NEWS
author obua
Mon Jul 11 14:52:55 2005 +0200 (2005-07-11)
changeset 16766 ea667a5426fe
parent 16718 70c94b82c556
child 16799 978dcf30c3dd
permissions -rw-r--r--
Improved implementation of Defs.is_overloaded.
     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.  Use isatool fixheaders to convert
    21 existing theory files.  Note that there is no change in ancient
    22 non-Isar theories.
    23 
    24 * Theory loader: parent theories can now also be referred to via
    25 relative and absolute paths.
    26 
    27 * Improved version of thms_containing searches for a list of criteria
    28 instead of a list of constants. Known criteria are: intro, elim, dest,
    29 name:string, simp:term, and any term. Criteria can be preceded by '-'
    30 to select theorems that do not match. Intro, elim, dest select
    31 theorems that match the current goal, name:s selects theorems whose
    32 fully qualified name contain s, and simp:term selects all
    33 simplification rules whose lhs match term.  Any other term is
    34 interpreted as pattern and selects all theorems matching the
    35 pattern. Available in ProofGeneral under 'ProofGeneral -> Find
    36 Theorems' or C-c C-f.  Example:
    37 
    38   C-c C-f (100) "(_::nat) + _ + _" intro -name:"HOL."
    39 
    40 prints the last 100 theorems matching the pattern "(_::nat) + _ + _",
    41 matching the current goal as introduction rule and not having "HOL."
    42 in their name (i.e. not being defined in theory HOL).
    43 
    44 
    45 *** Document preparation ***
    46 
    47 * Commands 'display_drafts' and 'print_drafts' perform simple output
    48 of raw sources.  Only those symbols that do not require additional
    49 LaTeX packages (depending on comments in isabellesym.sty) are
    50 displayed properly, everything else is left verbatim.  isatool display
    51 and isatool print are used as front ends (these are subject to the
    52 DVI/PDF_VIEWER and PRINT_COMMAND settings, respectively).
    53 
    54 * There is now a flag to control hiding of proofs and some other
    55 commands (such as 'ML' or 'parse/print_translation') in document
    56 output.  Hiding is enabled by default, and can be disabled by the
    57 option '-H false' of isatool usedir or by resetting the reference
    58 variable IsarOutput.hide_commands in ML.  Additional commands to be
    59 hidden may be declared using IsarOutput.add_hidden_commands.
    60 
    61 * Several new antiquotation:
    62 
    63   @{term_type term} prints a term with its type annotated;
    64 
    65   @{typeof term} prints the type of a term;
    66 
    67   @{const const} is the same as @{term const}, but checks that the
    68   argument is a known logical constant;
    69 
    70   @{term_style style term} and @{thm_style style thm} print a term or
    71   theorem applying a "style" to it
    72 
    73 Predefined styles are 'lhs' and 'rhs' printing the lhs/rhs of
    74 definitions, equations, inequations etc., 'concl' printing only the
    75 conclusion of a meta-logical statement theorem, and 'prem1' .. 'prem9'
    76 to print the specified premise.  TermStyle.add_style provides an ML
    77 interface for introducing further styles.  See also the "LaTeX Sugar"
    78 document practical applications.
    79 
    80 
    81 *** Pure ***
    82 
    83 * Considerably improved version of 'constdefs' command.  Now performs
    84 automatic type-inference of declared constants; additional support for
    85 local structure declarations (cf. locales and HOL records), see also
    86 isar-ref manual.  Potential INCOMPATIBILITY: need to observe strictly
    87 sequential dependencies of definitions within a single 'constdefs'
    88 section; moreover, the declared name needs to be an identifier.  If
    89 all fails, consider to fall back on 'consts' and 'defs' separately.
    90 
    91 * Improved indexed syntax and implicit structures.  First of all,
    92 indexed syntax provides a notational device for subscripted
    93 application, using the new syntax \<^bsub>term\<^esub> for arbitrary
    94 expressions.  Secondly, in a local context with structure
    95 declarations, number indexes \<^sub>n or the empty index (default
    96 number 1) refer to a certain fixed variable implicitly; option
    97 show_structs controls printing of implicit structures.  Typical
    98 applications of these concepts involve record types and locales.
    99 
   100 * New command 'no_syntax' removes grammar declarations (and
   101 translations) resulting from the given syntax specification, which is
   102 interpreted in the same manner as for the 'syntax' command.
   103 
   104 * 'Advanced' translation functions (parse_translation etc.) may depend
   105 on the signature of the theory context being presently used for
   106 parsing/printing, see also isar-ref manual.
   107 
   108 * Improved internal renaming of symbolic identifiers -- attach primes
   109 instead of base 26 numbers.
   110 
   111 * New flag show_question_marks controls printing of leading question
   112 marks in schematic variable names.
   113 
   114 * In schematic variable names, *any* symbol following \<^isub> or
   115 \<^isup> is now treated as part of the base name.  For example, the
   116 following works without printing of awkward ".0" indexes:
   117 
   118   lemma "x\<^isub>1 = x\<^isub>2 ==> x\<^isub>2 = x\<^isub>1"
   119     by simp
   120 
   121 * Inner syntax includes (*(*nested*) comments*).
   122 
   123 * Pretty pinter now supports unbreakable blocks, specified in mixfix
   124 annotations as "(00...)".
   125 
   126 * Clear separation of logical types and nonterminals, where the latter
   127 may only occur in 'syntax' specifications or type abbreviations.
   128 Before that distinction was only partially implemented via type class
   129 "logic" vs. "{}".  Potential INCOMPATIBILITY in rare cases of improper
   130 use of 'types'/'consts' instead of 'nonterminals'/'syntax'.  Some very
   131 exotic syntax specifications may require further adaption
   132 (e.g. Cube/Base.thy).
   133 
   134 * Removed obsolete type class "logic", use the top sort {} instead.
   135 Note that non-logical types should be declared as 'nonterminals'
   136 rather than 'types'.  INCOMPATIBILITY for new object-logic
   137 specifications.
   138 
   139 * Simplifier: can now control the depth to which conditional rewriting
   140 is traced via the PG menu Isabelle -> Settings -> Trace Simp Depth
   141 Limit.
   142 
   143 * Simplifier: simplification procedures may now take the current
   144 simpset into account (cf. Simplifier.simproc(_i) / mk_simproc
   145 interface), which is very useful for calling the Simplifier
   146 recursively.  Minor INCOMPATIBILITY: the 'prems' argument of simprocs
   147 is gone -- use prems_of_ss on the simpset instead.  Moreover, the
   148 low-level mk_simproc no longer applies Logic.varify internally, to
   149 allow for use in a context of fixed variables.
   150 
   151 * thin_tac now works even if the assumption being deleted contains !!
   152 or ==>.  More generally, erule now works even if the major premise of
   153 the elimination rule contains !! or ==>.
   154 
   155 * Reorganized bootstrapping of the Pure theories; CPure is now derived
   156 from Pure, which contains all common declarations already.  Both
   157 theories are defined via plain Isabelle/Isar .thy files.
   158 INCOMPATIBILITY: elements of CPure (such as the CPure.intro /
   159 CPure.elim / CPure.dest attributes) now appear in the Pure name space;
   160 use isatool fixcpure to adapt your theory and ML sources.
   161 
   162 * New syntax 'name(i-j, i-, i, ...)' for referring to specific
   163 selections of theorems in named facts via index ranges.
   164 
   165 * More efficient treatment of intermediate checkpoints in interactive
   166 theory development.
   167 
   168 
   169 *** Locales ***
   170   
   171 * New commands for the interpretation of locale expressions in
   172 theories ('interpretation') and proof contexts ('interpret').  These
   173 take an instantiation of the locale parameters and compute proof
   174 obligations from the instantiated specification.  After the
   175 obligations have been discharged, the instantiated theorems of the
   176 locale are added to the theory or proof context.  Interpretation is
   177 smart in that already active interpretations do not occur in proof
   178 obligations, neither are instantiated theorems stored in duplicate.
   179 Use print_interps to inspect active interpretations of a particular
   180 locale.  For details, see the Isar Reference manual.
   181 
   182 INCOMPATIBILITY: former 'instantiate' has been withdrawn, use
   183 'interpret' instead.
   184 
   185 * Proper static binding of attribute syntax -- i.e. types / terms /
   186 facts mentioned as arguments are always those of the locale definition
   187 context, independently of the context of later invocations.  Moreover,
   188 locale operations (renaming and type / term instantiation) are applied
   189 to attribute arguments as expected.
   190 
   191 INCOMPATIBILITY of the ML interface: always pass Attrib.src instead of
   192 actual attributes; rare situations may require Attrib.attribute to
   193 embed those attributes into Attrib.src that lack concrete syntax.
   194 Attribute implementations need to cooperate properly with the static
   195 binding mechanism.  Basic parsers Args.XXX_typ/term/prop and
   196 Attrib.XXX_thm etc. already do the right thing without further
   197 intervention.  Only unusual applications -- such as "where" or "of"
   198 (cf. src/Pure/Isar/attrib.ML), which process arguments depending both
   199 on the context and the facts involved -- may have to assign parsed
   200 values to argument tokens explicitly.
   201 
   202 * New context element "constrains" adds type constraints to parameters --
   203 there is no logical significance.
   204 
   205 * Context expressions: renaming parameters permits syntax
   206 redeclaration as well.
   207 
   208 * Locale definition: 'includes' now disallowed.
   209 
   210 * Changed parameter management in theorem generation for long goal
   211 statements with 'includes'.  INCOMPATIBILITY: produces a different
   212 theorem statement in rare situations.
   213 
   214 * Attributes 'induct' and 'cases': type or set names may now be
   215 locally fixed variables as well.
   216 
   217 * Antiquotations now provide the option 'locale=NAME' to specify an
   218 alternative context used for evaluating and printing the subsequent
   219 argument, as in @{thm [locale=LC] fold_commute}, for example.
   220 
   221 
   222 *** Provers ***
   223 
   224 * Provers/hypsubst.ML: improved version of the subst method, for
   225 single-step rewriting: it now works in bound variable contexts. New is
   226 'subst (asm)', for rewriting an assumption.  INCOMPATIBILITY: may
   227 rewrite a different subterm than the original subst method, which is
   228 still available as 'simplesubst'.
   229 
   230 * Provers/quasi.ML: new transitivity reasoners for transitivity only
   231 and quasi orders.
   232 
   233 * Provers/trancl.ML: new transitivity reasoner for transitive and
   234 reflexive-transitive closure of relations.
   235 
   236 * Provers/blast.ML: new reference depth_limit to make blast's depth
   237 limit (previously hard-coded with a value of 20) user-definable.
   238 
   239 * Provers/simplifier.ML has been moved to Pure, where Simplifier.setup
   240 is peformed already.  Object-logics merely need to finish their
   241 initial simpset configuration as before.  INCOMPATIBILITY.
   242 
   243 
   244 *** HOL ***
   245 
   246 * Symbolic syntax of Hilbert Choice Operator is now as follows:
   247 
   248   syntax (epsilon)
   249     "_Eps" :: "[pttrn, bool] => 'a"    ("(3\<some>_./ _)" [0, 10] 10)
   250 
   251 The symbol \<some> is displayed as the alternative epsilon of LaTeX
   252 and x-symbol; use option '-m epsilon' to get it actually printed.
   253 Moreover, the mathematically important symbolic identifier \<epsilon>
   254 becomes available as variable, constant etc.  INCOMPATIBILITY,
   255 
   256 * "x > y" abbreviates "y < x" and "x >= y" abbreviates "y <= x".
   257 Similarly for all quantifiers: "ALL x > y" etc.  The x-symbol for >=
   258 is \<ge>.
   259 
   260 * "{x:A. P}" abbreviates "{x. x:A & P}", and similarly for "\<in>"
   261 instead of ":".
   262 
   263 * theory SetInterval: changed the syntax for open intervals:
   264 
   265   Old       New
   266   {..n(}    {..<n}
   267   {)n..}    {n<..}
   268   {m..n(}   {m..<n}
   269   {)m..n}   {m<..n}
   270   {)m..n(}  {m<..<n}
   271 
   272 The old syntax is still supported but will disappear in the next
   273 release.  For conversion use the following Emacs search and replace
   274 patterns (these are not perfect but work quite well):
   275 
   276   {)\([^\.]*\)\.\.  ->  {\1<\.\.}
   277   \.\.\([^(}]*\)(}  ->  \.\.<\1}
   278 
   279 * theory Finite_Set: changed the syntax for 'setsum', summation over
   280 finite sets: "setsum (%x. e) A", which used to be "\<Sum>x:A. e", is
   281 now either "SUM x:A. e" or "\<Sum>x \<in> A. e".
   282 
   283 Some new syntax forms are available:
   284 
   285   "\<Sum>x | P. e"      for     "setsum (%x. e) {x. P}"
   286   "\<Sum>x = a..b. e"   for     "setsum (%x. e) {a..b}"
   287   "\<Sum>x = a..<b. e"  for     "setsum (%x. e) {a..<b}"
   288   "\<Sum>x < k. e"      for     "setsum (%x. e) {..<k}"
   289 
   290 The latter form "\<Sum>x < k. e" used to be based on a separate
   291 function "Summation", which has been discontinued.
   292 
   293 * theory Finite_Set: in structured induction proofs, the insert case
   294 is now 'case (insert x F)' instead of the old counterintuitive 'case
   295 (insert F x)'.
   296 
   297 * The 'refute' command has been extended to support a much larger
   298 fragment of HOL, including axiomatic type classes, constdefs and
   299 typedefs, inductive datatypes and recursion.
   300 
   301 * Datatype induction via method 'induct' now preserves the name of the
   302 induction variable. For example, when proving P(xs::'a list) by
   303 induction on xs, the induction step is now P(xs) ==> P(a#xs) rather
   304 than P(list) ==> P(a#list) as previously.  Potential INCOMPATIBILITY
   305 in unstructured proof scripts.
   306 
   307 * Reworked implementation of records.  Improved scalability for
   308 records with many fields, avoiding performance problems for type
   309 inference. Records are no longer composed of nested field types, but
   310 of nested extension types. Therefore the record type only grows linear
   311 in the number of extensions and not in the number of fields.  The
   312 top-level (users) view on records is preserved.  Potential
   313 INCOMPATIBILITY only in strange cases, where the theory depends on the
   314 old record representation. The type generated for a record is called
   315 <record_name>_ext_type.
