NEWS
author wenzelm
Sat Jun 04 18:20:00 2005 +0200 (2005-06-04)
changeset 16234 421c3522f160
parent 16181 22324687e2d2
child 16251 121dc80d120a
permissions -rw-r--r--
major reorganization and cleanup;
     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   uses <file1> ... <fileM>
    14   begin
    15 
    16 where the 'uses' part is optional.  The previous syntax
    17 
    18   theory <name> = <theory1> + ... + <theoryN>:
    19 
    20 will disappear in the next release.  Note that there is no change in
    21 ancient non-Isar theories.
    22 
    23 * Theory loader: parent theories can now also be referred to via
    24 relative and absolute paths.
    25 
    26 * Improved version of thms_containing searches for a list of criteria
    27 instead of a list of constants. Known criteria are: intro, elim, dest,
    28 name:string, simp:term, and any term. Criteria can be preceded by '-'
    29 to select theorems that do not match. Intro, elim, dest select
    30 theorems that match the current goal, name:s selects theorems whose
    31 fully qualified name contain s, and simp:term selects all
    32 simplification rules whose lhs match term.  Any other term is
    33 interpreted as pattern and selects all theorems matching the
    34 pattern. Available in ProofGeneral under 'ProofGeneral -> Find
    35 Theorems' or C-c C-f.  Example:
    36 
    37   C-c C-f (100) "(_::nat) + _ + _" intro -name:"HOL."
    38 
    39 prints the last 100 theorems matching the pattern "(_::nat) + _ + _",
    40 matching the current goal as introduction rule and not having "HOL."
    41 in their name (i.e. not being defined in theory HOL).
    42 
    43 
    44 *** Document preparation ***
    45 
    46 * Commands 'display_drafts' and 'print_drafts' perform simple output
    47 of raw sources.  Only those symbols that do not require additional
    48 LaTeX packages (depending on comments in isabellesym.sty) are
    49 displayed properly, everything else is left verbatim.  isatool display
    50 and isatool print are used as front ends (these are subject to the
    51 DVI/PDF_VIEWER and PRINT_COMMAND settings, respectively).
    52 
    53 * There is now a flag to control hiding of proofs and some other
    54 commands (such as 'ML' or 'parse/print_translation') in document
    55 output.  Hiding is enabled by default, and can be disabled by the
    56 option '-H false' of isatool usedir or by resetting the reference
    57 variable IsarOutput.hide_commands in ML.  Additional commands to be
    58 hidden may be declared using IsarOutput.add_hidden_commands.
    59 
    60 * Several new antiquotation:
    61 
    62   @{term_type term} prints a term with its type annotated;
    63 
    64   @{typeof term} prints the type of a term;
    65 
    66   @{const const} is the same as @{term const}, but checks that the
    67   argument is a known logical constant;
    68 
    69   @{term_style style term} and @{thm_style style thm} print a term or
    70   theorem applying a "style" to it
    71 
    72 Predefined styles are 'lhs' and 'rhs' printing the lhs/rhs of
    73 definitions, equations, inequations etc., 'concl' printing only the
    74 conclusion of a meta-logical statement theorem, and 'prem1' .. 'prem9'
    75 to print the specified premise.  TermStyle.add_style provides an ML
    76 interface for introducing further styles.  See also the "LaTeX Sugar"
    77 document practical applications.
    78 
    79 
    80 *** Pure ***
    81 
    82 * Considerably improved version of 'constdefs' command.  Now performs
    83 automatic type-inference of declared constants; additional support for
    84 local structure declarations (cf. locales and HOL records), see also
    85 isar-ref manual.  Potential INCOMPATIBILITY: need to observe strictly
    86 sequential dependencies of definitions within a single 'constdefs'
    87 section; moreover, the declared name needs to be an identifier.  If
    88 all fails, consider to fall back on 'consts' and 'defs' separately.
    89 
    90 * Improved indexed syntax and implicit structures.  First of all,
    91 indexed syntax provides a notational device for subscripted
    92 application, using the new syntax \<^bsub>term\<^esub> for arbitrary
    93 expressions.  Secondly, in a local context with structure
    94 declarations, number indexes \<^sub>n or the empty index (default
    95 number 1) refer to a certain fixed variable implicitly; option
    96 show_structs controls printing of implicit structures.  Typical
    97 applications of these concepts involve record types and locales.
    98 
    99 * New command 'no_syntax' removes grammar declarations (and
   100 translations) resulting from the given syntax specification, which is
   101 interpreted in the same manner as for the 'syntax' command.
   102 
   103 * 'Advanced' translation functions (parse_translation etc.) may depend
   104 on the signature of the theory context being presently used for
   105 parsing/printing, see also isar-ref manual.
   106 
   107 * Improved internal renaming of symbolic identifiers -- attach primes
   108 instead of base 26 numbers.
   109 
   110 * New flag show_question_marks controls printing of leading question
   111 marks in schematic variable names.
   112 
   113 * In schematic variable names, *any* symbol following \<^isub> or
   114 \<^isup> is now treated as part of the base name.  For example, the
   115 following works without printing of awkward ".0" indexes:
   116 
   117   lemma "x\<^isub>1 = x\<^isub>2 ==> x\<^isub>2 = x\<^isub>1"
   118     by simp
   119 
   120 * Inner syntax includes (*(*nested*) comments*).
   121 
   122 * Pretty pinter now supports unbreakable blocks, specified in mixfix
   123 annotations as "(00...)".
   124 
   125 * Clear separation of logical types and nonterminals, where the latter
   126 may only occur in 'syntax' specifications or type abbreviations.
   127 Before that distinction was only partially implemented via type class
   128 "logic" vs. "{}".  Potential INCOMPATIBILITY in rare cases of improper
   129 use of 'types'/'consts' instead of 'nonterminals'/'syntax'.  Some very
   130 exotic syntax specifications may require further adaption
   131 (e.g. Cube/Base.thy).
   132 
   133 * Removed obsolete type class "logic", use the top sort {} instead.
   134 Note that non-logical types should be declared as 'nonterminals'
   135 rather than 'types'.  INCOMPATIBILITY for new object-logic
   136 specifications.
   137 
   138 * Simplifier: can now control the depth to which conditional rewriting
   139 is traced via the PG menu Isabelle -> Settings -> Trace Simp Depth
   140 Limit.
   141 
   142 * Simplifier: simplification procedures may now take the current
   143 simpset into account (cf. Simplifier.simproc(_i) / mk_simproc
   144 interface), which is very useful for calling the Simplifier
   145 recursively.  Minor INCOMPATIBILITY: the 'prems' argument of simprocs
   146 is gone -- use prems_of_ss on the simpset instead.  Moreover, the
   147 low-level mk_simproc no longer applies Logic.varify internally, to
   148 allow for use in a context of fixed variables.
   149 
   150 * thin_tac now works even if the assumption being deleted contains !!
   151 or ==>.  More generally, erule now works even if the major premise of
   152 the elimination rule contains !! or ==>.
   153 
   154 * Reorganized bootstrapping of the Pure theories; CPure is now derived
   155 from Pure, which contains all common declarations already.  Both
   156 theories are defined via plain Isabelle/Isar .thy files.
   157 INCOMPATIBILITY: elements of CPure (such as the CPure.intro /
   158 CPure.elim / CPure.dest attributes) now appear in the Pure name space;
   159 use isatool fixcpure to adapt your theory and ML sources.
   160 
   161 * New syntax 'name(i-j, i-, i, ...)' for referring to specific
   162 selections of theorems in named facts via index ranges.
   163 
   164 
   165 *** Locales ***
   166   
   167 * New commands for the interpretation of locale expressions in
   168 theories ('interpretation') and proof contexts ('interpret').  These
   169 take an instantiation of the locale parameters and compute proof
   170 obligations from the instantiated specification.  After the
   171 obligations have been discharged, the instantiated theorems of the
   172 locale are added to the theory or proof context.  Interpretation is
   173 smart in that already active interpretations do not occur in proof
   174 obligations, neither are instantiated theorems stored in duplicate.
   175 Use print_interps to inspect active interpretations of a particular
   176 locale.  For details, see the Isar Reference manual.
   177 
   178 INCOMPATIBILITY: former 'instantiate' has been withdrawn, use
   179 'interpret' instead.
   180 
   181 * Proper static binding of attribute syntax -- i.e. types / terms /
   182 facts mentioned as arguments are always those of the locale definition
   183 context, independently of the context of later invocations.  Moreover,
   184 locale operations (renaming and type / term instantiation) are applied
   185 to attribute arguments as expected.
   186 
   187 INCOMPATIBILITY of the ML interface: always pass Attrib.src instead of
   188 actual attributes; rare situations may require Attrib.attribute to
   189 embed those attributes into Attrib.src that lack concrete syntax.
   190 Attribute implementations need to cooperate properly with the static
   191 binding mechanism.  Basic parsers Args.XXX_typ/term/prop and
   192 Attrib.XXX_thm etc. already do the right thing without further
   193 intervention.  Only unusual applications -- such as "where" or "of"
   194 (cf. src/Pure/Isar/attrib.ML), which process arguments depending both
   195 on the context and the facts involved -- may have to assign parsed
   196 values to argument tokens explicitly.
   197 
   198 * New context element "constrains" adds type constraints to parameters --
   199 there is no logical significance.
   200 
   201 * Context expressions: renaming parameters permits syntax
   202 redeclaration as well.
   203 
   204 * Locale definition: 'includes' now disallowed.
   205 
   206 * Changed parameter management in theorem generation for long goal
   207 statements with 'includes'.  INCOMPATIBILITY: produces a different
   208 theorem statement in rare situations.
   209 
   210 * Attributes 'induct' and 'cases': type or set names may now be
   211 locally fixed variables as well.
   212 
   213 * Antiquotations now provide the option 'locale=NAME' to specify an
   214 alternative context used for evaluating and printing the subsequent
   215 argument, as in @{thm [locale=LC] fold_commute}, for example.
   216 
   217 
   218 *** Provers ***
   219 
   220 * Provers/hypsubst.ML: improved version of the subst method, for
   221 single-step rewriting: it now works in bound variable contexts. New is
   222 'subst (asm)', for rewriting an assumption.  INCOMPATIBILITY: may
   223 rewrite a different subterm than the original subst method, which is
   224 still available as 'simplesubst'.
   225 
   226 * Provers/quasi.ML: new transitivity reasoners for transitivity only
   227 and quasi orders.
   228 
   229 * Provers/trancl.ML: new transitivity reasoner for transitive and
   230 reflexive-transitive closure of relations.
   231 
   232 * Provers/blast.ML: new reference depth_limit to make blast's depth
   233 limit (previously hard-coded with a value of 20) user-definable.
   234 
   235 * Provers/simplifier.ML has been moved to Pure, where Simplifier.setup
   236 is peformed already.  Object-logics merely need to finish their
   237 initial simpset configuration as before.  INCOMPATIBILITY.
   238 
   239 
   240 *** HOL ***
   241 
   242 * Symbolic syntax of Hilbert Choice Operator is now as follows:
   243 
   244   syntax (epsilon)
   245     "_Eps" :: "[pttrn, bool] => 'a"    ("(3\<some>_./ _)" [0, 10] 10)
   246 
   247 The symbol \<some> is displayed as the alternative epsilon of LaTeX
   248 and x-symbol; use option '-m epsilon' to get it actually printed.
   249 Moreover, the mathematically important symbolic identifier \<epsilon>
   250 becomes available as variable, constant etc.  INCOMPATIBILITY,
   251 
   252 * "x > y" abbreviates "y < x" and "x >= y" abbreviates "y <= x".
   253 Similarly for all quantifiers: "ALL x > y" etc.  The x-symbol for >=
   254 is \<ge>.
   255 
   256 * "{x:A. P}" abbreviates "{x. x:A & P}", and similarly for "\<in>"
   257 instead of ":".
   258 
   259 * theory SetInterval: changed the syntax for open intervals:
   260 
   261   Old       New
   262   {..n(}    {..<n}
   263   {)n..}    {n<..}
   264   {m..n(}   {m..<n}
   265   {)m..n}   {m<..n}
   266   {)m..n(}  {m<..<n}
   267 
   268 The old syntax is still supported but will disappear in the next
   269 release.  For conversion use the following Emacs search and replace
   270 patterns (these are not perfect but work quite well):
   271 
   272   {)\([^\.]*\)\.\.  ->  {\1<\.\.}
   273   \.\.\([^(}]*\)(}  ->  \.\.<\1}
   274 
   275 * theory Finite_Set: changed the syntax for 'setsum', summation over
   276 finite sets: "setsum (%x. e) A", which used to be "\<Sum>x:A. e", is
   277 now either "SUM x:A. e" or "\<Sum>x \<in> A. e".
   278 
   279 Some new syntax forms are available:
   280 
   281   "\<Sum>x | P. e"      for     "setsum (%x. e) {x. P}"
   282   "\<Sum>x = a..b. e"   for     "setsum (%x. e) {a..b}"
   283   "\<Sum>x = a..<b. e"  for     "setsum (%x. e) {a..<b}"
   284   "\<Sum>x < k. e"      for     "setsum (%x. e) {..<k}"
   285 
   286 The latter form "\<Sum>x < k. e" used to be based on a separate
   287 function "Summation", which has been discontinued.
   288 
   289 * theory Finite_Set: in structured induction proofs, the insert case
   290 is now 'case (insert x F)' instead of the old counterintuitive 'case
   291 (insert F x)'.
   292 
   293 * The 'refute' command has been extended to support a much larger
   294 fragment of HOL, including axiomatic type classes, constdefs and
   295 typedefs, inductive datatypes and recursion.
   296 
   297 * Datatype induction via method 'induct' now preserves the name of the
   298 induction variable. For example, when proving P(xs::'a list) by
   299 induction on xs, the induction step is now P(xs) ==> P(a#xs) rather
   300 than P(list) ==> P(a#list) as previously.  Potential INCOMPATIBILITY
   301 in unstructured proof scripts.
   302 
   303 * Reworked implementation of records.  Improved scalability for
   304 records with many fields, avoiding performance problems for type
   305 inference. Records are no longer composed of nested field types, but
   306 of nested extension types. Therefore the record type only grows linear
   307 in the number of extensions and not in the number of fields.  The
   308 top-level (users) view on records is preserved.  Potential
   309 INCOMPATIBILITY only in strange cases, where the theory depends on the
   310 old record representation. The type generated for a record is called
   311 <record_name>_ext_type.
   312 
   313 Flag record_quick_and_dirty_sensitive can be enabled to skip the
   314 proofs triggered by a record definition or a simproc (if
   315 quick_and_dirty is enabled).  Definitions of large records can take
   316 quite long.
   317 
   318 New simproc record_upd_simproc for simplification of multiple record
   319 updates enabled by default.  Moreover, trivial updates are also
   320 removed: r(|x := x r|) = r.  INCOMPATIBILITY: old proofs break
   321 occasionally, since simplification is more powerful by default.
   322 
   323 * Simplifier: automatically reasons about transitivity chains
   324 involving "trancl" (r^+) and "rtrancl" (r^*) by setting up tactics
   325 provided by Provers/trancl.ML as additional solvers.  INCOMPATIBILITY:
   326 old proofs break occasionally as simplification may now solve more
   327 goals than previously.
   328 
   329 * Simplifier: converts x <= y into x = y if assumption y <= x is
   330 present.  Works for all partial orders (class "order"), in particular
   331 numbers and sets.  For linear orders (e.g. numbers) it treats ~ x < y
   332 just like y <= x.
   333 
   334 * Simplifier: new simproc for "let x = a in f x".  If a is a free or
   335 bound variable or a constant then the let is unfolded.  Otherwise
   336 first a is simplified to b, and then f b is simplified to g. If
   337 possible we abstract b from g arriving at "let x = b in h x",
   338 otherwise we unfold the let and arrive at g.  The simproc can be
   339 enabled/disabled by the reference use_let_simproc.  Potential
   340 INCOMPATIBILITY since simplification is more powerful by default.
   341 
   342 
   343 *** HOLCF ***
   344 
   345 * HOLCF: discontinued special version of 'constdefs' (which used to
   346 support continuous functions) in favor of the general Pure one with
   347 full type-inference.
   348 
   349 
   350 *** ZF ***
   351 
   352 * ZF/ex: theories Group and Ring provide examples in abstract algebra,
   353 including the First Isomorphism Theorem (on quotienting by the kernel
   354 of a homomorphism).
   355 
   356 * ZF/Simplifier: install second copy of type solver that actually
   357 makes use of TC rules declared to Isar proof contexts (or locales);
   358 the old version is still required for ML proof scripts.
   359 
   360 
   361 *** ML ***
   362 
   363 * Pure/library.ML no longer defines its own option datatype, but uses
   364 that of the SML basis, which has constructors NONE and SOME instead of
   365 None and Some, as well as exception Option.Option instead of OPTION.
   366 The functions the, if_none, is_some, is_none have been adapted
   367 accordingly, while Option.map replaces apsome.
   368 
   369 * The exception LIST has been given up in favour of the standard
   370 exceptions Empty and Subscript, as well as Library.UnequalLengths.
   371 Function like Library.hd and Library.tl are superceded by the standard
   372 hd and tl functions etc.
