expand numerals on nat to Suc/0
  1080 representation (depends on bin_arith_simps in the default context);
  1081 
  1082 * HOL: symbolic syntax for x^2 (numeral 2);
  1083 
  1084 * HOL: the class of all HOL types is now called "type" rather than
  1085 "term"; INCOMPATIBILITY, need to adapt references to this type class
  1086 in axclass/classes, instance/arities, and (usually rare) occurrences
  1087 in typings (of consts etc.); internally the class is called
  1088 "HOL.type", ML programs should refer to HOLogic.typeS;
  1089 
  1090 * HOL/record package improvements:
  1091   - new derived operations "fields" to build a partial record section,
  1092     "extend" to promote a fixed record to a record scheme, and
  1093     "truncate" for the reverse; cf. theorems "xxx.defs", which are *not*
  1094     declared as simp by default;
  1095   - shared operations ("more", "fields", etc.) now need to be always
  1096     qualified) --- potential INCOMPATIBILITY;
  1097   - removed "make_scheme" operations (use "make" with "extend") --
  1098     INCOMPATIBILITY;
  1099   - removed "more" class (simply use "term") -- INCOMPATIBILITY;
  1100   - provides cases/induct rules for use with corresponding Isar
  1101     methods (for concrete records, record schemes, concrete more
  1102     parts, and schematic more parts -- in that order);
  1103   - internal definitions directly based on a light-weight abstract
  1104     theory of product types over typedef rather than datatype;
  1105 
  1106 * HOL: generic code generator for generating executable ML code from
  1107 specifications; specific support for HOL constructs such as inductive
  1108 datatypes and sets, as well as recursive functions; can be invoked
  1109 via 'generate_code' theory section;
  1110 
  1111 * HOL: canonical cases/induct rules for n-tuples (n = 3..7);
  1112 
  1113 * HOL: consolidated and renamed several theories.  In particular:
  1114         Ord.thy has been absorbed into HOL.thy
  1115         String.thy has been absorbed into List.thy
  1116 
  1117 * HOL: concrete setsum syntax "\<Sum>i:A. b" == "setsum (%i. b) A"
  1118 (beware of argument permutation!);
  1119 
  1120 * HOL: linorder_less_split superseded by linorder_cases;
  1121 
  1122 * HOL/List: "nodups" renamed to "distinct";
  1123 
  1124 * HOL: added "The" definite description operator; move Hilbert's "Eps"
  1125 to peripheral theory "Hilbert_Choice"; some INCOMPATIBILITIES:
  1126   - Ex_def has changed, now need to use some_eq_ex
  1127 
  1128 * HOL: made split_all_tac safe; EXISTING PROOFS MAY FAIL OR LOOP, so
  1129 in this (rare) case use:
  1130 
  1131   delSWrapper "split_all_tac"
  1132   addSbefore ("unsafe_split_all_tac", unsafe_split_all_tac)
  1133 
  1134 * HOL: added safe wrapper "split_conv_tac" to claset; EXISTING PROOFS
  1135 MAY FAIL;
  1136 
  1137 * HOL: introduced f^n = f o ... o f; warning: due to the limits of
  1138 Isabelle's type classes, ^ on functions and relations has too general
  1139 a domain, namely ('a * 'b) set and 'a => 'b; this means that it may be
  1140 necessary to attach explicit type constraints;
  1141 
  1142 * HOL/Relation: the prefix name of the infix "O" has been changed from
  1143 "comp" to "rel_comp"; INCOMPATIBILITY: a few theorems have been
  1144 renamed accordingly (eg "compI" -> "rel_compI").
  1145 
  1146 * HOL: syntax translations now work properly with numerals and records
  1147 expressions;
  1148 
  1149 * HOL: bounded abstraction now uses syntax "%" / "\<lambda>" instead
  1150 of "lam" -- INCOMPATIBILITY;
  1151 
  1152 * HOL: got rid of some global declarations (potential INCOMPATIBILITY
  1153 for ML tools): const "()" renamed "Product_Type.Unity", type "unit"
  1154 renamed "Product_Type.unit";
  1155 
  1156 * HOL: renamed rtrancl_into_rtrancl2 to converse_rtrancl_into_rtrancl
  1157 
  1158 * HOL: removed obsolete theorem "optionE" (use "option.exhaust", or
  1159 the "cases" method);
  1160 
  1161 * HOL/GroupTheory: group theory examples including Sylow's theorem (by
  1162 Florian Kammller);
  1163 
  1164 * HOL/IMP: updated and converted to new-style theory format; several
  1165 parts turned into readable document, with proper Isar proof texts and
  1166 some explanations (by Gerwin Klein);
  1167 
  1168 * HOL-Real: added Complex_Numbers (by Gertrud Bauer);
  1169 
  1170 * HOL-Hyperreal is now a logic image;
  1171 
  1172 
  1173 *** HOLCF ***
  1174 
  1175 * Isar: consts/constdefs supports mixfix syntax for continuous
  1176 operations;
  1177 
  1178 * Isar: domain package adapted to new-style theory format, e.g. see
  1179 HOLCF/ex/Dnat.thy;
  1180 
  1181 * theory Lift: proper use of rep_datatype lift instead of ML hacks --
  1182 potential INCOMPATIBILITY; now use plain induct_tac instead of former
  1183 lift.induct_tac, always use UU instead of Undef;
  1184 
  1185 * HOLCF/IMP: updated and converted to new-style theory;
  1186 
  1187 
  1188 *** ZF ***
  1189 
  1190 * Isar: proper integration of logic-specific tools and packages,
  1191 including theory commands '(co)inductive', '(co)datatype',
  1192 'rep_datatype', 'inductive_cases', as well as methods 'ind_cases',
  1193 'induct_tac', 'case_tac', and 'typecheck' (with attribute 'TC');
  1194 
  1195 * theory Main no longer includes AC; for the Axiom of Choice, base
  1196 your theory on Main_ZFC;
  1197 
  1198 * the integer library now covers quotients and remainders, with many
  1199 laws relating division to addition, multiplication, etc.;
  1200 
  1201 * ZF/UNITY: Chandy and Misra's UNITY is now available in ZF, giving a
  1202 typeless version of the formalism;
  1203 
  1204 * ZF/AC, Coind, IMP, Resid: updated and converted to new-style theory
  1205 format;
  1206 
  1207 * ZF/Induct: new directory for examples of inductive definitions,
  1208 including theory Multiset for multiset orderings; converted to
  1209 new-style theory format;
  1210 
  1211 * ZF: many new theorems about lists, ordinals, etc.;
  1212 
  1213 
  1214 *** General ***
  1215 
  1216 * Pure/kernel: meta-level proof terms (by Stefan Berghofer); reference
  1217 variable proof controls level of detail: 0 = no proofs (only oracle
  1218 dependencies), 1 = lemma dependencies, 2 = compact proof terms; see
  1219 also ref manual for further ML interfaces;
  1220 
  1221 * Pure/axclass: removed obsolete ML interface
  1222 goal_subclass/goal_arity;
  1223 
  1224 * Pure/syntax: new token syntax "num" for plain numerals (without "#"
  1225 of "xnum"); potential INCOMPATIBILITY, since -0, -1 etc. are now
  1226 separate tokens, so expressions involving minus need to be spaced
  1227 properly;
  1228 
  1229 * Pure/syntax: support non-oriented infixes, using keyword "infix"
  1230 rather than "infixl" or "infixr";
  1231 
  1232 * Pure/syntax: concrete syntax for dummy type variables admits genuine
  1233 sort constraint specifications in type inference; e.g. "x::_::foo"
  1234 ensures that the type of "x" is of sort "foo" (but not necessarily a
  1235 type variable);
  1236 
  1237 * Pure/syntax: print modes "type_brackets" and "no_type_brackets"
  1238 control output of nested => (types); the default behavior is
  1239 "type_brackets";
  1240 
  1241 * Pure/syntax: builtin parse translation for "_constify" turns valued
  1242 tokens into AST constants;
  1243 
  1244 * Pure/syntax: prefer later declarations of translations and print
  1245 translation functions; potential INCOMPATIBILITY: need to reverse
  1246 multiple declarations for same syntax element constant;
  1247 
  1248 * Pure/show_hyps reset by default (in accordance to existing Isar
  1249 practice);
  1250 
  1251 * Provers/classical: renamed addaltern to addafter, addSaltern to
  1252 addSafter;
  1253 
  1254 * Provers/clasimp: ``iff'' declarations now handle conditional rules
  1255 as well;
  1256 
  1257 * system: tested support for MacOS X; should be able to get Isabelle +
  1258 Proof General to work in a plain Terminal after installing Poly/ML
  1259 (e.g. from the Isabelle distribution area) and GNU bash alone
  1260 (e.g. from http://www.apple.com); full X11, XEmacs and X-Symbol
  1261 support requires further installations, e.g. from
  1262 http://fink.sourceforge.net/);
  1263 
  1264 * system: support Poly/ML 4.1.1 (able to manage larger heaps);
  1265 
  1266 * system: reduced base memory usage by Poly/ML (approx. 20 MB instead
  1267 of 40 MB), cf. ML_OPTIONS;
  1268 
  1269 * system: Proof General keywords specification is now part of the
  1270 Isabelle distribution (see etc/isar-keywords.el);
  1271 
  1272 * system: support for persistent Proof General sessions (refrain from
  1273 outdating all loaded theories on startup); user may create writable
  1274 logic images like this: ``isabelle -q HOL Test'';
  1275 
  1276 * system: smart selection of Isabelle process versus Isabelle
  1277 interface, accommodates case-insensitive file systems (e.g. HFS+); may
  1278 run both "isabelle" and "Isabelle" even if file names are badly
  1279 damaged (executable inspects the case of the first letter of its own
  1280 name); added separate "isabelle-process" and "isabelle-interface";
  1281 
  1282 * system: refrain from any attempt at filtering input streams; no
  1283 longer support ``8bit'' encoding of old isabelle font, instead proper
  1284 iso-latin characters may now be used; the related isatools
  1285 "symbolinput" and "nonascii" have disappeared as well;
  1286 
  1287 * system: removed old "xterm" interface (the print modes "xterm" and
  1288 "xterm_color" are still available for direct use in a suitable
  1289 terminal);
  1290 
  1291 
  1292 
  1293 New in Isabelle99-2 (February 2001)
  1294 -----------------------------------
  1295 
  1296 *** Overview of INCOMPATIBILITIES ***
  1297 
  1298 * HOL: please note that theories in the Library and elsewhere often use the
  1299 new-style (Isar) format; to refer to their theorems in an ML script you must
  1300 bind them to ML identifers by e.g.      val thm_name = thm "thm_name";
  1301 
  1302 * HOL: inductive package no longer splits induction rule aggressively,
  1303 but only as far as specified by the introductions given; the old
  1304 format may be recovered via ML function complete_split_rule or attribute
  1305 'split_rule (complete)';
  1306 
  1307 * HOL: induct renamed to lfp_induct, lfp_Tarski to lfp_unfold,
  1308 gfp_Tarski to gfp_unfold;
  1309 
  1310 * HOL: contrapos, contrapos2 renamed to contrapos_nn, contrapos_pp;
  1311 
  1312 * HOL: infix "dvd" now has priority 50 rather than 70 (because it is a
  1313 relation); infix "^^" has been renamed "``"; infix "``" has been
  1314 renamed "`"; "univalent" has been renamed "single_valued";
  1315 
  1316 * HOL/Real: "rinv" and "hrinv" replaced by overloaded "inverse"
  1317 operation;
  1318 
  1319 * HOLCF: infix "`" has been renamed "$"; the symbol syntax is \<cdot>;
  1320 
  1321 * Isar: 'obtain' no longer declares "that" fact as simp/intro;
  1322 
  1323 * Isar/HOL: method 'induct' now handles non-atomic goals; as a
  1324 consequence, it is no longer monotonic wrt. the local goal context
  1325 (which is now passed through the inductive cases);
  1326 
  1327 * Document preparation: renamed standard symbols \<ll> to \<lless> and
  1328 \<gg> to \<ggreater>;
  1329 
  1330 
  1331 *** Document preparation ***
  1332 
  1333 * \isabellestyle{NAME} selects version of Isabelle output (currently
  1334 available: are "it" for near math-mode best-style output, "sl" for
  1335 slanted text style, and "tt" for plain type-writer; if no
  1336 \isabellestyle command is given, output is according to slanted
  1337 type-writer);
  1338 
  1339 * support sub/super scripts (for single symbols only), input syntax is
  1340 like this: "A\<^sup>*" or "A\<^sup>\<star>";
  1341 
  1342 * some more standard symbols; see Appendix A of the system manual for
  1343 the complete list of symbols defined in isabellesym.sty;
  1344 
  1345 * improved isabelle style files; more abstract symbol implementation
  1346 (should now use \isamath{...} and \isatext{...} in custom symbol
  1347 definitions);
  1348 
  1349 * antiquotation @{goals} and @{subgoals} for output of *dynamic* goals
  1350 state; Note that presentation of goal states does not conform to
  1351 actual human-readable proof documents.  Please do not include goal
  1352 states into document output unless you really know what you are doing!