   316 
   317 Flag record_quick_and_dirty_sensitive can be enabled to skip the
   318 proofs triggered by a record definition or a simproc (if
   319 quick_and_dirty is enabled).  Definitions of large records can take
   320 quite long.
   321 
   322 New simproc record_upd_simproc for simplification of multiple record
   323 updates enabled by default.  Moreover, trivial updates are also
   324 removed: r(|x := x r|) = r.  INCOMPATIBILITY: old proofs break
   325 occasionally, since simplification is more powerful by default.
   326 
   327 * Simplifier: automatically reasons about transitivity chains
   328 involving "trancl" (r^+) and "rtrancl" (r^*) by setting up tactics
   329 provided by Provers/trancl.ML as additional solvers.  INCOMPATIBILITY:
   330 old proofs break occasionally as simplification may now solve more
   331 goals than previously.
   332 
   333 * Simplifier: converts x <= y into x = y if assumption y <= x is
   334 present.  Works for all partial orders (class "order"), in particular
   335 numbers and sets.  For linear orders (e.g. numbers) it treats ~ x < y
   336 just like y <= x.
   337 
   338 * Simplifier: new simproc for "let x = a in f x".  If a is a free or
   339 bound variable or a constant then the let is unfolded.  Otherwise
   340 first a is simplified to b, and then f b is simplified to g. If
   341 possible we abstract b from g arriving at "let x = b in h x",
   342 otherwise we unfold the let and arrive at g.  The simproc can be
   343 enabled/disabled by the reference use_let_simproc.  Potential
   344 INCOMPATIBILITY since simplification is more powerful by default.
   345 
   346 * Classical reasoning: the meson method now accepts theorems as arguments.
   347 
   348 
   349 *** HOLCF ***
   350 
   351 * HOLCF: discontinued special version of 'constdefs' (which used to
   352 support continuous functions) in favor of the general Pure one with
   353 full type-inference.
   354 
   355 
   356 *** ZF ***
   357 
   358 * ZF/ex: theories Group and Ring provide examples in abstract algebra,
   359 including the First Isomorphism Theorem (on quotienting by the kernel
   360 of a homomorphism).
   361 
   362 * ZF/Simplifier: install second copy of type solver that actually
   363 makes use of TC rules declared to Isar proof contexts (or locales);
   364 the old version is still required for ML proof scripts.
   365 
   366 
   367 *** ML ***
   368 
   369 * Pure/library.ML no longer defines its own option datatype, but uses
   370 that of the SML basis, which has constructors NONE and SOME instead of
   371 None and Some, as well as exception Option.Option instead of OPTION.
   372 The functions the, if_none, is_some, is_none have been adapted
   373 accordingly, while Option.map replaces apsome.
   374 
   375 * The exception LIST has been given up in favour of the standard
   376 exceptions Empty and Subscript, as well as Library.UnequalLengths.
   377 Function like Library.hd and Library.tl are superceded by the standard
   378 hd and tl functions etc.
   379 
   380 A number of basic functions are now no longer exported to the ML
   381 toplevel, as they are variants of standard functions.  The following
   382 suggests how one can translate existing code:
   383 
   384     rev_append xs ys = List.revAppend (xs, ys)
   385     nth_elem (i, xs) = List.nth (xs, i)
   386     last_elem xs = List.last xs
   387     flat xss = List.concat xss
   388     seq fs = List.app fs
   389     partition P xs = List.partition P xs
   390     filter P xs = List.filter P xs
   391     mapfilter f xs = List.mapPartial f xs
   392 
   393 * Pure: output via the Isabelle channels of writeln/warning/error
   394 etc. is now passed through Output.output, with a hook for arbitrary
   395 transformations depending on the print_mode (cf. Output.add_mode --
   396 the first active mode that provides a output function wins).  Already
   397 formatted output may be embedded into further text via Output.raw; the
   398 result of Pretty.string_of/str_of and derived functions
   399 (string_of_term/cterm/thm etc.) is already marked raw to accommodate
   400 easy composition of diagnostic messages etc.  Programmers rarely need
   401 to care about Output.output or Output.raw at all, with some notable
   402 exceptions: Output.output is required when bypassing the standard
   403 channels (writeln etc.), or in token translations to produce properly
   404 formatted results; Output.raw is required when capturing already
   405 output material that will eventually be presented to the user a second
   406 time.  For the default print mode, both Output.output and Output.raw
   407 have no effect.
   408 
   409 * Pure: Output.time_accumulator NAME creates an operator ('a -> 'b) ->
   410 'a -> 'b to measure runtime and count invocations; the cumulative
   411 results are displayed at the end of a batch session.
   412 
   413 * Isar toplevel: improved diagnostics, mostly for Poly/ML only.
   414 Reference Toplevel.debug (default false) controls detailed printing
   415 and tracing of low-level exceptions; Toplevel.profiling (default 0)
   416 controls execution profiling -- set to 1 for time and 2 for space
   417 (both increase the runtime).
   418 
   419 * Pure: structure OrdList (cf. Pure/General/ord_list.ML) provides a
   420 reasonably efficient light-weight implementation of sets as lists.
   421 
   422 * Pure: more efficient orders for basic syntactic entities: added
   423 fast_string_ord, fast_indexname_ord, fast_term_ord; changed sort_ord
   424 and typ_ord to use fast_string_ord and fast_indexname_ord (term_ord is
   425 NOT affected); structures Symtab, Vartab, Typtab, Termtab use the fast
   426 orders now -- potential INCOMPATIBILITY for code that depends on a
   427 particular order for Symtab.keys, Symtab.dest, etc. (consider using
   428 Library.sort_strings on result).
   429 
   430 * Pure: name spaces have been refined, with significant changes of the
   431 internal interfaces -- INCOMPATIBILITY.  Renamed cond_extern(_table)
   432 to extern(_table).  The plain name entry path is superceded by a
   433 general 'naming' context, which also includes the 'policy' to produce
   434 a fully qualified name and external accesses of a fully qualified
   435 name; NameSpace.extend is superceded by context dependent
   436 Sign.declare_name.  Several theory and proof context operations modify
   437 the naming context.  Especially note Theory.restore_naming and
   438 ProofContext.restore_naming to get back to a sane state; note that
   439 Theory.add_path is no longer sufficient to recover from
   440 Theory.absolute_path in particular.
   441 
   442 * Pure: new flags short_names (default false) and unique_names
   443 (default true) for controlling output of qualified names.  If
   444 short_names is set, names are printed unqualified.  If unique_names is
   445 reset, the name prefix is reduced to the minimum required to achieve
   446 the original result when interning again, even if there is an overlap
   447 with earlier declarations.
   448 
   449 * Pure/TheoryDataFun: change of the argument structure; 'prep_ext' is
   450 now 'extend', and 'merge' gets an additional Pretty.pp argument
   451 (useful for printing error messages).  INCOMPATIBILITY.
   452 
   453 * Pure: major reorganization of the theory context.  Type Sign.sg and
   454 Theory.theory are now identified, referring to the universal
   455 Context.theory (see Pure/context.ML).  Actual signature and theory
   456 content is managed as theory data.  The old code and interfaces were
   457 spread over many files and structures; the new arrangement introduces
   458 considerable INCOMPATIBILITY to gain more clarity:
   459 
   460   Context -- theory management operations (name, identity, inclusion,
   461     parents, ancestors, merge, etc.), plus generic theory data;
   462 
   463   Sign -- logical signature and syntax operations (declaring consts,
   464     types, etc.), plus certify/read for common entities;
   465 
   466   Theory -- logical theory operations (stating axioms, definitions,
   467     oracles), plus a copy of logical signature operations (consts,
   468     types, etc.); also a few basic management operations (Theory.copy,
   469     Theory.merge, etc.)
   470 
   471 The most basic sign_of operations (Theory.sign_of, Thm.sign_of_thm
   472 etc.) as well as the sign field in Thm.rep_thm etc. have been retained
   473 for convenience -- they merely return the theory.
   474 
   475 * Pure: the Isar proof context type is already defined early in Pure
   476 as Context.proof (note that ProofContext.context and Proof.context are
   477 aliases, where the latter is the preferred name).  This enables other
   478 Isabelle components to refer to that type even before Isar is present.
   479 
   480 * Pure/sign/theory: discontinued named name spaces (i.e. classK,
   481 typeK, constK, axiomK, oracleK), but provide explicit operations for
   482 any of these kinds.  For example, Sign.intern typeK is now
   483 Sign.intern_type, Theory.hide_space Sign.typeK is now
   484 Theory.hide_types.  Also note that former
   485 Theory.hide_classes/types/consts are now
   486 Theory.hide_classes_i/types_i/consts_i, while the non '_i' versions
   487 internalize their arguments!  INCOMPATIBILITY.
   488 
   489 * Pure: get_thm interface (of PureThy and ProofContext) expects
   490 datatype thmref (with constructors Name and NameSelection) instead of
   491 plain string -- INCOMPATIBILITY;
   492 
   493 * Pure: cases produced by proof methods specify options, where NONE
   494 means to remove case bindings -- INCOMPATIBILITY in
   495 (RAW_)METHOD_CASES.
   496 
   497 * Pure: the following operations retrieve axioms or theorems from a
   498 theory node or theory hierarchy, respectively:
   499 
   500   Theory.axioms_of: theory -> (string * term) list
   501   Theory.all_axioms_of: theory -> (string * term) list
   502   PureThy.thms_of: theory -> (string * thm) list
   503   PureThy.all_thms_of: theory -> (string * thm) list
   504 
   505 * Pure: print_tac now outputs the goal through the trace channel.
   506 
   507 * Provers: Simplifier and Classical Reasoner now support proof context
   508 dependent plug-ins (simprocs, solvers, wrappers etc.).  These extra
   509 components are stored in the theory and patched into the
   510 simpset/claset when used in an Isar proof context.  Context dependent
   511 components are maintained by the following theory operations:
   512 
   513   Simplifier.add_context_simprocs
   514   Simplifier.del_context_simprocs
   515   Simplifier.set_context_subgoaler
   516   Simplifier.reset_context_subgoaler
   517   Simplifier.add_context_looper
   518   Simplifier.del_context_looper
   519   Simplifier.add_context_unsafe_solver
   520   Simplifier.add_context_safe_solver
   521 
   522   Classical.add_context_safe_wrapper
   523   Classical.del_context_safe_wrapper
   524   Classical.add_context_unsafe_wrapper
   525   Classical.del_context_unsafe_wrapper
   526 
   527 IMPORTANT NOTE: proof tools (methods etc.) need to use
   528 local_simpset_of and local_claset_of to instead of the primitive
   529 Simplifier.get_local_simpset and Classical.get_local_claset,
   530 respectively, in order to see the context dependent fields!
   531 
   532 * File.sysify_path and File.quote_sysify path have been replaced by
   533 File.platform_path and File.shell_path (with appropriate hooks).  This
   534 provides a clean interface for unusual systems where the internal and
   535 external process view of file names are different.
   536 
   537 
   538 *** System ***
   539 
   540 * Allow symlinks to all proper Isabelle executables (Isabelle,
   541 isabelle, isatool etc.).
   542 
   543 * ISABELLE_DOC_FORMAT setting specifies preferred document format (for
   544 isatool doc, isatool mkdir, display_drafts etc.).
   545 
   546 * isatool usedir: option -f allows specification of the ML file to be
   547 used by Isabelle; default is ROOT.ML.
   548 
   549 * New isatool version outputs the version identifier of the Isabelle
   550 distribution being used.
   551 
   552 * HOL: new isatool dimacs2hol converts files in DIMACS CNF format
   553 (containing Boolean satisfiability problems) into Isabelle/HOL
   554 theories.
   555 
   556 
   557 
   558 New in Isabelle2004 (April 2004)
   559 --------------------------------
   560 
   561 *** General ***
   562 
   563 * Provers/order.ML:  new efficient reasoner for partial and linear orders.
   564   Replaces linorder.ML.
   565 
   566 * Pure: Greek letters (except small lambda, \<lambda>), as well as Gothic
   567   (\<aa>...\<zz>\<AA>...\<ZZ>), calligraphic (\<A>...\<Z>), and Euler
   568   (\<a>...\<z>), are now considered normal letters, and can therefore
   569   be used anywhere where an ASCII letter (a...zA...Z) has until
   570   now. COMPATIBILITY: This obviously changes the parsing of some
   571   terms, especially where a symbol has been used as a binder, say
   572   '\<Pi>x. ...', which is now a type error since \<Pi>x will be parsed
   573   as an identifier.  Fix it by inserting a space around former
   574   symbols.  Call 'isatool fixgreek' to try to fix parsing errors in
   575   existing theory and ML files.
   576 
   577 * Pure: Macintosh and Windows line-breaks are now allowed in theory files.
   578 
   579 * Pure: single letter sub/superscripts (\<^isub> and \<^isup>) are now
   580   allowed in identifiers. Similar to Greek letters \<^isub> is now considered
   581   a normal (but invisible) letter. For multiple letter subscripts repeat
   582   \<^isub> like this: x\<^isub>1\<^isub>2.
   583 
   584 * Pure: There are now sub-/superscripts that can span more than one
   585   character. Text between \<^bsub> and \<^esub> is set in subscript in
   586   ProofGeneral and LaTeX, text between \<^bsup> and \<^esup> in
   587   superscript. The new control characters are not identifier parts.
   588 
   589 * Pure: Control-symbols of the form \<^raw:...> will literally print the
   590   content of "..." to the latex file instead of \isacntrl... . The "..."
   591   may consist of any printable characters excluding the end bracket >.
   592 
   593 * Pure: Using new Isar command "finalconsts" (or the ML functions
   594   Theory.add_finals or Theory.add_finals_i) it is now possible to
   595   declare constants "final", which prevents their being given a definition
   596   later.  It is useful for constants whose behaviour is fixed axiomatically
   597   rather than definitionally, such as the meta-logic connectives.
   598 
   599 * Pure: 'instance' now handles general arities with general sorts
   600   (i.e. intersections of classes),
   601 
   602 * Presentation: generated HTML now uses a CSS style sheet to make layout
   603   (somewhat) independent of content. It is copied from lib/html/isabelle.css.
   604   It can be changed to alter the colors/layout of generated pages.
   605 
   606 
   607 *** Isar ***
   608 
   609 * Tactic emulation methods rule_tac, erule_tac, drule_tac, frule_tac,
   610   cut_tac, subgoal_tac and thin_tac:
   611   - Now understand static (Isar) contexts.  As a consequence, users of Isar
   612     locales are no longer forced to write Isar proof scripts.