   373 
   374 A number of basic functions are now no longer exported to the ML
   375 toplevel, as they are variants of standard functions.  The following
   376 suggests how one can translate existing code:
   377 
   378     rev_append xs ys = List.revAppend (xs, ys)
   379     nth_elem (i, xs) = List.nth (xs, i)
   380     last_elem xs = List.last xs
   381     flat xss = List.concat xss
   382     seq fs = List.app fs
   383     partition P xs = List.partition P xs
   384     filter P xs = List.filter P xs
   385     mapfilter f xs = List.mapPartial f xs
   386 
   387 * Pure: output via the Isabelle channels of writeln/warning/error
   388 etc. is now passed through Output.output, with a hook for arbitrary
   389 transformations depending on the print_mode (cf. Output.add_mode --
   390 the first active mode that provides a output function wins).  Already
   391 formatted output may be embedded into further text via Output.raw; the
   392 result of Pretty.string_of/str_of and derived functions
   393 (string_of_term/cterm/thm etc.) is already marked raw to accommodate
   394 easy composition of diagnostic messages etc.  Programmers rarely need
   395 to care about Output.output or Output.raw at all, with some notable
   396 exceptions: Output.output is required when bypassing the standard
   397 channels (writeln etc.), or in token translations to produce properly
   398 formatted results; Output.raw is required when capturing already
   399 output material that will eventually be presented to the user a second
   400 time.  For the default print mode, both Output.output and Output.raw
   401 have no effect.
   402 
   403 * Pure: print_tac now outputs the goal through the trace channel.
   404 
   405 * Isar debugging: new reference Toplevel.debug; default false.  Set to
   406 make printing of exceptions THM, TERM, TYPE and THEORY more verbose.
   407 
   408 * Pure: name spaces have been refined, with significant changes of the
   409 internal interfaces -- INCOMPATIBILITY.  Renamed cond_extern(_table)
   410 to extern(_table).  The plain name entry path is superceded by a
   411 general 'naming' context, which also includes the 'policy' to produce
   412 a fully qualified name and external accesses of a fully qualified
   413 name; NameSpace.extend is superceded by context dependent
   414 Sign.declare_name.  Several theory and proof context operations modify
   415 the naming context.  Especially note Theory.restore_naming and
   416 ProofContext.restore_naming to get back to a sane state; note that
   417 Theory.add_path is no longer sufficient to recover from
   418 Theory.absolute_path in particular.
   419 
   420 * Pure: new flags short_names (default false) and unique_names
   421 (default true) for controlling output of qualified names.  If
   422 short_names is set, names are printed unqualified.  If unique_names is
   423 reset, the name prefix is reduced to the minimum required to achieve
   424 the original result when interning again, even if there is an overlap
   425 with earlier declarations.
   426 
   427 * Pure: cases produced by proof methods specify options, where NONE
   428 means to remove case bindings -- INCOMPATIBILITY in
   429 (RAW_)METHOD_CASES.
   430 
   431 * Provers: Simplifier and Classical Reasoner now support proof context
   432 dependent plug-ins (simprocs, solvers, wrappers etc.).  These extra
   433 components are stored in the theory and patched into the
   434 simpset/claset when used in an Isar proof context.  Context dependent
   435 components are maintained by the following theory operations:
   436 
   437   Simplifier.add_context_simprocs
   438   Simplifier.del_context_simprocs
   439   Simplifier.set_context_subgoaler
   440   Simplifier.reset_context_subgoaler
   441   Simplifier.add_context_looper
   442   Simplifier.del_context_looper
   443   Simplifier.add_context_unsafe_solver
   444   Simplifier.add_context_safe_solver
   445 
   446   Classical.add_context_safe_wrapper
   447   Classical.del_context_safe_wrapper
   448   Classical.add_context_unsafe_wrapper
   449   Classical.del_context_unsafe_wrapper
   450 
   451 IMPORTANT NOTE: proof tools (methods etc.) need to use
   452 local_simpset_of and local_claset_of to instead of the primitive
   453 Simplifier.get_local_simpset and Classical.get_local_claset,
   454 respectively, in order to see the context dependent fields!
   455 
   456 
   457 *** System ***
   458 
   459 * Allow symlinks to all proper Isabelle executables (Isabelle,
   460 isabelle, isatool etc.).
   461 
   462 * ISABELLE_DOC_FORMAT setting specifies preferred document format (for
   463 isatool doc, isatool mkdir, display_drafts etc.).
   464 
   465 * isatool usedir: option -f allows specification of the ML file to be
   466 used by Isabelle; default is ROOT.ML.
   467 
   468 * HOL: isatool dimacs2hol converts files in DIMACS CNF format
   469 (containing Boolean satisfiability problems) into Isabelle/HOL
   470 theories.
   471 
   472 
   473 
   474 New in Isabelle2004 (April 2004)
   475 --------------------------------
   476 
   477 *** General ***
   478 
   479 * Provers/order.ML:  new efficient reasoner for partial and linear orders.
   480   Replaces linorder.ML.
   481 
   482 * Pure: Greek letters (except small lambda, \<lambda>), as well as Gothic
   483   (\<aa>...\<zz>\<AA>...\<ZZ>), calligraphic (\<A>...\<Z>), and Euler
   484   (\<a>...\<z>), are now considered normal letters, and can therefore
   485   be used anywhere where an ASCII letter (a...zA...Z) has until
   486   now. COMPATIBILITY: This obviously changes the parsing of some
   487   terms, especially where a symbol has been used as a binder, say
   488   '\<Pi>x. ...', which is now a type error since \<Pi>x will be parsed
   489   as an identifier.  Fix it by inserting a space around former
   490   symbols.  Call 'isatool fixgreek' to try to fix parsing errors in
   491   existing theory and ML files.
   492 
   493 * Pure: Macintosh and Windows line-breaks are now allowed in theory files.
   494 
   495 * Pure: single letter sub/superscripts (\<^isub> and \<^isup>) are now
   496   allowed in identifiers. Similar to Greek letters \<^isub> is now considered
   497   a normal (but invisible) letter. For multiple letter subscripts repeat
   498   \<^isub> like this: x\<^isub>1\<^isub>2.
   499 
   500 * Pure: There are now sub-/superscripts that can span more than one
   501   character. Text between \<^bsub> and \<^esub> is set in subscript in
   502   ProofGeneral and LaTeX, text between \<^bsup> and \<^esup> in
   503   superscript. The new control characters are not identifier parts.
   504 
   505 * Pure: Control-symbols of the form \<^raw:...> will literally print the
   506   content of "..." to the latex file instead of \isacntrl... . The "..."
   507   may consist of any printable characters excluding the end bracket >.
   508 
   509 * Pure: Using new Isar command "finalconsts" (or the ML functions
   510   Theory.add_finals or Theory.add_finals_i) it is now possible to
   511   declare constants "final", which prevents their being given a definition
   512   later.  It is useful for constants whose behaviour is fixed axiomatically
   513   rather than definitionally, such as the meta-logic connectives.
   514 
   515 * Pure: 'instance' now handles general arities with general sorts
   516   (i.e. intersections of classes),
   517 
   518 * Presentation: generated HTML now uses a CSS style sheet to make layout
   519   (somewhat) independent of content. It is copied from lib/html/isabelle.css.
   520   It can be changed to alter the colors/layout of generated pages.
   521 
   522 
   523 *** Isar ***
   524 
   525 * Tactic emulation methods rule_tac, erule_tac, drule_tac, frule_tac,
   526   cut_tac, subgoal_tac and thin_tac:
   527   - Now understand static (Isar) contexts.  As a consequence, users of Isar
   528     locales are no longer forced to write Isar proof scripts.
   529     For details see Isar Reference Manual, paragraph 4.3.2: Further tactic
   530     emulations.
   531   - INCOMPATIBILITY: names of variables to be instantiated may no
   532     longer be enclosed in quotes.  Instead, precede variable name with `?'.
   533     This is consistent with the instantiation attribute "where".
   534 
   535 * Attributes "where" and "of":
   536   - Now take type variables of instantiated theorem into account when reading
   537     the instantiation string.  This fixes a bug that caused instantiated
   538     theorems to have too special types in some circumstances.
   539   - "where" permits explicit instantiations of type variables.
   540 
   541 * Calculation commands "moreover" and "also" no longer interfere with
   542   current facts ("this"), admitting arbitrary combinations with "then"
   543   and derived forms.
   544 
   545 * Locales:
   546   - Goal statements involving the context element "includes" no longer
   547     generate theorems with internal delta predicates (those ending on
   548     "_axioms") in the premise.
   549     Resolve particular premise with <locale>.intro to obtain old form.
   550   - Fixed bug in type inference ("unify_frozen") that prevented mix of target
   551     specification and "includes" elements in goal statement.
   552   - Rule sets <locale>.intro and <locale>.axioms no longer declared as
   553     [intro?] and [elim?] (respectively) by default.
   554   - Experimental command for instantiation of locales in proof contexts:
   555         instantiate <label>[<attrs>]: <loc>
   556     Instantiates locale <loc> and adds all its theorems to the current context
   557     taking into account their attributes.  Label and attrs are optional
   558     modifiers, like in theorem declarations.  If present, names of
   559     instantiated theorems are qualified with <label>, and the attributes
   560     <attrs> are applied after any attributes these theorems might have already.
   561       If the locale has assumptions, a chained fact of the form
   562     "<loc> t1 ... tn" is expected from which instantiations of the parameters
   563     are derived.  The command does not support old-style locales declared
   564     with "locale (open)".
   565       A few (very simple) examples can be found in FOL/ex/LocaleInst.thy.
   566 
   567 * HOL: Tactic emulation methods induct_tac and case_tac understand static
   568   (Isar) contexts.
   569 
   570 
   571 *** HOL ***
   572 
   573 * Proof import: new image HOL4 contains the imported library from
   574   the HOL4 system with about 2500 theorems. It is imported by
   575   replaying proof terms produced by HOL4 in Isabelle. The HOL4 image
   576   can be used like any other Isabelle image.  See
   577   HOL/Import/HOL/README for more information.
   578 
   579 * Simplifier:
   580   - Much improved handling of linear and partial orders.
   581     Reasoners for linear and partial orders are set up for type classes
   582     "linorder" and "order" respectively, and are added to the default simpset
   583     as solvers.  This means that the simplifier can build transitivity chains
   584     to solve goals from the assumptions.
   585   - INCOMPATIBILITY: old proofs break occasionally.  Typically, applications
   586     of blast or auto after simplification become unnecessary because the goal
   587     is solved by simplification already.
   588 
   589 * Numerics: new theory Ring_and_Field contains over 250 basic numerical laws,
   590     all proved in axiomatic type classes for semirings, rings and fields.
   591 
   592 * Numerics:
   593   - Numeric types (nat, int, and in HOL-Complex rat, real, complex, etc.) are
   594     now formalized using the Ring_and_Field theory mentioned above.
   595   - INCOMPATIBILITY: simplification and arithmetic behaves somewhat differently
   596     than before, because now they are set up once in a generic manner.
   597   - INCOMPATIBILITY: many type-specific arithmetic laws have gone.
   598     Look for the general versions in Ring_and_Field (and Power if they concern
   599     exponentiation).
   600 
   601 * Type "rat" of the rational numbers is now available in HOL-Complex.
   602 
   603 * Records:
   604   - Record types are now by default printed with their type abbreviation
   605     instead of the list of all field types. This can be configured via
   606     the reference "print_record_type_abbr".
   607   - Simproc "record_upd_simproc" for simplification of multiple updates added
   608     (not enabled by default).
   609   - Simproc "record_ex_sel_eq_simproc" to simplify EX x. sel r = x resp.
   610     EX x. x = sel r to True (not enabled by default).
   611   - Tactic "record_split_simp_tac" to split and simplify records added.
   612 
   613 * 'specification' command added, allowing for definition by
   614   specification.  There is also an 'ax_specification' command that
   615   introduces the new constants axiomatically.
   616 
   617 * arith(_tac) is now able to generate counterexamples for reals as well.
   618 
   619 * HOL-Algebra: new locale "ring" for non-commutative rings.
   620 
   621 * HOL-ex: InductiveInvariant_examples illustrates advanced recursive function
   622   definitions, thanks to Sava Krsti\'{c} and John Matthews.
   623 
   624 * HOL-Matrix: a first theory for matrices in HOL with an application of
   625   matrix theory to linear programming.
   626 
   627 * Unions and Intersections:
   628   The latex output syntax of UN and INT has been changed
   629   from "\Union x \in A. B" to "\Union_{x \in A} B"
   630   i.e. the index formulae has become a subscript.
   631   Similarly for "\Union x. B", and for \Inter instead of \Union.
   632 
   633 * Unions and Intersections over Intervals:
   634   There is new short syntax "UN i<=n. A" for "UN i:{0..n}. A". There is
   635   also an x-symbol version with subscripts "\<Union>\<^bsub>i <= n\<^esub>. A"
   636   like in normal math, and corresponding versions for < and for intersection.
   637 
   638 * HOL/List: Ordering "lexico" is renamed "lenlex" and the standard
   639   lexicographic dictonary ordering has been added as "lexord".
   640 
   641 * ML: the legacy theory structures Int and List have been removed. They had
   642   conflicted with ML Basis Library structures having the same names.
   643 
   644 * 'refute' command added to search for (finite) countermodels.  Only works
   645   for a fragment of HOL.  The installation of an external SAT solver is
   646   highly recommended.  See "HOL/Refute.thy" for details.
   647 
   648 * 'quickcheck' command: Allows to find counterexamples by evaluating
   649   formulae under an assignment of free variables to random values.
   650   In contrast to 'refute', it can deal with inductive datatypes,
   651   but cannot handle quantifiers. See "HOL/ex/Quickcheck_Examples.thy"
   652   for examples.
   653 
   654 
   655 *** HOLCF ***
   656 
   657 * Streams now come with concatenation and are part of the HOLCF image
   658 
   659 
   660 
   661 New in Isabelle2003 (May 2003)
   662 ------------------------------
   663 
   664 *** General ***
   665 
   666 * Provers/simplifier:
   667 
   668   - Completely reimplemented method simp (ML: Asm_full_simp_tac):
   669     Assumptions are now subject to complete mutual simplification,
   670     not just from left to right. The simplifier now preserves
   671     the order of assumptions.
   672 
   673     Potential INCOMPATIBILITY:
   674 
   675     -- simp sometimes diverges where the old version did
   676        not, e.g. invoking simp on the goal
   677 
   678         [| P (f x); y = x; f x = f y |] ==> Q
   679 
   680        now gives rise to the infinite reduction sequence
   681 
   682         P(f x) --(f x = f y)--> P(f y) --(y = x)--> P(f x) --(f x = f y)--> ...
   683 
   684        Using "simp (asm_lr)" (ML: Asm_lr_simp_tac) instead often solves this
   685        kind of problem.
   686 
   687     -- Tactics combining classical reasoner and simplification (such as auto)
   688        are also affected by this change, because many of them rely on
   689        simp. They may sometimes diverge as well or yield a different numbers
   690        of subgoals. Try to use e.g. force, fastsimp, or safe instead of auto
   691        in case of problems. Sometimes subsequent calls to the classical
   692        reasoner will fail because a preceeding call to the simplifier too
   693        eagerly simplified the goal, e.g. deleted redundant premises.
   694 
   695   - The simplifier trace now shows the names of the applied rewrite rules
   696 
   697   - You can limit the number of recursive invocations of the simplifier
   698     during conditional rewriting (where the simplifie tries to solve the
   699     conditions before applying the rewrite rule):
   700     ML "simp_depth_limit := n"
   701     where n is an integer. Thus you can force termination where previously
   702     the simplifier would diverge.
   703 
   704   - Accepts free variables as head terms in congruence rules.  Useful in Isar.
   705 
   706   - No longer aborts on failed congruence proof.  Instead, the
   707     congruence is ignored.
   708 
   709 * Pure: New generic framework for extracting programs from constructive
   710   proofs. See HOL/Extraction.thy for an example instantiation, as well
   711   as HOL/Extraction for some case studies.
   712 
   713 * Pure: The main goal of the proof state is no longer shown by default, only
   714 the subgoals. This behaviour is controlled by a new flag.
   715    PG menu: Isabelle/Isar -> Settings -> Show Main Goal
   716 (ML: Proof.show_main_goal).
   717 
   718 * Pure: You can find all matching introduction rules for subgoal 1, i.e. all
   719 rules whose conclusion matches subgoal 1:
   720       PG menu: Isabelle/Isar -> Show me -> matching rules
   721 The rules are ordered by how closely they match the subgoal.
   722 In particular, rules that solve a subgoal outright are displayed first
   723 (or rather last, the way they are printed).
   724 (ML: ProofGeneral.print_intros())
   725 
   726 * Pure: New flag trace_unify_fail causes unification to print
   727 diagnostic information (PG: in trace buffer) when it fails. This is
   728 useful for figuring out why single step proofs like rule, erule or
   729 assumption failed.
   730 
   731 * Pure: Locale specifications now produce predicate definitions
   732 according to the body of text (covering assumptions modulo local
   733 definitions); predicate "loc_axioms" covers newly introduced text,
   734 while "loc" is cumulative wrt. all included locale expressions; the
   735 latter view is presented only on export into the global theory
   736 context; potential INCOMPATIBILITY, use "(open)" option to fall back
   737 on the old view without predicates;
   738 
   739 * Pure: predefined locales "var" and "struct" are useful for sharing
   740 parameters (as in CASL, for example); just specify something like
   741 ``var x + var y + struct M'' as import;
   742 
   743 * Pure: improved thms_containing: proper indexing of facts instead of
   744 raw theorems; check validity of results wrt. current name space;
   745 include local facts of proof configuration (also covers active
   746 locales), cover fixed variables in index; may use "_" in term
   747 specification; an optional limit for the number of printed facts may
   748 be given (the default is 40);
   749 
   750 * Pure: disallow duplicate fact bindings within new-style theory files
   751 (batch-mode only);
   752 
   753 * Provers: improved induct method: assumptions introduced by case
   754 "foo" are split into "foo.hyps" (from the rule) and "foo.prems" (from
   755 the goal statement); "foo" still refers to all facts collectively;
   756 
   757 * Provers: the function blast.overloaded has been removed: all constants
   758 are regarded as potentially overloaded, which improves robustness in exchange
   759 for slight decrease in efficiency;
   760 
   761 * Provers/linorder: New generic prover for transitivity reasoning over
   762 linear orders.  Note: this prover is not efficient!