  1353 
  1354 * proper indentation of antiquoted output with proportional LaTeX
  1355 fonts;
  1356 
  1357 * no_document ML operator temporarily disables LaTeX document
  1358 generation;
  1359 
  1360 * isatool unsymbolize tunes sources for plain ASCII communication;
  1361 
  1362 
  1363 *** Isar ***
  1364 
  1365 * Pure: Isar now suffers initial goal statements to contain unbound
  1366 schematic variables (this does not conform to actual readable proof
  1367 documents, due to unpredictable outcome and non-compositional proof
  1368 checking); users who know what they are doing may use schematic goals
  1369 for Prolog-style synthesis of proven results;
  1370 
  1371 * Pure: assumption method (an implicit finishing) now handles actual
  1372 rules as well;
  1373 
  1374 * Pure: improved 'obtain' --- moved to Pure, insert "that" into
  1375 initial goal, declare "that" only as Pure intro (only for single
  1376 steps); the "that" rule assumption may now be involved in implicit
  1377 finishing, thus ".." becomes a feasible for trivial obtains;
  1378 
  1379 * Pure: default proof step now includes 'intro_classes'; thus trivial
  1380 instance proofs may be performed by "..";
  1381 
  1382 * Pure: ?thesis / ?this / "..." now work for pure meta-level
  1383 statements as well;
  1384 
  1385 * Pure: more robust selection of calculational rules;
  1386 
  1387 * Pure: the builtin notion of 'finished' goal now includes the ==-refl
  1388 rule (as well as the assumption rule);
  1389 
  1390 * Pure: 'thm_deps' command visualizes dependencies of theorems and
  1391 lemmas, using the graph browser tool;
  1392 
  1393 * Pure: predict failure of "show" in interactive mode;
  1394 
  1395 * Pure: 'thms_containing' now takes actual terms as arguments;
  1396 
  1397 * HOL: improved method 'induct' --- now handles non-atomic goals
  1398 (potential INCOMPATIBILITY); tuned error handling;
  1399 
  1400 * HOL: cases and induct rules now provide explicit hints about the
  1401 number of facts to be consumed (0 for "type" and 1 for "set" rules);
  1402 any remaining facts are inserted into the goal verbatim;
  1403 
  1404 * HOL: local contexts (aka cases) may now contain term bindings as
  1405 well; the 'cases' and 'induct' methods new provide a ?case binding for
  1406 the result to be shown in each case;
  1407 
  1408 * HOL: added 'recdef_tc' command;
  1409 
  1410 * isatool convert assists in eliminating legacy ML scripts;
  1411 
  1412 
  1413 *** HOL ***
  1414 
  1415 * HOL/Library: a collection of generic theories to be used together
  1416 with main HOL; the theory loader path already includes this directory
  1417 by default; the following existing theories have been moved here:
  1418 HOL/Induct/Multiset, HOL/Induct/Acc (as Accessible_Part), HOL/While
  1419 (as While_Combinator), HOL/Lex/Prefix (as List_Prefix);
  1420 
  1421 * HOL/Unix: "Some aspects of Unix file-system security", a typical
  1422 modelling and verification task performed in Isabelle/HOL +
  1423 Isabelle/Isar + Isabelle document preparation (by Markus Wenzel).
  1424 
  1425 * HOL/Algebra: special summation operator SUM no longer exists, it has
  1426 been replaced by setsum; infix 'assoc' now has priority 50 (like
  1427 'dvd'); axiom 'one_not_zero' has been moved from axclass 'ring' to
  1428 'domain', this makes the theory consistent with mathematical
  1429 literature;
  1430 
  1431 * HOL basics: added overloaded operations "inverse" and "divide"
  1432 (infix "/"), syntax for generic "abs" operation, generic summation
  1433 operator \<Sum>;
  1434 
  1435 * HOL/typedef: simplified package, provide more useful rules (see also
  1436 HOL/subset.thy);
  1437 
  1438 * HOL/datatype: induction rule for arbitrarily branching datatypes is
  1439 now expressed as a proper nested rule (old-style tactic scripts may
  1440 require atomize_strip_tac to cope with non-atomic premises);
  1441 
  1442 * HOL: renamed theory "Prod" to "Product_Type", renamed "split" rule
  1443 to "split_conv" (old name still available for compatibility);
  1444 
  1445 * HOL: improved concrete syntax for strings (e.g. allows translation
  1446 rules with string literals);
  1447 
  1448 * HOL-Real-Hyperreal: this extends HOL-Real with the hyperreals
  1449  and Fleuriot's mechanization of analysis, including the transcendental
  1450  functions for the reals;
  1451 
  1452 * HOL/Real, HOL/Hyperreal: improved arithmetic simplification;
  1453 
  1454 
  1455 *** CTT ***
  1456 
  1457 * CTT: x-symbol support for Pi, Sigma, -->, : (membership); note that
  1458 "lam" is displayed as TWO lambda-symbols
  1459 
  1460 * CTT: theory Main now available, containing everything (that is, Bool
  1461 and Arith);
  1462 
  1463 
  1464 *** General ***
  1465 
  1466 * Pure: the Simplifier has been implemented properly as a derived rule
  1467 outside of the actual kernel (at last!); the overall performance
  1468 penalty in practical applications is about 50%, while reliability of
  1469 the Isabelle inference kernel has been greatly improved;
  1470 
  1471 * print modes "brackets" and "no_brackets" control output of nested =>
  1472 (types) and ==> (props); the default behaviour is "brackets";
  1473 
  1474 * Provers: fast_tac (and friends) now handle actual object-logic rules
  1475 as assumptions as well;
  1476 
  1477 * system: support Poly/ML 4.0;
  1478 
  1479 * system: isatool install handles KDE version 1 or 2;
  1480 
  1481 
  1482 
  1483 New in Isabelle99-1 (October 2000)
  1484 ----------------------------------
  1485 
  1486 *** Overview of INCOMPATIBILITIES ***
  1487 
  1488 * HOL: simplification of natural numbers is much changed; to partly
  1489 recover the old behaviour (e.g. to prevent n+n rewriting to #2*n)
  1490 issue the following ML commands:
  1491 
  1492   Delsimprocs Nat_Numeral_Simprocs.cancel_numerals;
  1493   Delsimprocs [Nat_Numeral_Simprocs.combine_numerals];
  1494 
  1495 * HOL: simplification no longer dives into case-expressions; this is
  1496 controlled by "t.weak_case_cong" for each datatype t;
  1497 
  1498 * HOL: nat_less_induct renamed to less_induct;
  1499 
  1500 * HOL: systematic renaming of the SOME (Eps) rules, may use isatool
  1501 fixsome to patch .thy and .ML sources automatically;
  1502 
  1503   select_equality  -> some_equality
  1504   select_eq_Ex     -> some_eq_ex
  1505   selectI2EX       -> someI2_ex
  1506   selectI2         -> someI2
  1507   selectI          -> someI
  1508   select1_equality -> some1_equality
  1509   Eps_sym_eq       -> some_sym_eq_trivial
  1510   Eps_eq           -> some_eq_trivial
  1511 
  1512 * HOL: exhaust_tac on datatypes superceded by new generic case_tac;
  1513 
  1514 * HOL: removed obsolete theorem binding expand_if (refer to split_if
  1515 instead);
  1516 
  1517 * HOL: the recursion equations generated by 'recdef' are now called
  1518 f.simps instead of f.rules;
  1519 
  1520 * HOL: qed_spec_mp now also handles bounded ALL as well;
  1521 
  1522 * HOL: 0 is now overloaded, so the type constraint ":: nat" may
  1523 sometimes be needed;
  1524 
  1525 * HOL: the constant for "f``x" is now "image" rather than "op ``";
  1526 
  1527 * HOL: the constant for "f-``x" is now "vimage" rather than "op -``";
  1528 
  1529 * HOL: the disjoint sum is now "<+>" instead of "Plus"; the cartesian
  1530 product is now "<*>" instead of "Times"; the lexicographic product is
  1531 now "<*lex*>" instead of "**";
  1532 
  1533 * HOL: theory Sexp is now in HOL/Induct examples (it used to be part
  1534 of main HOL, but was unused); better use HOL's datatype package;
  1535 
  1536 * HOL: removed "symbols" syntax for constant "override" of theory Map;
  1537 the old syntax may be recovered as follows:
  1538 
  1539   syntax (symbols)
  1540     override  :: "('a ~=> 'b) => ('a ~=> 'b) => ('a ~=> 'b)"
  1541       (infixl "\\<oplus>" 100)
  1542 
  1543 * HOL/Real: "rabs" replaced by overloaded "abs" function;
  1544 
  1545 * HOL/ML: even fewer consts are declared as global (see theories Ord,
  1546 Lfp, Gfp, WF); this only affects ML packages that refer to const names
  1547 internally;
  1548 
  1549 * HOL and ZF: syntax for quotienting wrt an equivalence relation
  1550 changed from A/r to A//r;
  1551 
  1552 * ZF: new treatment of arithmetic (nat & int) may break some old
  1553 proofs;
  1554 
  1555 * Isar: renamed some attributes (RS -> THEN, simplify -> simplified,
  1556 rulify -> rule_format, elimify -> elim_format, ...);
  1557 
  1558 * Isar/Provers: intro/elim/dest attributes changed; renamed
  1559 intro/intro!/intro!! flags to intro!/intro/intro? (in most cases, one
  1560 should have to change intro!! to intro? only); replaced "delrule" by
  1561 "rule del";
  1562 
  1563 * Isar/HOL: renamed "intrs" to "intros" in inductive definitions;
  1564 
  1565 * Provers: strengthened force_tac by using new first_best_tac;
  1566 
  1567 * LaTeX document preparation: several changes of isabelle.sty (see
  1568 lib/texinputs);
  1569 
  1570 
  1571 *** Document preparation ***
  1572 
  1573 * formal comments (text blocks etc.) in new-style theories may now
  1574 contain antiquotations of thm/prop/term/typ/text to be presented
  1575 according to latex print mode; concrete syntax is like this:
  1576 @{term[show_types] "f(x) = a + x"};
  1577 
  1578 * isatool mkdir provides easy setup of Isabelle session directories,
  1579 including proper document sources;
  1580 
  1581 * generated LaTeX sources are now deleted after successful run
  1582 (isatool document -c); may retain a copy somewhere else via -D option
  1583 of isatool usedir;
  1584 
  1585 * isatool usedir -D now lets isatool latex -o sty update the Isabelle
  1586 style files, achieving self-contained LaTeX sources and simplifying
  1587 LaTeX debugging;
  1588 
  1589 * old-style theories now produce (crude) LaTeX output as well;
  1590 
  1591 * browser info session directories are now self-contained (may be put