   613     For details see Isar Reference Manual, paragraph 4.3.2: Further tactic
   614     emulations.
   615   - INCOMPATIBILITY: names of variables to be instantiated may no
   616     longer be enclosed in quotes.  Instead, precede variable name with `?'.
   617     This is consistent with the instantiation attribute "where".
   618 
   619 * Attributes "where" and "of":
   620   - Now take type variables of instantiated theorem into account when reading
   621     the instantiation string.  This fixes a bug that caused instantiated
   622     theorems to have too special types in some circumstances.
   623   - "where" permits explicit instantiations of type variables.
   624 
   625 * Calculation commands "moreover" and "also" no longer interfere with
   626   current facts ("this"), admitting arbitrary combinations with "then"
   627   and derived forms.
   628 
   629 * Locales:
   630   - Goal statements involving the context element "includes" no longer
   631     generate theorems with internal delta predicates (those ending on
   632     "_axioms") in the premise.
   633     Resolve particular premise with <locale>.intro to obtain old form.
   634   - Fixed bug in type inference ("unify_frozen") that prevented mix of target
   635     specification and "includes" elements in goal statement.
   636   - Rule sets <locale>.intro and <locale>.axioms no longer declared as
   637     [intro?] and [elim?] (respectively) by default.
   638   - Experimental command for instantiation of locales in proof contexts:
   639         instantiate <label>[<attrs>]: <loc>
   640     Instantiates locale <loc> and adds all its theorems to the current context
   641     taking into account their attributes.  Label and attrs are optional
   642     modifiers, like in theorem declarations.  If present, names of
   643     instantiated theorems are qualified with <label>, and the attributes
   644     <attrs> are applied after any attributes these theorems might have already.
   645       If the locale has assumptions, a chained fact of the form
   646     "<loc> t1 ... tn" is expected from which instantiations of the parameters
   647     are derived.  The command does not support old-style locales declared
   648     with "locale (open)".
   649       A few (very simple) examples can be found in FOL/ex/LocaleInst.thy.
   650 
   651 * HOL: Tactic emulation methods induct_tac and case_tac understand static
   652   (Isar) contexts.
   653 
   654 
   655 *** HOL ***
   656 
   657 * Proof import: new image HOL4 contains the imported library from
   658   the HOL4 system with about 2500 theorems. It is imported by
   659   replaying proof terms produced by HOL4 in Isabelle. The HOL4 image
   660   can be used like any other Isabelle image.  See
   661   HOL/Import/HOL/README for more information.
   662 
   663 * Simplifier:
   664   - Much improved handling of linear and partial orders.
   665     Reasoners for linear and partial orders are set up for type classes
   666     "linorder" and "order" respectively, and are added to the default simpset
   667     as solvers.  This means that the simplifier can build transitivity chains
   668     to solve goals from the assumptions.
   669   - INCOMPATIBILITY: old proofs break occasionally.  Typically, applications
   670     of blast or auto after simplification become unnecessary because the goal
   671     is solved by simplification already.
   672 
   673 * Numerics: new theory Ring_and_Field contains over 250 basic numerical laws,
   674     all proved in axiomatic type classes for semirings, rings and fields.
   675 
   676 * Numerics:
   677   - Numeric types (nat, int, and in HOL-Complex rat, real, complex, etc.) are
   678     now formalized using the Ring_and_Field theory mentioned above.
   679   - INCOMPATIBILITY: simplification and arithmetic behaves somewhat differently
   680     than before, because now they are set up once in a generic manner.
   681   - INCOMPATIBILITY: many type-specific arithmetic laws have gone.
   682     Look for the general versions in Ring_and_Field (and Power if they concern
   683     exponentiation).
   684 
   685 * Type "rat" of the rational numbers is now available in HOL-Complex.
   686 
   687 * Records:
   688   - Record types are now by default printed with their type abbreviation
   689     instead of the list of all field types. This can be configured via
   690     the reference "print_record_type_abbr".
   691   - Simproc "record_upd_simproc" for simplification of multiple updates added
   692     (not enabled by default).
   693   - Simproc "record_ex_sel_eq_simproc" to simplify EX x. sel r = x resp.
   694     EX x. x = sel r to True (not enabled by default).
   695   - Tactic "record_split_simp_tac" to split and simplify records added.
   696 
   697 * 'specification' command added, allowing for definition by
   698   specification.  There is also an 'ax_specification' command that
   699   introduces the new constants axiomatically.
   700 
   701 * arith(_tac) is now able to generate counterexamples for reals as well.
   702 
   703 * HOL-Algebra: new locale "ring" for non-commutative rings.
   704 
   705 * HOL-ex: InductiveInvariant_examples illustrates advanced recursive function
   706   definitions, thanks to Sava Krsti\'{c} and John Matthews.
   707 
   708 * HOL-Matrix: a first theory for matrices in HOL with an application of
   709   matrix theory to linear programming.
   710 
   711 * Unions and Intersections:
   712   The latex output syntax of UN and INT has been changed
   713   from "\Union x \in A. B" to "\Union_{x \in A} B"
   714   i.e. the index formulae has become a subscript.
   715   Similarly for "\Union x. B", and for \Inter instead of \Union.
   716 
   717 * Unions and Intersections over Intervals:
   718   There is new short syntax "UN i<=n. A" for "UN i:{0..n}. A". There is
   719   also an x-symbol version with subscripts "\<Union>\<^bsub>i <= n\<^esub>. A"
   720   like in normal math, and corresponding versions for < and for intersection.
   721 
   722 * HOL/List: Ordering "lexico" is renamed "lenlex" and the standard
   723   lexicographic dictonary ordering has been added as "lexord".
   724 
   725 * ML: the legacy theory structures Int and List have been removed. They had
   726   conflicted with ML Basis Library structures having the same names.
   727 
   728 * 'refute' command added to search for (finite) countermodels.  Only works
   729   for a fragment of HOL.  The installation of an external SAT solver is
   730   highly recommended.  See "HOL/Refute.thy" for details.
   731 
   732 * 'quickcheck' command: Allows to find counterexamples by evaluating
   733   formulae under an assignment of free variables to random values.
   734   In contrast to 'refute', it can deal with inductive datatypes,
   735   but cannot handle quantifiers. See "HOL/ex/Quickcheck_Examples.thy"
   736   for examples.
   737 
   738 
   739 *** HOLCF ***
   740 
   741 * Streams now come with concatenation and are part of the HOLCF image
   742 
   743 
   744 
   745 New in Isabelle2003 (May 2003)
   746 ------------------------------
   747 
   748 *** General ***
   749 
   750 * Provers/simplifier:
   751 
   752   - Completely reimplemented method simp (ML: Asm_full_simp_tac):
   753     Assumptions are now subject to complete mutual simplification,
   754     not just from left to right. The simplifier now preserves
   755     the order of assumptions.
   756 
   757     Potential INCOMPATIBILITY:
   758 
   759     -- simp sometimes diverges where the old version did
   760        not, e.g. invoking simp on the goal
   761 
   762         [| P (f x); y = x; f x = f y |] ==> Q
   763 
   764        now gives rise to the infinite reduction sequence
   765 
   766         P(f x) --(f x = f y)--> P(f y) --(y = x)--> P(f x) --(f x = f y)--> ...
   767 
   768        Using "simp (asm_lr)" (ML: Asm_lr_simp_tac) instead often solves this
   769        kind of problem.
   770 
   771     -- Tactics combining classical reasoner and simplification (such as auto)
   772        are also affected by this change, because many of them rely on
   773        simp. They may sometimes diverge as well or yield a different numbers
   774        of subgoals. Try to use e.g. force, fastsimp, or safe instead of auto
   775        in case of problems. Sometimes subsequent calls to the classical
   776        reasoner will fail because a preceeding call to the simplifier too
   777        eagerly simplified the goal, e.g. deleted redundant premises.
   778 
   779   - The simplifier trace now shows the names of the applied rewrite rules
   780 
   781   - You can limit the number of recursive invocations of the simplifier
   782     during conditional rewriting (where the simplifie tries to solve the
   783     conditions before applying the rewrite rule):
   784     ML "simp_depth_limit := n"
   785     where n is an integer. Thus you can force termination where previously
   786     the simplifier would diverge.
   787 
   788   - Accepts free variables as head terms in congruence rules.  Useful in Isar.
   789 
   790   - No longer aborts on failed congruence proof.  Instead, the
   791     congruence is ignored.
   792 
   793 * Pure: New generic framework for extracting programs from constructive
   794   proofs. See HOL/Extraction.thy for an example instantiation, as well
   795   as HOL/Extraction for some case studies.
   796 
   797 * Pure: The main goal of the proof state is no longer shown by default, only
   798 the subgoals. This behaviour is controlled by a new flag.
   799    PG menu: Isabelle/Isar -> Settings -> Show Main Goal
   800 (ML: Proof.show_main_goal).
   801 
   802 * Pure: You can find all matching introduction rules for subgoal 1, i.e. all
   803 rules whose conclusion matches subgoal 1:
   804       PG menu: Isabelle/Isar -> Show me -> matching rules
   805 The rules are ordered by how closely they match the subgoal.
   806 In particular, rules that solve a subgoal outright are displayed first
   807 (or rather last, the way they are printed).
   808 (ML: ProofGeneral.print_intros())
   809 
   810 * Pure: New flag trace_unify_fail causes unification to print
   811 diagnostic information (PG: in trace buffer) when it fails. This is
   812 useful for figuring out why single step proofs like rule, erule or
   813 assumption failed.
   814 
   815 * Pure: Locale specifications now produce predicate definitions
   816 according to the body of text (covering assumptions modulo local
   817 definitions); predicate "loc_axioms" covers newly introduced text,
   818 while "loc" is cumulative wrt. all included locale expressions; the
   819 latter view is presented only on export into the global theory
   820 context; potential INCOMPATIBILITY, use "(open)" option to fall back
   821 on the old view without predicates;
   822 
   823 * Pure: predefined locales "var" and "struct" are useful for sharing
   824 parameters (as in CASL, for example); just specify something like
   825 ``var x + var y + struct M'' as import;
   826 
   827 * Pure: improved thms_containing: proper indexing of facts instead of
   828 raw theorems; check validity of results wrt. current name space;
   829 include local facts of proof configuration (also covers active
   830 locales), cover fixed variables in index; may use "_" in term
   831 specification; an optional limit for the number of printed facts may
   832 be given (the default is 40);
   833 
   834 * Pure: disallow duplicate fact bindings within new-style theory files
   835 (batch-mode only);
   836 
   837 * Provers: improved induct method: assumptions introduced by case
   838 "foo" are split into "foo.hyps" (from the rule) and "foo.prems" (from
   839 the goal statement); "foo" still refers to all facts collectively;
   840 
   841 * Provers: the function blast.overloaded has been removed: all constants
   842 are regarded as potentially overloaded, which improves robustness in exchange
   843 for slight decrease in efficiency;
   844 
   845 * Provers/linorder: New generic prover for transitivity reasoning over
   846 linear orders.  Note: this prover is not efficient!
   847 
   848 * Isar: preview of problems to finish 'show' now produce an error
   849 rather than just a warning (in interactive mode);
   850 
   851 
   852 *** HOL ***
   853 
   854 * arith(_tac)
   855 
   856  - Produces a counter example if it cannot prove a goal.
   857    Note that the counter example may be spurious if the goal is not a formula
   858    of quantifier-free linear arithmetic.
   859    In ProofGeneral the counter example appears in the trace buffer.
   860 
   861  - Knows about div k and mod k where k is a numeral of type nat or int.
   862 
   863  - Calls full Presburger arithmetic (by Amine Chaieb) if quantifier-free
   864    linear arithmetic fails. This takes account of quantifiers and divisibility.
   865    Presburger arithmetic can also be called explicitly via presburger(_tac).
   866 
   867 * simp's arithmetic capabilities have been enhanced a bit: it now
   868 takes ~= in premises into account (by performing a case split);
   869 
   870 * simp reduces "m*(n div m) + n mod m" to n, even if the two summands
   871 are distributed over a sum of terms;
   872 
   873 * New tactic "trans_tac" and method "trans" instantiate
   874 Provers/linorder.ML for axclasses "order" and "linorder" (predicates
   875 "<=", "<" and "=").
   876 
   877 * function INCOMPATIBILITIES: Pi-sets have been redefined and moved from main
   878 HOL to Library/FuncSet; constant "Fun.op o" is now called "Fun.comp";
   879 
   880 * 'typedef' command has new option "open" to suppress the set
   881 definition;
   882 
   883 * functions Min and Max on finite sets have been introduced (theory
   884 Finite_Set);
   885 
   886 * attribute [symmetric] now works for relations as well; it turns
   887 (x,y) : R^-1 into (y,x) : R, and vice versa;
   888 
   889 * induct over a !!-quantified statement (say !!x1..xn):
   890   each "case" automatically performs "fix x1 .. xn" with exactly those names.
   891 
   892 * Map: `empty' is no longer a constant but a syntactic abbreviation for
   893 %x. None. Warning: empty_def now refers to the previously hidden definition
   894 of the empty set.
   895 
   896 * Algebra: formalization of classical algebra.  Intended as base for
   897 any algebraic development in Isabelle.  Currently covers group theory
   898 (up to Sylow's theorem) and ring theory (Universal Property of
   899 Univariate Polynomials).  Contributions welcome;
   900 
   901 * GroupTheory: deleted, since its material has been moved to Algebra;
   902 
   903 * Complex: new directory of the complex numbers with numeric constants,
   904 nonstandard complex numbers, and some complex analysis, standard and
   905 nonstandard (Jacques Fleuriot);
   906 
   907 * HOL-Complex: new image for analysis, replacing HOL-Real and HOL-Hyperreal;
   908 
   909 * Hyperreal: introduced Gauge integration and hyperreal logarithms (Jacques
   910 Fleuriot);
   911 
   912 * Real/HahnBanach: updated and adapted to locales;
   913 
   914 * NumberTheory: added Gauss's law of quadratic reciprocity (by Avigad,
   915 Gray and Kramer);
   916 
   917 * UNITY: added the Meier-Sanders theory of progress sets;
   918 
   919 * MicroJava: bytecode verifier and lightweight bytecode verifier
   920 as abstract algorithms, instantiated to the JVM;
   921 
   922 * Bali: Java source language formalization. Type system, operational
   923 semantics, axiomatic semantics. Supported language features:
   924 classes, interfaces, objects,virtual methods, static methods,
   925 static/instance fields, arrays, access modifiers, definite
   926 assignment, exceptions.