   763 
   764 * Isar: preview of problems to finish 'show' now produce an error
   765 rather than just a warning (in interactive mode);
   766 
   767 
   768 *** HOL ***
   769 
   770 * arith(_tac)
   771 
   772  - Produces a counter example if it cannot prove a goal.
   773    Note that the counter example may be spurious if the goal is not a formula
   774    of quantifier-free linear arithmetic.
   775    In ProofGeneral the counter example appears in the trace buffer.
   776 
   777  - Knows about div k and mod k where k is a numeral of type nat or int.
   778 
   779  - Calls full Presburger arithmetic (by Amine Chaieb) if quantifier-free
   780    linear arithmetic fails. This takes account of quantifiers and divisibility.
   781    Presburger arithmetic can also be called explicitly via presburger(_tac).
   782 
   783 * simp's arithmetic capabilities have been enhanced a bit: it now
   784 takes ~= in premises into account (by performing a case split);
   785 
   786 * simp reduces "m*(n div m) + n mod m" to n, even if the two summands
   787 are distributed over a sum of terms;
   788 
   789 * New tactic "trans_tac" and method "trans" instantiate
   790 Provers/linorder.ML for axclasses "order" and "linorder" (predicates
   791 "<=", "<" and "=").
   792 
   793 * function INCOMPATIBILITIES: Pi-sets have been redefined and moved from main
   794 HOL to Library/FuncSet; constant "Fun.op o" is now called "Fun.comp";
   795 
   796 * 'typedef' command has new option "open" to suppress the set
   797 definition;
   798 
   799 * functions Min and Max on finite sets have been introduced (theory
   800 Finite_Set);
   801 
   802 * attribute [symmetric] now works for relations as well; it turns
   803 (x,y) : R^-1 into (y,x) : R, and vice versa;
   804 
   805 * induct over a !!-quantified statement (say !!x1..xn):
   806   each "case" automatically performs "fix x1 .. xn" with exactly those names.
   807 
   808 * Map: `empty' is no longer a constant but a syntactic abbreviation for
   809 %x. None. Warning: empty_def now refers to the previously hidden definition
   810 of the empty set.
   811 
   812 * Algebra: formalization of classical algebra.  Intended as base for
   813 any algebraic development in Isabelle.  Currently covers group theory
   814 (up to Sylow's theorem) and ring theory (Universal Property of
   815 Univariate Polynomials).  Contributions welcome;
   816 
   817 * GroupTheory: deleted, since its material has been moved to Algebra;
   818 
   819 * Complex: new directory of the complex numbers with numeric constants,
   820 nonstandard complex numbers, and some complex analysis, standard and
   821 nonstandard (Jacques Fleuriot);
   822 
   823 * HOL-Complex: new image for analysis, replacing HOL-Real and HOL-Hyperreal;
   824 
   825 * Hyperreal: introduced Gauge integration and hyperreal logarithms (Jacques
   826 Fleuriot);
   827 
   828 * Real/HahnBanach: updated and adapted to locales;
   829 
   830 * NumberTheory: added Gauss's law of quadratic reciprocity (by Avigad,
   831 Gray and Kramer);
   832 
   833 * UNITY: added the Meier-Sanders theory of progress sets;
   834 
   835 * MicroJava: bytecode verifier and lightweight bytecode verifier
   836 as abstract algorithms, instantiated to the JVM;
   837 
   838 * Bali: Java source language formalization. Type system, operational
   839 semantics, axiomatic semantics. Supported language features:
   840 classes, interfaces, objects,virtual methods, static methods,
   841 static/instance fields, arrays, access modifiers, definite
   842 assignment, exceptions.
   843 
   844 
   845 *** ZF ***
   846 
   847 * ZF/Constructible: consistency proof for AC (Gdel's constructible
   848 universe, etc.);
   849 
   850 * Main ZF: virtually all theories converted to new-style format;
   851 
   852 
   853 *** ML ***
   854 
   855 * Pure: Tactic.prove provides sane interface for internal proofs;
   856 omits the infamous "standard" operation, so this is more appropriate
   857 than prove_goalw_cterm in many situations (e.g. in simprocs);
   858 
   859 * Pure: improved error reporting of simprocs;
   860 
   861 * Provers: Simplifier.simproc(_i) provides sane interface for setting
   862 up simprocs;
   863 
   864 
   865 *** Document preparation ***
   866 
   867 * uses \par instead of \\ for line breaks in theory text. This may
   868 shift some page breaks in large documents. To get the old behaviour
   869 use \renewcommand{\isanewline}{\mbox{}\\\mbox{}} in root.tex.
   870 
   871 * minimized dependencies of isabelle.sty and isabellesym.sty on
   872 other packages
   873 
   874 * \<euro> now needs package babel/greek instead of marvosym (which
   875 broke \Rightarrow)
   876 
   877 * normal size for \<zero>...\<nine> (uses \mathbf instead of
   878 textcomp package)
   879 
   880 
   881 
   882 New in Isabelle2002 (March 2002)
   883 --------------------------------
   884 
   885 *** Document preparation ***
   886 
   887 * greatly simplified document preparation setup, including more
   888 graceful interpretation of isatool usedir -i/-d/-D options, and more
   889 instructive isatool mkdir; users should basically be able to get
   890 started with "isatool mkdir HOL Test && isatool make"; alternatively,
   891 users may run a separate document processing stage manually like this:
   892 "isatool usedir -D output HOL Test && isatool document Test/output";
   893 
   894 * theory dependency graph may now be incorporated into documents;
   895 isatool usedir -g true will produce session_graph.eps/.pdf for use
   896 with \includegraphics of LaTeX;
   897 
   898 * proper spacing of consecutive markup elements, especially text
   899 blocks after section headings;
   900 
   901 * support bold style (for single symbols only), input syntax is like
   902 this: "\<^bold>\<alpha>" or "\<^bold>A";
   903 
   904 * \<bullet> is now output as bold \cdot by default, which looks much
   905 better in printed text;
   906 
   907 * added default LaTeX bindings for \<tturnstile> and \<TTurnstile>;
   908 note that these symbols are currently unavailable in Proof General /
   909 X-Symbol; new symbols \<zero>, \<one>, ..., \<nine>, and \<euro>;
   910 
   911 * isatool latex no longer depends on changed TEXINPUTS, instead
   912 isatool document copies the Isabelle style files to the target
   913 location;
   914 
   915 
   916 *** Isar ***
   917 
   918 * Pure/Provers: improved proof by cases and induction;
   919   - 'case' command admits impromptu naming of parameters (such as
   920     "case (Suc n)");
   921   - 'induct' method divinates rule instantiation from the inductive
   922     claim; no longer requires excessive ?P bindings for proper
   923     instantiation of cases;
   924   - 'induct' method properly enumerates all possibilities of set/type
   925     rules; as a consequence facts may be also passed through *type*
   926     rules without further ado;
   927   - 'induct' method now derives symbolic cases from the *rulified*
   928     rule (before it used to rulify cases stemming from the internal
   929     atomized version); this means that the context of a non-atomic
   930     statement becomes is included in the hypothesis, avoiding the
   931     slightly cumbersome show "PROP ?case" form;
   932   - 'induct' may now use elim-style induction rules without chaining
   933     facts, using ``missing'' premises from the goal state; this allows
   934     rules stemming from inductive sets to be applied in unstructured
   935     scripts, while still benefitting from proper handling of non-atomic
   936     statements; NB: major inductive premises need to be put first, all
   937     the rest of the goal is passed through the induction;
   938   - 'induct' proper support for mutual induction involving non-atomic
   939     rule statements (uses the new concept of simultaneous goals, see
   940     below);
   941   - append all possible rule selections, but only use the first
   942     success (no backtracking);
   943   - removed obsolete "(simplified)" and "(stripped)" options of methods;
   944   - undeclared rule case names default to numbers 1, 2, 3, ...;
   945   - added 'print_induct_rules' (covered by help item in recent Proof
   946     General versions);
   947   - moved induct/cases attributes to Pure, methods to Provers;
   948   - generic method setup instantiated for FOL and HOL;
   949 
   950 * Pure: support multiple simultaneous goal statements, for example
   951 "have a: A and b: B" (same for 'theorem' etc.); being a pure
   952 meta-level mechanism, this acts as if several individual goals had
   953 been stated separately; in particular common proof methods need to be
   954 repeated in order to cover all claims; note that a single elimination
   955 step is *not* sufficient to establish the two conjunctions, so this
   956 fails:
   957 
   958   assume "A & B" then have A and B ..   (*".." fails*)
   959 
   960 better use "obtain" in situations as above; alternative refer to
   961 multi-step methods like 'auto', 'simp_all', 'blast+' etc.;
   962 
   963 * Pure: proper integration with ``locales''; unlike the original
   964 version by Florian Kammller, Isar locales package high-level proof
   965 contexts rather than raw logical ones (e.g. we admit to include
   966 attributes everywhere); operations on locales include merge and
   967 rename; support for implicit arguments (``structures''); simultaneous
   968 type-inference over imports and text; see also HOL/ex/Locales.thy for
   969 some examples;
   970 
   971 * Pure: the following commands have been ``localized'', supporting a
   972 target locale specification "(in name)": 'lemma', 'theorem',
   973 'corollary', 'lemmas', 'theorems', 'declare'; the results will be
   974 stored both within the locale and at the theory level (exported and
   975 qualified by the locale name);
   976 
   977 * Pure: theory goals may now be specified in ``long'' form, with
   978 ad-hoc contexts consisting of arbitrary locale elements. for example
   979 ``lemma foo: fixes x assumes "A x" shows "B x"'' (local syntax and
   980 definitions may be given, too); the result is a meta-level rule with
   981 the context elements being discharged in the obvious way;
   982 
   983 * Pure: new proof command 'using' allows to augment currently used
   984 facts after a goal statement ('using' is syntactically analogous to
   985 'apply', but acts on the goal's facts only); this allows chained facts
   986 to be separated into parts given before and after a claim, as in
   987 ``from a and b have C using d and e <proof>'';
   988 
   989 * Pure: renamed "antecedent" case to "rule_context";
   990 
   991 * Pure: new 'judgment' command records explicit information about the
   992 object-logic embedding (used by several tools internally); no longer
   993 use hard-wired "Trueprop";
   994 
   995 * Pure: added 'corollary' command;
   996 
   997 * Pure: fixed 'token_translation' command;
   998 
   999 * Pure: removed obsolete 'exported' attribute;
  1000 
  1001 * Pure: dummy pattern "_" in is/let is now automatically lifted over
  1002 bound variables: "ALL x. P x --> Q x" (is "ALL x. _ --> ?C x")
  1003 supersedes more cumbersome ... (is "ALL x. _ x --> ?C x");
  1004 
  1005 * Pure: method 'atomize' presents local goal premises as object-level
  1006 statements (atomic meta-level propositions); setup controlled via
  1007 rewrite rules declarations of 'atomize' attribute; example
  1008 application: 'induct' method with proper rule statements in improper
  1009 proof *scripts*;
  1010 
  1011 * Pure: emulation of instantiation tactics (rule_tac, cut_tac, etc.)
  1012 now consider the syntactic context of assumptions, giving a better
  1013 chance to get type-inference of the arguments right (this is
  1014 especially important for locales);
  1015 
  1016 * Pure: "sorry" no longer requires quick_and_dirty in interactive
  1017 mode;
  1018 
  1019 * Pure/obtain: the formal conclusion "thesis", being marked as
  1020 ``internal'', may no longer be reference directly in the text;
  1021 potential INCOMPATIBILITY, may need to use "?thesis" in rare
  1022 situations;
  1023 
  1024 * Pure: generic 'sym' attribute which declares a rule both as pure
  1025 'elim?' and for the 'symmetric' operation;
  1026 
  1027 * Pure: marginal comments ``--'' may now occur just anywhere in the
  1028 text; the fixed correlation with particular command syntax has been
  1029 discontinued;
  1030 
  1031 * Pure: new method 'rules' is particularly well-suited for proof
  1032 search in intuitionistic logic; a bit slower than 'blast' or 'fast',
  1033 but often produces more compact proof terms with less detours;
  1034 
  1035 * Pure/Provers/classical: simplified integration with pure rule
  1036 attributes and methods; the classical "intro?/elim?/dest?"
  1037 declarations coincide with the pure ones; the "rule" method no longer
  1038 includes classically swapped intros; "intro" and "elim" methods no
  1039 longer pick rules from the context; also got rid of ML declarations
  1040 AddXIs/AddXEs/AddXDs; all of this has some potential for
  1041 INCOMPATIBILITY;
  1042 
  1043 * Provers/classical: attribute 'swapped' produces classical inversions
  1044 of introduction rules;
  1045 
  1046 * Provers/simplifier: 'simplified' attribute may refer to explicit
  1047 rules instead of full simplifier context; 'iff' attribute handles
  1048 conditional rules;
  1049 
  1050 * HOL: 'typedef' now allows alternative names for Rep/Abs morphisms;
  1051 
  1052 * HOL: 'recdef' now fails on unfinished automated proofs, use
  1053 "(permissive)" option to recover old behavior;
  1054 
  1055 * HOL: 'inductive' no longer features separate (collective) attributes
  1056 for 'intros' (was found too confusing);
  1057 
  1058 * HOL: properly declared induction rules less_induct and
  1059 wf_induct_rule;
  1060 
  1061 
  1062 *** HOL ***
  1063 
  1064 * HOL: moved over to sane numeral syntax; the new policy is as
  1065 follows:
  1066 
  1067   - 0 and 1 are polymorphic constants, which are defined on any
  1068   numeric type (nat, int, real etc.);
  1069 
  1070   - 2, 3, 4, ... and -1, -2, -3, ... are polymorphic numerals, based
  1071   binary representation internally;
  1072 
  1073   - type nat has special constructor Suc, and generally prefers Suc 0
  1074   over 1::nat and Suc (Suc 0) over 2::nat;
  1075 
  1076 This change may cause significant problems of INCOMPATIBILITY; here
  1077 are some hints on converting existing sources:
  1078 
  1079   - due to the new "num" token, "-0" and "-1" etc. are now atomic
  1080   entities, so expressions involving "-" (unary or binary minus) need
  1081   to be spaced properly;
  1082 
  1083   - existing occurrences of "1" may need to be constraint "1::nat" or
  1084   even replaced by Suc 0; similar for old "2";
  1085 
  1086   - replace "#nnn" by "nnn", and "#-nnn" by "-nnn";
  1087 
  1088   - remove all special provisions on numerals in proofs;
  1089 
  1090 * HOL: simp rules nat_number expand numerals on nat to Suc/0
  1091 representation (depends on bin_arith_simps in the default context);
  1092 
  1093 * HOL: symbolic syntax for x^2 (numeral 2);
  1094 
  1095 * HOL: the class of all HOL types is now called "type" rather than
  1096 "term"; INCOMPATIBILITY, need to adapt references to this type class
  1097 in axclass/classes, instance/arities, and (usually rare) occurrences
  1098 in typings (of consts etc.); internally the class is called
  1099 "HOL.type", ML programs should refer to HOLogic.typeS;
  1100 
  1101 * HOL/record package improvements:
  1102   - new derived operations "fields" to build a partial record section,
  1103     "extend" to promote a fixed record to a record scheme, and
  1104     "truncate" for the reverse; cf. theorems "xxx.defs", which are *not*
  1105     declared as simp by default;
  1106   - shared operations ("more", "fields", etc.) now need to be always
  1107     qualified) --- potential INCOMPATIBILITY;
  1108   - removed "make_scheme" operations (use "make" with "extend") --
  1109     INCOMPATIBILITY;
  1110   - removed "more" class (simply use "term") -- INCOMPATIBILITY;
  1111   - provides cases/induct rules for use with corresponding Isar
  1112     methods (for concrete records, record schemes, concrete more
  1113     parts, and schematic more parts -- in that order);
  1114   - internal definitions directly based on a light-weight abstract
  1115     theory of product types over typedef rather than datatype;
  1116 
  1117 * HOL: generic code generator for generating executable ML code from
  1118 specifications; specific support for HOL constructs such as inductive
  1119 datatypes and sets, as well as recursive functions; can be invoked
  1120 via 'generate_code' theory section;
  1121 
  1122 * HOL: canonical cases/induct rules for n-tuples (n = 3..7);
  1123 
  1124 * HOL: consolidated and renamed several theories.  In particular:
  1125         Ord.thy has been absorbed into HOL.thy
  1126         String.thy has been absorbed into List.thy
  1127 
  1128 * HOL: concrete setsum syntax "\<Sum>i:A. b" == "setsum (%i. b) A"
  1129 (beware of argument permutation!);
  1130 
  1131 * HOL: linorder_less_split superseded by linorder_cases;
  1132 
  1133 * HOL/List: "nodups" renamed to "distinct";
  1134 
  1135 * HOL: added "The" definite description operator; move Hilbert's "Eps"
  1136 to peripheral theory "Hilbert_Choice"; some INCOMPATIBILITIES:
  1137   - Ex_def has changed, now need to use some_eq_ex
  1138 
  1139 * HOL: made split_all_tac safe; EXISTING PROOFS MAY FAIL OR LOOP, so
  1140 in this (rare) case use:
  1141 
  1142   delSWrapper "split_all_tac"
  1143   addSbefore ("unsafe_split_all_tac", unsafe_split_all_tac)
  1144 
  1145 * HOL: added safe wrapper "split_conv_tac" to claset; EXISTING PROOFS
  1146 MAY FAIL;
  1147 
  1148 * HOL: introduced f^n = f o ... o f; warning: due to the limits of
  1149 Isabelle's type classes, ^ on functions and relations has too general
  1150 a domain, namely ('a * 'b) set and 'a => 'b; this means that it may be
  1151 necessary to attach explicit type constraints;
  1152 
  1153 * HOL/Relation: the prefix name of the infix "O" has been changed from
  1154 "comp" to "rel_comp"; INCOMPATIBILITY: a few theorems have been
  1155 renamed accordingly (eg "compI" -> "rel_compI").