  1592 on WWW server seperately); improved graphs of nested sessions; removed
  1593 graph for 'all sessions';
  1594 
  1595 * several improvements in isabelle style files; \isabellestyle{it}
  1596 produces fake math mode output; \isamarkupheader is now \section by
  1597 default; see lib/texinputs/isabelle.sty etc.;
  1598 
  1599 
  1600 *** Isar ***
  1601 
  1602 * Isar/Pure: local results and corresponding term bindings are now
  1603 subject to Hindley-Milner polymorphism (similar to ML); this
  1604 accommodates incremental type-inference very nicely;
  1605 
  1606 * Isar/Pure: new derived language element 'obtain' supports
  1607 generalized existence reasoning;
  1608 
  1609 * Isar/Pure: new calculational elements 'moreover' and 'ultimately'
  1610 support accumulation of results, without applying any rules yet;
  1611 useful to collect intermediate results without explicit name
  1612 references, and for use with transitivity rules with more than 2
  1613 premises;
  1614 
  1615 * Isar/Pure: scalable support for case-analysis type proofs: new
  1616 'case' language element refers to local contexts symbolically, as
  1617 produced by certain proof methods; internally, case names are attached
  1618 to theorems as "tags";
  1619 
  1620 * Isar/Pure: theory command 'hide' removes declarations from
  1621 class/type/const name spaces;
  1622 
  1623 * Isar/Pure: theory command 'defs' supports option "(overloaded)" to
  1624 indicate potential overloading;
  1625 
  1626 * Isar/Pure: changed syntax of local blocks from {{ }} to { };
  1627 
  1628 * Isar/Pure: syntax of sorts made 'inner', i.e. have to write
  1629 "{a,b,c}" instead of {a,b,c};
  1630 
  1631 * Isar/Pure now provides its own version of intro/elim/dest
  1632 attributes; useful for building new logics, but beware of confusion
  1633 with the version in Provers/classical;
  1634 
  1635 * Isar/Pure: the local context of (non-atomic) goals is provided via
  1636 case name 'antecedent';
  1637 
  1638 * Isar/Pure: removed obsolete 'transfer' attribute (transfer of thms
  1639 to the current context is now done automatically);
  1640 
  1641 * Isar/Pure: theory command 'method_setup' provides a simple interface
  1642 for definining proof methods in ML;
  1643 
  1644 * Isar/Provers: intro/elim/dest attributes changed; renamed
  1645 intro/intro!/intro!! flags to intro!/intro/intro? (INCOMPATIBILITY, in
  1646 most cases, one should have to change intro!! to intro? only);
  1647 replaced "delrule" by "rule del";
  1648 
  1649 * Isar/Provers: new 'hypsubst' method, plain 'subst' method and
  1650 'symmetric' attribute (the latter supercedes [RS sym]);
  1651 
  1652 * Isar/Provers: splitter support (via 'split' attribute and 'simp'
  1653 method modifier); 'simp' method: 'only:' modifier removes loopers as
  1654 well (including splits);
  1655 
  1656 * Isar/Provers: Simplifier and Classical methods now support all kind
  1657 of modifiers used in the past, including 'cong', 'iff', etc.
  1658 
  1659 * Isar/Provers: added 'fastsimp' and 'clarsimp' methods (combination
  1660 of Simplifier and Classical reasoner);
  1661 
  1662 * Isar/HOL: new proof method 'cases' and improved version of 'induct'
  1663 now support named cases; major packages (inductive, datatype, primrec,
  1664 recdef) support case names and properly name parameters;
  1665 
  1666 * Isar/HOL: new transitivity rules for substitution in inequalities --
  1667 monotonicity conditions are extracted to be proven at end of
  1668 calculations;
  1669 
  1670 * Isar/HOL: removed 'case_split' thm binding, should use 'cases' proof
  1671 method anyway;
  1672 
  1673 * Isar/HOL: removed old expand_if = split_if; theorems if_splits =
  1674 split_if split_if_asm; datatype package provides theorems foo.splits =
  1675 foo.split foo.split_asm for each datatype;
  1676 
  1677 * Isar/HOL: tuned inductive package, rename "intrs" to "intros"
  1678 (potential INCOMPATIBILITY), emulation of mk_cases feature for proof
  1679 scripts: new 'inductive_cases' command and 'ind_cases' method; (Note:
  1680 use "(cases (simplified))" method in proper proof texts);
  1681 
  1682 * Isar/HOL: added global 'arith_split' attribute for 'arith' method;
  1683 
  1684 * Isar: names of theorems etc. may be natural numbers as well;
  1685 
  1686 * Isar: 'pr' command: optional arguments for goals_limit and
  1687 ProofContext.prems_limit; no longer prints theory contexts, but only
  1688 proof states;
  1689 
  1690 * Isar: diagnostic commands 'pr', 'thm', 'prop', 'term', 'typ' admit
  1691 additional print modes to be specified; e.g. "pr(latex)" will print
  1692 proof state according to the Isabelle LaTeX style;
  1693 
  1694 * Isar: improved support for emulating tactic scripts, including proof
  1695 methods 'rule_tac' etc., 'cut_tac', 'thin_tac', 'subgoal_tac',
  1696 'rename_tac', 'rotate_tac', 'tactic', and 'case_tac' / 'induct_tac'
  1697 (for HOL datatypes);
  1698 
  1699 * Isar: simplified (more robust) goal selection of proof methods: 1st
  1700 goal, all goals, or explicit goal specifier (tactic emulation); thus
  1701 'proof method scripts' have to be in depth-first order;
  1702 
  1703 * Isar: tuned 'let' syntax: replaced 'as' keyword by 'and';
  1704 
  1705 * Isar: removed 'help' command, which hasn't been too helpful anyway;
  1706 should instead use individual commands for printing items
  1707 (print_commands, print_methods etc.);
  1708 
  1709 * Isar: added 'nothing' --- the empty list of theorems;
  1710 
  1711 
  1712 *** HOL ***
  1713 
  1714 * HOL/MicroJava: formalization of a fragment of Java, together with a
  1715 corresponding virtual machine and a specification of its bytecode
  1716 verifier and a lightweight bytecode verifier, including proofs of
  1717 type-safety; by Gerwin Klein, Tobias Nipkow, David von Oheimb, and
  1718 Cornelia Pusch (see also the homepage of project Bali at
  1719 http://isabelle.in.tum.de/Bali/);
  1720 
  1721 * HOL/Algebra: new theory of rings and univariate polynomials, by
  1722 Clemens Ballarin;
  1723 
  1724 * HOL/NumberTheory: fundamental Theorem of Arithmetic, Chinese
  1725 Remainder Theorem, Fermat/Euler Theorem, Wilson's Theorem, by Thomas M
  1726 Rasmussen;
  1727 
  1728 * HOL/Lattice: fundamental concepts of lattice theory and order
  1729 structures, including duals, properties of bounds versus algebraic
  1730 laws, lattice operations versus set-theoretic ones, the Knaster-Tarski
  1731 Theorem for complete lattices etc.; may also serve as a demonstration
  1732 for abstract algebraic reasoning using axiomatic type classes, and
  1733 mathematics-style proof in Isabelle/Isar; by Markus Wenzel;
  1734 
  1735 * HOL/Prolog: a (bare-bones) implementation of Lambda-Prolog, by David
  1736 von Oheimb;
  1737 
  1738 * HOL/IMPP: extension of IMP with local variables and mutually
  1739 recursive procedures, by David von Oheimb;
  1740 
  1741 * HOL/Lambda: converted into new-style theory and document;
  1742 
  1743 * HOL/ex/Multiquote: example of multiple nested quotations and
  1744 anti-quotations -- basically a generalized version of de-Bruijn
  1745 representation; very useful in avoiding lifting of operations;
  1746 
  1747 * HOL/record: added general record equality rule to simpset; fixed
  1748 select-update simplification procedure to handle extended records as
  1749 well; admit "r" as field name;
  1750 
  1751 * HOL: 0 is now overloaded over the new sort "zero", allowing its use with
  1752 other numeric types and also as the identity of groups, rings, etc.;
  1753 
  1754 * HOL: new axclass plus_ac0 for addition with the AC-laws and 0 as identity.
  1755 Types nat and int belong to this axclass;
  1756 
  1757 * HOL: greatly improved simplification involving numerals of type nat, int, real:
  1758    (i + #8 + j) = Suc k simplifies to  #7 + (i + j) = k
  1759    i*j + k + j*#3*i     simplifies to  #4*(i*j) + k
  1760   two terms #m*u and #n*u are replaced by #(m+n)*u
  1761     (where #m, #n and u can implicitly be 1; this is simproc combine_numerals)
  1762   and the term/formula #m*u+x ~~ #n*u+y simplifies simplifies to #(m-n)+x ~~ y
  1763     or x ~~ #(n-m)+y, where ~~ is one of = < <= or - (simproc cancel_numerals);
  1764 
  1765 * HOL: meson_tac is available (previously in ex/meson.ML); it is a
  1766 powerful prover for predicate logic but knows nothing of clasets; see
  1767 ex/mesontest.ML and ex/mesontest2.ML for example applications;
  1768 
  1769 * HOL: new version of "case_tac" subsumes both boolean case split and
  1770 "exhaust_tac" on datatypes; INCOMPATIBILITY: exhaust_tac no longer
  1771 exists, may define val exhaust_tac = case_tac for ad-hoc portability;
  1772 
  1773 * HOL: simplification no longer dives into case-expressions: only the
  1774 selector expression is simplified, but not the remaining arms; to
  1775 enable full simplification of case-expressions for datatype t, you may
  1776 remove t.weak_case_cong from the simpset, either globally (Delcongs
  1777 [thm"t.weak_case_cong"];) or locally (delcongs [...]).
  1778 
  1779 * HOL/recdef: the recursion equations generated by 'recdef' for
  1780 function 'f' are now called f.simps instead of f.rules; if all
  1781 termination conditions are proved automatically, these simplification
  1782 rules are added to the simpset, as in primrec; rules may be named
  1783 individually as well, resulting in a separate list of theorems for
  1784 each equation;
  1785 
  1786 * HOL/While is a new theory that provides a while-combinator. It
  1787 permits the definition of tail-recursive functions without the
  1788 provision of a termination measure. The latter is necessary once the
  1789 invariant proof rule for while is applied.
  1790 
  1791 * HOL: new (overloaded) notation for the set of elements below/above
  1792 some element: {..u}, {..u(}, {l..}, {)l..}. See theory SetInterval.