   927 
   928 
   929 *** ZF ***
   930 
   931 * ZF/Constructible: consistency proof for AC (Gdel's constructible
   932 universe, etc.);
   933 
   934 * Main ZF: virtually all theories converted to new-style format;
   935 
   936 
   937 *** ML ***
   938 
   939 * Pure: Tactic.prove provides sane interface for internal proofs;
   940 omits the infamous "standard" operation, so this is more appropriate
   941 than prove_goalw_cterm in many situations (e.g. in simprocs);
   942 
   943 * Pure: improved error reporting of simprocs;
   944 
   945 * Provers: Simplifier.simproc(_i) provides sane interface for setting
   946 up simprocs;
   947 
   948 
   949 *** Document preparation ***
   950 
   951 * uses \par instead of \\ for line breaks in theory text. This may
   952 shift some page breaks in large documents. To get the old behaviour
   953 use \renewcommand{\isanewline}{\mbox{}\\\mbox{}} in root.tex.
   954 
   955 * minimized dependencies of isabelle.sty and isabellesym.sty on
   956 other packages
   957 
   958 * \<euro> now needs package babel/greek instead of marvosym (which
   959 broke \Rightarrow)
   960 
   961 * normal size for \<zero>...\<nine> (uses \mathbf instead of
   962 textcomp package)
   963 
   964 
   965 
   966 New in Isabelle2002 (March 2002)
   967 --------------------------------
   968 
   969 *** Document preparation ***
   970 
   971 * greatly simplified document preparation setup, including more
   972 graceful interpretation of isatool usedir -i/-d/-D options, and more
   973 instructive isatool mkdir; users should basically be able to get
   974 started with "isatool mkdir HOL Test && isatool make"; alternatively,
   975 users may run a separate document processing stage manually like this:
   976 "isatool usedir -D output HOL Test && isatool document Test/output";
   977 
   978 * theory dependency graph may now be incorporated into documents;
   979 isatool usedir -g true will produce session_graph.eps/.pdf for use
   980 with \includegraphics of LaTeX;
   981 
   982 * proper spacing of consecutive markup elements, especially text
   983 blocks after section headings;
   984 
   985 * support bold style (for single symbols only), input syntax is like
   986 this: "\<^bold>\<alpha>" or "\<^bold>A";
   987 
   988 * \<bullet> is now output as bold \cdot by default, which looks much
   989 better in printed text;
   990 
   991 * added default LaTeX bindings for \<tturnstile> and \<TTurnstile>;
   992 note that these symbols are currently unavailable in Proof General /
   993 X-Symbol; new symbols \<zero>, \<one>, ..., \<nine>, and \<euro>;
   994 
   995 * isatool latex no longer depends on changed TEXINPUTS, instead
   996 isatool document copies the Isabelle style files to the target
   997 location;
   998 
   999 
  1000 *** Isar ***
  1001 
  1002 * Pure/Provers: improved proof by cases and induction;
  1003   - 'case' command admits impromptu naming of parameters (such as
  1004     "case (Suc n)");
  1005   - 'induct' method divinates rule instantiation from the inductive
  1006     claim; no longer requires excessive ?P bindings for proper
  1007     instantiation of cases;
  1008   - 'induct' method properly enumerates all possibilities of set/type
  1009     rules; as a consequence facts may be also passed through *type*
  1010     rules without further ado;
  1011   - 'induct' method now derives symbolic cases from the *rulified*
  1012     rule (before it used to rulify cases stemming from the internal
  1013     atomized version); this means that the context of a non-atomic
  1014     statement becomes is included in the hypothesis, avoiding the
  1015     slightly cumbersome show "PROP ?case" form;
  1016   - 'induct' may now use elim-style induction rules without chaining
  1017     facts, using ``missing'' premises from the goal state; this allows
  1018     rules stemming from inductive sets to be applied in unstructured
  1019     scripts, while still benefitting from proper handling of non-atomic
  1020     statements; NB: major inductive premises need to be put first, all
  1021     the rest of the goal is passed through the induction;
  1022   - 'induct' proper support for mutual induction involving non-atomic
  1023     rule statements (uses the new concept of simultaneous goals, see
  1024     below);
  1025   - append all possible rule selections, but only use the first
  1026     success (no backtracking);
  1027   - removed obsolete "(simplified)" and "(stripped)" options of methods;
  1028   - undeclared rule case names default to numbers 1, 2, 3, ...;
  1029   - added 'print_induct_rules' (covered by help item in recent Proof
  1030     General versions);
  1031   - moved induct/cases attributes to Pure, methods to Provers;
  1032   - generic method setup instantiated for FOL and HOL;
  1033 
  1034 * Pure: support multiple simultaneous goal statements, for example
  1035 "have a: A and b: B" (same for 'theorem' etc.); being a pure
  1036 meta-level mechanism, this acts as if several individual goals had
  1037 been stated separately; in particular common proof methods need to be
  1038 repeated in order to cover all claims; note that a single elimination
  1039 step is *not* sufficient to establish the two conjunctions, so this
  1040 fails:
  1041 
  1042   assume "A & B" then have A and B ..   (*".." fails*)
  1043 
  1044 better use "obtain" in situations as above; alternative refer to
  1045 multi-step methods like 'auto', 'simp_all', 'blast+' etc.;
  1046 
  1047 * Pure: proper integration with ``locales''; unlike the original
  1048 version by Florian Kammller, Isar locales package high-level proof
  1049 contexts rather than raw logical ones (e.g. we admit to include
  1050 attributes everywhere); operations on locales include merge and
  1051 rename; support for implicit arguments (``structures''); simultaneous
  1052 type-inference over imports and text; see also HOL/ex/Locales.thy for
  1053 some examples;
  1054 
  1055 * Pure: the following commands have been ``localized'', supporting a
  1056 target locale specification "(in name)": 'lemma', 'theorem',
  1057 'corollary', 'lemmas', 'theorems', 'declare'; the results will be
  1058 stored both within the locale and at the theory level (exported and
  1059 qualified by the locale name);
  1060 
  1061 * Pure: theory goals may now be specified in ``long'' form, with
  1062 ad-hoc contexts consisting of arbitrary locale elements. for example
  1063 ``lemma foo: fixes x assumes "A x" shows "B x"'' (local syntax and
  1064 definitions may be given, too); the result is a meta-level rule with
  1065 the context elements being discharged in the obvious way;
  1066 
  1067 * Pure: new proof command 'using' allows to augment currently used
  1068 facts after a goal statement ('using' is syntactically analogous to
  1069 'apply', but acts on the goal's facts only); this allows chained facts
  1070 to be separated into parts given before and after a claim, as in
  1071 ``from a and b have C using d and e <proof>'';
  1072 
  1073 * Pure: renamed "antecedent" case to "rule_context";
  1074 
  1075 * Pure: new 'judgment' command records explicit information about the
  1076 object-logic embedding (used by several tools internally); no longer
  1077 use hard-wired "Trueprop";
  1078 
  1079 * Pure: added 'corollary' command;
  1080 
  1081 * Pure: fixed 'token_translation' command;
  1082 
  1083 * Pure: removed obsolete 'exported' attribute;
  1084 
  1085 * Pure: dummy pattern "_" in is/let is now automatically lifted over
  1086 bound variables: "ALL x. P x --> Q x" (is "ALL x. _ --> ?C x")
  1087 supersedes more cumbersome ... (is "ALL x. _ x --> ?C x");
  1088 
  1089 * Pure: method 'atomize' presents local goal premises as object-level
  1090 statements (atomic meta-level propositions); setup controlled via
  1091 rewrite rules declarations of 'atomize' attribute; example
  1092 application: 'induct' method with proper rule statements in improper
  1093 proof *scripts*;
  1094 
  1095 * Pure: emulation of instantiation tactics (rule_tac, cut_tac, etc.)
  1096 now consider the syntactic context of assumptions, giving a better
  1097 chance to get type-inference of the arguments right (this is
  1098 especially important for locales);
  1099 
  1100 * Pure: "sorry" no longer requires quick_and_dirty in interactive
  1101 mode;
  1102 
  1103 * Pure/obtain: the formal conclusion "thesis", being marked as
  1104 ``internal'', may no longer be reference directly in the text;
  1105 potential INCOMPATIBILITY, may need to use "?thesis" in rare
  1106 situations;
  1107 
  1108 * Pure: generic 'sym' attribute which declares a rule both as pure
  1109 'elim?' and for the 'symmetric' operation;
  1110 
  1111 * Pure: marginal comments ``--'' may now occur just anywhere in the
  1112 text; the fixed correlation with particular command syntax has been
  1113 discontinued;
  1114 
  1115 * Pure: new method 'rules' is particularly well-suited for proof
  1116 search in intuitionistic logic; a bit slower than 'blast' or 'fast',
  1117 but often produces more compact proof terms with less detours;
  1118 
  1119 * Pure/Provers/classical: simplified integration with pure rule
  1120 attributes and methods; the classical "intro?/elim?/dest?"
  1121 declarations coincide with the pure ones; the "rule" method no longer
  1122 includes classically swapped intros; "intro" and "elim" methods no
  1123 longer pick rules from the context; also got rid of ML declarations
  1124 AddXIs/AddXEs/AddXDs; all of this has some potential for
  1125 INCOMPATIBILITY;
  1126 
  1127 * Provers/classical: attribute 'swapped' produces classical inversions
  1128 of introduction rules;
  1129 
  1130 * Provers/simplifier: 'simplified' attribute may refer to explicit
  1131 rules instead of full simplifier context; 'iff' attribute handles
  1132 conditional rules;
  1133 
  1134 * HOL: 'typedef' now allows alternative names for Rep/Abs morphisms;
  1135 
  1136 * HOL: 'recdef' now fails on unfinished automated proofs, use
  1137 "(permissive)" option to recover old behavior;
  1138 
  1139 * HOL: 'inductive' no longer features separate (collective) attributes
  1140 for 'intros' (was found too confusing);
  1141 
  1142 * HOL: properly declared induction rules less_induct and
  1143 wf_induct_rule;
  1144 
  1145 
  1146 *** HOL ***
  1147 
  1148 * HOL: moved over to sane numeral syntax; the new policy is as
  1149 follows:
  1150 
  1151   - 0 and 1 are polymorphic constants, which are defined on any
  1152   numeric type (nat, int, real etc.);
  1153 
  1154   - 2, 3, 4, ... and -1, -2, -3, ... are polymorphic numerals, based
  1155   binary representation internally;
  1156 
  1157   - type nat has special constructor Suc, and generally prefers Suc 0
  1158   over 1::nat and Suc (Suc 0) over 2::nat;
  1159 
  1160 This change may cause significant problems of INCOMPATIBILITY; here
  1161 are some hints on converting existing sources:
  1162 
  1163   - due to the new "num" token, "-0" and "-1" etc. are now atomic
  1164   entities, so expressions involving "-" (unary or binary minus) need
  1165   to be spaced properly;
  1166 
  1167   - existing occurrences of "1" may need to be constraint "1::nat" or
  1168   even replaced by Suc 0; similar for old "2";
  1169 
  1170   - replace "#nnn" by "nnn", and "#-nnn" by "-nnn";
  1171 
  1172   - remove all special provisions on numerals in proofs;
  1173 
  1174 * HOL: simp rules nat_number expand numerals on nat to Suc/0
  1175 representation (depends on bin_arith_simps in the default context);
  1176 
  1177 * HOL: symbolic syntax for x^2 (numeral 2);
  1178 
  1179 * HOL: the class of all HOL types is now called "type" rather than
  1180 "term"; INCOMPATIBILITY, need to adapt references to this type class
  1181 in axclass/classes, instance/arities, and (usually rare) occurrences
  1182 in typings (of consts etc.); internally the class is called
  1183 "HOL.type", ML programs should refer to HOLogic.typeS;
  1184 
  1185 * HOL/record package improvements:
  1186   - new derived operations "fields" to build a partial record section,
  1187     "extend" to promote a fixed record to a record scheme, and
  1188     "truncate" for the reverse; cf. theorems "xxx.defs", which are *not*
  1189     declared as simp by default;
  1190   - shared operations ("more", "fields", etc.) now need to be always
  1191     qualified) --- potential INCOMPATIBILITY;
  1192   - removed "make_scheme" operations (use "make" with "extend") --
  1193     INCOMPATIBILITY;
  1194   - removed "more" class (simply use "term") -- INCOMPATIBILITY;
  1195   - provides cases/induct rules for use with corresponding Isar
  1196     methods (for concrete records, record schemes, concrete more
  1197     parts, and schematic more parts -- in that order);
  1198   - internal definitions directly based on a light-weight abstract
  1199     theory of product types over typedef rather than datatype;
  1200 
  1201 * HOL: generic code generator for generating executable ML code from
  1202 specifications; specific support for HOL constructs such as inductive
  1203 datatypes and sets, as well as recursive functions; can be invoked
  1204 via 'generate_code' theory section;
  1205 
  1206 * HOL: canonical cases/induct rules for n-tuples (n = 3..7);
  1207 
  1208 * HOL: consolidated and renamed several theories.  In particular:
  1209         Ord.thy has been absorbed into HOL.thy
  1210         String.thy has been absorbed into List.thy
  1211 
  1212 * HOL: concrete setsum syntax "\<Sum>i:A. b" == "setsum (%i. b) A"
  1213 (beware of argument permutation!);
  1214 
  1215 * HOL: linorder_less_split superseded by linorder_cases;
  1216 
  1217 * HOL/List: "nodups" renamed to "distinct";
  1218 
  1219 * HOL: added "The" definite description operator; move Hilbert's "Eps"
  1220 to peripheral theory "Hilbert_Choice"; some INCOMPATIBILITIES:
  1221   - Ex_def has changed, now need to use some_eq_ex
  1222 
  1223 * HOL: made split_all_tac safe; EXISTING PROOFS MAY FAIL OR LOOP, so
  1224 in this (rare) case use:
  1225 
  1226   delSWrapper "split_all_tac"
  1227   addSbefore ("unsafe_split_all_tac", unsafe_split_all_tac)
  1228 
  1229 * HOL: added safe wrapper "split_conv_tac" to claset; EXISTING PROOFS
  1230 MAY FAIL;
  1231 
  1232 * HOL: introduced f^n = f o ... o f; warning: due to the limits of
  1233 Isabelle's type classes, ^ on functions and relations has too general
  1234 a domain, namely ('a * 'b) set and 'a => 'b; this means that it may be
  1235 necessary to attach explicit type constraints;
  1236 
  1237 * HOL/Relation: the prefix name of the infix "O" has been changed from
  1238 "comp" to "rel_comp"; INCOMPATIBILITY: a few theorems have been
  1239 renamed accordingly (eg "compI" -> "rel_compI").