  1156 
  1157 * HOL: syntax translations now work properly with numerals and records
  1158 expressions;
  1159 
  1160 * HOL: bounded abstraction now uses syntax "%" / "\<lambda>" instead
  1161 of "lam" -- INCOMPATIBILITY;
  1162 
  1163 * HOL: got rid of some global declarations (potential INCOMPATIBILITY
  1164 for ML tools): const "()" renamed "Product_Type.Unity", type "unit"
  1165 renamed "Product_Type.unit";
  1166 
  1167 * HOL: renamed rtrancl_into_rtrancl2 to converse_rtrancl_into_rtrancl
  1168 
  1169 * HOL: removed obsolete theorem "optionE" (use "option.exhaust", or
  1170 the "cases" method);
  1171 
  1172 * HOL/GroupTheory: group theory examples including Sylow's theorem (by
  1173 Florian Kammller);
  1174 
  1175 * HOL/IMP: updated and converted to new-style theory format; several
  1176 parts turned into readable document, with proper Isar proof texts and
  1177 some explanations (by Gerwin Klein);
  1178 
  1179 * HOL-Real: added Complex_Numbers (by Gertrud Bauer);
  1180 
  1181 * HOL-Hyperreal is now a logic image;
  1182 
  1183 
  1184 *** HOLCF ***
  1185 
  1186 * Isar: consts/constdefs supports mixfix syntax for continuous
  1187 operations;
  1188 
  1189 * Isar: domain package adapted to new-style theory format, e.g. see
  1190 HOLCF/ex/Dnat.thy;
  1191 
  1192 * theory Lift: proper use of rep_datatype lift instead of ML hacks --
  1193 potential INCOMPATIBILITY; now use plain induct_tac instead of former
  1194 lift.induct_tac, always use UU instead of Undef;
  1195 
  1196 * HOLCF/IMP: updated and converted to new-style theory;
  1197 
  1198 
  1199 *** ZF ***
  1200 
  1201 * Isar: proper integration of logic-specific tools and packages,
  1202 including theory commands '(co)inductive', '(co)datatype',
  1203 'rep_datatype', 'inductive_cases', as well as methods 'ind_cases',
  1204 'induct_tac', 'case_tac', and 'typecheck' (with attribute 'TC');
  1205 
  1206 * theory Main no longer includes AC; for the Axiom of Choice, base
  1207 your theory on Main_ZFC;
  1208 
  1209 * the integer library now covers quotients and remainders, with many
  1210 laws relating division to addition, multiplication, etc.;
  1211 
  1212 * ZF/UNITY: Chandy and Misra's UNITY is now available in ZF, giving a
  1213 typeless version of the formalism;
  1214 
  1215 * ZF/AC, Coind, IMP, Resid: updated and converted to new-style theory
  1216 format;
  1217 
  1218 * ZF/Induct: new directory for examples of inductive definitions,
  1219 including theory Multiset for multiset orderings; converted to
  1220 new-style theory format;
  1221 
  1222 * ZF: many new theorems about lists, ordinals, etc.;
  1223 
  1224 
  1225 *** General ***
  1226 
  1227 * Pure/kernel: meta-level proof terms (by Stefan Berghofer); reference
  1228 variable proof controls level of detail: 0 = no proofs (only oracle
  1229 dependencies), 1 = lemma dependencies, 2 = compact proof terms; see
  1230 also ref manual for further ML interfaces;
  1231 
  1232 * Pure/axclass: removed obsolete ML interface
  1233 goal_subclass/goal_arity;
  1234 
  1235 * Pure/syntax: new token syntax "num" for plain numerals (without "#"
  1236 of "xnum"); potential INCOMPATIBILITY, since -0, -1 etc. are now
  1237 separate tokens, so expressions involving minus need to be spaced
  1238 properly;
  1239 
  1240 * Pure/syntax: support non-oriented infixes, using keyword "infix"
  1241 rather than "infixl" or "infixr";
  1242 
  1243 * Pure/syntax: concrete syntax for dummy type variables admits genuine
  1244 sort constraint specifications in type inference; e.g. "x::_::foo"
  1245 ensures that the type of "x" is of sort "foo" (but not necessarily a
  1246 type variable);
  1247 
  1248 * Pure/syntax: print modes "type_brackets" and "no_type_brackets"
  1249 control output of nested => (types); the default behavior is
  1250 "type_brackets";
  1251 
  1252 * Pure/syntax: builtin parse translation for "_constify" turns valued
  1253 tokens into AST constants;
  1254 
  1255 * Pure/syntax: prefer later declarations of translations and print
  1256 translation functions; potential INCOMPATIBILITY: need to reverse
  1257 multiple declarations for same syntax element constant;
  1258 
  1259 * Pure/show_hyps reset by default (in accordance to existing Isar
  1260 practice);
  1261 
  1262 * Provers/classical: renamed addaltern to addafter, addSaltern to
  1263 addSafter;
  1264 
  1265 * Provers/clasimp: ``iff'' declarations now handle conditional rules
  1266 as well;
  1267 
  1268 * system: tested support for MacOS X; should be able to get Isabelle +
  1269 Proof General to work in a plain Terminal after installing Poly/ML
  1270 (e.g. from the Isabelle distribution area) and GNU bash alone
  1271 (e.g. from http://www.apple.com); full X11, XEmacs and X-Symbol
  1272 support requires further installations, e.g. from
  1273 http://fink.sourceforge.net/);
  1274 
  1275 * system: support Poly/ML 4.1.1 (able to manage larger heaps);
  1276 
  1277 * system: reduced base memory usage by Poly/ML (approx. 20 MB instead
  1278 of 40 MB), cf. ML_OPTIONS;
  1279 
  1280 * system: Proof General keywords specification is now part of the
  1281 Isabelle distribution (see etc/isar-keywords.el);
  1282 
  1283 * system: support for persistent Proof General sessions (refrain from
  1284 outdating all loaded theories on startup); user may create writable
  1285 logic images like this: ``isabelle -q HOL Test'';
  1286 
  1287 * system: smart selection of Isabelle process versus Isabelle
  1288 interface, accommodates case-insensitive file systems (e.g. HFS+); may
  1289 run both "isabelle" and "Isabelle" even if file names are badly
  1290 damaged (executable inspects the case of the first letter of its own
  1291 name); added separate "isabelle-process" and "isabelle-interface";
  1292 
  1293 * system: refrain from any attempt at filtering input streams; no
  1294 longer support ``8bit'' encoding of old isabelle font, instead proper
  1295 iso-latin characters may now be used; the related isatools
  1296 "symbolinput" and "nonascii" have disappeared as well;
  1297 
  1298 * system: removed old "xterm" interface (the print modes "xterm" and
  1299 "xterm_color" are still available for direct use in a suitable
  1300 terminal);
  1301 
  1302 
  1303 
  1304 New in Isabelle99-2 (February 2001)
  1305 -----------------------------------
  1306 
  1307 *** Overview of INCOMPATIBILITIES ***
  1308 
  1309 * HOL: please note that theories in the Library and elsewhere often use the
  1310 new-style (Isar) format; to refer to their theorems in an ML script you must
  1311 bind them to ML identifers by e.g.      val thm_name = thm "thm_name";
  1312 
  1313 * HOL: inductive package no longer splits induction rule aggressively,
  1314 but only as far as specified by the introductions given; the old
  1315 format may be recovered via ML function complete_split_rule or attribute
  1316 'split_rule (complete)';
  1317 
  1318 * HOL: induct renamed to lfp_induct, lfp_Tarski to lfp_unfold,
  1319 gfp_Tarski to gfp_unfold;
  1320 
  1321 * HOL: contrapos, contrapos2 renamed to contrapos_nn, contrapos_pp;
  1322 
  1323 * HOL: infix "dvd" now has priority 50 rather than 70 (because it is a
  1324 relation); infix "^^" has been renamed "``"; infix "``" has been
  1325 renamed "`"; "univalent" has been renamed "single_valued";
  1326 
  1327 * HOL/Real: "rinv" and "hrinv" replaced by overloaded "inverse"
  1328 operation;
  1329 
  1330 * HOLCF: infix "`" has been renamed "$"; the symbol syntax is \<cdot>;
  1331 
  1332 * Isar: 'obtain' no longer declares "that" fact as simp/intro;
  1333 
  1334 * Isar/HOL: method 'induct' now handles non-atomic goals; as a
  1335 consequence, it is no longer monotonic wrt. the local goal context
  1336 (which is now passed through the inductive cases);
  1337 
  1338 * Document preparation: renamed standard symbols \<ll> to \<lless> and
  1339 \<gg> to \<ggreater>;
  1340 
  1341 
  1342 *** Document preparation ***
  1343 
  1344 * \isabellestyle{NAME} selects version of Isabelle output (currently
  1345 available: are "it" for near math-mode best-style output, "sl" for
  1346 slanted text style, and "tt" for plain type-writer; if no
  1347 \isabellestyle command is given, output is according to slanted
  1348 type-writer);
  1349 
  1350 * support sub/super scripts (for single symbols only), input syntax is
  1351 like this: "A\<^sup>*" or "A\<^sup>\<star>";
  1352 
  1353 * some more standard symbols; see Appendix A of the system manual for
  1354 the complete list of symbols defined in isabellesym.sty;
  1355 
  1356 * improved isabelle style files; more abstract symbol implementation
  1357 (should now use \isamath{...} and \isatext{...} in custom symbol
  1358 definitions);
  1359 
  1360 * antiquotation @{goals} and @{subgoals} for output of *dynamic* goals
  1361 state; Note that presentation of goal states does not conform to
  1362 actual human-readable proof documents.  Please do not include goal
  1363 states into document output unless you really know what you are doing!
  1364 
  1365 * proper indentation of antiquoted output with proportional LaTeX
  1366 fonts;
  1367 
  1368 * no_document ML operator temporarily disables LaTeX document
  1369 generation;
  1370 
  1371 * isatool unsymbolize tunes sources for plain ASCII communication;
  1372 
  1373 
  1374 *** Isar ***
  1375 
  1376 * Pure: Isar now suffers initial goal statements to contain unbound
  1377 schematic variables (this does not conform to actual readable proof
  1378 documents, due to unpredictable outcome and non-compositional proof
  1379 checking); users who know what they are doing may use schematic goals
  1380 for Prolog-style synthesis of proven results;
  1381 
  1382 * Pure: assumption method (an implicit finishing) now handles actual
  1383 rules as well;
  1384 
  1385 * Pure: improved 'obtain' --- moved to Pure, insert "that" into
  1386 initial goal, declare "that" only as Pure intro (only for single
  1387 steps); the "that" rule assumption may now be involved in implicit
  1388 finishing, thus ".." becomes a feasible for trivial obtains;
  1389 
  1390 * Pure: default proof step now includes 'intro_classes'; thus trivial
  1391 instance proofs may be performed by "..";
  1392 
  1393 * Pure: ?thesis / ?this / "..." now work for pure meta-level
  1394 statements as well;
  1395 
  1396 * Pure: more robust selection of calculational rules;
  1397 
  1398 * Pure: the builtin notion of 'finished' goal now includes the ==-refl
  1399 rule (as well as the assumption rule);
  1400 
  1401 * Pure: 'thm_deps' command visualizes dependencies of theorems and
  1402 lemmas, using the graph browser tool;
  1403 
  1404 * Pure: predict failure of "show" in interactive mode;
  1405 
  1406 * Pure: 'thms_containing' now takes actual terms as arguments;
  1407 
  1408 * HOL: improved method 'induct' --- now handles non-atomic goals
  1409 (potential INCOMPATIBILITY); tuned error handling;
  1410 
  1411 * HOL: cases and induct rules now provide explicit hints about the
  1412 number of facts to be consumed (0 for "type" and 1 for "set" rules);
  1413 any remaining facts are inserted into the goal verbatim;
  1414 
  1415 * HOL: local contexts (aka cases) may now contain term bindings as
  1416 well; the 'cases' and 'induct' methods new provide a ?case binding for
  1417 the result to be shown in each case;
  1418 
  1419 * HOL: added 'recdef_tc' command;
  1420 
  1421 * isatool convert assists in eliminating legacy ML scripts;
  1422 
  1423 
  1424 *** HOL ***
  1425 
  1426 * HOL/Library: a collection of generic theories to be used together
  1427 with main HOL; the theory loader path already includes this directory
  1428 by default; the following existing theories have been moved here:
  1429 HOL/Induct/Multiset, HOL/Induct/Acc (as Accessible_Part), HOL/While
  1430 (as While_Combinator), HOL/Lex/Prefix (as List_Prefix);