  1793 
  1794 * HOL: theorems impI, allI, ballI bound as "strip";
  1795 
  1796 * HOL: new tactic induct_thm_tac: thm -> string -> int -> tactic
  1797 induct_tac th "x1 ... xn" expects th to have a conclusion of the form
  1798 P v1 ... vn and abbreviates res_inst_tac [("v1","x1"),...,("vn","xn")] th;
  1799 
  1800 * HOL/Real: "rabs" replaced by overloaded "abs" function;
  1801 
  1802 * HOL: theory Sexp now in HOL/Induct examples (it used to be part of
  1803 main HOL, but was unused);
  1804 
  1805 * HOL: fewer consts declared as global (e.g. have to refer to
  1806 "Lfp.lfp" instead of "lfp" internally; affects ML packages only);
  1807 
  1808 * HOL: tuned AST representation of nested pairs, avoiding bogus output
  1809 in case of overlap with user translations (e.g. judgements over
  1810 tuples); (note that the underlying logical represenation is still
  1811 bogus);
  1812 
  1813 
  1814 *** ZF ***
  1815 
  1816 * ZF: simplification automatically cancels common terms in arithmetic
  1817 expressions over nat and int;
  1818 
  1819 * ZF: new treatment of nat to minimize type-checking: all operators
  1820 coerce their operands to a natural number using the function natify,
  1821 making the algebraic laws unconditional;
  1822 
  1823 * ZF: as above, for int: operators coerce their operands to an integer
  1824 using the function intify;
  1825 
  1826 * ZF: the integer library now contains many of the usual laws for the
  1827 orderings, including $<=, and monotonicity laws for $+ and $*;
  1828 
  1829 * ZF: new example ZF/ex/NatSum to demonstrate integer arithmetic
  1830 simplification;
  1831 
  1832 * FOL and ZF: AddIffs now available, giving theorems of the form P<->Q
  1833 to the simplifier and classical reasoner simultaneously;
  1834 
  1835 
  1836 *** General ***
  1837 
  1838 * Provers: blast_tac now handles actual object-logic rules as
  1839 assumptions; note that auto_tac uses blast_tac internally as well;
  1840 
  1841 * Provers: new functions rulify/rulify_no_asm: thm -> thm for turning
  1842 outer -->/All/Ball into ==>/!!; qed_spec_mp now uses rulify_no_asm;
  1843 
  1844 * Provers: delrules now handles destruct rules as well (no longer need
  1845 explicit make_elim);
  1846 
  1847 * Provers: Blast_tac now warns of and ignores "weak elimination rules" e.g.
  1848   [| inj ?f;          ?f ?x = ?f ?y; ?x = ?y ==> ?W |] ==> ?W
  1849 use instead the strong form,
  1850   [| inj ?f; ~ ?W ==> ?f ?x = ?f ?y; ?x = ?y ==> ?W |] ==> ?W
  1851 in HOL, FOL and ZF the function cla_make_elim will create such rules
  1852 from destruct-rules;
  1853 
  1854 * Provers: Simplifier.easy_setup provides a fast path to basic
  1855 Simplifier setup for new object-logics;
  1856 
  1857 * Pure: AST translation rules no longer require constant head on LHS;
  1858 
  1859 * Pure: improved name spaces: ambiguous output is qualified; support
  1860 for hiding of names;
  1861 
  1862 * system: smart setup of canonical ML_HOME, ISABELLE_INTERFACE, and
  1863 XSYMBOL_HOME; no longer need to do manual configuration in most
  1864 situations;
  1865 
  1866 * system: compression of ML heaps images may now be controlled via -c
  1867 option of isabelle and isatool usedir (currently only observed by
  1868 Poly/ML);
  1869 
  1870 * system: isatool installfonts may handle X-Symbol fonts as well (very
  1871 useful for remote X11);
  1872 
  1873 * system: provide TAGS file for Isabelle sources;
  1874 
  1875 * ML: infix 'OF' is a version of 'MRS' with more appropriate argument
  1876 order;
  1877 
  1878 * ML: renamed flags Syntax.trace_norm_ast to Syntax.trace_ast; global
  1879 timing flag supersedes proof_timing and Toplevel.trace;
  1880 
  1881 * ML: new combinators |>> and |>>> for incremental transformations
  1882 with secondary results (e.g. certain theory extensions):
  1883 
  1884 * ML: PureThy.add_defs gets additional argument to indicate potential
  1885 overloading (usually false);
  1886 
  1887 * ML: PureThy.add_thms/add_axioms/add_defs now return theorems as
  1888 results;
  1889 
  1890 
  1891 
  1892 New in Isabelle99 (October 1999)
  1893 --------------------------------
  1894 
  1895 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  1896 
  1897 * HOL: The THEN and ELSE parts of conditional expressions (if P then x else y)
  1898 are no longer simplified.  (This allows the simplifier to unfold recursive
  1899 functional programs.)  To restore the old behaviour, declare
  1900 
  1901     Delcongs [if_weak_cong];
  1902 
  1903 * HOL: Removed the obsolete syntax "Compl A"; use -A for set
  1904 complement;
  1905 
  1906 * HOL: the predicate "inj" is now defined by translation to "inj_on";
  1907 
  1908 * HOL/datatype: mutual_induct_tac no longer exists --
  1909   use induct_tac "x_1 ... x_n" instead of mutual_induct_tac ["x_1", ..., "x_n"]
  1910 
  1911 * HOL/typedef: fixed type inference for representing set; type
  1912 arguments now have to occur explicitly on the rhs as type constraints;
  1913 
  1914 * ZF: The con_defs part of an inductive definition may no longer refer
  1915 to constants declared in the same theory;
  1916 
  1917 * HOL, ZF: the function mk_cases, generated by the inductive
  1918 definition package, has lost an argument.  To simplify its result, it
  1919 uses the default simpset instead of a supplied list of theorems.
  1920 
  1921 * HOL/List: the constructors of type list are now Nil and Cons;
  1922 
  1923 * Simplifier: the type of the infix ML functions
  1924         setSSolver addSSolver setSolver addSolver
  1925 is now  simpset * solver -> simpset  where `solver' is a new abstract type
  1926 for packaging solvers. A solver is created via
  1927         mk_solver: string -> (thm list -> int -> tactic) -> solver
  1928 where the string argument is only a comment.
  1929 
  1930 
  1931 *** Proof tools ***
  1932 
  1933 * Provers/Arith/fast_lin_arith.ML contains a functor for creating a
  1934 decision procedure for linear arithmetic. Currently it is used for
  1935 types `nat', `int', and `real' in HOL (see below); it can, should and
  1936 will be instantiated for other types and logics as well.
  1937 
  1938 * The simplifier now accepts rewrite rules with flexible heads, eg
  1939      hom ?f ==> ?f(?x+?y) = ?f ?x + ?f ?y
  1940   They are applied like any rule with a non-pattern lhs, i.e. by first-order
  1941   matching.
  1942 
  1943 
  1944 *** General ***
  1945 
  1946 * New Isabelle/Isar subsystem provides an alternative to traditional
  1947 tactical theorem proving; together with the ProofGeneral/isar user
  1948 interface it offers an interactive environment for developing human
  1949 readable proof documents (Isar == Intelligible semi-automated
  1950 reasoning); for further information see isatool doc isar-ref,
  1951 src/HOL/Isar_examples and http://isabelle.in.tum.de/Isar/
  1952 
  1953 * improved and simplified presentation of theories: better HTML markup
  1954 (including colors), graph views in several sizes; isatool usedir now
  1955 provides a proper interface for user theories (via -P option); actual
  1956 document preparation based on (PDF)LaTeX is available as well (for
  1957 new-style theories only); see isatool doc system for more information;
  1958 
  1959 * native support for Proof General, both for classic Isabelle and
  1960 Isabelle/Isar;
  1961 
  1962 * ML function thm_deps visualizes dependencies of theorems and lemmas,
  1963 using the graph browser tool;
  1964 
  1965 * Isabelle manuals now also available as PDF;
  1966 
  1967 * theory loader rewritten from scratch (may not be fully
  1968 bug-compatible); old loadpath variable has been replaced by show_path,
  1969 add_path, del_path, reset_path functions; new operations such as
  1970 update_thy, touch_thy, remove_thy, use/update_thy_only (see also
  1971 isatool doc ref);
  1972 
  1973 * improved isatool install: option -k creates KDE application icon,
  1974 option -p DIR installs standalone binaries;
  1975 
  1976 * added ML_PLATFORM setting (useful for cross-platform installations);
  1977 more robust handling of platform specific ML images for SML/NJ;
  1978 
  1979 * the settings environment is now statically scoped, i.e. it is never
  1980 created again in sub-processes invoked from isabelle, isatool, or
  1981 Isabelle;
  1982 
  1983 * path element specification '~~' refers to '$ISABELLE_HOME';
  1984 
  1985 * in locales, the "assumes" and "defines" parts may be omitted if
  1986 empty;
  1987 
  1988 * new print_mode "xsymbols" for extended symbol support (e.g. genuine
  1989 long arrows);
  1990 
  1991 * new print_mode "HTML";
  1992 
  1993 * new flag show_tags controls display of tags of theorems (which are
  1994 basically just comments that may be attached by some tools);
  1995 
  1996 * Isamode 2.6 requires patch to accomodate change of Isabelle font
  1997 mode and goal output format:
  1998 
  1999 diff -r Isamode-2.6/elisp/isa-load.el Isamode/elisp/isa-load.el
  2000 244c244
  2001 <       (list (isa-getenv "ISABELLE") "-msymbols" logic-name)
  2002 ---
  2003 >       (list (isa-getenv "ISABELLE") "-misabelle_font" "-msymbols" logic-name)
  2004 diff -r Isabelle-2.6/elisp/isa-proofstate.el Isamode/elisp/isa-proofstate.el
  2005 181c181
  2006 < (defconst proofstate-proofstart-regexp "^Level [0-9]+$"
  2007 ---
  2008 > (defconst proofstate-proofstart-regexp "^Level [0-9]+"
  2009 
  2010 * function bind_thms stores lists of theorems (cf. bind_thm);
  2011 
  2012 * new shorthand tactics ftac, eatac, datac, fatac;
  2013 
  2014 * qed (and friends) now accept "" as result name; in that case the
  2015 theorem is not stored, but proper checks and presentation of the
  2016 result still apply;
  2017 
  2018 * theorem database now also indexes constants "Trueprop", "all",
  2019 "==>", "=="; thus thms_containing, findI etc. may retrieve more rules;
  2020 
  2021 
  2022 *** HOL ***
  2023 
  2024 ** HOL arithmetic **
  2025 
  2026 * There are now decision procedures for linear arithmetic over nat and
  2027 int:
  2028 
  2029 1. arith_tac copes with arbitrary formulae involving `=', `<', `<=',
  2030 `+', `-', `Suc', `min', `max' and numerical constants; other subterms
  2031 are treated as atomic; subformulae not involving type `nat' or `int'
  2032 are ignored; quantified subformulae are ignored unless they are
  2033 positive universal or negative existential. The tactic has to be
  2034 invoked by hand and can be a little bit slow. In particular, the
  2035 running time is exponential in the number of occurrences of `min' and
  2036 `max', and `-' on `nat'.
  2037 
  2038 2. fast_arith_tac is a cut-down version of arith_tac: it only takes
  2039 (negated) (in)equalities among the premises and the conclusion into
  2040 account (i.e. no compound formulae) and does not know about `min' and
  2041 `max', and `-' on `nat'. It is fast and is used automatically by the
  2042 simplifier.
  2043 
  2044 NB: At the moment, these decision procedures do not cope with mixed
  2045 nat/int formulae where the two parts interact, such as `m < n ==>
  2046 int(m) < int(n)'.