  1240 
  1241 * HOL: syntax translations now work properly with numerals and records
  1242 expressions;
  1243 
  1244 * HOL: bounded abstraction now uses syntax "%" / "\<lambda>" instead
  1245 of "lam" -- INCOMPATIBILITY;
  1246 
  1247 * HOL: got rid of some global declarations (potential INCOMPATIBILITY
  1248 for ML tools): const "()" renamed "Product_Type.Unity", type "unit"
  1249 renamed "Product_Type.unit";
  1250 
  1251 * HOL: renamed rtrancl_into_rtrancl2 to converse_rtrancl_into_rtrancl
  1252 
  1253 * HOL: removed obsolete theorem "optionE" (use "option.exhaust", or
  1254 the "cases" method);
  1255 
  1256 * HOL/GroupTheory: group theory examples including Sylow's theorem (by
  1257 Florian Kammller);
  1258 
  1259 * HOL/IMP: updated and converted to new-style theory format; several
  1260 parts turned into readable document, with proper Isar proof texts and
  1261 some explanations (by Gerwin Klein);
  1262 
  1263 * HOL-Real: added Complex_Numbers (by Gertrud Bauer);
  1264 
  1265 * HOL-Hyperreal is now a logic image;
  1266 
  1267 
  1268 *** HOLCF ***
  1269 
  1270 * Isar: consts/constdefs supports mixfix syntax for continuous
  1271 operations;
  1272 
  1273 * Isar: domain package adapted to new-style theory format, e.g. see
  1274 HOLCF/ex/Dnat.thy;
  1275 
  1276 * theory Lift: proper use of rep_datatype lift instead of ML hacks --
  1277 potential INCOMPATIBILITY; now use plain induct_tac instead of former
  1278 lift.induct_tac, always use UU instead of Undef;
  1279 
  1280 * HOLCF/IMP: updated and converted to new-style theory;
  1281 
  1282 
  1283 *** ZF ***
  1284 
  1285 * Isar: proper integration of logic-specific tools and packages,
  1286 including theory commands '(co)inductive', '(co)datatype',
  1287 'rep_datatype', 'inductive_cases', as well as methods 'ind_cases',
  1288 'induct_tac', 'case_tac', and 'typecheck' (with attribute 'TC');
  1289 
  1290 * theory Main no longer includes AC; for the Axiom of Choice, base
  1291 your theory on Main_ZFC;
  1292 
  1293 * the integer library now covers quotients and remainders, with many
  1294 laws relating division to addition, multiplication, etc.;
  1295 
  1296 * ZF/UNITY: Chandy and Misra's UNITY is now available in ZF, giving a
  1297 typeless version of the formalism;
  1298 
  1299 * ZF/AC, Coind, IMP, Resid: updated and converted to new-style theory
  1300 format;
  1301 
  1302 * ZF/Induct: new directory for examples of inductive definitions,
  1303 including theory Multiset for multiset orderings; converted to
  1304 new-style theory format;
  1305 
  1306 * ZF: many new theorems about lists, ordinals, etc.;
  1307 
  1308 
  1309 *** General ***
  1310 
  1311 * Pure/kernel: meta-level proof terms (by Stefan Berghofer); reference
  1312 variable proof controls level of detail: 0 = no proofs (only oracle
  1313 dependencies), 1 = lemma dependencies, 2 = compact proof terms; see
  1314 also ref manual for further ML interfaces;
  1315 
  1316 * Pure/axclass: removed obsolete ML interface
  1317 goal_subclass/goal_arity;
  1318 
  1319 * Pure/syntax: new token syntax "num" for plain numerals (without "#"
  1320 of "xnum"); potential INCOMPATIBILITY, since -0, -1 etc. are now
  1321 separate tokens, so expressions involving minus need to be spaced
  1322 properly;
  1323 
  1324 * Pure/syntax: support non-oriented infixes, using keyword "infix"
  1325 rather than "infixl" or "infixr";
  1326 
  1327 * Pure/syntax: concrete syntax for dummy type variables admits genuine
  1328 sort constraint specifications in type inference; e.g. "x::_::foo"
  1329 ensures that the type of "x" is of sort "foo" (but not necessarily a
  1330 type variable);
  1331 
  1332 * Pure/syntax: print modes "type_brackets" and "no_type_brackets"
  1333 control output of nested => (types); the default behavior is
  1334 "type_brackets";
  1335 
  1336 * Pure/syntax: builtin parse translation for "_constify" turns valued
  1337 tokens into AST constants;
  1338 
  1339 * Pure/syntax: prefer later declarations of translations and print
  1340 translation functions; potential INCOMPATIBILITY: need to reverse
  1341 multiple declarations for same syntax element constant;
  1342 
  1343 * Pure/show_hyps reset by default (in accordance to existing Isar
  1344 practice);
  1345 
  1346 * Provers/classical: renamed addaltern to addafter, addSaltern to
  1347 addSafter;
  1348 
  1349 * Provers/clasimp: ``iff'' declarations now handle conditional rules
  1350 as well;
  1351 
  1352 * system: tested support for MacOS X; should be able to get Isabelle +
  1353 Proof General to work in a plain Terminal after installing Poly/ML
  1354 (e.g. from the Isabelle distribution area) and GNU bash alone
  1355 (e.g. from http://www.apple.com); full X11, XEmacs and X-Symbol
  1356 support requires further installations, e.g. from
  1357 http://fink.sourceforge.net/);
  1358 
  1359 * system: support Poly/ML 4.1.1 (able to manage larger heaps);
  1360 
  1361 * system: reduced base memory usage by Poly/ML (approx. 20 MB instead
  1362 of 40 MB), cf. ML_OPTIONS;
  1363 
  1364 * system: Proof General keywords specification is now part of the
  1365 Isabelle distribution (see etc/isar-keywords.el);
  1366 
  1367 * system: support for persistent Proof General sessions (refrain from
  1368 outdating all loaded theories on startup); user may create writable
  1369 logic images like this: ``isabelle -q HOL Test'';
  1370 
  1371 * system: smart selection of Isabelle process versus Isabelle
  1372 interface, accommodates case-insensitive file systems (e.g. HFS+); may
  1373 run both "isabelle" and "Isabelle" even if file names are badly
  1374 damaged (executable inspects the case of the first letter of its own
  1375 name); added separate "isabelle-process" and "isabelle-interface";
  1376 
  1377 * system: refrain from any attempt at filtering input streams; no
  1378 longer support ``8bit'' encoding of old isabelle font, instead proper
  1379 iso-latin characters may now be used; the related isatools
  1380 "symbolinput" and "nonascii" have disappeared as well;
  1381 
  1382 * system: removed old "xterm" interface (the print modes "xterm" and
  1383 "xterm_color" are still available for direct use in a suitable
  1384 terminal);
  1385 
  1386 
  1387 
  1388 New in Isabelle99-2 (February 2001)
  1389 -----------------------------------
  1390 
  1391 *** Overview of INCOMPATIBILITIES ***
  1392 
  1393 * HOL: please note that theories in the Library and elsewhere often use the
  1394 new-style (Isar) format; to refer to their theorems in an ML script you must
  1395 bind them to ML identifers by e.g.      val thm_name = thm "thm_name";
  1396 
  1397 * HOL: inductive package no longer splits induction rule aggressively,
  1398 but only as far as specified by the introductions given; the old
  1399 format may be recovered via ML function complete_split_rule or attribute
  1400 'split_rule (complete)';
  1401 
  1402 * HOL: induct renamed to lfp_induct, lfp_Tarski to lfp_unfold,
  1403 gfp_Tarski to gfp_unfold;
  1404 
  1405 * HOL: contrapos, contrapos2 renamed to contrapos_nn, contrapos_pp;
  1406 
  1407 * HOL: infix "dvd" now has priority 50 rather than 70 (because it is a
  1408 relation); infix "^^" has been renamed "``"; infix "``" has been
  1409 renamed "`"; "univalent" has been renamed "single_valued";
  1410 
  1411 * HOL/Real: "rinv" and "hrinv" replaced by overloaded "inverse"
  1412 operation;
  1413 
  1414 * HOLCF: infix "`" has been renamed "$"; the symbol syntax is \<cdot>;
  1415 
  1416 * Isar: 'obtain' no longer declares "that" fact as simp/intro;
  1417 
  1418 * Isar/HOL: method 'induct' now handles non-atomic goals; as a
  1419 consequence, it is no longer monotonic wrt. the local goal context
  1420 (which is now passed through the inductive cases);
  1421 
  1422 * Document preparation: renamed standard symbols \<ll> to \<lless> and
  1423 \<gg> to \<ggreater>;
  1424 
  1425 
  1426 *** Document preparation ***
  1427 
  1428 * \isabellestyle{NAME} selects version of Isabelle output (currently
  1429 available: are "it" for near math-mode best-style output, "sl" for
  1430 slanted text style, and "tt" for plain type-writer; if no
  1431 \isabellestyle command is given, output is according to slanted
  1432 type-writer);
  1433 
  1434 * support sub/super scripts (for single symbols only), input syntax is
  1435 like this: "A\<^sup>*" or "A\<^sup>\<star>";
  1436 
  1437 * some more standard symbols; see Appendix A of the system manual for
  1438 the complete list of symbols defined in isabellesym.sty;
  1439 
  1440 * improved isabelle style files; more abstract symbol implementation
  1441 (should now use \isamath{...} and \isatext{...} in custom symbol
  1442 definitions);
  1443 
  1444 * antiquotation @{goals} and @{subgoals} for output of *dynamic* goals
  1445 state; Note that presentation of goal states does not conform to
  1446 actual human-readable proof documents.  Please do not include goal
  1447 states into document output unless you really know what you are doing!
  1448 
  1449 * proper indentation of antiquoted output with proportional LaTeX
  1450 fonts;
  1451 
  1452 * no_document ML operator temporarily disables LaTeX document
  1453 generation;
  1454 
  1455 * isatool unsymbolize tunes sources for plain ASCII communication;
  1456 
  1457 
  1458 *** Isar ***
  1459 
  1460 * Pure: Isar now suffers initial goal statements to contain unbound
  1461 schematic variables (this does not conform to actual readable proof
  1462 documents, due to unpredictable outcome and non-compositional proof
  1463 checking); users who know what they are doing may use schematic goals
  1464 for Prolog-style synthesis of proven results;
  1465 
  1466 * Pure: assumption method (an implicit finishing) now handles actual
  1467 rules as well;
  1468 
  1469 * Pure: improved 'obtain' --- moved to Pure, insert "that" into
  1470 initial goal, declare "that" only as Pure intro (only for single
  1471 steps); the "that" rule assumption may now be involved in implicit
  1472 finishing, thus ".." becomes a feasible for trivial obtains;
  1473 
  1474 * Pure: default proof step now includes 'intro_classes'; thus trivial
  1475 instance proofs may be performed by "..";
  1476 
  1477 * Pure: ?thesis / ?this / "..." now work for pure meta-level
  1478 statements as well;
  1479 
  1480 * Pure: more robust selection of calculational rules;
  1481 
  1482 * Pure: the builtin notion of 'finished' goal now includes the ==-refl
  1483 rule (as well as the assumption rule);
  1484 
  1485 * Pure: 'thm_deps' command visualizes dependencies of theorems and
  1486 lemmas, using the graph browser tool;
  1487 
  1488 * Pure: predict failure of "show" in interactive mode;
  1489 
  1490 * Pure: 'thms_containing' now takes actual terms as arguments;
  1491 
  1492 * HOL: improved method 'induct' --- now handles non-atomic goals
  1493 (potential INCOMPATIBILITY); tuned error handling;
  1494 
  1495 * HOL: cases and induct rules now provide explicit hints about the
  1496 number of facts to be consumed (0 for "type" and 1 for "set" rules);
  1497 any remaining facts are inserted into the goal verbatim;
  1498 
  1499 * HOL: local contexts (aka cases) may now contain term bindings as
  1500 well; the 'cases' and 'induct' methods new provide a ?case binding for
  1501 the result to be shown in each case;
  1502 
  1503 * HOL: added 'recdef_tc' command;
  1504 
  1505 * isatool convert assists in eliminating legacy ML scripts;
  1506 
  1507 
  1508 *** HOL ***
  1509 
  1510 * HOL/Library: a collection of generic theories to be used together
  1511 with main HOL; the theory loader path already includes this directory
  1512 by default; the following existing theories have been moved here:
  1513 HOL/Induct/Multiset, HOL/Induct/Acc (as Accessible_Part), HOL/While
  1514 (as While_Combinator), HOL/Lex/Prefix (as List_Prefix);