  1431 
  1432 * HOL/Unix: "Some aspects of Unix file-system security", a typical
  1433 modelling and verification task performed in Isabelle/HOL +
  1434 Isabelle/Isar + Isabelle document preparation (by Markus Wenzel).
  1435 
  1436 * HOL/Algebra: special summation operator SUM no longer exists, it has
  1437 been replaced by setsum; infix 'assoc' now has priority 50 (like
  1438 'dvd'); axiom 'one_not_zero' has been moved from axclass 'ring' to
  1439 'domain', this makes the theory consistent with mathematical
  1440 literature;
  1441 
  1442 * HOL basics: added overloaded operations "inverse" and "divide"
  1443 (infix "/"), syntax for generic "abs" operation, generic summation
  1444 operator \<Sum>;
  1445 
  1446 * HOL/typedef: simplified package, provide more useful rules (see also
  1447 HOL/subset.thy);
  1448 
  1449 * HOL/datatype: induction rule for arbitrarily branching datatypes is
  1450 now expressed as a proper nested rule (old-style tactic scripts may
  1451 require atomize_strip_tac to cope with non-atomic premises);
  1452 
  1453 * HOL: renamed theory "Prod" to "Product_Type", renamed "split" rule
  1454 to "split_conv" (old name still available for compatibility);
  1455 
  1456 * HOL: improved concrete syntax for strings (e.g. allows translation
  1457 rules with string literals);
  1458 
  1459 * HOL-Real-Hyperreal: this extends HOL-Real with the hyperreals
  1460  and Fleuriot's mechanization of analysis, including the transcendental
  1461  functions for the reals;
  1462 
  1463 * HOL/Real, HOL/Hyperreal: improved arithmetic simplification;
  1464 
  1465 
  1466 *** CTT ***
  1467 
  1468 * CTT: x-symbol support for Pi, Sigma, -->, : (membership); note that
  1469 "lam" is displayed as TWO lambda-symbols
  1470 
  1471 * CTT: theory Main now available, containing everything (that is, Bool
  1472 and Arith);
  1473 
  1474 
  1475 *** General ***
  1476 
  1477 * Pure: the Simplifier has been implemented properly as a derived rule
  1478 outside of the actual kernel (at last!); the overall performance
  1479 penalty in practical applications is about 50%, while reliability of
  1480 the Isabelle inference kernel has been greatly improved;
  1481 
  1482 * print modes "brackets" and "no_brackets" control output of nested =>
  1483 (types) and ==> (props); the default behaviour is "brackets";
  1484 
  1485 * Provers: fast_tac (and friends) now handle actual object-logic rules
  1486 as assumptions as well;
  1487 
  1488 * system: support Poly/ML 4.0;
  1489 
  1490 * system: isatool install handles KDE version 1 or 2;
  1491 
  1492 
  1493 
  1494 New in Isabelle99-1 (October 2000)
  1495 ----------------------------------
  1496 
  1497 *** Overview of INCOMPATIBILITIES ***
  1498 
  1499 * HOL: simplification of natural numbers is much changed; to partly
  1500 recover the old behaviour (e.g. to prevent n+n rewriting to #2*n)
  1501 issue the following ML commands:
  1502 
  1503   Delsimprocs Nat_Numeral_Simprocs.cancel_numerals;
  1504   Delsimprocs [Nat_Numeral_Simprocs.combine_numerals];
  1505 
  1506 * HOL: simplification no longer dives into case-expressions; this is
  1507 controlled by "t.weak_case_cong" for each datatype t;
  1508 
  1509 * HOL: nat_less_induct renamed to less_induct;
  1510 
  1511 * HOL: systematic renaming of the SOME (Eps) rules, may use isatool
  1512 fixsome to patch .thy and .ML sources automatically;
  1513 
  1514   select_equality  -> some_equality
  1515   select_eq_Ex     -> some_eq_ex
  1516   selectI2EX       -> someI2_ex
  1517   selectI2         -> someI2
  1518   selectI          -> someI
  1519   select1_equality -> some1_equality
  1520   Eps_sym_eq       -> some_sym_eq_trivial
  1521   Eps_eq           -> some_eq_trivial
  1522 
  1523 * HOL: exhaust_tac on datatypes superceded by new generic case_tac;
  1524 
  1525 * HOL: removed obsolete theorem binding expand_if (refer to split_if
  1526 instead);
  1527 
  1528 * HOL: the recursion equations generated by 'recdef' are now called
  1529 f.simps instead of f.rules;
  1530 
  1531 * HOL: qed_spec_mp now also handles bounded ALL as well;
  1532 
  1533 * HOL: 0 is now overloaded, so the type constraint ":: nat" may
  1534 sometimes be needed;
  1535 
  1536 * HOL: the constant for "f``x" is now "image" rather than "op ``";
  1537 
  1538 * HOL: the constant for "f-``x" is now "vimage" rather than "op -``";
  1539 
  1540 * HOL: the disjoint sum is now "<+>" instead of "Plus"; the cartesian
  1541 product is now "<*>" instead of "Times"; the lexicographic product is
  1542 now "<*lex*>" instead of "**";
  1543 
  1544 * HOL: theory Sexp is now in HOL/Induct examples (it used to be part
  1545 of main HOL, but was unused); better use HOL's datatype package;
  1546 
  1547 * HOL: removed "symbols" syntax for constant "override" of theory Map;
  1548 the old syntax may be recovered as follows:
  1549 
  1550   syntax (symbols)
  1551     override  :: "('a ~=> 'b) => ('a ~=> 'b) => ('a ~=> 'b)"
  1552       (infixl "\\<oplus>" 100)
  1553 
  1554 * HOL/Real: "rabs" replaced by overloaded "abs" function;
  1555 
  1556 * HOL/ML: even fewer consts are declared as global (see theories Ord,
  1557 Lfp, Gfp, WF); this only affects ML packages that refer to const names
  1558 internally;
  1559 
  1560 * HOL and ZF: syntax for quotienting wrt an equivalence relation
  1561 changed from A/r to A//r;
  1562 
  1563 * ZF: new treatment of arithmetic (nat & int) may break some old
  1564 proofs;
  1565 
  1566 * Isar: renamed some attributes (RS -> THEN, simplify -> simplified,
  1567 rulify -> rule_format, elimify -> elim_format, ...);
  1568 
  1569 * Isar/Provers: intro/elim/dest attributes changed; renamed
  1570 intro/intro!/intro!! flags to intro!/intro/intro? (in most cases, one
  1571 should have to change intro!! to intro? only); replaced "delrule" by
  1572 "rule del";
  1573 
  1574 * Isar/HOL: renamed "intrs" to "intros" in inductive definitions;
  1575 
  1576 * Provers: strengthened force_tac by using new first_best_tac;
  1577 
  1578 * LaTeX document preparation: several changes of isabelle.sty (see
  1579 lib/texinputs);
  1580 
  1581 
  1582 *** Document preparation ***
  1583 
  1584 * formal comments (text blocks etc.) in new-style theories may now
  1585 contain antiquotations of thm/prop/term/typ/text to be presented
  1586 according to latex print mode; concrete syntax is like this:
  1587 @{term[show_types] "f(x) = a + x"};
  1588 
  1589 * isatool mkdir provides easy setup of Isabelle session directories,
  1590 including proper document sources;
  1591 
  1592 * generated LaTeX sources are now deleted after successful run
  1593 (isatool document -c); may retain a copy somewhere else via -D option
  1594 of isatool usedir;
  1595 
  1596 * isatool usedir -D now lets isatool latex -o sty update the Isabelle
  1597 style files, achieving self-contained LaTeX sources and simplifying
  1598 LaTeX debugging;
  1599 
  1600 * old-style theories now produce (crude) LaTeX output as well;
  1601 
  1602 * browser info session directories are now self-contained (may be put
  1603 on WWW server seperately); improved graphs of nested sessions; removed
  1604 graph for 'all sessions';
  1605 
  1606 * several improvements in isabelle style files; \isabellestyle{it}
  1607 produces fake math mode output; \isamarkupheader is now \section by
  1608 default; see lib/texinputs/isabelle.sty etc.;
  1609 
  1610 
  1611 *** Isar ***
  1612 
  1613 * Isar/Pure: local results and corresponding term bindings are now
  1614 subject to Hindley-Milner polymorphism (similar to ML); this
  1615 accommodates incremental type-inference very nicely;
  1616 
  1617 * Isar/Pure: new derived language element 'obtain' supports
  1618 generalized existence reasoning;
  1619 
  1620 * Isar/Pure: new calculational elements 'moreover' and 'ultimately'
  1621 support accumulation of results, without applying any rules yet;
  1622 useful to collect intermediate results without explicit name
  1623 references, and for use with transitivity rules with more than 2
  1624 premises;
  1625 
  1626 * Isar/Pure: scalable support for case-analysis type proofs: new
  1627 'case' language element refers to local contexts symbolically, as
  1628 produced by certain proof methods; internally, case names are attached
  1629 to theorems as "tags";
  1630 
  1631 * Isar/Pure: theory command 'hide' removes declarations from
  1632 class/type/const name spaces;
  1633 
  1634 * Isar/Pure: theory command 'defs' supports option "(overloaded)" to
  1635 indicate potential overloading;
  1636 
  1637 * Isar/Pure: changed syntax of local blocks from {{ }} to { };
  1638 
  1639 * Isar/Pure: syntax of sorts made 'inner', i.e. have to write
  1640 "{a,b,c}" instead of {a,b,c};
  1641 
  1642 * Isar/Pure now provides its own version of intro/elim/dest
  1643 attributes; useful for building new logics, but beware of confusion
  1644 with the version in Provers/classical;
  1645 
  1646 * Isar/Pure: the local context of (non-atomic) goals is provided via
  1647 case name 'antecedent';
  1648 
  1649 * Isar/Pure: removed obsolete 'transfer' attribute (transfer of thms
  1650 to the current context is now done automatically);
  1651 
  1652 * Isar/Pure: theory command 'method_setup' provides a simple interface
  1653 for definining proof methods in ML;
  1654 
  1655 * Isar/Provers: intro/elim/dest attributes changed; renamed
  1656 intro/intro!/intro!! flags to intro!/intro/intro? (INCOMPATIBILITY, in
  1657 most cases, one should have to change intro!! to intro? only);
  1658 replaced "delrule" by "rule del";
  1659 
  1660 * Isar/Provers: new 'hypsubst' method, plain 'subst' method and
  1661 'symmetric' attribute (the latter supercedes [RS sym]);
  1662 
  1663 * Isar/Provers: splitter support (via 'split' attribute and 'simp'
  1664 method modifier); 'simp' method: 'only:' modifier removes loopers as
  1665 well (including splits);
  1666 
  1667 * Isar/Provers: Simplifier and Classical methods now support all kind
  1668 of modifiers used in the past, including 'cong', 'iff', etc.
  1669 
  1670 * Isar/Provers: added 'fastsimp' and 'clarsimp' methods (combination
  1671 of Simplifier and Classical reasoner);
  1672 
  1673 * Isar/HOL: new proof method 'cases' and improved version of 'induct'
  1674 now support named cases; major packages (inductive, datatype, primrec,
  1675 recdef) support case names and properly name parameters;
  1676 
  1677 * Isar/HOL: new transitivity rules for substitution in inequalities --
  1678 monotonicity conditions are extracted to be proven at end of
  1679 calculations;
  1680 
  1681 * Isar/HOL: removed 'case_split' thm binding, should use 'cases' proof
  1682 method anyway;
  1683 
  1684 * Isar/HOL: removed old expand_if = split_if; theorems if_splits =
  1685 split_if split_if_asm; datatype package provides theorems foo.splits =
  1686 foo.split foo.split_asm for each datatype;
  1687 
  1688 * Isar/HOL: tuned inductive package, rename "intrs" to "intros"
  1689 (potential INCOMPATIBILITY), emulation of mk_cases feature for proof
  1690 scripts: new 'inductive_cases' command and 'ind_cases' method; (Note:
  1691 use "(cases (simplified))" method in proper proof texts);
  1692 
  1693 * Isar/HOL: added global 'arith_split' attribute for 'arith' method;
  1694 
  1695 * Isar: names of theorems etc. may be natural numbers as well;
  1696 
  1697 * Isar: 'pr' command: optional arguments for goals_limit and
  1698 ProofContext.prems_limit; no longer prints theory contexts, but only
  1699 proof states;
  1700 
  1701 * Isar: diagnostic commands 'pr', 'thm', 'prop', 'term', 'typ' admit
  1702 additional print modes to be specified; e.g. "pr(latex)" will print
  1703 proof state according to the Isabelle LaTeX style;
  1704 
  1705 * Isar: improved support for emulating tactic scripts, including proof
  1706 methods 'rule_tac' etc., 'cut_tac', 'thin_tac', 'subgoal_tac',
  1707 'rename_tac', 'rotate_tac', 'tactic', and 'case_tac' / 'induct_tac'
  1708 (for HOL datatypes);
  1709 
  1710 * Isar: simplified (more robust) goal selection of proof methods: 1st
  1711 goal, all goals, or explicit goal specifier (tactic emulation); thus
  1712 'proof method scripts' have to be in depth-first order;
  1713 
  1714 * Isar: tuned 'let' syntax: replaced 'as' keyword by 'and';
  1715 
  1716 * Isar: removed 'help' command, which hasn't been too helpful anyway;
  1717 should instead use individual commands for printing items
  1718 (print_commands, print_methods etc.);
  1719 
  1720 * Isar: added 'nothing' --- the empty list of theorems;
  1721 
  1722 
  1723 *** HOL ***
  1724 
  1725 * HOL/MicroJava: formalization of a fragment of Java, together with a
  1726 corresponding virtual machine and a specification of its bytecode
  1727 verifier and a lightweight bytecode verifier, including proofs of
  1728 type-safety; by Gerwin Klein, Tobias Nipkow, David von Oheimb, and
  1729 Cornelia Pusch (see also the homepage of project Bali at
  1730 http://isabelle.in.tum.de/Bali/);
  1731 
  1732 * HOL/Algebra: new theory of rings and univariate polynomials, by
  1733 Clemens Ballarin;
  1734 
  1735 * HOL/NumberTheory: fundamental Theorem of Arithmetic, Chinese
  1736 Remainder Theorem, Fermat/Euler Theorem, Wilson's Theorem, by Thomas M
  1737 Rasmussen;
  1738 
  1739 * HOL/Lattice: fundamental concepts of lattice theory and order
  1740 structures, including duals, properties of bounds versus algebraic
  1741 laws, lattice operations versus set-theoretic ones, the Knaster-Tarski
  1742 Theorem for complete lattices etc.; may also serve as a demonstration
  1743 for abstract algebraic reasoning using axiomatic type classes, and
  1744 mathematics-style proof in Isabelle/Isar; by Markus Wenzel;
  1745 
  1746 * HOL/Prolog: a (bare-bones) implementation of Lambda-Prolog, by David
  1747 von Oheimb;
  1748 
  1749 * HOL/IMPP: extension of IMP with local variables and mutually
  1750 recursive procedures, by David von Oheimb;
  1751 
  1752 * HOL/Lambda: converted into new-style theory and document;
  1753 
  1754 * HOL/ex/Multiquote: example of multiple nested quotations and
  1755 anti-quotations -- basically a generalized version of de-Bruijn
  1756 representation; very useful in avoiding lifting of operations;
  1757 
  1758 * HOL/record: added general record equality rule to simpset; fixed
  1759 select-update simplification procedure to handle extended records as
  1760 well; admit "r" as field name;
  1761 
  1762 * HOL: 0 is now overloaded over the new sort "zero", allowing its use with
  1763 other numeric types and also as the identity of groups, rings, etc.;
  1764 
  1765 * HOL: new axclass plus_ac0 for addition with the AC-laws and 0 as identity.
  1766 Types nat and int belong to this axclass;
  1767 
  1768 * HOL: greatly improved simplification involving numerals of type nat, int, real:
  1769    (i + #8 + j) = Suc k simplifies to  #7 + (i + j) = k
  1770    i*j + k + j*#3*i     simplifies to  #4*(i*j) + k
  1771   two terms #m*u and #n*u are replaced by #(m+n)*u
  1772     (where #m, #n and u can implicitly be 1; this is simproc combine_numerals)
  1773   and the term/formula #m*u+x ~~ #n*u+y simplifies simplifies to #(m-n)+x ~~ y
  1774     or x ~~ #(n-m)+y, where ~~ is one of = < <= or - (simproc cancel_numerals);
  1775 
  1776 * HOL: meson_tac is available (previously in ex/meson.ML); it is a
  1777 powerful prover for predicate logic but knows nothing of clasets; see
  1778 ex/mesontest.ML and ex/mesontest2.ML for example applications;
  1779 
  1780 * HOL: new version of "case_tac" subsumes both boolean case split and
  1781 "exhaust_tac" on datatypes; INCOMPATIBILITY: exhaust_tac no longer
  1782 exists, may define val exhaust_tac = case_tac for ad-hoc portability;
  1783 
  1784 * HOL: simplification no longer dives into case-expressions: only the
  1785 selector expression is simplified, but not the remaining arms; to
  1786 enable full simplification of case-expressions for datatype t, you may
  1787 remove t.weak_case_cong from the simpset, either globally (Delcongs
  1788 [thm"t.weak_case_cong"];) or locally (delcongs [...]).
  1789 
  1790 * HOL/recdef: the recursion equations generated by 'recdef' for
  1791 function 'f' are now called f.simps instead of f.rules; if all
  1792 termination conditions are proved automatically, these simplification
  1793 rules are added to the simpset, as in primrec; rules may be named
  1794 individually as well, resulting in a separate list of theorems for
  1795 each equation;
  1796 
  1797 * HOL/While is a new theory that provides a while-combinator. It
  1798 permits the definition of tail-recursive functions without the
  1799 provision of a termination measure. The latter is necessary once the
  1800 invariant proof rule for while is applied.
  1801 
  1802 * HOL: new (overloaded) notation for the set of elements below/above
  1803 some element: {..u}, {..u(}, {l..}, {)l..}. See theory SetInterval.
  1804 
  1805 * HOL: theorems impI, allI, ballI bound as "strip";
  1806 
  1807 * HOL: new tactic induct_thm_tac: thm -> string -> int -> tactic
  1808 induct_tac th "x1 ... xn" expects th to have a conclusion of the form
  1809 P v1 ... vn and abbreviates res_inst_tac [("v1","x1"),...,("vn","xn")] th;
  1810 
  1811 * HOL/Real: "rabs" replaced by overloaded "abs" function;
  1812 
  1813 * HOL: theory Sexp now in HOL/Induct examples (it used to be part of
  1814 main HOL, but was unused);
  1815 
  1816 * HOL: fewer consts declared as global (e.g. have to refer to
  1817 "Lfp.lfp" instead of "lfp" internally; affects ML packages only);
  1818 
  1819 * HOL: tuned AST representation of nested pairs, avoiding bogus output
  1820 in case of overlap with user translations (e.g. judgements over
  1821 tuples); (note that the underlying logical represenation is still
  1822 bogus);
  1823 
  1824 
  1825 *** ZF ***
  1826 
  1827 * ZF: simplification automatically cancels common terms in arithmetic
  1828 expressions over nat and int;
  1829 
  1830 * ZF: new treatment of nat to minimize type-checking: all operators
  1831 coerce their operands to a natural number using the function natify,
  1832 making the algebraic laws unconditional;
  1833 
  1834 * ZF: as above, for int: operators coerce their operands to an integer
  1835 using the function intify;
  1836 
  1837 * ZF: the integer library now contains many of the usual laws for the
  1838 orderings, including $<=, and monotonicity laws for $+ and $*;
  1839 
  1840 * ZF: new example ZF/ex/NatSum to demonstrate integer arithmetic
  1841 simplification;
  1842 
  1843 * FOL and ZF: AddIffs now available, giving theorems of the form P<->Q
  1844 to the simplifier and classical reasoner simultaneously;
  1845 
  1846 
  1847 *** General ***
  1848 
  1849 * Provers: blast_tac now handles actual object-logic rules as
  1850 assumptions; note that auto_tac uses blast_tac internally as well;
  1851 
  1852 * Provers: new functions rulify/rulify_no_asm: thm -> thm for turning
  1853 outer -->/All/Ball into ==>/!!; qed_spec_mp now uses rulify_no_asm;
  1854 
  1855 * Provers: delrules now handles destruct rules as well (no longer need
  1856 explicit make_elim);
  1857 
  1858 * Provers: Blast_tac now warns of and ignores "weak elimination rules" e.g.
  1859   [| inj ?f;          ?f ?x = ?f ?y; ?x = ?y ==> ?W |] ==> ?W
  1860 use instead the strong form,
  1861   [| inj ?f; ~ ?W ==> ?f ?x = ?f ?y; ?x = ?y ==> ?W |] ==> ?W
  1862 in HOL, FOL and ZF the function cla_make_elim will create such rules
  1863 from destruct-rules;
  1864 
  1865 * Provers: Simplifier.easy_setup provides a fast path to basic
  1866 Simplifier setup for new object-logics;
  1867 
  1868 * Pure: AST translation rules no longer require constant head on LHS;
  1869 
  1870 * Pure: improved name spaces: ambiguous output is qualified; support
  1871 for hiding of names;
  1872 
  1873 * system: smart setup of canonical ML_HOME, ISABELLE_INTERFACE, and
  1874 XSYMBOL_HOME; no longer need to do manual configuration in most
  1875 situations;
  1876 
  1877 * system: compression of ML heaps images may now be controlled via -c
  1878 option of isabelle and isatool usedir (currently only observed by
  1879 Poly/ML);
  1880 
  1881 * system: isatool installfonts may handle X-Symbol fonts as well (very
  1882 useful for remote X11);
  1883 
  1884 * system: provide TAGS file for Isabelle sources;
  1885 
  1886 * ML: infix 'OF' is a version of 'MRS' with more appropriate argument
  1887 order;
  1888 
  1889 * ML: renamed flags Syntax.trace_norm_ast to Syntax.trace_ast; global
  1890 timing flag supersedes proof_timing and Toplevel.trace;
  1891 
  1892 * ML: new combinators |>> and |>>> for incremental transformations
  1893 with secondary results (e.g. certain theory extensions):
  1894 
  1895 * ML: PureThy.add_defs gets additional argument to indicate potential
  1896 overloading (usually false);
  1897 
  1898 * ML: PureThy.add_thms/add_axioms/add_defs now return theorems as
  1899 results;
  1900 
  1901 
  1902 
  1903 New in Isabelle99 (October 1999)
  1904 --------------------------------
  1905 
  1906 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  1907 
  1908 * HOL: The THEN and ELSE parts of conditional expressions (if P then x else y)
  1909 are no longer simplified.  (This allows the simplifier to unfold recursive
  1910 functional programs.)  To restore the old behaviour, declare
  1911 
  1912     Delcongs [if_weak_cong];
  1913 
  1914 * HOL: Removed the obsolete syntax "Compl A"; use -A for set
  1915 complement;
  1916 
  1917 * HOL: the predicate "inj" is now defined by translation to "inj_on";
  1918 
  1919 * HOL/datatype: mutual_induct_tac no longer exists --
  1920   use induct_tac "x_1 ... x_n" instead of mutual_induct_tac ["x_1", ..., "x_n"]
  1921 
  1922 * HOL/typedef: fixed type inference for representing set; type
  1923 arguments now have to occur explicitly on the rhs as type constraints;
  1924 
  1925 * ZF: The con_defs part of an inductive definition may no longer refer
  1926 to constants declared in the same theory;
  1927 
  1928 * HOL, ZF: the function mk_cases, generated by the inductive
  1929 definition package, has lost an argument.  To simplify its result, it
  1930 uses the default simpset instead of a supplied list of theorems.