  2047 
  2048 * HOL/Numeral provides a generic theory of numerals (encoded
  2049 efficiently as bit strings); setup for types nat/int/real is in place;
  2050 INCOMPATIBILITY: since numeral syntax is now polymorphic, rather than
  2051 int, existing theories and proof scripts may require a few additional
  2052 type constraints;
  2053 
  2054 * integer division and remainder can now be performed on constant
  2055 arguments;
  2056 
  2057 * many properties of integer multiplication, division and remainder
  2058 are now available;
  2059 
  2060 * An interface to the Stanford Validity Checker (SVC) is available through the
  2061 tactic svc_tac.  Propositional tautologies and theorems of linear arithmetic
  2062 are proved automatically.  SVC must be installed separately, and its results
  2063 must be TAKEN ON TRUST (Isabelle does not check the proofs, but tags any
  2064 invocation of the underlying oracle).  For SVC see
  2065   http://verify.stanford.edu/SVC
  2066 
  2067 * IsaMakefile: the HOL-Real target now builds an actual image;
  2068 
  2069 
  2070 ** HOL misc **
  2071 
  2072 * HOL/Real/HahnBanach: the Hahn-Banach theorem for real vector spaces
  2073 (in Isabelle/Isar) -- by Gertrud Bauer;
  2074 
  2075 * HOL/BCV: generic model of bytecode verification, i.e. data-flow
  2076 analysis for assembly languages with subtypes;
  2077 
  2078 * HOL/TLA (Lamport's Temporal Logic of Actions): major reorganization
  2079 -- avoids syntactic ambiguities and treats state, transition, and
  2080 temporal levels more uniformly; introduces INCOMPATIBILITIES due to
  2081 changed syntax and (many) tactics;
  2082 
  2083 * HOL/inductive: Now also handles more general introduction rules such
  2084   as "ALL y. (y, x) : r --> y : acc r ==> x : acc r"; monotonicity
  2085   theorems are now maintained within the theory (maintained via the
  2086   "mono" attribute);
  2087 
  2088 * HOL/datatype: Now also handles arbitrarily branching datatypes
  2089   (using function types) such as
  2090 
  2091   datatype 'a tree = Atom 'a | Branch "nat => 'a tree"
  2092 
  2093 * HOL/record: record_simproc (part of the default simpset) takes care
  2094 of selectors applied to updated records; record_split_tac is no longer
  2095 part of the default claset; update_defs may now be removed from the
  2096 simpset in many cases; COMPATIBILITY: old behavior achieved by
  2097 
  2098   claset_ref () := claset() addSWrapper record_split_wrapper;
  2099   Delsimprocs [record_simproc]
  2100 
  2101 * HOL/typedef: fixed type inference for representing set; type
  2102 arguments now have to occur explicitly on the rhs as type constraints;
  2103 
  2104 * HOL/recdef (TFL): 'congs' syntax now expects comma separated list of theorem
  2105 names rather than an ML expression;
  2106 
  2107 * HOL/defer_recdef (TFL): like recdef but the well-founded relation can be
  2108 supplied later.  Program schemes can be defined, such as
  2109     "While B C s = (if B s then While B C (C s) else s)"
  2110 where the well-founded relation can be chosen after B and C have been given.
  2111 
  2112 * HOL/List: the constructors of type list are now Nil and Cons;
  2113 INCOMPATIBILITY: while [] and infix # syntax is still there, of
  2114 course, ML tools referring to List.list.op # etc. have to be adapted;
  2115 
  2116 * HOL_quantifiers flag superseded by "HOL" print mode, which is
  2117 disabled by default; run isabelle with option -m HOL to get back to
  2118 the original Gordon/HOL-style output;
  2119 
  2120 * HOL/Ord.thy: new bounded quantifier syntax (input only): ALL x<y. P,
  2121 ALL x<=y. P, EX x<y. P, EX x<=y. P;
  2122 
  2123 * HOL basic syntax simplified (more orthogonal): all variants of
  2124 All/Ex now support plain / symbolic / HOL notation; plain syntax for
  2125 Eps operator is provided as well: "SOME x. P[x]";
  2126 
  2127 * HOL/Sum.thy: sum_case has been moved to HOL/Datatype;
  2128 
  2129 * HOL/Univ.thy: infix syntax <*>, <+>, <**>, <+> eliminated and made
  2130 thus available for user theories;
  2131 
  2132 * HOLCF/IOA/Sequents: renamed 'Cons' to 'Consq' to avoid clash with
  2133 HOL/List; hardly an INCOMPATIBILITY since '>>' syntax is used all the
  2134 time;
  2135 
  2136 * HOL: new tactic smp_tac: int -> int -> tactic, which applies spec
  2137 several times and then mp;
  2138 
  2139 
  2140 *** LK ***
  2141 
  2142 * the notation <<...>> is now available as a notation for sequences of
  2143 formulas;
  2144 
  2145 * the simplifier is now installed
  2146 
  2147 * the axiom system has been generalized (thanks to Soren Heilmann)
  2148 
  2149 * the classical reasoner now has a default rule database
  2150 
  2151 
  2152 *** ZF ***
  2153 
  2154 * new primrec section allows primitive recursive functions to be given
  2155 directly (as in HOL) over datatypes and the natural numbers;
  2156 
  2157 * new tactics induct_tac and exhaust_tac for induction (or case
  2158 analysis) over datatypes and the natural numbers;
  2159 
  2160 * the datatype declaration of type T now defines the recursor T_rec;
  2161 
  2162 * simplification automatically does freeness reasoning for datatype
  2163 constructors;
  2164 
  2165 * automatic type-inference, with AddTCs command to insert new
  2166 type-checking rules;
  2167 
  2168 * datatype introduction rules are now added as Safe Introduction rules
  2169 to the claset;
  2170 
  2171 * the syntax "if P then x else y" is now available in addition to
  2172 if(P,x,y);
  2173 
  2174 
  2175 *** Internal programming interfaces ***
  2176 
  2177 * tuned simplifier trace output; new flag debug_simp;
  2178 
  2179 * structures Vartab / Termtab (instances of TableFun) offer efficient
  2180 tables indexed by indexname_ord / term_ord (compatible with aconv);
  2181 
  2182 * AxClass.axclass_tac lost the theory argument;
  2183 
  2184 * tuned current_goals_markers semantics: begin / end goal avoids
  2185 printing empty lines;
  2186 
  2187 * removed prs and prs_fn hook, which was broken because it did not
  2188 include \n in its semantics, forcing writeln to add one
  2189 uncoditionally; replaced prs_fn by writeln_fn; consider std_output:
  2190 string -> unit if you really want to output text without newline;
  2191 
  2192 * Symbol.output subject to print mode; INCOMPATIBILITY: defaults to
  2193 plain output, interface builders may have to enable 'isabelle_font'
  2194 mode to get Isabelle font glyphs as before;
  2195 
  2196 * refined token_translation interface; INCOMPATIBILITY: output length
  2197 now of type real instead of int;
  2198 
  2199 * theory loader actions may be traced via new ThyInfo.add_hook
  2200 interface (see src/Pure/Thy/thy_info.ML); example application: keep
  2201 your own database of information attached to *whole* theories -- as
  2202 opposed to intra-theory data slots offered via TheoryDataFun;
  2203 
  2204 * proper handling of dangling sort hypotheses (at last!);
  2205 Thm.strip_shyps and Drule.strip_shyps_warning take care of removing
  2206 extra sort hypotheses that can be witnessed from the type signature;
  2207 the force_strip_shyps flag is gone, any remaining shyps are simply
  2208 left in the theorem (with a warning issued by strip_shyps_warning);
  2209 
  2210 
  2211 
  2212 New in Isabelle98-1 (October 1998)
  2213 ----------------------------------
  2214 
  2215 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  2216 
  2217 * several changes of automated proof tools;
  2218 
  2219 * HOL: major changes to the inductive and datatype packages, including
  2220 some minor incompatibilities of theory syntax;
  2221 
  2222 * HOL: renamed r^-1 to 'converse' from 'inverse'; 'inj_onto' is now
  2223 called `inj_on';
  2224 
  2225 * HOL: removed duplicate thms in Arith:
  2226   less_imp_add_less  should be replaced by  trans_less_add1
  2227   le_imp_add_le      should be replaced by  trans_le_add1
  2228 
  2229 * HOL: unary minus is now overloaded (new type constraints may be
  2230 required);
  2231 
  2232 * HOL and ZF: unary minus for integers is now #- instead of #~.  In
  2233 ZF, expressions such as n#-1 must be changed to n#- 1, since #-1 is
  2234 now taken as an integer constant.
  2235 
  2236 * Pure: ML function 'theory_of' renamed to 'theory';
  2237 
  2238 
  2239 *** Proof tools ***
  2240 
  2241 * Simplifier:
  2242   1. Asm_full_simp_tac is now more aggressive.
  2243      1. It will sometimes reorient premises if that increases their power to
  2244         simplify.
  2245      2. It does no longer proceed strictly from left to right but may also
  2246         rotate premises to achieve further simplification.
  2247      For compatibility reasons there is now Asm_lr_simp_tac which is like the
  2248      old Asm_full_simp_tac in that it does not rotate premises.
  2249   2. The simplifier now knows a little bit about nat-arithmetic.
  2250 
  2251 * Classical reasoner: wrapper mechanism for the classical reasoner now
  2252 allows for selected deletion of wrappers, by introduction of names for
  2253 wrapper functionals.  This implies that addbefore, addSbefore,
  2254 addaltern, and addSaltern now take a pair (name, tactic) as argument,
  2255 and that adding two tactics with the same name overwrites the first
  2256 one (emitting a warning).
  2257   type wrapper = (int -> tactic) -> (int -> tactic)
  2258   setWrapper, setSWrapper, compWrapper and compSWrapper are replaced by
  2259   addWrapper, addSWrapper: claset * (string * wrapper) -> claset
  2260   delWrapper, delSWrapper: claset *  string            -> claset
  2261   getWrapper is renamed to appWrappers, getSWrapper to appSWrappers;
  2262 
  2263 * Classical reasoner: addbefore/addSbefore now have APPEND/ORELSE
  2264 semantics; addbefore now affects only the unsafe part of step_tac
  2265 etc.; this affects addss/auto_tac/force_tac, so EXISTING PROOFS MAY
  2266 FAIL, but proofs should be fixable easily, e.g. by replacing Auto_tac
  2267 by Force_tac;
  2268 
  2269 * Classical reasoner: setwrapper to setWrapper and compwrapper to
  2270 compWrapper; added safe wrapper (and access functions for it);
  2271 
  2272 * HOL/split_all_tac is now much faster and fails if there is nothing
  2273 to split.  Some EXISTING PROOFS MAY REQUIRE ADAPTION because the order
  2274 and the names of the automatically generated variables have changed.
  2275 split_all_tac has moved within claset() from unsafe wrappers to safe
  2276 wrappers, which means that !!-bound variables are split much more
  2277 aggressively, and safe_tac and clarify_tac now split such variables.
  2278 If this splitting is not appropriate, use delSWrapper "split_all_tac".
  2279 Note: the same holds for record_split_tac, which does the job of
  2280 split_all_tac for record fields.
  2281 
  2282 * HOL/Simplifier: Rewrite rules for case distinctions can now be added
  2283 permanently to the default simpset using Addsplits just like
  2284 Addsimps. They can be removed via Delsplits just like
  2285 Delsimps. Lower-case versions are also available.
  2286 
  2287 * HOL/Simplifier: The rule split_if is now part of the default
  2288 simpset. This means that the simplifier will eliminate all occurrences
  2289 of if-then-else in the conclusion of a goal. To prevent this, you can
  2290 either remove split_if completely from the default simpset by
  2291 `Delsplits [split_if]' or remove it in a specific call of the
  2292 simplifier using `... delsplits [split_if]'.  You can also add/delete
  2293 other case splitting rules to/from the default simpset: every datatype
  2294 generates suitable rules `split_t_case' and `split_t_case_asm' (where
  2295 t is the name of the datatype).