  1515 
  1516 * HOL/Unix: "Some aspects of Unix file-system security", a typical
  1517 modelling and verification task performed in Isabelle/HOL +
  1518 Isabelle/Isar + Isabelle document preparation (by Markus Wenzel).
  1519 
  1520 * HOL/Algebra: special summation operator SUM no longer exists, it has
  1521 been replaced by setsum; infix 'assoc' now has priority 50 (like
  1522 'dvd'); axiom 'one_not_zero' has been moved from axclass 'ring' to
  1523 'domain', this makes the theory consistent with mathematical
  1524 literature;
  1525 
  1526 * HOL basics: added overloaded operations "inverse" and "divide"
  1527 (infix "/"), syntax for generic "abs" operation, generic summation
  1528 operator \<Sum>;
  1529 
  1530 * HOL/typedef: simplified package, provide more useful rules (see also
  1531 HOL/subset.thy);
  1532 
  1533 * HOL/datatype: induction rule for arbitrarily branching datatypes is
  1534 now expressed as a proper nested rule (old-style tactic scripts may
  1535 require atomize_strip_tac to cope with non-atomic premises);
  1536 
  1537 * HOL: renamed theory "Prod" to "Product_Type", renamed "split" rule
  1538 to "split_conv" (old name still available for compatibility);
  1539 
  1540 * HOL: improved concrete syntax for strings (e.g. allows translation
  1541 rules with string literals);
  1542 
  1543 * HOL-Real-Hyperreal: this extends HOL-Real with the hyperreals
  1544  and Fleuriot's mechanization of analysis, including the transcendental
  1545  functions for the reals;
  1546 
  1547 * HOL/Real, HOL/Hyperreal: improved arithmetic simplification;
  1548 
  1549 
  1550 *** CTT ***
  1551 
  1552 * CTT: x-symbol support for Pi, Sigma, -->, : (membership); note that
  1553 "lam" is displayed as TWO lambda-symbols
  1554 
  1555 * CTT: theory Main now available, containing everything (that is, Bool
  1556 and Arith);
  1557 
  1558 
  1559 *** General ***
  1560 
  1561 * Pure: the Simplifier has been implemented properly as a derived rule
  1562 outside of the actual kernel (at last!); the overall performance
  1563 penalty in practical applications is about 50%, while reliability of
  1564 the Isabelle inference kernel has been greatly improved;
  1565 
  1566 * print modes "brackets" and "no_brackets" control output of nested =>
  1567 (types) and ==> (props); the default behaviour is "brackets";
  1568 
  1569 * Provers: fast_tac (and friends) now handle actual object-logic rules
  1570 as assumptions as well;
  1571 
  1572 * system: support Poly/ML 4.0;
  1573 
  1574 * system: isatool install handles KDE version 1 or 2;
  1575 
  1576 
  1577 
  1578 New in Isabelle99-1 (October 2000)
  1579 ----------------------------------
  1580 
  1581 *** Overview of INCOMPATIBILITIES ***
  1582 
  1583 * HOL: simplification of natural numbers is much changed; to partly
  1584 recover the old behaviour (e.g. to prevent n+n rewriting to #2*n)
  1585 issue the following ML commands:
  1586 
  1587   Delsimprocs Nat_Numeral_Simprocs.cancel_numerals;
  1588   Delsimprocs [Nat_Numeral_Simprocs.combine_numerals];
  1589 
  1590 * HOL: simplification no longer dives into case-expressions; this is
  1591 controlled by "t.weak_case_cong" for each datatype t;
  1592 
  1593 * HOL: nat_less_induct renamed to less_induct;
  1594 
  1595 * HOL: systematic renaming of the SOME (Eps) rules, may use isatool
  1596 fixsome to patch .thy and .ML sources automatically;
  1597 
  1598   select_equality  -> some_equality
  1599   select_eq_Ex     -> some_eq_ex
  1600   selectI2EX       -> someI2_ex
  1601   selectI2         -> someI2
  1602   selectI          -> someI
  1603   select1_equality -> some1_equality
  1604   Eps_sym_eq       -> some_sym_eq_trivial
  1605   Eps_eq           -> some_eq_trivial
  1606 
  1607 * HOL: exhaust_tac on datatypes superceded by new generic case_tac;
  1608 
  1609 * HOL: removed obsolete theorem binding expand_if (refer to split_if
  1610 instead);
  1611 
  1612 * HOL: the recursion equations generated by 'recdef' are now called
  1613 f.simps instead of f.rules;
  1614 
  1615 * HOL: qed_spec_mp now also handles bounded ALL as well;
  1616 
  1617 * HOL: 0 is now overloaded, so the type constraint ":: nat" may
  1618 sometimes be needed;
  1619 
  1620 * HOL: the constant for "f``x" is now "image" rather than "op ``";
  1621 
  1622 * HOL: the constant for "f-``x" is now "vimage" rather than "op -``";
  1623 
  1624 * HOL: the disjoint sum is now "<+>" instead of "Plus"; the cartesian
  1625 product is now "<*>" instead of "Times"; the lexicographic product is
  1626 now "<*lex*>" instead of "**";
  1627 
  1628 * HOL: theory Sexp is now in HOL/Induct examples (it used to be part
  1629 of main HOL, but was unused); better use HOL's datatype package;
  1630 
  1631 * HOL: removed "symbols" syntax for constant "override" of theory Map;
  1632 the old syntax may be recovered as follows:
  1633 
  1634   syntax (symbols)
  1635     override  :: "('a ~=> 'b) => ('a ~=> 'b) => ('a ~=> 'b)"
  1636       (infixl "\\<oplus>" 100)
  1637 
  1638 * HOL/Real: "rabs" replaced by overloaded "abs" function;
  1639 
  1640 * HOL/ML: even fewer consts are declared as global (see theories Ord,
  1641 Lfp, Gfp, WF); this only affects ML packages that refer to const names
  1642 internally;
  1643 
  1644 * HOL and ZF: syntax for quotienting wrt an equivalence relation
  1645 changed from A/r to A//r;
  1646 
  1647 * ZF: new treatment of arithmetic (nat & int) may break some old
  1648 proofs;
  1649 
  1650 * Isar: renamed some attributes (RS -> THEN, simplify -> simplified,
  1651 rulify -> rule_format, elimify -> elim_format, ...);
  1652 
  1653 * Isar/Provers: intro/elim/dest attributes changed; renamed
  1654 intro/intro!/intro!! flags to intro!/intro/intro? (in most cases, one
  1655 should have to change intro!! to intro? only); replaced "delrule" by
  1656 "rule del";
  1657 
  1658 * Isar/HOL: renamed "intrs" to "intros" in inductive definitions;
  1659 
  1660 * Provers: strengthened force_tac by using new first_best_tac;
  1661 
  1662 * LaTeX document preparation: several changes of isabelle.sty (see
  1663 lib/texinputs);
  1664 
  1665 
  1666 *** Document preparation ***
  1667 
  1668 * formal comments (text blocks etc.) in new-style theories may now
  1669 contain antiquotations of thm/prop/term/typ/text to be presented
  1670 according to latex print mode; concrete syntax is like this:
  1671 @{term[show_types] "f(x) = a + x"};
  1672 
  1673 * isatool mkdir provides easy setup of Isabelle session directories,
  1674 including proper document sources;
  1675 
  1676 * generated LaTeX sources are now deleted after successful run
  1677 (isatool document -c); may retain a copy somewhere else via -D option
  1678 of isatool usedir;
  1679 
  1680 * isatool usedir -D now lets isatool latex -o sty update the Isabelle
  1681 style files, achieving self-contained LaTeX sources and simplifying
  1682 LaTeX debugging;
  1683 
  1684 * old-style theories now produce (crude) LaTeX output as well;
  1685 
  1686 * browser info session directories are now self-contained (may be put
  1687 on WWW server seperately); improved graphs of nested sessions; removed
  1688 graph for 'all sessions';
  1689 
  1690 * several improvements in isabelle style files; \isabellestyle{it}
  1691 produces fake math mode output; \isamarkupheader is now \section by
  1692 default; see lib/texinputs/isabelle.sty etc.;
  1693 
  1694 
  1695 *** Isar ***
  1696 
  1697 * Isar/Pure: local results and corresponding term bindings are now
  1698 subject to Hindley-Milner polymorphism (similar to ML); this
  1699 accommodates incremental type-inference very nicely;
  1700 
  1701 * Isar/Pure: new derived language element 'obtain' supports
  1702 generalized existence reasoning;
  1703 
  1704 * Isar/Pure: new calculational elements 'moreover' and 'ultimately'
  1705 support accumulation of results, without applying any rules yet;
  1706 useful to collect intermediate results without explicit name
  1707 references, and for use with transitivity rules with more than 2
  1708 premises;
  1709 
  1710 * Isar/Pure: scalable support for case-analysis type proofs: new
  1711 'case' language element refers to local contexts symbolically, as
  1712 produced by certain proof methods; internally, case names are attached
  1713 to theorems as "tags";
  1714 
  1715 * Isar/Pure: theory command 'hide' removes declarations from
  1716 class/type/const name spaces;
  1717 
  1718 * Isar/Pure: theory command 'defs' supports option "(overloaded)" to
  1719 indicate potential overloading;
  1720 
  1721 * Isar/Pure: changed syntax of local blocks from {{ }} to { };
  1722 
  1723 * Isar/Pure: syntax of sorts made 'inner', i.e. have to write
  1724 "{a,b,c}" instead of {a,b,c};
  1725 
  1726 * Isar/Pure now provides its own version of intro/elim/dest
  1727 attributes; useful for building new logics, but beware of confusion
  1728 with the version in Provers/classical;
  1729 
  1730 * Isar/Pure: the local context of (non-atomic) goals is provided via
  1731 case name 'antecedent';
  1732 
  1733 * Isar/Pure: removed obsolete 'transfer' attribute (transfer of thms
  1734 to the current context is now done automatically);
  1735 
  1736 * Isar/Pure: theory command 'method_setup' provides a simple interface
  1737 for definining proof methods in ML;
  1738 
  1739 * Isar/Provers: intro/elim/dest attributes changed; renamed
  1740 intro/intro!/intro!! flags to intro!/intro/intro? (INCOMPATIBILITY, in
  1741 most cases, one should have to change intro!! to intro? only);
  1742 replaced "delrule" by "rule del";
  1743 
  1744 * Isar/Provers: new 'hypsubst' method, plain 'subst' method and
  1745 'symmetric' attribute (the latter supercedes [RS sym]);
  1746 
  1747 * Isar/Provers: splitter support (via 'split' attribute and 'simp'
  1748 method modifier); 'simp' method: 'only:' modifier removes loopers as
  1749 well (including splits);
  1750 
  1751 * Isar/Provers: Simplifier and Classical methods now support all kind
  1752 of modifiers used in the past, including 'cong', 'iff', etc.
  1753 
  1754 * Isar/Provers: added 'fastsimp' and 'clarsimp' methods (combination
  1755 of Simplifier and Classical reasoner);
  1756 
  1757 * Isar/HOL: new proof method 'cases' and improved version of 'induct'
  1758 now support named cases; major packages (inductive, datatype, primrec,
  1759 recdef) support case names and properly name parameters;
  1760 
  1761 * Isar/HOL: new transitivity rules for substitution in inequalities --
  1762 monotonicity conditions are extracted to be proven at end of
  1763 calculations;
  1764 
  1765 * Isar/HOL: removed 'case_split' thm binding, should use 'cases' proof
  1766 method anyway;
  1767 
  1768 * Isar/HOL: removed old expand_if = split_if; theorems if_splits =
  1769 split_if split_if_asm; datatype package provides theorems foo.splits =
  1770 foo.split foo.split_asm for each datatype;
  1771 
  1772 * Isar/HOL: tuned inductive package, rename "intrs" to "intros"
  1773 (potential INCOMPATIBILITY), emulation of mk_cases feature for proof
  1774 scripts: new 'inductive_cases' command and 'ind_cases' method; (Note:
  1775 use "(cases (simplified))" method in proper proof texts);
  1776 
  1777 * Isar/HOL: added global 'arith_split' attribute for 'arith' method;
  1778 
  1779 * Isar: names of theorems etc. may be natural numbers as well;
  1780 
  1781 * Isar: 'pr' command: optional arguments for goals_limit and
  1782 ProofContext.prems_limit; no longer prints theory contexts, but only
  1783 proof states;
  1784 
  1785 * Isar: diagnostic commands 'pr', 'thm', 'prop', 'term', 'typ' admit
  1786 additional print modes to be specified; e.g. "pr(latex)" will print
  1787 proof state according to the Isabelle LaTeX style;
  1788 
  1789 * Isar: improved support for emulating tactic scripts, including proof
  1790 methods 'rule_tac' etc., 'cut_tac', 'thin_tac', 'subgoal_tac',
  1791 'rename_tac', 'rotate_tac', 'tactic', and 'case_tac' / 'induct_tac'
  1792 (for HOL datatypes);
  1793 
  1794 * Isar: simplified (more robust) goal selection of proof methods: 1st
  1795 goal, all goals, or explicit goal specifier (tactic emulation); thus
  1796 'proof method scripts' have to be in depth-first order;
  1797 
  1798 * Isar: tuned 'let' syntax: replaced 'as' keyword by 'and';
  1799 
  1800 * Isar: removed 'help' command, which hasn't been too helpful anyway;
  1801 should instead use individual commands for printing items
  1802 (print_commands, print_methods etc.);
  1803 
  1804 * Isar: added 'nothing' --- the empty list of theorems;
  1805 
  1806 
  1807 *** HOL ***
  1808 
  1809 * HOL/MicroJava: formalization of a fragment of Java, together with a
  1810 corresponding virtual machine and a specification of its bytecode
  1811 verifier and a lightweight bytecode verifier, including proofs of
  1812 type-safety; by Gerwin Klein, Tobias Nipkow, David von Oheimb, and
  1813 Cornelia Pusch (see also the homepage of project Bali at
  1814 http://isabelle.in.tum.de/Bali/);
  1815 
  1816 * HOL/Algebra: new theory of rings and univariate polynomials, by
  1817 Clemens Ballarin;
  1818 
  1819 * HOL/NumberTheory: fundamental Theorem of Arithmetic, Chinese
  1820 Remainder Theorem, Fermat/Euler Theorem, Wilson's Theorem, by Thomas M
  1821 Rasmussen;
  1822 
  1823 * HOL/Lattice: fundamental concepts of lattice theory and order
  1824 structures, including duals, properties of bounds versus algebraic
  1825 laws, lattice operations versus set-theoretic ones, the Knaster-Tarski
  1826 Theorem for complete lattices etc.; may also serve as a demonstration
  1827 for abstract algebraic reasoning using axiomatic type classes, and
  1828 mathematics-style proof in Isabelle/Isar; by Markus Wenzel;
  1829 
  1830 * HOL/Prolog: a (bare-bones) implementation of Lambda-Prolog, by David
  1831 von Oheimb;
  1832 
  1833 * HOL/IMPP: extension of IMP with local variables and mutually
  1834 recursive procedures, by David von Oheimb;
  1835 
  1836 * HOL/Lambda: converted into new-style theory and document;
  1837 
  1838 * HOL/ex/Multiquote: example of multiple nested quotations and
  1839 anti-quotations -- basically a generalized version of de-Bruijn
  1840 representation; very useful in avoiding lifting of operations;
  1841 
  1842 * HOL/record: added general record equality rule to simpset; fixed
  1843 select-update simplification procedure to handle extended records as
  1844 well; admit "r" as field name;
  1845 
  1846 * HOL: 0 is now overloaded over the new sort "zero", allowing its use with
  1847 other numeric types and also as the identity of groups, rings, etc.;
  1848 
  1849 * HOL: new axclass plus_ac0 for addition with the AC-laws and 0 as identity.