  1931 
  1932 * HOL/List: the constructors of type list are now Nil and Cons;
  1933 
  1934 * Simplifier: the type of the infix ML functions
  1935         setSSolver addSSolver setSolver addSolver
  1936 is now  simpset * solver -> simpset  where `solver' is a new abstract type
  1937 for packaging solvers. A solver is created via
  1938         mk_solver: string -> (thm list -> int -> tactic) -> solver
  1939 where the string argument is only a comment.
  1940 
  1941 
  1942 *** Proof tools ***
  1943 
  1944 * Provers/Arith/fast_lin_arith.ML contains a functor for creating a
  1945 decision procedure for linear arithmetic. Currently it is used for
  1946 types `nat', `int', and `real' in HOL (see below); it can, should and
  1947 will be instantiated for other types and logics as well.
  1948 
  1949 * The simplifier now accepts rewrite rules with flexible heads, eg
  1950      hom ?f ==> ?f(?x+?y) = ?f ?x + ?f ?y
  1951   They are applied like any rule with a non-pattern lhs, i.e. by first-order
  1952   matching.
  1953 
  1954 
  1955 *** General ***
  1956 
  1957 * New Isabelle/Isar subsystem provides an alternative to traditional
  1958 tactical theorem proving; together with the ProofGeneral/isar user
  1959 interface it offers an interactive environment for developing human
  1960 readable proof documents (Isar == Intelligible semi-automated
  1961 reasoning); for further information see isatool doc isar-ref,
  1962 src/HOL/Isar_examples and http://isabelle.in.tum.de/Isar/
  1963 
  1964 * improved and simplified presentation of theories: better HTML markup
  1965 (including colors), graph views in several sizes; isatool usedir now
  1966 provides a proper interface for user theories (via -P option); actual
  1967 document preparation based on (PDF)LaTeX is available as well (for
  1968 new-style theories only); see isatool doc system for more information;
  1969 
  1970 * native support for Proof General, both for classic Isabelle and
  1971 Isabelle/Isar;
  1972 
  1973 * ML function thm_deps visualizes dependencies of theorems and lemmas,
  1974 using the graph browser tool;
  1975 
  1976 * Isabelle manuals now also available as PDF;
  1977 
  1978 * theory loader rewritten from scratch (may not be fully
  1979 bug-compatible); old loadpath variable has been replaced by show_path,
  1980 add_path, del_path, reset_path functions; new operations such as
  1981 update_thy, touch_thy, remove_thy, use/update_thy_only (see also
  1982 isatool doc ref);
  1983 
  1984 * improved isatool install: option -k creates KDE application icon,
  1985 option -p DIR installs standalone binaries;
  1986 
  1987 * added ML_PLATFORM setting (useful for cross-platform installations);
  1988 more robust handling of platform specific ML images for SML/NJ;
  1989 
  1990 * the settings environment is now statically scoped, i.e. it is never
  1991 created again in sub-processes invoked from isabelle, isatool, or
  1992 Isabelle;
  1993 
  1994 * path element specification '~~' refers to '$ISABELLE_HOME';
  1995 
  1996 * in locales, the "assumes" and "defines" parts may be omitted if
  1997 empty;
  1998 
  1999 * new print_mode "xsymbols" for extended symbol support (e.g. genuine
  2000 long arrows);
  2001 
  2002 * new print_mode "HTML";
  2003 
  2004 * new flag show_tags controls display of tags of theorems (which are
  2005 basically just comments that may be attached by some tools);
  2006 
  2007 * Isamode 2.6 requires patch to accomodate change of Isabelle font
  2008 mode and goal output format:
  2009 
  2010 diff -r Isamode-2.6/elisp/isa-load.el Isamode/elisp/isa-load.el
  2011 244c244
  2012 <       (list (isa-getenv "ISABELLE") "-msymbols" logic-name)
  2013 ---
  2014 >       (list (isa-getenv "ISABELLE") "-misabelle_font" "-msymbols" logic-name)
  2015 diff -r Isabelle-2.6/elisp/isa-proofstate.el Isamode/elisp/isa-proofstate.el
  2016 181c181
  2017 < (defconst proofstate-proofstart-regexp "^Level [0-9]+$"
  2018 ---
  2019 > (defconst proofstate-proofstart-regexp "^Level [0-9]+"
  2020 
  2021 * function bind_thms stores lists of theorems (cf. bind_thm);
  2022 
  2023 * new shorthand tactics ftac, eatac, datac, fatac;
  2024 
  2025 * qed (and friends) now accept "" as result name; in that case the
  2026 theorem is not stored, but proper checks and presentation of the
  2027 result still apply;
  2028 
  2029 * theorem database now also indexes constants "Trueprop", "all",
  2030 "==>", "=="; thus thms_containing, findI etc. may retrieve more rules;
  2031 
  2032 
  2033 *** HOL ***
  2034 
  2035 ** HOL arithmetic **
  2036 
  2037 * There are now decision procedures for linear arithmetic over nat and
  2038 int:
  2039 
  2040 1. arith_tac copes with arbitrary formulae involving `=', `<', `<=',
  2041 `+', `-', `Suc', `min', `max' and numerical constants; other subterms
  2042 are treated as atomic; subformulae not involving type `nat' or `int'
  2043 are ignored; quantified subformulae are ignored unless they are
  2044 positive universal or negative existential. The tactic has to be
  2045 invoked by hand and can be a little bit slow. In particular, the
  2046 running time is exponential in the number of occurrences of `min' and
  2047 `max', and `-' on `nat'.
  2048 
  2049 2. fast_arith_tac is a cut-down version of arith_tac: it only takes
  2050 (negated) (in)equalities among the premises and the conclusion into
  2051 account (i.e. no compound formulae) and does not know about `min' and
  2052 `max', and `-' on `nat'. It is fast and is used automatically by the
  2053 simplifier.
  2054 
  2055 NB: At the moment, these decision procedures do not cope with mixed
  2056 nat/int formulae where the two parts interact, such as `m < n ==>
  2057 int(m) < int(n)'.
  2058 
  2059 * HOL/Numeral provides a generic theory of numerals (encoded
  2060 efficiently as bit strings); setup for types nat/int/real is in place;
  2061 INCOMPATIBILITY: since numeral syntax is now polymorphic, rather than
  2062 int, existing theories and proof scripts may require a few additional
  2063 type constraints;
  2064 
  2065 * integer division and remainder can now be performed on constant
  2066 arguments;
  2067 
  2068 * many properties of integer multiplication, division and remainder
  2069 are now available;
  2070 
  2071 * An interface to the Stanford Validity Checker (SVC) is available through the
  2072 tactic svc_tac.  Propositional tautologies and theorems of linear arithmetic
  2073 are proved automatically.  SVC must be installed separately, and its results
  2074 must be TAKEN ON TRUST (Isabelle does not check the proofs, but tags any
  2075 invocation of the underlying oracle).  For SVC see
  2076   http://verify.stanford.edu/SVC
  2077 
  2078 * IsaMakefile: the HOL-Real target now builds an actual image;
  2079 
  2080 
  2081 ** HOL misc **
  2082 
  2083 * HOL/Real/HahnBanach: the Hahn-Banach theorem for real vector spaces
  2084 (in Isabelle/Isar) -- by Gertrud Bauer;
  2085 
  2086 * HOL/BCV: generic model of bytecode verification, i.e. data-flow
  2087 analysis for assembly languages with subtypes;
  2088 
  2089 * HOL/TLA (Lamport's Temporal Logic of Actions): major reorganization
  2090 -- avoids syntactic ambiguities and treats state, transition, and
  2091 temporal levels more uniformly; introduces INCOMPATIBILITIES due to
  2092 changed syntax and (many) tactics;
  2093 
  2094 * HOL/inductive: Now also handles more general introduction rules such
  2095   as "ALL y. (y, x) : r --> y : acc r ==> x : acc r"; monotonicity
  2096   theorems are now maintained within the theory (maintained via the
  2097   "mono" attribute);
  2098 
  2099 * HOL/datatype: Now also handles arbitrarily branching datatypes
  2100   (using function types) such as
  2101 
  2102   datatype 'a tree = Atom 'a | Branch "nat => 'a tree"
  2103 
  2104 * HOL/record: record_simproc (part of the default simpset) takes care
  2105 of selectors applied to updated records; record_split_tac is no longer
  2106 part of the default claset; update_defs may now be removed from the
  2107 simpset in many cases; COMPATIBILITY: old behavior achieved by
  2108 
  2109   claset_ref () := claset() addSWrapper record_split_wrapper;
  2110   Delsimprocs [record_simproc]
  2111 
  2112 * HOL/typedef: fixed type inference for representing set; type
  2113 arguments now have to occur explicitly on the rhs as type constraints;
  2114 
  2115 * HOL/recdef (TFL): 'congs' syntax now expects comma separated list of theorem
  2116 names rather than an ML expression;
  2117 
  2118 * HOL/defer_recdef (TFL): like recdef but the well-founded relation can be
  2119 supplied later.  Program schemes can be defined, such as
  2120     "While B C s = (if B s then While B C (C s) else s)"
  2121 where the well-founded relation can be chosen after B and C have been given.
  2122 
  2123 * HOL/List: the constructors of type list are now Nil and Cons;
  2124 INCOMPATIBILITY: while [] and infix # syntax is still there, of
  2125 course, ML tools referring to List.list.op # etc. have to be adapted;
  2126 
  2127 * HOL_quantifiers flag superseded by "HOL" print mode, which is
  2128 disabled by default; run isabelle with option -m HOL to get back to
  2129 the original Gordon/HOL-style output;
  2130 
  2131 * HOL/Ord.thy: new bounded quantifier syntax (input only): ALL x<y. P,
  2132 ALL x<=y. P, EX x<y. P, EX x<=y. P;
  2133 
  2134 * HOL basic syntax simplified (more orthogonal): all variants of
  2135 All/Ex now support plain / symbolic / HOL notation; plain syntax for
  2136 Eps operator is provided as well: "SOME x. P[x]";
  2137 
  2138 * HOL/Sum.thy: sum_case has been moved to HOL/Datatype;
  2139 
  2140 * HOL/Univ.thy: infix syntax <*>, <+>, <**>, <+> eliminated and made
  2141 thus available for user theories;
  2142 
  2143 * HOLCF/IOA/Sequents: renamed 'Cons' to 'Consq' to avoid clash with
  2144 HOL/List; hardly an INCOMPATIBILITY since '>>' syntax is used all the
  2145 time;
  2146 
  2147 * HOL: new tactic smp_tac: int -> int -> tactic, which applies spec
  2148 several times and then mp;
  2149 
  2150 
  2151 *** LK ***
  2152 
  2153 * the notation <<...>> is now available as a notation for sequences of
  2154 formulas;
  2155 
  2156 * the simplifier is now installed
  2157 
  2158 * the axiom system has been generalized (thanks to Soren Heilmann)
  2159 
  2160 * the classical reasoner now has a default rule database
  2161 
  2162 
  2163 *** ZF ***
  2164 
  2165 * new primrec section allows primitive recursive functions to be given
  2166 directly (as in HOL) over datatypes and the natural numbers;
  2167 
  2168 * new tactics induct_tac and exhaust_tac for induction (or case
  2169 analysis) over datatypes and the natural numbers;
  2170 
  2171 * the datatype declaration of type T now defines the recursor T_rec;
  2172 
  2173 * simplification automatically does freeness reasoning for datatype
  2174 constructors;
  2175 
  2176 * automatic type-inference, with AddTCs command to insert new
  2177 type-checking rules;
  2178 
  2179 * datatype introduction rules are now added as Safe Introduction rules
  2180 to the claset;
  2181 
  2182 * the syntax "if P then x else y" is now available in addition to
  2183 if(P,x,y);
  2184 
  2185 
  2186 *** Internal programming interfaces ***
  2187 
  2188 * tuned simplifier trace output; new flag debug_simp;
  2189 
  2190 * structures Vartab / Termtab (instances of TableFun) offer efficient
  2191 tables indexed by indexname_ord / term_ord (compatible with aconv);
  2192 
  2193 * AxClass.axclass_tac lost the theory argument;
  2194 
  2195 * tuned current_goals_markers semantics: begin / end goal avoids
  2196 printing empty lines;
  2197 
  2198 * removed prs and prs_fn hook, which was broken because it did not
  2199 include \n in its semantics, forcing writeln to add one
  2200 uncoditionally; replaced prs_fn by writeln_fn; consider std_output:
  2201 string -> unit if you really want to output text without newline;
  2202 
  2203 * Symbol.output subject to print mode; INCOMPATIBILITY: defaults to
  2204 plain output, interface builders may have to enable 'isabelle_font'
  2205 mode to get Isabelle font glyphs as before;
  2206 
  2207 * refined token_translation interface; INCOMPATIBILITY: output length
  2208 now of type real instead of int;
  2209 
  2210 * theory loader actions may be traced via new ThyInfo.add_hook
  2211 interface (see src/Pure/Thy/thy_info.ML); example application: keep
  2212 your own database of information attached to *whole* theories -- as
  2213 opposed to intra-theory data slots offered via TheoryDataFun;
  2214 
  2215 * proper handling of dangling sort hypotheses (at last!);
  2216 Thm.strip_shyps and Drule.strip_shyps_warning take care of removing
  2217 extra sort hypotheses that can be witnessed from the type signature;
  2218 the force_strip_shyps flag is gone, any remaining shyps are simply
  2219 left in the theorem (with a warning issued by strip_shyps_warning);
  2220 
  2221 
  2222 
  2223 New in Isabelle98-1 (October 1998)
  2224 ----------------------------------
  2225 
  2226 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  2227 
  2228 * several changes of automated proof tools;
  2229 
  2230 * HOL: major changes to the inductive and datatype packages, including
  2231 some minor incompatibilities of theory syntax;
  2232 
  2233 * HOL: renamed r^-1 to 'converse' from 'inverse'; 'inj_onto' is now
  2234 called `inj_on';
  2235 
  2236 * HOL: removed duplicate thms in Arith:
  2237   less_imp_add_less  should be replaced by  trans_less_add1
  2238   le_imp_add_le      should be replaced by  trans_le_add1
  2239 
  2240 * HOL: unary minus is now overloaded (new type constraints may be
  2241 required);
  2242 
  2243 * HOL and ZF: unary minus for integers is now #- instead of #~.  In
  2244 ZF, expressions such as n#-1 must be changed to n#- 1, since #-1 is
  2245 now taken as an integer constant.
  2246 
  2247 * Pure: ML function 'theory_of' renamed to 'theory';
  2248 
  2249 
  2250 *** Proof tools ***
  2251 
  2252 * Simplifier:
  2253   1. Asm_full_simp_tac is now more aggressive.
  2254      1. It will sometimes reorient premises if that increases their power to
  2255         simplify.
  2256      2. It does no longer proceed strictly from left to right but may also
  2257         rotate premises to achieve further simplification.
  2258      For compatibility reasons there is now Asm_lr_simp_tac which is like the
  2259      old Asm_full_simp_tac in that it does not rotate premises.
  2260   2. The simplifier now knows a little bit about nat-arithmetic.
  2261 
  2262 * Classical reasoner: wrapper mechanism for the classical reasoner now
  2263 allows for selected deletion of wrappers, by introduction of names for
  2264 wrapper functionals.  This implies that addbefore, addSbefore,
  2265 addaltern, and addSaltern now take a pair (name, tactic) as argument,
  2266 and that adding two tactics with the same name overwrites the first
  2267 one (emitting a warning).
  2268   type wrapper = (int -> tactic) -> (int -> tactic)
  2269   setWrapper, setSWrapper, compWrapper and compSWrapper are replaced by
  2270   addWrapper, addSWrapper: claset * (string * wrapper) -> claset
  2271   delWrapper, delSWrapper: claset *  string            -> claset
  2272   getWrapper is renamed to appWrappers, getSWrapper to appSWrappers;
  2273 
  2274 * Classical reasoner: addbefore/addSbefore now have APPEND/ORELSE
  2275 semantics; addbefore now affects only the unsafe part of step_tac
  2276 etc.; this affects addss/auto_tac/force_tac, so EXISTING PROOFS MAY
  2277 FAIL, but proofs should be fixable easily, e.g. by replacing Auto_tac
  2278 by Force_tac;
  2279 
  2280 * Classical reasoner: setwrapper to setWrapper and compwrapper to
  2281 compWrapper; added safe wrapper (and access functions for it);
  2282 
  2283 * HOL/split_all_tac is now much faster and fails if there is nothing
  2284 to split.  Some EXISTING PROOFS MAY REQUIRE ADAPTION because the order
  2285 and the names of the automatically generated variables have changed.