  2296 
  2297 * Classical reasoner / Simplifier combination: new force_tac (and
  2298 derivatives Force_tac, force) combines rewriting and classical
  2299 reasoning (and whatever other tools) similarly to auto_tac, but is
  2300 aimed to solve the given subgoal completely.
  2301 
  2302 
  2303 *** General ***
  2304 
  2305 * new top-level commands `Goal' and `Goalw' that improve upon `goal'
  2306 and `goalw': the theory is no longer needed as an explicit argument -
  2307 the current theory context is used; assumptions are no longer returned
  2308 at the ML-level unless one of them starts with ==> or !!; it is
  2309 recommended to convert to these new commands using isatool fixgoal
  2310 (backup your sources first!);
  2311 
  2312 * new top-level commands 'thm' and 'thms' for retrieving theorems from
  2313 the current theory context, and 'theory' to lookup stored theories;
  2314 
  2315 * new theory section 'locale' for declaring constants, assumptions and
  2316 definitions that have local scope;
  2317 
  2318 * new theory section 'nonterminals' for purely syntactic types;
  2319 
  2320 * new theory section 'setup' for generic ML setup functions
  2321 (e.g. package initialization);
  2322 
  2323 * the distribution now includes Isabelle icons: see
  2324 lib/logo/isabelle-{small,tiny}.xpm;
  2325 
  2326 * isatool install - install binaries with absolute references to
  2327 ISABELLE_HOME/bin;
  2328 
  2329 * isatool logo -- create instances of the Isabelle logo (as EPS);
  2330 
  2331 * print mode 'emacs' reserved for Isamode;
  2332 
  2333 * support multiple print (ast) translations per constant name;
  2334 
  2335 * theorems involving oracles are now printed with a suffixed [!];
  2336 
  2337 
  2338 *** HOL ***
  2339 
  2340 * there is now a tutorial on Isabelle/HOL (do 'isatool doc tutorial');
  2341 
  2342 * HOL/inductive package reorganized and improved: now supports mutual
  2343 definitions such as
  2344 
  2345   inductive EVEN ODD
  2346     intrs
  2347       null "0 : EVEN"
  2348       oddI "n : EVEN ==> Suc n : ODD"
  2349       evenI "n : ODD ==> Suc n : EVEN"
  2350 
  2351 new theorem list "elims" contains an elimination rule for each of the
  2352 recursive sets; inductive definitions now handle disjunctive premises
  2353 correctly (also ZF);
  2354 
  2355 INCOMPATIBILITIES: requires Inductive as an ancestor; component
  2356 "mutual_induct" no longer exists - the induction rule is always
  2357 contained in "induct";
  2358 
  2359 
  2360 * HOL/datatype package re-implemented and greatly improved: now
  2361 supports mutually recursive datatypes such as
  2362 
  2363   datatype
  2364     'a aexp = IF_THEN_ELSE ('a bexp) ('a aexp) ('a aexp)
  2365             | SUM ('a aexp) ('a aexp)
  2366             | DIFF ('a aexp) ('a aexp)
  2367             | NUM 'a
  2368   and
  2369     'a bexp = LESS ('a aexp) ('a aexp)
  2370             | AND ('a bexp) ('a bexp)
  2371             | OR ('a bexp) ('a bexp)
  2372 
  2373 as well as indirectly recursive datatypes such as
  2374 
  2375   datatype
  2376     ('a, 'b) term = Var 'a
  2377                   | App 'b ((('a, 'b) term) list)
  2378 
  2379 The new tactic  mutual_induct_tac [<var_1>, ..., <var_n>] i  performs
  2380 induction on mutually / indirectly recursive datatypes.
  2381 
  2382 Primrec equations are now stored in theory and can be accessed via
  2383 <function_name>.simps.
  2384 
  2385 INCOMPATIBILITIES:
  2386 
  2387   - Theories using datatypes must now have theory Datatype as an
  2388     ancestor.
  2389   - The specific <typename>.induct_tac no longer exists - use the
  2390     generic induct_tac instead.
  2391   - natE has been renamed to nat.exhaust - use exhaust_tac
  2392     instead of res_inst_tac ... natE. Note that the variable
  2393     names in nat.exhaust differ from the names in natE, this
  2394     may cause some "fragile" proofs to fail.
  2395   - The theorems split_<typename>_case and split_<typename>_case_asm
  2396     have been renamed to <typename>.split and <typename>.split_asm.
  2397   - Since default sorts of type variables are now handled correctly,
  2398     some datatype definitions may have to be annotated with explicit
  2399     sort constraints.
  2400   - Primrec definitions no longer require function name and type
  2401     of recursive argument.
  2402 
  2403 Consider using isatool fixdatatype to adapt your theories and proof
  2404 scripts to the new package (backup your sources first!).
  2405 
  2406 
  2407 * HOL/record package: considerably improved implementation; now
  2408 includes concrete syntax for record types, terms, updates; theorems
  2409 for surjective pairing and splitting !!-bound record variables; proof
  2410 support is as follows:
  2411 
  2412   1) standard conversions (selectors or updates applied to record
  2413 constructor terms) are part of the standard simpset;
  2414 
  2415   2) inject equations of the form ((x, y) = (x', y')) == x=x' & y=y' are
  2416 made part of standard simpset and claset via addIffs;
  2417 
  2418   3) a tactic for record field splitting (record_split_tac) is part of
  2419 the standard claset (addSWrapper);
  2420 
  2421 To get a better idea about these rules you may retrieve them via
  2422 something like 'thms "foo.simps"' or 'thms "foo.iffs"', where "foo" is
  2423 the name of your record type.
  2424 
  2425 The split tactic 3) conceptually simplifies by the following rule:
  2426 
  2427   "(!!x. PROP ?P x) == (!!a b. PROP ?P (a, b))"
  2428 
  2429 Thus any record variable that is bound by meta-all will automatically
  2430 blow up into some record constructor term, consequently the
  2431 simplifications of 1), 2) apply.  Thus force_tac, auto_tac etc. shall
  2432 solve record problems automatically.
  2433 
  2434 
  2435 * reorganized the main HOL image: HOL/Integ and String loaded by
  2436 default; theory Main includes everything;
  2437 
  2438 * automatic simplification of integer sums and comparisons, using cancellation;
  2439 
  2440 * added option_map_eq_Some and not_Some_eq to the default simpset and claset;
  2441 
  2442 * added disj_not1 = "(~P | Q) = (P --> Q)" to the default simpset;
  2443 
  2444 * many new identities for unions, intersections, set difference, etc.;
  2445 
  2446 * expand_if, expand_split, expand_sum_case and expand_nat_case are now
  2447 called split_if, split_split, split_sum_case and split_nat_case (to go
  2448 with add/delsplits);
  2449 
  2450 * HOL/Prod introduces simplification procedure unit_eq_proc rewriting
  2451 (?x::unit) = (); this is made part of the default simpset, which COULD
  2452 MAKE EXISTING PROOFS FAIL under rare circumstances (consider
  2453 'Delsimprocs [unit_eq_proc];' as last resort); also note that
  2454 unit_abs_eta_conv is added in order to counter the effect of
  2455 unit_eq_proc on (%u::unit. f u), replacing it by f rather than by
  2456 %u.f();
  2457 
  2458 * HOL/Fun INCOMPATIBILITY: `inj_onto' is now called `inj_on' (which
  2459 makes more sense);
  2460 
  2461 * HOL/Set INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
  2462   It and 'sym RS equals0D' are now in the default  claset, giving automatic
  2463   disjointness reasoning but breaking a few old proofs.
  2464 
  2465 * HOL/Relation INCOMPATIBILITY: renamed the relational operator r^-1
  2466 to 'converse' from 'inverse' (for compatibility with ZF and some
  2467 literature);
  2468 
  2469 * HOL/recdef can now declare non-recursive functions, with {} supplied as
  2470 the well-founded relation;
  2471 
  2472 * HOL/Set INCOMPATIBILITY: the complement of set A is now written -A instead of
  2473     Compl A.  The "Compl" syntax remains available as input syntax for this
  2474     release ONLY.
  2475 
  2476 * HOL/Update: new theory of function updates:
  2477     f(a:=b) == %x. if x=a then b else f x
  2478 may also be iterated as in f(a:=b,c:=d,...);
  2479 
  2480 * HOL/Vimage: new theory for inverse image of a function, syntax f-``B;
  2481 
  2482 * HOL/List:
  2483   - new function list_update written xs[i:=v] that updates the i-th
  2484     list position. May also be iterated as in xs[i:=a,j:=b,...].
  2485   - new function `upt' written [i..j(] which generates the list
  2486     [i,i+1,...,j-1], i.e. the upper bound is excluded. To include the upper
  2487     bound write [i..j], which is a shorthand for [i..j+1(].
  2488   - new lexicographic orderings and corresponding wellfoundedness theorems.
  2489 
  2490 * HOL/Arith:
  2491   - removed 'pred' (predecessor) function;
  2492   - generalized some theorems about n-1;
  2493   - many new laws about "div" and "mod";
  2494   - new laws about greatest common divisors (see theory ex/Primes);
  2495 
  2496 * HOL/Relation: renamed the relational operator r^-1 "converse"
  2497 instead of "inverse";
  2498 
  2499 * HOL/Induct/Multiset: a theory of multisets, including the wellfoundedness
  2500   of the multiset ordering;
  2501 
  2502 * directory HOL/Real: a construction of the reals using Dedekind cuts
  2503   (not included by default);
  2504 
  2505 * directory HOL/UNITY: Chandy and Misra's UNITY formalism;
  2506 
  2507 * directory HOL/Hoare: a new version of Hoare logic which permits many-sorted
  2508   programs, i.e. different program variables may have different types.
  2509 
  2510 * calling (stac rew i) now fails if "rew" has no effect on the goal
  2511   [previously, this check worked only if the rewrite rule was unconditional]
  2512   Now rew can involve either definitions or equalities (either == or =).
  2513 
  2514 
  2515 *** ZF ***
  2516 
  2517 * theory Main includes everything; INCOMPATIBILITY: theory ZF.thy contains
  2518   only the theorems proved on ZF.ML;
  2519 
  2520 * ZF INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
  2521   It and 'sym RS equals0D' are now in the default  claset, giving automatic
  2522   disjointness reasoning but breaking a few old proofs.
  2523 
  2524 * ZF/Update: new theory of function updates
  2525     with default rewrite rule  f(x:=y) ` z = if(z=x, y, f`z)
  2526   may also be iterated as in f(a:=b,c:=d,...);
  2527 
  2528 * in  let x=t in u(x), neither t nor u(x) has to be an FOL term.