  1850 Types nat and int belong to this axclass;
  1851 
  1852 * HOL: greatly improved simplification involving numerals of type nat, int, real:
  1853    (i + #8 + j) = Suc k simplifies to  #7 + (i + j) = k
  1854    i*j + k + j*#3*i     simplifies to  #4*(i*j) + k
  1855   two terms #m*u and #n*u are replaced by #(m+n)*u
  1856     (where #m, #n and u can implicitly be 1; this is simproc combine_numerals)
  1857   and the term/formula #m*u+x ~~ #n*u+y simplifies simplifies to #(m-n)+x ~~ y
  1858     or x ~~ #(n-m)+y, where ~~ is one of = < <= or - (simproc cancel_numerals);
  1859 
  1860 * HOL: meson_tac is available (previously in ex/meson.ML); it is a
  1861 powerful prover for predicate logic but knows nothing of clasets; see
  1862 ex/mesontest.ML and ex/mesontest2.ML for example applications;
  1863 
  1864 * HOL: new version of "case_tac" subsumes both boolean case split and
  1865 "exhaust_tac" on datatypes; INCOMPATIBILITY: exhaust_tac no longer
  1866 exists, may define val exhaust_tac = case_tac for ad-hoc portability;
  1867 
  1868 * HOL: simplification no longer dives into case-expressions: only the
  1869 selector expression is simplified, but not the remaining arms; to
  1870 enable full simplification of case-expressions for datatype t, you may
  1871 remove t.weak_case_cong from the simpset, either globally (Delcongs
  1872 [thm"t.weak_case_cong"];) or locally (delcongs [...]).
  1873 
  1874 * HOL/recdef: the recursion equations generated by 'recdef' for
  1875 function 'f' are now called f.simps instead of f.rules; if all
  1876 termination conditions are proved automatically, these simplification
  1877 rules are added to the simpset, as in primrec; rules may be named
  1878 individually as well, resulting in a separate list of theorems for
  1879 each equation;
  1880 
  1881 * HOL/While is a new theory that provides a while-combinator. It
  1882 permits the definition of tail-recursive functions without the
  1883 provision of a termination measure. The latter is necessary once the
  1884 invariant proof rule for while is applied.
  1885 
  1886 * HOL: new (overloaded) notation for the set of elements below/above
  1887 some element: {..u}, {..u(}, {l..}, {)l..}. See theory SetInterval.
  1888 
  1889 * HOL: theorems impI, allI, ballI bound as "strip";
  1890 
  1891 * HOL: new tactic induct_thm_tac: thm -> string -> int -> tactic
  1892 induct_tac th "x1 ... xn" expects th to have a conclusion of the form
  1893 P v1 ... vn and abbreviates res_inst_tac [("v1","x1"),...,("vn","xn")] th;
  1894 
  1895 * HOL/Real: "rabs" replaced by overloaded "abs" function;
  1896 
  1897 * HOL: theory Sexp now in HOL/Induct examples (it used to be part of
  1898 main HOL, but was unused);
  1899 
  1900 * HOL: fewer consts declared as global (e.g. have to refer to
  1901 "Lfp.lfp" instead of "lfp" internally; affects ML packages only);
  1902 
  1903 * HOL: tuned AST representation of nested pairs, avoiding bogus output
  1904 in case of overlap with user translations (e.g. judgements over
  1905 tuples); (note that the underlying logical represenation is still
  1906 bogus);
  1907 
  1908 
  1909 *** ZF ***
  1910 
  1911 * ZF: simplification automatically cancels common terms in arithmetic
  1912 expressions over nat and int;
  1913 
  1914 * ZF: new treatment of nat to minimize type-checking: all operators
  1915 coerce their operands to a natural number using the function natify,
  1916 making the algebraic laws unconditional;
  1917 
  1918 * ZF: as above, for int: operators coerce their operands to an integer
  1919 using the function intify;
  1920 
  1921 * ZF: the integer library now contains many of the usual laws for the
  1922 orderings, including $<=, and monotonicity laws for $+ and $*;
  1923 
  1924 * ZF: new example ZF/ex/NatSum to demonstrate integer arithmetic
  1925 simplification;
  1926 
  1927 * FOL and ZF: AddIffs now available, giving theorems of the form P<->Q
  1928 to the simplifier and classical reasoner simultaneously;
  1929 
  1930 
  1931 *** General ***
  1932 
  1933 * Provers: blast_tac now handles actual object-logic rules as
  1934 assumptions; note that auto_tac uses blast_tac internally as well;
  1935 
  1936 * Provers: new functions rulify/rulify_no_asm: thm -> thm for turning
  1937 outer -->/All/Ball into ==>/!!; qed_spec_mp now uses rulify_no_asm;
  1938 
  1939 * Provers: delrules now handles destruct rules as well (no longer need
  1940 explicit make_elim);
  1941 
  1942 * Provers: Blast_tac now warns of and ignores "weak elimination rules" e.g.
  1943   [| inj ?f;          ?f ?x = ?f ?y; ?x = ?y ==> ?W |] ==> ?W
  1944 use instead the strong form,
  1945   [| inj ?f; ~ ?W ==> ?f ?x = ?f ?y; ?x = ?y ==> ?W |] ==> ?W
  1946 in HOL, FOL and ZF the function cla_make_elim will create such rules
  1947 from destruct-rules;
  1948 
  1949 * Provers: Simplifier.easy_setup provides a fast path to basic
  1950 Simplifier setup for new object-logics;
  1951 
  1952 * Pure: AST translation rules no longer require constant head on LHS;
  1953 
  1954 * Pure: improved name spaces: ambiguous output is qualified; support
  1955 for hiding of names;
  1956 
  1957 * system: smart setup of canonical ML_HOME, ISABELLE_INTERFACE, and
  1958 XSYMBOL_HOME; no longer need to do manual configuration in most
  1959 situations;
  1960 
  1961 * system: compression of ML heaps images may now be controlled via -c
  1962 option of isabelle and isatool usedir (currently only observed by
  1963 Poly/ML);
  1964 
  1965 * system: isatool installfonts may handle X-Symbol fonts as well (very
  1966 useful for remote X11);
  1967 
  1968 * system: provide TAGS file for Isabelle sources;
  1969 
  1970 * ML: infix 'OF' is a version of 'MRS' with more appropriate argument
  1971 order;
  1972 
  1973 * ML: renamed flags Syntax.trace_norm_ast to Syntax.trace_ast; global
  1974 timing flag supersedes proof_timing and Toplevel.trace;
  1975 
  1976 * ML: new combinators |>> and |>>> for incremental transformations
  1977 with secondary results (e.g. certain theory extensions):
  1978 
  1979 * ML: PureThy.add_defs gets additional argument to indicate potential
  1980 overloading (usually false);
  1981 
  1982 * ML: PureThy.add_thms/add_axioms/add_defs now return theorems as
  1983 results;
  1984 
  1985 
  1986 
  1987 New in Isabelle99 (October 1999)
  1988 --------------------------------
  1989 
  1990 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  1991 
  1992 * HOL: The THEN and ELSE parts of conditional expressions (if P then x else y)
  1993 are no longer simplified.  (This allows the simplifier to unfold recursive
  1994 functional programs.)  To restore the old behaviour, declare
  1995 
  1996     Delcongs [if_weak_cong];
  1997 
  1998 * HOL: Removed the obsolete syntax "Compl A"; use -A for set
  1999 complement;
  2000 
  2001 * HOL: the predicate "inj" is now defined by translation to "inj_on";
  2002 
  2003 * HOL/datatype: mutual_induct_tac no longer exists --
  2004   use induct_tac "x_1 ... x_n" instead of mutual_induct_tac ["x_1", ..., "x_n"]
  2005 
  2006 * HOL/typedef: fixed type inference for representing set; type
  2007 arguments now have to occur explicitly on the rhs as type constraints;
  2008 
  2009 * ZF: The con_defs part of an inductive definition may no longer refer
  2010 to constants declared in the same theory;
  2011 
  2012 * HOL, ZF: the function mk_cases, generated by the inductive
  2013 definition package, has lost an argument.  To simplify its result, it
  2014 uses the default simpset instead of a supplied list of theorems.
  2015 
  2016 * HOL/List: the constructors of type list are now Nil and Cons;
  2017 
  2018 * Simplifier: the type of the infix ML functions
  2019         setSSolver addSSolver setSolver addSolver
  2020 is now  simpset * solver -> simpset  where `solver' is a new abstract type
  2021 for packaging solvers. A solver is created via
  2022         mk_solver: string -> (thm list -> int -> tactic) -> solver
  2023 where the string argument is only a comment.
  2024 
  2025 
  2026 *** Proof tools ***
  2027 
  2028 * Provers/Arith/fast_lin_arith.ML contains a functor for creating a
  2029 decision procedure for linear arithmetic. Currently it is used for
  2030 types `nat', `int', and `real' in HOL (see below); it can, should and
  2031 will be instantiated for other types and logics as well.
  2032 
  2033 * The simplifier now accepts rewrite rules with flexible heads, eg
  2034      hom ?f ==> ?f(?x+?y) = ?f ?x + ?f ?y
  2035   They are applied like any rule with a non-pattern lhs, i.e. by first-order
  2036   matching.
  2037 
  2038 
  2039 *** General ***
  2040 
  2041 * New Isabelle/Isar subsystem provides an alternative to traditional
  2042 tactical theorem proving; together with the ProofGeneral/isar user
  2043 interface it offers an interactive environment for developing human
  2044 readable proof documents (Isar == Intelligible semi-automated
  2045 reasoning); for further information see isatool doc isar-ref,
  2046 src/HOL/Isar_examples and http://isabelle.in.tum.de/Isar/
  2047 
  2048 * improved and simplified presentation of theories: better HTML markup
  2049 (including colors), graph views in several sizes; isatool usedir now
  2050 provides a proper interface for user theories (via -P option); actual
  2051 document preparation based on (PDF)LaTeX is available as well (for
  2052 new-style theories only); see isatool doc system for more information;
  2053 
  2054 * native support for Proof General, both for classic Isabelle and
  2055 Isabelle/Isar;
  2056 
  2057 * ML function thm_deps visualizes dependencies of theorems and lemmas,
  2058 using the graph browser tool;
  2059 
  2060 * Isabelle manuals now also available as PDF;
  2061 
  2062 * theory loader rewritten from scratch (may not be fully
  2063 bug-compatible); old loadpath variable has been replaced by show_path,
  2064 add_path, del_path, reset_path functions; new operations such as
  2065 update_thy, touch_thy, remove_thy, use/update_thy_only (see also
  2066 isatool doc ref);
  2067 
  2068 * improved isatool install: option -k creates KDE application icon,
  2069 option -p DIR installs standalone binaries;
  2070 
  2071 * added ML_PLATFORM setting (useful for cross-platform installations);
  2072 more robust handling of platform specific ML images for SML/NJ;
  2073 
  2074 * the settings environment is now statically scoped, i.e. it is never
  2075 created again in sub-processes invoked from isabelle, isatool, or
  2076 Isabelle;
  2077 
  2078 * path element specification '~~' refers to '$ISABELLE_HOME';
  2079 
  2080 * in locales, the "assumes" and "defines" parts may be omitted if
  2081 empty;
  2082 
  2083 * new print_mode "xsymbols" for extended symbol support (e.g. genuine
  2084 long arrows);
  2085 
  2086 * new print_mode "HTML";
  2087 
  2088 * new flag show_tags controls display of tags of theorems (which are
  2089 basically just comments that may be attached by some tools);
  2090 
  2091 * Isamode 2.6 requires patch to accomodate change of Isabelle font
  2092 mode and goal output format:
  2093 
  2094 diff -r Isamode-2.6/elisp/isa-load.el Isamode/elisp/isa-load.el
  2095 244c244
  2096 <       (list (isa-getenv "ISABELLE") "-msymbols" logic-name)
  2097 ---
  2098 >       (list (isa-getenv "ISABELLE") "-misabelle_font" "-msymbols" logic-name)
  2099 diff -r Isabelle-2.6/elisp/isa-proofstate.el Isamode/elisp/isa-proofstate.el
  2100 181c181
  2101 < (defconst proofstate-proofstart-regexp "^Level [0-9]+$"
  2102 ---
  2103 > (defconst proofstate-proofstart-regexp "^Level [0-9]+"
  2104 
  2105 * function bind_thms stores lists of theorems (cf. bind_thm);
  2106 
  2107 * new shorthand tactics ftac, eatac, datac, fatac;
  2108 
  2109 * qed (and friends) now accept "" as result name; in that case the
  2110 theorem is not stored, but proper checks and presentation of the
  2111 result still apply;
  2112 
  2113 * theorem database now also indexes constants "Trueprop", "all",
  2114 "==>", "=="; thus thms_containing, findI etc. may retrieve more rules;
  2115 
  2116 
  2117 *** HOL ***
  2118 
  2119 ** HOL arithmetic **
  2120 
  2121 * There are now decision procedures for linear arithmetic over nat and
  2122 int:
  2123 
  2124 1. arith_tac copes with arbitrary formulae involving `=', `<', `<=',
  2125 `+', `-', `Suc', `min', `max' and numerical constants; other subterms
  2126 are treated as atomic; subformulae not involving type `nat' or `int'
  2127 are ignored; quantified subformulae are ignored unless they are
  2128 positive universal or negative existential. The tactic has to be
  2129 invoked by hand and can be a little bit slow. In particular, the
  2130 running time is exponential in the number of occurrences of `min' and
  2131 `max', and `-' on `nat'.
  2132 
  2133 2. fast_arith_tac is a cut-down version of arith_tac: it only takes
  2134 (negated) (in)equalities among the premises and the conclusion into
  2135 account (i.e. no compound formulae) and does not know about `min' and
  2136 `max', and `-' on `nat'. It is fast and is used automatically by the
  2137 simplifier.
  2138 
  2139 NB: At the moment, these decision procedures do not cope with mixed
  2140 nat/int formulae where the two parts interact, such as `m < n ==>
  2141 int(m) < int(n)'.