  2286 split_all_tac has moved within claset() from unsafe wrappers to safe
  2287 wrappers, which means that !!-bound variables are split much more
  2288 aggressively, and safe_tac and clarify_tac now split such variables.
  2289 If this splitting is not appropriate, use delSWrapper "split_all_tac".
  2290 Note: the same holds for record_split_tac, which does the job of
  2291 split_all_tac for record fields.
  2292 
  2293 * HOL/Simplifier: Rewrite rules for case distinctions can now be added
  2294 permanently to the default simpset using Addsplits just like
  2295 Addsimps. They can be removed via Delsplits just like
  2296 Delsimps. Lower-case versions are also available.
  2297 
  2298 * HOL/Simplifier: The rule split_if is now part of the default
  2299 simpset. This means that the simplifier will eliminate all occurrences
  2300 of if-then-else in the conclusion of a goal. To prevent this, you can
  2301 either remove split_if completely from the default simpset by
  2302 `Delsplits [split_if]' or remove it in a specific call of the
  2303 simplifier using `... delsplits [split_if]'.  You can also add/delete
  2304 other case splitting rules to/from the default simpset: every datatype
  2305 generates suitable rules `split_t_case' and `split_t_case_asm' (where
  2306 t is the name of the datatype).
  2307 
  2308 * Classical reasoner / Simplifier combination: new force_tac (and
  2309 derivatives Force_tac, force) combines rewriting and classical
  2310 reasoning (and whatever other tools) similarly to auto_tac, but is
  2311 aimed to solve the given subgoal completely.
  2312 
  2313 
  2314 *** General ***
  2315 
  2316 * new top-level commands `Goal' and `Goalw' that improve upon `goal'
  2317 and `goalw': the theory is no longer needed as an explicit argument -
  2318 the current theory context is used; assumptions are no longer returned
  2319 at the ML-level unless one of them starts with ==> or !!; it is
  2320 recommended to convert to these new commands using isatool fixgoal
  2321 (backup your sources first!);
  2322 
  2323 * new top-level commands 'thm' and 'thms' for retrieving theorems from
  2324 the current theory context, and 'theory' to lookup stored theories;
  2325 
  2326 * new theory section 'locale' for declaring constants, assumptions and
  2327 definitions that have local scope;
  2328 
  2329 * new theory section 'nonterminals' for purely syntactic types;
  2330 
  2331 * new theory section 'setup' for generic ML setup functions
  2332 (e.g. package initialization);
  2333 
  2334 * the distribution now includes Isabelle icons: see
  2335 lib/logo/isabelle-{small,tiny}.xpm;
  2336 
  2337 * isatool install - install binaries with absolute references to
  2338 ISABELLE_HOME/bin;
  2339 
  2340 * isatool logo -- create instances of the Isabelle logo (as EPS);
  2341 
  2342 * print mode 'emacs' reserved for Isamode;
  2343 
  2344 * support multiple print (ast) translations per constant name;
  2345 
  2346 * theorems involving oracles are now printed with a suffixed [!];
  2347 
  2348 
  2349 *** HOL ***
  2350 
  2351 * there is now a tutorial on Isabelle/HOL (do 'isatool doc tutorial');
  2352 
  2353 * HOL/inductive package reorganized and improved: now supports mutual
  2354 definitions such as
  2355 
  2356   inductive EVEN ODD
  2357     intrs
  2358       null "0 : EVEN"
  2359       oddI "n : EVEN ==> Suc n : ODD"
  2360       evenI "n : ODD ==> Suc n : EVEN"
  2361 
  2362 new theorem list "elims" contains an elimination rule for each of the
  2363 recursive sets; inductive definitions now handle disjunctive premises
  2364 correctly (also ZF);
  2365 
  2366 INCOMPATIBILITIES: requires Inductive as an ancestor; component
  2367 "mutual_induct" no longer exists - the induction rule is always
  2368 contained in "induct";
  2369 
  2370 
  2371 * HOL/datatype package re-implemented and greatly improved: now
  2372 supports mutually recursive datatypes such as
  2373 
  2374   datatype
  2375     'a aexp = IF_THEN_ELSE ('a bexp) ('a aexp) ('a aexp)
  2376             | SUM ('a aexp) ('a aexp)
  2377             | DIFF ('a aexp) ('a aexp)
  2378             | NUM 'a
  2379   and
  2380     'a bexp = LESS ('a aexp) ('a aexp)
  2381             | AND ('a bexp) ('a bexp)
  2382             | OR ('a bexp) ('a bexp)
  2383 
  2384 as well as indirectly recursive datatypes such as
  2385 
  2386   datatype
  2387     ('a, 'b) term = Var 'a
  2388                   | App 'b ((('a, 'b) term) list)
  2389 
  2390 The new tactic  mutual_induct_tac [<var_1>, ..., <var_n>] i  performs
  2391 induction on mutually / indirectly recursive datatypes.
  2392 
  2393 Primrec equations are now stored in theory and can be accessed via
  2394 <function_name>.simps.
  2395 
  2396 INCOMPATIBILITIES:
  2397 
  2398   - Theories using datatypes must now have theory Datatype as an
  2399     ancestor.
  2400   - The specific <typename>.induct_tac no longer exists - use the
  2401     generic induct_tac instead.
  2402   - natE has been renamed to nat.exhaust - use exhaust_tac
  2403     instead of res_inst_tac ... natE. Note that the variable
  2404     names in nat.exhaust differ from the names in natE, this
  2405     may cause some "fragile" proofs to fail.
  2406   - The theorems split_<typename>_case and split_<typename>_case_asm
  2407     have been renamed to <typename>.split and <typename>.split_asm.
  2408   - Since default sorts of type variables are now handled correctly,
  2409     some datatype definitions may have to be annotated with explicit
  2410     sort constraints.
  2411   - Primrec definitions no longer require function name and type
  2412     of recursive argument.
  2413 
  2414 Consider using isatool fixdatatype to adapt your theories and proof
  2415 scripts to the new package (backup your sources first!).
  2416 
  2417 
  2418 * HOL/record package: considerably improved implementation; now
  2419 includes concrete syntax for record types, terms, updates; theorems
  2420 for surjective pairing and splitting !!-bound record variables; proof
  2421 support is as follows:
  2422 
  2423   1) standard conversions (selectors or updates applied to record
  2424 constructor terms) are part of the standard simpset;
  2425 
  2426   2) inject equations of the form ((x, y) = (x', y')) == x=x' & y=y' are
  2427 made part of standard simpset and claset via addIffs;
  2428 
  2429   3) a tactic for record field splitting (record_split_tac) is part of
  2430 the standard claset (addSWrapper);
  2431 
  2432 To get a better idea about these rules you may retrieve them via
  2433 something like 'thms "foo.simps"' or 'thms "foo.iffs"', where "foo" is
  2434 the name of your record type.
  2435 
  2436 The split tactic 3) conceptually simplifies by the following rule:
  2437 
  2438   "(!!x. PROP ?P x) == (!!a b. PROP ?P (a, b))"
  2439 
  2440 Thus any record variable that is bound by meta-all will automatically
  2441 blow up into some record constructor term, consequently the
  2442 simplifications of 1), 2) apply.  Thus force_tac, auto_tac etc. shall
  2443 solve record problems automatically.
  2444 
  2445 
  2446 * reorganized the main HOL image: HOL/Integ and String loaded by
  2447 default; theory Main includes everything;
  2448 
  2449 * automatic simplification of integer sums and comparisons, using cancellation;
  2450 
  2451 * added option_map_eq_Some and not_Some_eq to the default simpset and claset;
  2452 
  2453 * added disj_not1 = "(~P | Q) = (P --> Q)" to the default simpset;
  2454 
  2455 * many new identities for unions, intersections, set difference, etc.;
  2456 
  2457 * expand_if, expand_split, expand_sum_case and expand_nat_case are now
  2458 called split_if, split_split, split_sum_case and split_nat_case (to go
  2459 with add/delsplits);
  2460 
  2461 * HOL/Prod introduces simplification procedure unit_eq_proc rewriting
  2462 (?x::unit) = (); this is made part of the default simpset, which COULD
  2463 MAKE EXISTING PROOFS FAIL under rare circumstances (consider
  2464 'Delsimprocs [unit_eq_proc];' as last resort); also note that
  2465 unit_abs_eta_conv is added in order to counter the effect of
  2466 unit_eq_proc on (%u::unit. f u), replacing it by f rather than by
  2467 %u.f();
  2468 
  2469 * HOL/Fun INCOMPATIBILITY: `inj_onto' is now called `inj_on' (which
  2470 makes more sense);
  2471 
  2472 * HOL/Set INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
  2473   It and 'sym RS equals0D' are now in the default  claset, giving automatic
  2474   disjointness reasoning but breaking a few old proofs.
  2475 
  2476 * HOL/Relation INCOMPATIBILITY: renamed the relational operator r^-1
  2477 to 'converse' from 'inverse' (for compatibility with ZF and some
  2478 literature);
  2479 
  2480 * HOL/recdef can now declare non-recursive functions, with {} supplied as
  2481 the well-founded relation;
  2482 
  2483 * HOL/Set INCOMPATIBILITY: the complement of set A is now written -A instead of
  2484     Compl A.  The "Compl" syntax remains available as input syntax for this
  2485     release ONLY.
  2486 
  2487 * HOL/Update: new theory of function updates:
  2488     f(a:=b) == %x. if x=a then b else f x
  2489 may also be iterated as in f(a:=b,c:=d,...);
  2490 
  2491 * HOL/Vimage: new theory for inverse image of a function, syntax f-``B;
  2492 
  2493 * HOL/List:
  2494   - new function list_update written xs[i:=v] that updates the i-th
  2495     list position. May also be iterated as in xs[i:=a,j:=b,...].
  2496   - new function `upt' written [i..j(] which generates the list
  2497     [i,i+1,...,j-1], i.e. the upper bound is excluded. To include the upper
  2498     bound write [i..j], which is a shorthand for [i..j+1(].
  2499   - new lexicographic orderings and corresponding wellfoundedness theorems.
  2500 
  2501 * HOL/Arith:
  2502   - removed 'pred' (predecessor) function;
  2503   - generalized some theorems about n-1;
  2504   - many new laws about "div" and "mod";
  2505   - new laws about greatest common divisors (see theory ex/Primes);
  2506 
  2507 * HOL/Relation: renamed the relational operator r^-1 "converse"
  2508 instead of "inverse";
  2509 
  2510 * HOL/Induct/Multiset: a theory of multisets, including the wellfoundedness
  2511   of the multiset ordering;
  2512 
  2513 * directory HOL/Real: a construction of the reals using Dedekind cuts
  2514   (not included by default);
  2515 
  2516 * directory HOL/UNITY: Chandy and Misra's UNITY formalism;
  2517 
  2518 * directory HOL/Hoare: a new version of Hoare logic which permits many-sorted
  2519   programs, i.e. different program variables may have different types.
  2520 
  2521 * calling (stac rew i) now fails if "rew" has no effect on the goal
  2522   [previously, this check worked only if the rewrite rule was unconditional]
  2523   Now rew can involve either definitions or equalities (either == or =).
  2524 
  2525 
  2526 *** ZF ***
  2527 
  2528 * theory Main includes everything; INCOMPATIBILITY: theory ZF.thy contains
  2529   only the theorems proved on ZF.ML;
  2530 
  2531 * ZF INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
  2532   It and 'sym RS equals0D' are now in the default  claset, giving automatic
  2533   disjointness reasoning but breaking a few old proofs.
  2534 
  2535 * ZF/Update: new theory of function updates
  2536     with default rewrite rule  f(x:=y) ` z = if(z=x, y, f`z)
  2537   may also be iterated as in f(a:=b,c:=d,...);
  2538 
  2539 * in  let x=t in u(x), neither t nor u(x) has to be an FOL term.
  2540 
  2541 * calling (stac rew i) now fails if "rew" has no effect on the goal
  2542   [previously, this check worked only if the rewrite rule was unconditional]
  2543   Now rew can involve either definitions or equalities (either == or =).
  2544 
  2545 * case_tac provided for compatibility with HOL
  2546     (like the old excluded_middle_tac, but with subgoals swapped)
  2547 
  2548 
  2549 *** Internal programming interfaces ***
  2550 
  2551 * Pure: several new basic modules made available for general use, see
  2552 also src/Pure/README;
  2553 
  2554 * improved the theory data mechanism to support encapsulation (data
  2555 kind name replaced by private Object.kind, acting as authorization
  2556 key); new type-safe user interface via functor TheoryDataFun; generic
  2557 print_data function becomes basically useless;
  2558 
  2559 * removed global_names compatibility flag -- all theory declarations
  2560 are qualified by default;
  2561 
  2562 * module Pure/Syntax now offers quote / antiquote translation
  2563 functions (useful for Hoare logic etc. with implicit dependencies);
  2564 see HOL/ex/Antiquote for an example use;
  2565 
  2566 * Simplifier now offers conversions (asm_)(full_)rewrite: simpset ->
  2567 cterm -> thm;
  2568 
  2569 * new tactical CHANGED_GOAL for checking that a tactic modifies a
  2570 subgoal;
  2571 
  2572 * Display.print_goals function moved to Locale.print_goals;
  2573 
  2574 * standard print function for goals supports current_goals_markers
  2575 variable for marking begin of proof, end of proof, start of goal; the
  2576 default is ("", "", ""); setting current_goals_markers := ("<proof>",
  2577 "</proof>", "<goal>") causes SGML like tagged proof state printing,
  2578 for example;
  2579 
  2580 
  2581 
  2582 New in Isabelle98 (January 1998)
  2583 --------------------------------
  2584 
  2585 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  2586 
  2587 * changed lexical syntax of terms / types: dots made part of long
  2588 identifiers, e.g. "%x.x" no longer possible, should be "%x. x";
  2589 
  2590 * simpset (and claset) reference variable replaced by functions
  2591 simpset / simpset_ref;
  2592 
  2593 * no longer supports theory aliases (via merge) and non-trivial
  2594 implicit merge of thms' signatures;
  2595 
  2596 * most internal names of constants changed due to qualified names;
  2597 
  2598 * changed Pure/Sequence interface (see Pure/seq.ML);
  2599 
  2600 
  2601 *** General Changes ***
  2602 
  2603 * hierachically structured name spaces (for consts, types, axms, thms
  2604 etc.); new lexical class 'longid' (e.g. Foo.bar.x) may render much of
  2605 old input syntactically incorrect (e.g. "%x.x"); COMPATIBILITY:
  2606 isatool fixdots ensures space after dots (e.g. "%x. x"); set
  2607 long_names for fully qualified output names; NOTE: ML programs
  2608 (special tactics, packages etc.) referring to internal names may have
  2609 to be adapted to cope with fully qualified names; in case of severe
  2610 backward campatibility problems try setting 'global_names' at compile
  2611 time to have enrything declared within a flat name space; one may also
  2612 fine tune name declarations in theories via the 'global' and 'local'
  2613 section;
  2614 
  2615 * reimplemented the implicit simpset and claset using the new anytype
  2616 data filed in signatures; references simpset:simpset ref etc. are
  2617 replaced by functions simpset:unit->simpset and
  2618 simpset_ref:unit->simpset ref; COMPATIBILITY: use isatool fixclasimp
  2619 to patch your ML files accordingly;
  2620 
  2621 * HTML output now includes theory graph data for display with Java
  2622 applet or isatool browser; data generated automatically via isatool
  2623 usedir (see -i option, ISABELLE_USEDIR_OPTIONS);
  2624 
  2625 * defs may now be conditional; improved rewrite_goals_tac to handle
  2626 conditional equations;
  2627 
  2628 * defs now admits additional type arguments, using TYPE('a) syntax;
  2629 
  2630 * theory aliases via merge (e.g. M=A+B+C) no longer supported, always
  2631 creates a new theory node; implicit merge of thms' signatures is
  2632 restricted to 'trivial' ones; COMPATIBILITY: one may have to use
  2633 transfer:theory->thm->thm in (rare) cases;
  2634 
  2635 * improved handling of draft signatures / theories; draft thms (and
  2636 ctyps, cterms) are automatically promoted to real ones;
  2637 
  2638 * slightly changed interfaces for oracles: admit many per theory, named
  2639 (e.g. oracle foo = mlfun), additional name argument for invoke_oracle;
  2640 
  2641 * print_goals: optional output of const types (set show_consts and
  2642 show_types);
  2643 
  2644 * improved output of warnings (###) and errors (***);
  2645 
  2646 * subgoal_tac displays a warning if the new subgoal has type variables;
  2647 
  2648 * removed old README and Makefiles;
  2649 
  2650 * replaced print_goals_ref hook by print_current_goals_fn and result_error_fn;
  2651 
  2652 * removed obsolete init_pps and init_database;
  2653 
  2654 * deleted the obsolete tactical STATE, which was declared by
  2655     fun STATE tacfun st = tacfun st st;
  2656 
  2657 * cd and use now support path variables, e.g. $ISABELLE_HOME, or ~
  2658 (which abbreviates $HOME);
  2659 
  2660 * changed Pure/Sequence interface (see Pure/seq.ML); COMPATIBILITY:
  2661 use isatool fixseq to adapt your ML programs (this works for fully
  2662 qualified references to the Sequence structure only!);
  2663 
  2664 * use_thy no longer requires writable current directory; it always
  2665 reloads .ML *and* .thy file, if either one is out of date;
  2666 
  2667 
  2668 *** Classical Reasoner ***
  2669 
  2670 * Clarify_tac, clarify_tac, clarify_step_tac, Clarify_step_tac: new
  2671 tactics that use classical reasoning to simplify a subgoal without
  2672 splitting it into several subgoals;
  2673 
  2674 * Safe_tac: like safe_tac but uses the default claset;
  2675 
  2676 
  2677 *** Simplifier ***
  2678 
  2679 * added simplification meta rules:
  2680     (asm_)(full_)simplify: simpset -> thm -> thm;
  2681 
  2682 * simplifier.ML no longer part of Pure -- has to be loaded by object
  2683 logics (again);
  2684 
  2685 * added prems argument to simplification procedures;
  2686 
  2687 * HOL, FOL, ZF: added infix function `addsplits':
  2688   instead of `<simpset> setloop (split_tac <thms>)'
  2689   you can simply write `<simpset> addsplits <thms>'
  2690 
  2691 
  2692 *** Syntax ***
  2693 
  2694 * TYPE('a) syntax for type reflection terms;
  2695 
  2696 * no longer handles consts with name "" -- declare as 'syntax' instead;
  2697 
  2698 * pretty printer: changed order of mixfix annotation preference (again!);
  2699 
  2700 * Pure: fixed idt/idts vs. pttrn/pttrns syntactic categories;
  2701 
  2702 
  2703 *** HOL ***
  2704 
  2705 * HOL: there is a new splitter `split_asm_tac' that can be used e.g.