  2529 
  2530 * calling (stac rew i) now fails if "rew" has no effect on the goal
  2531   [previously, this check worked only if the rewrite rule was unconditional]
  2532   Now rew can involve either definitions or equalities (either == or =).
  2533 
  2534 * case_tac provided for compatibility with HOL
  2535     (like the old excluded_middle_tac, but with subgoals swapped)
  2536 
  2537 
  2538 *** Internal programming interfaces ***
  2539 
  2540 * Pure: several new basic modules made available for general use, see
  2541 also src/Pure/README;
  2542 
  2543 * improved the theory data mechanism to support encapsulation (data
  2544 kind name replaced by private Object.kind, acting as authorization
  2545 key); new type-safe user interface via functor TheoryDataFun; generic
  2546 print_data function becomes basically useless;
  2547 
  2548 * removed global_names compatibility flag -- all theory declarations
  2549 are qualified by default;
  2550 
  2551 * module Pure/Syntax now offers quote / antiquote translation
  2552 functions (useful for Hoare logic etc. with implicit dependencies);
  2553 see HOL/ex/Antiquote for an example use;
  2554 
  2555 * Simplifier now offers conversions (asm_)(full_)rewrite: simpset ->
  2556 cterm -> thm;
  2557 
  2558 * new tactical CHANGED_GOAL for checking that a tactic modifies a
  2559 subgoal;
  2560 
  2561 * Display.print_goals function moved to Locale.print_goals;
  2562 
  2563 * standard print function for goals supports current_goals_markers
  2564 variable for marking begin of proof, end of proof, start of goal; the
  2565 default is ("", "", ""); setting current_goals_markers := ("<proof>",
  2566 "</proof>", "<goal>") causes SGML like tagged proof state printing,
  2567 for example;
  2568 
  2569 
  2570 
  2571 New in Isabelle98 (January 1998)
  2572 --------------------------------
  2573 
  2574 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  2575 
  2576 * changed lexical syntax of terms / types: dots made part of long
  2577 identifiers, e.g. "%x.x" no longer possible, should be "%x. x";
  2578 
  2579 * simpset (and claset) reference variable replaced by functions
  2580 simpset / simpset_ref;
  2581 
  2582 * no longer supports theory aliases (via merge) and non-trivial
  2583 implicit merge of thms' signatures;
  2584 
  2585 * most internal names of constants changed due to qualified names;
  2586 
  2587 * changed Pure/Sequence interface (see Pure/seq.ML);
  2588 
  2589 
  2590 *** General Changes ***
  2591 
  2592 * hierachically structured name spaces (for consts, types, axms, thms
  2593 etc.); new lexical class 'longid' (e.g. Foo.bar.x) may render much of
  2594 old input syntactically incorrect (e.g. "%x.x"); COMPATIBILITY:
  2595 isatool fixdots ensures space after dots (e.g. "%x. x"); set
  2596 long_names for fully qualified output names; NOTE: ML programs
  2597 (special tactics, packages etc.) referring to internal names may have
  2598 to be adapted to cope with fully qualified names; in case of severe
  2599 backward campatibility problems try setting 'global_names' at compile
  2600 time to have enrything declared within a flat name space; one may also
  2601 fine tune name declarations in theories via the 'global' and 'local'
  2602 section;
  2603 
  2604 * reimplemented the implicit simpset and claset using the new anytype
  2605 data filed in signatures; references simpset:simpset ref etc. are
  2606 replaced by functions simpset:unit->simpset and
  2607 simpset_ref:unit->simpset ref; COMPATIBILITY: use isatool fixclasimp
  2608 to patch your ML files accordingly;
  2609 
  2610 * HTML output now includes theory graph data for display with Java
  2611 applet or isatool browser; data generated automatically via isatool
  2612 usedir (see -i option, ISABELLE_USEDIR_OPTIONS);
  2613 
  2614 * defs may now be conditional; improved rewrite_goals_tac to handle
  2615 conditional equations;
  2616 
  2617 * defs now admits additional type arguments, using TYPE('a) syntax;
  2618 
  2619 * theory aliases via merge (e.g. M=A+B+C) no longer supported, always
  2620 creates a new theory node; implicit merge of thms' signatures is
  2621 restricted to 'trivial' ones; COMPATIBILITY: one may have to use
  2622 transfer:theory->thm->thm in (rare) cases;
  2623 
  2624 * improved handling of draft signatures / theories; draft thms (and
  2625 ctyps, cterms) are automatically promoted to real ones;
  2626 
  2627 * slightly changed interfaces for oracles: admit many per theory, named
  2628 (e.g. oracle foo = mlfun), additional name argument for invoke_oracle;
  2629 
  2630 * print_goals: optional output of const types (set show_consts and
  2631 show_types);
  2632 
  2633 * improved output of warnings (###) and errors (***);
  2634 
  2635 * subgoal_tac displays a warning if the new subgoal has type variables;
  2636 
  2637 * removed old README and Makefiles;
  2638 
  2639 * replaced print_goals_ref hook by print_current_goals_fn and result_error_fn;
  2640 
  2641 * removed obsolete init_pps and init_database;
  2642 
  2643 * deleted the obsolete tactical STATE, which was declared by
  2644     fun STATE tacfun st = tacfun st st;
  2645 
  2646 * cd and use now support path variables, e.g. $ISABELLE_HOME, or ~
  2647 (which abbreviates $HOME);
  2648 
  2649 * changed Pure/Sequence interface (see Pure/seq.ML); COMPATIBILITY:
  2650 use isatool fixseq to adapt your ML programs (this works for fully
  2651 qualified references to the Sequence structure only!);
  2652 
  2653 * use_thy no longer requires writable current directory; it always
  2654 reloads .ML *and* .thy file, if either one is out of date;
  2655 
  2656 
  2657 *** Classical Reasoner ***
  2658 
  2659 * Clarify_tac, clarify_tac, clarify_step_tac, Clarify_step_tac: new
  2660 tactics that use classical reasoning to simplify a subgoal without
  2661 splitting it into several subgoals;
  2662 
  2663 * Safe_tac: like safe_tac but uses the default claset;
  2664 
  2665 
  2666 *** Simplifier ***
  2667 
  2668 * added simplification meta rules:
  2669     (asm_)(full_)simplify: simpset -> thm -> thm;
  2670 
  2671 * simplifier.ML no longer part of Pure -- has to be loaded by object
  2672 logics (again);
  2673 
  2674 * added prems argument to simplification procedures;
  2675 
  2676 * HOL, FOL, ZF: added infix function `addsplits':
  2677   instead of `<simpset> setloop (split_tac <thms>)'
  2678   you can simply write `<simpset> addsplits <thms>'
  2679 
  2680 
  2681 *** Syntax ***
  2682 
  2683 * TYPE('a) syntax for type reflection terms;
  2684 
  2685 * no longer handles consts with name "" -- declare as 'syntax' instead;
  2686 
  2687 * pretty printer: changed order of mixfix annotation preference (again!);
  2688 
  2689 * Pure: fixed idt/idts vs. pttrn/pttrns syntactic categories;
  2690 
  2691 
  2692 *** HOL ***
  2693 
  2694 * HOL: there is a new splitter `split_asm_tac' that can be used e.g.
  2695   with `addloop' of the simplifier to faciliate case splitting in premises.
  2696 
  2697 * HOL/TLA: Stephan Merz's formalization of Lamport's Temporal Logic of Actions;
  2698 
  2699 * HOL/Auth: new protocol proofs including some for the Internet
  2700   protocol TLS;
  2701 
  2702 * HOL/Map: new theory of `maps' a la VDM;
  2703 
  2704 * HOL/simplifier: simplification procedures nat_cancel_sums for
  2705 cancelling out common nat summands from =, <, <= (in)equalities, or
  2706 differences; simplification procedures nat_cancel_factor for
  2707 cancelling common factor from =, <, <= (in)equalities over natural
  2708 sums; nat_cancel contains both kinds of procedures, it is installed by
  2709 default in Arith.thy -- this COULD MAKE EXISTING PROOFS FAIL;
  2710 
  2711 * HOL/simplifier: terms of the form
  2712   `? x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x)'  (or t=x)
  2713   are rewritten to
  2714   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t)',
  2715   and those of the form
  2716   `! x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x) --> R(x)'  (or t=x)
  2717   are rewritten to
  2718   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t) --> R(t)',
  2719 
  2720 * HOL/datatype
  2721   Each datatype `t' now comes with a theorem `split_t_case' of the form
  2722 
  2723   P(t_case f1 ... fn x) =
  2724      ( (!y1 ... ym1. x = C1 y1 ... ym1 --> P(f1 y1 ... ym1)) &
  2725         ...
  2726        (!y1 ... ymn. x = Cn y1 ... ymn --> P(f1 y1 ... ymn))
  2727      )
  2728 
  2729   and a theorem `split_t_case_asm' of the form
  2730 
  2731   P(t_case f1 ... fn x) =
  2732     ~( (? y1 ... ym1. x = C1 y1 ... ym1 & ~P(f1 y1 ... ym1)) |
  2733         ...
  2734        (? y1 ... ymn. x = Cn y1 ... ymn & ~P(f1 y1 ... ymn))
  2735      )
  2736   which can be added to a simpset via `addsplits'. The existing theorems
  2737   expand_list_case and expand_option_case have been renamed to
  2738   split_list_case and split_option_case.
  2739 
  2740 * HOL/Arithmetic:
  2741   - `pred n' is automatically converted to `n-1'.
  2742     Users are strongly encouraged not to use `pred' any longer,
  2743     because it will disappear altogether at some point.
  2744   - Users are strongly encouraged to write "0 < n" rather than
  2745     "n ~= 0". Theorems and proof tools have been modified towards this
  2746     `standard'.
  2747 
  2748 * HOL/Lists:
  2749   the function "set_of_list" has been renamed "set" (and its theorems too);
  2750   the function "nth" now takes its arguments in the reverse order and
  2751   has acquired the infix notation "!" as in "xs!n".
  2752 
  2753 * HOL/Set: UNIV is now a constant and is no longer translated to Compl{};
  2754 
  2755 * HOL/Set: The operator (UN x.B x) now abbreviates (UN x:UNIV. B x) and its
  2756   specialist theorems (like UN1_I) are gone.  Similarly for (INT x.B x);
  2757 
  2758 * HOL/record: extensible records with schematic structural subtyping
  2759 (single inheritance); EXPERIMENTAL version demonstrating the encoding,
  2760 still lacks various theorems and concrete record syntax;
  2761 
  2762 
  2763 *** HOLCF ***
  2764 
  2765 * removed "axioms" and "generated by" sections;
  2766 
  2767 * replaced "ops" section by extended "consts" section, which is capable of
  2768   handling the continuous function space "->" directly;
  2769 
  2770 * domain package:
  2771   . proves theorems immediately and stores them in the theory,
  2772   . creates hierachical name space,
  2773   . now uses normal mixfix annotations (instead of cinfix...),
  2774   . minor changes to some names and values (for consistency),
  2775   . e.g. cases -> casedist, dists_eq -> dist_eqs, [take_lemma] -> take_lemmas,
  2776   . separator between mutual domain defs: changed "," to "and",
  2777   . improved handling of sort constraints;  now they have to
  2778     appear on the left-hand side of the equations only;
  2779 
  2780 * fixed LAM <x,y,zs>.b syntax;
  2781 
  2782 * added extended adm_tac to simplifier in HOLCF -- can now discharge
  2783 adm (%x. P (t x)), where P is chainfinite and t continuous;
  2784 
  2785 
  2786 *** FOL and ZF ***
  2787 
  2788 * FOL: there is a new splitter `split_asm_tac' that can be used e.g.
  2789   with `addloop' of the simplifier to faciliate case splitting in premises.