  2706   with `addloop' of the simplifier to faciliate case splitting in premises.
  2707 
  2708 * HOL/TLA: Stephan Merz's formalization of Lamport's Temporal Logic of Actions;
  2709 
  2710 * HOL/Auth: new protocol proofs including some for the Internet
  2711   protocol TLS;
  2712 
  2713 * HOL/Map: new theory of `maps' a la VDM;
  2714 
  2715 * HOL/simplifier: simplification procedures nat_cancel_sums for
  2716 cancelling out common nat summands from =, <, <= (in)equalities, or
  2717 differences; simplification procedures nat_cancel_factor for
  2718 cancelling common factor from =, <, <= (in)equalities over natural
  2719 sums; nat_cancel contains both kinds of procedures, it is installed by
  2720 default in Arith.thy -- this COULD MAKE EXISTING PROOFS FAIL;
  2721 
  2722 * HOL/simplifier: terms of the form
  2723   `? x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x)'  (or t=x)
  2724   are rewritten to
  2725   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t)',
  2726   and those of the form
  2727   `! x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x) --> R(x)'  (or t=x)
  2728   are rewritten to
  2729   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t) --> R(t)',
  2730 
  2731 * HOL/datatype
  2732   Each datatype `t' now comes with a theorem `split_t_case' of the form
  2733 
  2734   P(t_case f1 ... fn x) =
  2735      ( (!y1 ... ym1. x = C1 y1 ... ym1 --> P(f1 y1 ... ym1)) &
  2736         ...
  2737        (!y1 ... ymn. x = Cn y1 ... ymn --> P(f1 y1 ... ymn))
  2738      )
  2739 
  2740   and a theorem `split_t_case_asm' of the form
  2741 
  2742   P(t_case f1 ... fn x) =
  2743     ~( (? y1 ... ym1. x = C1 y1 ... ym1 & ~P(f1 y1 ... ym1)) |
  2744         ...
  2745        (? y1 ... ymn. x = Cn y1 ... ymn & ~P(f1 y1 ... ymn))
  2746      )
  2747   which can be added to a simpset via `addsplits'. The existing theorems
  2748   expand_list_case and expand_option_case have been renamed to
  2749   split_list_case and split_option_case.
  2750 
  2751 * HOL/Arithmetic:
  2752   - `pred n' is automatically converted to `n-1'.
  2753     Users are strongly encouraged not to use `pred' any longer,
  2754     because it will disappear altogether at some point.
  2755   - Users are strongly encouraged to write "0 < n" rather than
  2756     "n ~= 0". Theorems and proof tools have been modified towards this
  2757     `standard'.
  2758 
  2759 * HOL/Lists:
  2760   the function "set_of_list" has been renamed "set" (and its theorems too);
  2761   the function "nth" now takes its arguments in the reverse order and
  2762   has acquired the infix notation "!" as in "xs!n".
  2763 
  2764 * HOL/Set: UNIV is now a constant and is no longer translated to Compl{};
  2765 
  2766 * HOL/Set: The operator (UN x.B x) now abbreviates (UN x:UNIV. B x) and its
  2767   specialist theorems (like UN1_I) are gone.  Similarly for (INT x.B x);
  2768 
  2769 * HOL/record: extensible records with schematic structural subtyping
  2770 (single inheritance); EXPERIMENTAL version demonstrating the encoding,
  2771 still lacks various theorems and concrete record syntax;
  2772 
  2773 
  2774 *** HOLCF ***
  2775 
  2776 * removed "axioms" and "generated by" sections;
  2777 
  2778 * replaced "ops" section by extended "consts" section, which is capable of
  2779   handling the continuous function space "->" directly;
  2780 
  2781 * domain package:
  2782   . proves theorems immediately and stores them in the theory,
  2783   . creates hierachical name space,
  2784   . now uses normal mixfix annotations (instead of cinfix...),
  2785   . minor changes to some names and values (for consistency),
  2786   . e.g. cases -> casedist, dists_eq -> dist_eqs, [take_lemma] -> take_lemmas,
  2787   . separator between mutual domain defs: changed "," to "and",
  2788   . improved handling of sort constraints;  now they have to
  2789     appear on the left-hand side of the equations only;
  2790 
  2791 * fixed LAM <x,y,zs>.b syntax;
  2792 
  2793 * added extended adm_tac to simplifier in HOLCF -- can now discharge
  2794 adm (%x. P (t x)), where P is chainfinite and t continuous;
  2795 
  2796 
  2797 *** FOL and ZF ***
  2798 
  2799 * FOL: there is a new splitter `split_asm_tac' that can be used e.g.
  2800   with `addloop' of the simplifier to faciliate case splitting in premises.
  2801 
  2802 * qed_spec_mp, qed_goal_spec_mp, qed_goalw_spec_mp are available, as
  2803 in HOL, they strip ALL and --> from proved theorems;
  2804 
  2805 
  2806 
  2807 New in Isabelle94-8 (May 1997)
  2808 ------------------------------
  2809 
  2810 *** General Changes ***
  2811 
  2812 * new utilities to build / run / maintain Isabelle etc. (in parts
  2813 still somewhat experimental); old Makefiles etc. still functional;
  2814 
  2815 * new 'Isabelle System Manual';
  2816 
  2817 * INSTALL text, together with ./configure and ./build scripts;
  2818 
  2819 * reimplemented type inference for greater efficiency, better error
  2820 messages and clean internal interface;
  2821 
  2822 * prlim command for dealing with lots of subgoals (an easier way of
  2823 setting goals_limit);
  2824 
  2825 
  2826 *** Syntax ***
  2827 
  2828 * supports alternative (named) syntax tables (parser and pretty
  2829 printer); internal interface is provided by add_modesyntax(_i);
  2830 
  2831 * Pure, FOL, ZF, HOL, HOLCF now support symbolic input and output; to
  2832 be used in conjunction with the Isabelle symbol font; uses the
  2833 "symbols" syntax table;
  2834 
  2835 * added token_translation interface (may translate name tokens in
  2836 arbitrary ways, dependent on their type (free, bound, tfree, ...) and
  2837 the current print_mode); IMPORTANT: user print translation functions
  2838 are responsible for marking newly introduced bounds
  2839 (Syntax.mark_boundT);
  2840 
  2841 * token translations for modes "xterm" and "xterm_color" that display
  2842 names in bold, underline etc. or colors (which requires a color
  2843 version of xterm);
  2844 
  2845 * infixes may now be declared with names independent of their syntax;
  2846 
  2847 * added typed_print_translation (like print_translation, but may
  2848 access type of constant);
  2849 
  2850 
  2851 *** Classical Reasoner ***
  2852 
  2853 Blast_tac: a new tactic!  It is often more powerful than fast_tac, but has
  2854 some limitations.  Blast_tac...
  2855   + ignores addss, addbefore, addafter; this restriction is intrinsic
  2856   + ignores elimination rules that don't have the correct format
  2857         (the conclusion MUST be a formula variable)
  2858   + ignores types, which can make HOL proofs fail
  2859   + rules must not require higher-order unification, e.g. apply_type in ZF
  2860     [message "Function Var's argument not a bound variable" relates to this]
  2861   + its proof strategy is more general but can actually be slower
  2862 
  2863 * substitution with equality assumptions no longer permutes other
  2864 assumptions;
  2865 
  2866 * minor changes in semantics of addafter (now called addaltern); renamed
  2867 setwrapper to setWrapper and compwrapper to compWrapper; added safe wrapper
  2868 (and access functions for it);
  2869 
  2870 * improved combination of classical reasoner and simplifier:
  2871   + functions for handling clasimpsets
  2872   + improvement of addss: now the simplifier is called _after_ the
  2873     safe steps.
  2874   + safe variant of addss called addSss: uses safe simplifications
  2875     _during_ the safe steps. It is more complete as it allows multiple
  2876     instantiations of unknowns (e.g. with slow_tac).
  2877 
  2878 *** Simplifier ***
  2879 
  2880 * added interface for simplification procedures (functions that
  2881 produce *proven* rewrite rules on the fly, depending on current
  2882 redex);
  2883 
  2884 * ordering on terms as parameter (used for ordered rewriting);
  2885 
  2886 * new functions delcongs, deleqcongs, and Delcongs. richer rep_ss;
  2887 
  2888 * the solver is now split into a safe and an unsafe part.
  2889 This should be invisible for the normal user, except that the
  2890 functions setsolver and addsolver have been renamed to setSolver and
  2891 addSolver; added safe_asm_full_simp_tac;
  2892 
  2893 
  2894 *** HOL ***
  2895 
  2896 * a generic induction tactic `induct_tac' which works for all datatypes and
  2897 also for type `nat';
  2898 
  2899 * a generic case distinction tactic `exhaust_tac' which works for all
  2900 datatypes and also for type `nat';
  2901 
  2902 * each datatype comes with a function `size';
  2903 
  2904 * patterns in case expressions allow tuple patterns as arguments to
  2905 constructors, for example `case x of [] => ... | (x,y,z)#ps => ...';
  2906 
  2907 * primrec now also works with type nat;
  2908 
  2909 * recdef: a new declaration form, allows general recursive functions to be
  2910 defined in theory files.  See HOL/ex/Fib, HOL/ex/Primes, HOL/Subst/Unify.
  2911 
  2912 * the constant for negation has been renamed from "not" to "Not" to
  2913 harmonize with FOL, ZF, LK, etc.;
  2914 
  2915 * HOL/ex/LFilter theory of a corecursive "filter" functional for
  2916 infinite lists;
  2917 
  2918 * HOL/Modelcheck demonstrates invocation of model checker oracle;
  2919 
  2920 * HOL/ex/Ring.thy declares cring_simp, which solves equational
  2921 problems in commutative rings, using axiomatic type classes for + and *;
  2922 
  2923 * more examples in HOL/MiniML and HOL/Auth;
  2924 
  2925 * more default rewrite rules for quantifiers, union/intersection;
  2926 
  2927 * a new constant `arbitrary == @x.False';
  2928 
  2929 * HOLCF/IOA replaces old HOL/IOA;
  2930 
  2931 * HOLCF changes: derived all rules and arities
  2932   + axiomatic type classes instead of classes
  2933   + typedef instead of faking type definitions
  2934   + eliminated the internal constants less_fun, less_cfun, UU_fun, UU_cfun etc.
  2935   + new axclasses cpo, chfin, flat with flat < chfin < pcpo < cpo < po
  2936   + eliminated the types void, one, tr
  2937   + use unit lift and bool lift (with translations) instead of one and tr
  2938   + eliminated blift from Lift3.thy (use Def instead of blift)
  2939   all eliminated rules are derived as theorems --> no visible changes ;
  2940 
  2941 
  2942 *** ZF ***
  2943 
  2944 * ZF now has Fast_tac, Simp_tac and Auto_tac.  Union_iff is a now a default
  2945 rewrite rule; this may affect some proofs.  eq_cs is gone but can be put back
  2946 as ZF_cs addSIs [equalityI];
  2947 
  2948 
  2949 
  2950 New in Isabelle94-7 (November 96)
  2951 ---------------------------------
  2952 
  2953 * allowing negative levels (as offsets) in prlev and choplev;
  2954 
  2955 * super-linear speedup for large simplifications;
  2956 
  2957 * FOL, ZF and HOL now use miniscoping: rewriting pushes
  2958 quantifications in as far as possible (COULD MAKE EXISTING PROOFS
  2959 FAIL); can suppress it using the command Delsimps (ex_simps @
  2960 all_simps); De Morgan laws are also now included, by default;
  2961 
  2962 * improved printing of ==>  :  ~:
  2963 
  2964 * new object-logic "Sequents" adds linear logic, while replacing LK
  2965 and Modal (thanks to Sara Kalvala);
  2966 
  2967 * HOL/Auth: correctness proofs for authentication protocols;
  2968 
  2969 * HOL: new auto_tac combines rewriting and classical reasoning (many
  2970 examples on HOL/Auth);
  2971 
  2972 * HOL: new command AddIffs for declaring theorems of the form P=Q to
  2973 the rewriter and classical reasoner simultaneously;
  2974 
  2975 * function uresult no longer returns theorems in "standard" format;
  2976 regain previous version by: val uresult = standard o uresult;
  2977 
  2978 
  2979 
  2980 New in Isabelle94-6
  2981 -------------------
  2982 
  2983 * oracles -- these establish an interface between Isabelle and trusted
  2984 external reasoners, which may deliver results as theorems;
  2985 
  2986 * proof objects (in particular record all uses of oracles);
  2987 
  2988 * Simp_tac, Fast_tac, etc. that refer to implicit simpset / claset;
  2989 
  2990 * "constdefs" section in theory files;
  2991 
  2992 * "primrec" section (HOL) no longer requires names;
  2993 
  2994 * internal type "tactic" now simply "thm -> thm Sequence.seq";
  2995 
  2996 
  2997 
  2998 New in Isabelle94-5
  2999 -------------------
  3000 
  3001 * reduced space requirements;
  3002 
  3003 * automatic HTML generation from theories;
  3004 
  3005 * theory files no longer require "..." (quotes) around most types;
  3006 
  3007 * new examples, including two proofs of the Church-Rosser theorem;
  3008 
  3009 * non-curried (1994) version of HOL is no longer distributed;
  3010 
  3011 
  3012 
  3013 New in Isabelle94-4
  3014 -------------------
  3015 
  3016 * greatly reduced space requirements;
  3017 
  3018 * theory files (.thy) no longer require \...\ escapes at line breaks;
  3019 
  3020 * searchable theorem database (see the section "Retrieving theorems" on
  3021 page 8 of the Reference Manual);
  3022 
  3023 * new examples, including Grabczewski's monumental case study of the
  3024 Axiom of Choice;
  3025 
  3026 * The previous version of HOL renamed to Old_HOL;
  3027 
  3028 * The new version of HOL (previously called CHOL) uses a curried syntax
  3029 for functions.  Application looks like f a b instead of f(a,b);
  3030 
  3031 * Mutually recursive inductive definitions finally work in HOL;
  3032 
  3033 * In ZF, pattern-matching on tuples is now available in all abstractions and
  3034 translates to the operator "split";
  3035 
  3036 
  3037 
  3038 New in Isabelle94-3
  3039 -------------------
  3040 
  3041 * new infix operator, addss, allowing the classical reasoner to
  3042 perform simplification at each step of its search.  Example:
  3043         fast_tac (cs addss ss)
  3044 
  3045 * a new logic, CHOL, the same as HOL, but with a curried syntax
  3046 for functions.  Application looks like f a b instead of f(a,b).  Also pairs
  3047 look like (a,b) instead of <a,b>;
  3048 
  3049 * PLEASE NOTE: CHOL will eventually replace HOL!
  3050 
  3051 * In CHOL, pattern-matching on tuples is now available in all abstractions.
  3052 It translates to the operator "split".  A new theory of integers is available;
  3053 
  3054 * In ZF, integer numerals now denote two's-complement binary integers.
  3055 Arithmetic operations can be performed by rewriting.  See ZF/ex/Bin.ML;
  3056 
  3057 * Many new examples: I/O automata, Church-Rosser theorem, equivalents
  3058 of the Axiom of Choice;
  3059 
  3060 
  3061 
  3062 New in Isabelle94-2
  3063 -------------------
  3064 
  3065 * Significantly faster resolution;
  3066 
  3067 * the different sections in a .thy file can now be mixed and repeated
  3068 freely;
  3069 
  3070 * Database of theorems for FOL, HOL and ZF.  New
  3071 commands including qed, qed_goal and bind_thm store theorems in the database.
  3072 
  3073 * Simple database queries: return a named theorem (get_thm) or all theorems of
  3074 a given theory (thms_of), or find out what theory a theorem was proved in
  3075 (theory_of_thm);
  3076 
  3077 * Bugs fixed in the inductive definition and datatype packages;
  3078 
  3079 * The classical reasoner provides deepen_tac and depth_tac, making FOL_dup_cs
  3080 and HOL_dup_cs obsolete;
  3081 
  3082 * Syntactic ambiguities caused by the new treatment of syntax in Isabelle94-1
  3083 have been removed;
  3084 
  3085 * Simpler definition of function space in ZF;
  3086 
  3087 * new results about cardinal and ordinal arithmetic in ZF;
  3088 
  3089 * 'subtype' facility in HOL for introducing new types as subsets of existing
  3090 types;
  3091 
  3092 
  3093 $Id$