  2790 
  2791 * qed_spec_mp, qed_goal_spec_mp, qed_goalw_spec_mp are available, as
  2792 in HOL, they strip ALL and --> from proved theorems;
  2793 
  2794 
  2795 
  2796 New in Isabelle94-8 (May 1997)
  2797 ------------------------------
  2798 
  2799 *** General Changes ***
  2800 
  2801 * new utilities to build / run / maintain Isabelle etc. (in parts
  2802 still somewhat experimental); old Makefiles etc. still functional;
  2803 
  2804 * new 'Isabelle System Manual';
  2805 
  2806 * INSTALL text, together with ./configure and ./build scripts;
  2807 
  2808 * reimplemented type inference for greater efficiency, better error
  2809 messages and clean internal interface;
  2810 
  2811 * prlim command for dealing with lots of subgoals (an easier way of
  2812 setting goals_limit);
  2813 
  2814 
  2815 *** Syntax ***
  2816 
  2817 * supports alternative (named) syntax tables (parser and pretty
  2818 printer); internal interface is provided by add_modesyntax(_i);
  2819 
  2820 * Pure, FOL, ZF, HOL, HOLCF now support symbolic input and output; to
  2821 be used in conjunction with the Isabelle symbol font; uses the
  2822 "symbols" syntax table;
  2823 
  2824 * added token_translation interface (may translate name tokens in
  2825 arbitrary ways, dependent on their type (free, bound, tfree, ...) and
  2826 the current print_mode); IMPORTANT: user print translation functions
  2827 are responsible for marking newly introduced bounds
  2828 (Syntax.mark_boundT);
  2829 
  2830 * token translations for modes "xterm" and "xterm_color" that display
  2831 names in bold, underline etc. or colors (which requires a color
  2832 version of xterm);
  2833 
  2834 * infixes may now be declared with names independent of their syntax;
  2835 
  2836 * added typed_print_translation (like print_translation, but may
  2837 access type of constant);
  2838 
  2839 
  2840 *** Classical Reasoner ***
  2841 
  2842 Blast_tac: a new tactic!  It is often more powerful than fast_tac, but has
  2843 some limitations.  Blast_tac...
  2844   + ignores addss, addbefore, addafter; this restriction is intrinsic
  2845   + ignores elimination rules that don't have the correct format
  2846         (the conclusion MUST be a formula variable)
  2847   + ignores types, which can make HOL proofs fail
  2848   + rules must not require higher-order unification, e.g. apply_type in ZF
  2849     [message "Function Var's argument not a bound variable" relates to this]
  2850   + its proof strategy is more general but can actually be slower
  2851 
  2852 * substitution with equality assumptions no longer permutes other
  2853 assumptions;
  2854 
  2855 * minor changes in semantics of addafter (now called addaltern); renamed
  2856 setwrapper to setWrapper and compwrapper to compWrapper; added safe wrapper
  2857 (and access functions for it);
  2858 
  2859 * improved combination of classical reasoner and simplifier:
  2860   + functions for handling clasimpsets
  2861   + improvement of addss: now the simplifier is called _after_ the
  2862     safe steps.
  2863   + safe variant of addss called addSss: uses safe simplifications
  2864     _during_ the safe steps. It is more complete as it allows multiple
  2865     instantiations of unknowns (e.g. with slow_tac).
  2866 
  2867 *** Simplifier ***
  2868 
  2869 * added interface for simplification procedures (functions that
  2870 produce *proven* rewrite rules on the fly, depending on current
  2871 redex);
  2872 
  2873 * ordering on terms as parameter (used for ordered rewriting);
  2874 
  2875 * new functions delcongs, deleqcongs, and Delcongs. richer rep_ss;
  2876 
  2877 * the solver is now split into a safe and an unsafe part.
  2878 This should be invisible for the normal user, except that the
  2879 functions setsolver and addsolver have been renamed to setSolver and
  2880 addSolver; added safe_asm_full_simp_tac;
  2881 
  2882 
  2883 *** HOL ***
  2884 
  2885 * a generic induction tactic `induct_tac' which works for all datatypes and
  2886 also for type `nat';
  2887 
  2888 * a generic case distinction tactic `exhaust_tac' which works for all
  2889 datatypes and also for type `nat';
  2890 
  2891 * each datatype comes with a function `size';
  2892 
  2893 * patterns in case expressions allow tuple patterns as arguments to
  2894 constructors, for example `case x of [] => ... | (x,y,z)#ps => ...';
  2895 
  2896 * primrec now also works with type nat;
  2897 
  2898 * recdef: a new declaration form, allows general recursive functions to be
  2899 defined in theory files.  See HOL/ex/Fib, HOL/ex/Primes, HOL/Subst/Unify.
  2900 
  2901 * the constant for negation has been renamed from "not" to "Not" to
  2902 harmonize with FOL, ZF, LK, etc.;
  2903 
  2904 * HOL/ex/LFilter theory of a corecursive "filter" functional for
  2905 infinite lists;
  2906 
  2907 * HOL/Modelcheck demonstrates invocation of model checker oracle;
  2908 
  2909 * HOL/ex/Ring.thy declares cring_simp, which solves equational
  2910 problems in commutative rings, using axiomatic type classes for + and *;
  2911 
  2912 * more examples in HOL/MiniML and HOL/Auth;
  2913 
  2914 * more default rewrite rules for quantifiers, union/intersection;
  2915 
  2916 * a new constant `arbitrary == @x.False';
  2917 
  2918 * HOLCF/IOA replaces old HOL/IOA;
  2919 
  2920 * HOLCF changes: derived all rules and arities
  2921   + axiomatic type classes instead of classes
  2922   + typedef instead of faking type definitions
  2923   + eliminated the internal constants less_fun, less_cfun, UU_fun, UU_cfun etc.
  2924   + new axclasses cpo, chfin, flat with flat < chfin < pcpo < cpo < po
  2925   + eliminated the types void, one, tr
  2926   + use unit lift and bool lift (with translations) instead of one and tr
  2927   + eliminated blift from Lift3.thy (use Def instead of blift)
  2928   all eliminated rules are derived as theorems --> no visible changes ;
  2929 
  2930 
  2931 *** ZF ***
  2932 
  2933 * ZF now has Fast_tac, Simp_tac and Auto_tac.  Union_iff is a now a default
  2934 rewrite rule; this may affect some proofs.  eq_cs is gone but can be put back
  2935 as ZF_cs addSIs [equalityI];
  2936 
  2937 
  2938 
  2939 New in Isabelle94-7 (November 96)
  2940 ---------------------------------
  2941 
  2942 * allowing negative levels (as offsets) in prlev and choplev;
  2943 
  2944 * super-linear speedup for large simplifications;
  2945 
  2946 * FOL, ZF and HOL now use miniscoping: rewriting pushes
  2947 quantifications in as far as possible (COULD MAKE EXISTING PROOFS
  2948 FAIL); can suppress it using the command Delsimps (ex_simps @
  2949 all_simps); De Morgan laws are also now included, by default;
  2950 
  2951 * improved printing of ==>  :  ~:
  2952 
  2953 * new object-logic "Sequents" adds linear logic, while replacing LK
  2954 and Modal (thanks to Sara Kalvala);
  2955 
  2956 * HOL/Auth: correctness proofs for authentication protocols;
  2957 
  2958 * HOL: new auto_tac combines rewriting and classical reasoning (many
  2959 examples on HOL/Auth);
  2960 
  2961 * HOL: new command AddIffs for declaring theorems of the form P=Q to
  2962 the rewriter and classical reasoner simultaneously;
  2963 
  2964 * function uresult no longer returns theorems in "standard" format;
  2965 regain previous version by: val uresult = standard o uresult;
  2966 
  2967 
  2968 
  2969 New in Isabelle94-6
  2970 -------------------
  2971 
  2972 * oracles -- these establish an interface between Isabelle and trusted
  2973 external reasoners, which may deliver results as theorems;
  2974 
  2975 * proof objects (in particular record all uses of oracles);
  2976 
  2977 * Simp_tac, Fast_tac, etc. that refer to implicit simpset / claset;
  2978 
  2979 * "constdefs" section in theory files;
  2980 
  2981 * "primrec" section (HOL) no longer requires names;
  2982 
  2983 * internal type "tactic" now simply "thm -> thm Sequence.seq";
  2984 
  2985 
  2986 
  2987 New in Isabelle94-5
  2988 -------------------
  2989 
  2990 * reduced space requirements;
  2991 
  2992 * automatic HTML generation from theories;
  2993 
  2994 * theory files no longer require "..." (quotes) around most types;
  2995 
  2996 * new examples, including two proofs of the Church-Rosser theorem;
  2997 
  2998 * non-curried (1994) version of HOL is no longer distributed;
  2999 
  3000 
  3001 
  3002 New in Isabelle94-4
  3003 -------------------
  3004 
  3005 * greatly reduced space requirements;
  3006 
  3007 * theory files (.thy) no longer require \...\ escapes at line breaks;
  3008 
  3009 * searchable theorem database (see the section "Retrieving theorems" on
  3010 page 8 of the Reference Manual);
  3011 
  3012 * new examples, including Grabczewski's monumental case study of the
  3013 Axiom of Choice;
  3014 
  3015 * The previous version of HOL renamed to Old_HOL;
  3016 
  3017 * The new version of HOL (previously called CHOL) uses a curried syntax
  3018 for functions.  Application looks like f a b instead of f(a,b);
  3019 
  3020 * Mutually recursive inductive definitions finally work in HOL;
  3021 
  3022 * In ZF, pattern-matching on tuples is now available in all abstractions and
  3023 translates to the operator "split";
  3024 
  3025 
  3026 
  3027 New in Isabelle94-3
  3028 -------------------
  3029 
  3030 * new infix operator, addss, allowing the classical reasoner to
  3031 perform simplification at each step of its search.  Example:
  3032         fast_tac (cs addss ss)
  3033 
  3034 * a new logic, CHOL, the same as HOL, but with a curried syntax
  3035 for functions.  Application looks like f a b instead of f(a,b).  Also pairs
  3036 look like (a,b) instead of <a,b>;
  3037 
  3038 * PLEASE NOTE: CHOL will eventually replace HOL!
  3039 
  3040 * In CHOL, pattern-matching on tuples is now available in all abstractions.
  3041 It translates to the operator "split".  A new theory of integers is available;
  3042 
  3043 * In ZF, integer numerals now denote two's-complement binary integers.
  3044 Arithmetic operations can be performed by rewriting.  See ZF/ex/Bin.ML;
  3045 
  3046 * Many new examples: I/O automata, Church-Rosser theorem, equivalents
  3047 of the Axiom of Choice;
  3048 
  3049 
  3050 
  3051 New in Isabelle94-2
  3052 -------------------
  3053 
  3054 * Significantly faster resolution;
  3055 
  3056 * the different sections in a .thy file can now be mixed and repeated
  3057 freely;
  3058 
  3059 * Database of theorems for FOL, HOL and ZF.  New
  3060 commands including qed, qed_goal and bind_thm store theorems in the database.
  3061 
  3062 * Simple database queries: return a named theorem (get_thm) or all theorems of
  3063 a given theory (thms_of), or find out what theory a theorem was proved in
  3064 (theory_of_thm);
  3065 
  3066 * Bugs fixed in the inductive definition and datatype packages;
  3067 
  3068 * The classical reasoner provides deepen_tac and depth_tac, making FOL_dup_cs
  3069 and HOL_dup_cs obsolete;
  3070 
  3071 * Syntactic ambiguities caused by the new treatment of syntax in Isabelle94-1
  3072 have been removed;
  3073 
  3074 * Simpler definition of function space in ZF;
  3075 
  3076 * new results about cardinal and ordinal arithmetic in ZF;
  3077 
  3078 * 'subtype' facility in HOL for introducing new types as subsets of existing
  3079 types;
  3080 
  3081 
  3082 $Id$