  2142 
  2143 * HOL/Numeral provides a generic theory of numerals (encoded
  2144 efficiently as bit strings); setup for types nat/int/real is in place;
  2145 INCOMPATIBILITY: since numeral syntax is now polymorphic, rather than
  2146 int, existing theories and proof scripts may require a few additional
  2147 type constraints;
  2148 
  2149 * integer division and remainder can now be performed on constant
  2150 arguments;
  2151 
  2152 * many properties of integer multiplication, division and remainder
  2153 are now available;
  2154 
  2155 * An interface to the Stanford Validity Checker (SVC) is available through the
  2156 tactic svc_tac.  Propositional tautologies and theorems of linear arithmetic
  2157 are proved automatically.  SVC must be installed separately, and its results
  2158 must be TAKEN ON TRUST (Isabelle does not check the proofs, but tags any
  2159 invocation of the underlying oracle).  For SVC see
  2160   http://verify.stanford.edu/SVC
  2161 
  2162 * IsaMakefile: the HOL-Real target now builds an actual image;
  2163 
  2164 
  2165 ** HOL misc **
  2166 
  2167 * HOL/Real/HahnBanach: the Hahn-Banach theorem for real vector spaces
  2168 (in Isabelle/Isar) -- by Gertrud Bauer;
  2169 
  2170 * HOL/BCV: generic model of bytecode verification, i.e. data-flow
  2171 analysis for assembly languages with subtypes;
  2172 
  2173 * HOL/TLA (Lamport's Temporal Logic of Actions): major reorganization
  2174 -- avoids syntactic ambiguities and treats state, transition, and
  2175 temporal levels more uniformly; introduces INCOMPATIBILITIES due to
  2176 changed syntax and (many) tactics;
  2177 
  2178 * HOL/inductive: Now also handles more general introduction rules such
  2179   as "ALL y. (y, x) : r --> y : acc r ==> x : acc r"; monotonicity
  2180   theorems are now maintained within the theory (maintained via the
  2181   "mono" attribute);
  2182 
  2183 * HOL/datatype: Now also handles arbitrarily branching datatypes
  2184   (using function types) such as
  2185 
  2186   datatype 'a tree = Atom 'a | Branch "nat => 'a tree"
  2187 
  2188 * HOL/record: record_simproc (part of the default simpset) takes care
  2189 of selectors applied to updated records; record_split_tac is no longer
  2190 part of the default claset; update_defs may now be removed from the
  2191 simpset in many cases; COMPATIBILITY: old behavior achieved by
  2192 
  2193   claset_ref () := claset() addSWrapper record_split_wrapper;
  2194   Delsimprocs [record_simproc]
  2195 
  2196 * HOL/typedef: fixed type inference for representing set; type
  2197 arguments now have to occur explicitly on the rhs as type constraints;
  2198 
  2199 * HOL/recdef (TFL): 'congs' syntax now expects comma separated list of theorem
  2200 names rather than an ML expression;
  2201 
  2202 * HOL/defer_recdef (TFL): like recdef but the well-founded relation can be
  2203 supplied later.  Program schemes can be defined, such as
  2204     "While B C s = (if B s then While B C (C s) else s)"
  2205 where the well-founded relation can be chosen after B and C have been given.
  2206 
  2207 * HOL/List: the constructors of type list are now Nil and Cons;
  2208 INCOMPATIBILITY: while [] and infix # syntax is still there, of
  2209 course, ML tools referring to List.list.op # etc. have to be adapted;
  2210 
  2211 * HOL_quantifiers flag superseded by "HOL" print mode, which is
  2212 disabled by default; run isabelle with option -m HOL to get back to
  2213 the original Gordon/HOL-style output;
  2214 
  2215 * HOL/Ord.thy: new bounded quantifier syntax (input only): ALL x<y. P,
  2216 ALL x<=y. P, EX x<y. P, EX x<=y. P;
  2217 
  2218 * HOL basic syntax simplified (more orthogonal): all variants of
  2219 All/Ex now support plain / symbolic / HOL notation; plain syntax for
  2220 Eps operator is provided as well: "SOME x. P[x]";
  2221 
  2222 * HOL/Sum.thy: sum_case has been moved to HOL/Datatype;
  2223 
  2224 * HOL/Univ.thy: infix syntax <*>, <+>, <**>, <+> eliminated and made
  2225 thus available for user theories;
  2226 
  2227 * HOLCF/IOA/Sequents: renamed 'Cons' to 'Consq' to avoid clash with
  2228 HOL/List; hardly an INCOMPATIBILITY since '>>' syntax is used all the
  2229 time;
  2230 
  2231 * HOL: new tactic smp_tac: int -> int -> tactic, which applies spec
  2232 several times and then mp;
  2233 
  2234 
  2235 *** LK ***
  2236 
  2237 * the notation <<...>> is now available as a notation for sequences of
  2238 formulas;
  2239 
  2240 * the simplifier is now installed
  2241 
  2242 * the axiom system has been generalized (thanks to Soren Heilmann)
  2243 
  2244 * the classical reasoner now has a default rule database
  2245 
  2246 
  2247 *** ZF ***
  2248 
  2249 * new primrec section allows primitive recursive functions to be given
  2250 directly (as in HOL) over datatypes and the natural numbers;
  2251 
  2252 * new tactics induct_tac and exhaust_tac for induction (or case
  2253 analysis) over datatypes and the natural numbers;
  2254 
  2255 * the datatype declaration of type T now defines the recursor T_rec;
  2256 
  2257 * simplification automatically does freeness reasoning for datatype
  2258 constructors;
  2259 
  2260 * automatic type-inference, with AddTCs command to insert new
  2261 type-checking rules;
  2262 
  2263 * datatype introduction rules are now added as Safe Introduction rules
  2264 to the claset;
  2265 
  2266 * the syntax "if P then x else y" is now available in addition to
  2267 if(P,x,y);
  2268 
  2269 
  2270 *** Internal programming interfaces ***
  2271 
  2272 * tuned simplifier trace output; new flag debug_simp;
  2273 
  2274 * structures Vartab / Termtab (instances of TableFun) offer efficient
  2275 tables indexed by indexname_ord / term_ord (compatible with aconv);
  2276 
  2277 * AxClass.axclass_tac lost the theory argument;
  2278 
  2279 * tuned current_goals_markers semantics: begin / end goal avoids
  2280 printing empty lines;
  2281 
  2282 * removed prs and prs_fn hook, which was broken because it did not
  2283 include \n in its semantics, forcing writeln to add one
  2284 uncoditionally; replaced prs_fn by writeln_fn; consider std_output:
  2285 string -> unit if you really want to output text without newline;
  2286 
  2287 * Symbol.output subject to print mode; INCOMPATIBILITY: defaults to
  2288 plain output, interface builders may have to enable 'isabelle_font'
  2289 mode to get Isabelle font glyphs as before;
  2290 
  2291 * refined token_translation interface; INCOMPATIBILITY: output length
  2292 now of type real instead of int;
  2293 
  2294 * theory loader actions may be traced via new ThyInfo.add_hook
  2295 interface (see src/Pure/Thy/thy_info.ML); example application: keep
  2296 your own database of information attached to *whole* theories -- as
  2297 opposed to intra-theory data slots offered via TheoryDataFun;
  2298 
  2299 * proper handling of dangling sort hypotheses (at last!);
  2300 Thm.strip_shyps and Drule.strip_shyps_warning take care of removing
  2301 extra sort hypotheses that can be witnessed from the type signature;
  2302 the force_strip_shyps flag is gone, any remaining shyps are simply
  2303 left in the theorem (with a warning issued by strip_shyps_warning);
  2304 
  2305 
  2306 
  2307 New in Isabelle98-1 (October 1998)
  2308 ----------------------------------
  2309 
  2310 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  2311 
  2312 * several changes of automated proof tools;
  2313 
  2314 * HOL: major changes to the inductive and datatype packages, including
  2315 some minor incompatibilities of theory syntax;
  2316 
  2317 * HOL: renamed r^-1 to 'converse' from 'inverse'; 'inj_onto' is now
  2318 called `inj_on';
  2319 
  2320 * HOL: removed duplicate thms in Arith:
  2321   less_imp_add_less  should be replaced by  trans_less_add1
  2322   le_imp_add_le      should be replaced by  trans_le_add1
  2323 
  2324 * HOL: unary minus is now overloaded (new type constraints may be
  2325 required);
  2326 
  2327 * HOL and ZF: unary minus for integers is now #- instead of #~.  In
  2328 ZF, expressions such as n#-1 must be changed to n#- 1, since #-1 is
  2329 now taken as an integer constant.
  2330 
  2331 * Pure: ML function 'theory_of' renamed to 'theory';
  2332 
  2333 
  2334 *** Proof tools ***
  2335 
  2336 * Simplifier:
  2337   1. Asm_full_simp_tac is now more aggressive.
  2338      1. It will sometimes reorient premises if that increases their power to
  2339         simplify.
  2340      2. It does no longer proceed strictly from left to right but may also
  2341         rotate premises to achieve further simplification.
  2342      For compatibility reasons there is now Asm_lr_simp_tac which is like the
  2343      old Asm_full_simp_tac in that it does not rotate premises.
  2344   2. The simplifier now knows a little bit about nat-arithmetic.
  2345 
  2346 * Classical reasoner: wrapper mechanism for the classical reasoner now
  2347 allows for selected deletion of wrappers, by introduction of names for
  2348 wrapper functionals.  This implies that addbefore, addSbefore,
  2349 addaltern, and addSaltern now take a pair (name, tactic) as argument,
  2350 and that adding two tactics with the same name overwrites the first
  2351 one (emitting a warning).
  2352   type wrapper = (int -> tactic) -> (int -> tactic)
  2353   setWrapper, setSWrapper, compWrapper and compSWrapper are replaced by
  2354   addWrapper, addSWrapper: claset * (string * wrapper) -> claset
  2355   delWrapper, delSWrapper: claset *  string            -> claset
  2356   getWrapper is renamed to appWrappers, getSWrapper to appSWrappers;
  2357 
  2358 * Classical reasoner: addbefore/addSbefore now have APPEND/ORELSE
  2359 semantics; addbefore now affects only the unsafe part of step_tac
  2360 etc.; this affects addss/auto_tac/force_tac, so EXISTING PROOFS MAY
  2361 FAIL, but proofs should be fixable easily, e.g. by replacing Auto_tac
  2362 by Force_tac;
  2363 
  2364 * Classical reasoner: setwrapper to setWrapper and compwrapper to
  2365 compWrapper; added safe wrapper (and access functions for it);
  2366 
  2367 * HOL/split_all_tac is now much faster and fails if there is nothing
  2368 to split.  Some EXISTING PROOFS MAY REQUIRE ADAPTION because the order
  2369 and the names of the automatically generated variables have changed.
  2370 split_all_tac has moved within claset() from unsafe wrappers to safe
  2371 wrappers, which means that !!-bound variables are split much more
  2372 aggressively, and safe_tac and clarify_tac now split such variables.
  2373 If this splitting is not appropriate, use delSWrapper "split_all_tac".
  2374 Note: the same holds for record_split_tac, which does the job of
  2375 split_all_tac for record fields.
  2376 
  2377 * HOL/Simplifier: Rewrite rules for case distinctions can now be added
  2378 permanently to the default simpset using Addsplits just like
  2379 Addsimps. They can be removed via Delsplits just like
  2380 Delsimps. Lower-case versions are also available.
  2381 
  2382 * HOL/Simplifier: The rule split_if is now part of the default
  2383 simpset. This means that the simplifier will eliminate all occurrences
  2384 of if-then-else in the conclusion of a goal. To prevent this, you can
  2385 either remove split_if completely from the default simpset by
  2386 `Delsplits [split_if]' or remove it in a specific call of the
  2387 simplifier using `... delsplits [split_if]'.  You can also add/delete
  2388 other case splitting rules to/from the default simpset: every datatype
  2389 generates suitable rules `split_t_case' and `split_t_case_asm' (where
  2390 t is the name of the datatype).
  2391 
  2392 * Classical reasoner / Simplifier combination: new force_tac (and
  2393 derivatives Force_tac, force) combines rewriting and classical
  2394 reasoning (and whatever other tools) similarly to auto_tac, but is
  2395 aimed to solve the given subgoal completely.
  2396 
  2397 
  2398 *** General ***
  2399 
  2400 * new top-level commands `Goal' and `Goalw' that improve upon `goal'
  2401 and `goalw': the theory is no longer needed as an explicit argument -
  2402 the current theory context is used; assumptions are no longer returned
  2403 at the ML-level unless one of them starts with ==> or !!; it is
  2404 recommended to convert to these new commands using isatool fixgoal
  2405 (backup your sources first!);
  2406 
  2407 * new top-level commands 'thm' and 'thms' for retrieving theorems from
  2408 the current theory context, and 'theory' to lookup stored theories;
  2409 
  2410 * new theory section 'locale' for declaring constants, assumptions and
  2411 definitions that have local scope;
  2412 
  2413 * new theory section 'nonterminals' for purely syntactic types;
  2414 
  2415 * new theory section 'setup' for generic ML setup functions
  2416 (e.g. package initialization);
  2417 
  2418 * the distribution now includes Isabelle icons: see
  2419 lib/logo/isabelle-{small,tiny}.xpm;
  2420 
  2421 * isatool install - install binaries with absolute references to
  2422 ISABELLE_HOME/bin;
  2423 
  2424 * isatool logo -- create instances of the Isabelle logo (as EPS);
  2425 
  2426 * print mode 'emacs' reserved for Isamode;
  2427 
  2428 * support multiple print (ast) translations per constant name;
  2429 
  2430 * theorems involving oracles are now printed with a suffixed [!];
  2431 
  2432 
  2433 *** HOL ***
  2434 
  2435 * there is now a tutorial on Isabelle/HOL (do 'isatool doc tutorial');
  2436 
  2437 * HOL/inductive package reorganized and improved: now supports mutual
  2438 definitions such as
  2439 
  2440   inductive EVEN ODD
  2441     intrs
  2442       null "0 : EVEN"
  2443       oddI "n : EVEN ==> Suc n : ODD"
  2444       evenI "n : ODD ==> Suc n : EVEN"
  2445 
  2446 new theorem list "elims" contains an elimination rule for each of the
  2447 recursive sets; inductive definitions now handle disjunctive premises
  2448 correctly (also ZF);
  2449 
  2450 INCOMPATIBILITIES: requires Inductive as an ancestor; component
  2451 "mutual_induct" no longer exists - the induction rule is always
  2452 contained in "induct";
  2453 
  2454 
  2455 * HOL/datatype package re-implemented and greatly improved: now
  2456 supports mutually recursive datatypes such as
  2457 
  2458   datatype
  2459     'a aexp = IF_THEN_ELSE ('a bexp) ('a aexp) ('a aexp)
  2460             | SUM ('a aexp) ('a aexp)
  2461             | DIFF ('a aexp) ('a aexp)
  2462             | NUM 'a
  2463   and
  2464     'a bexp = LESS ('a aexp) ('a aexp)
  2465             | AND ('a bexp) ('a bexp)
  2466             | OR ('a bexp) ('a bexp)
  2467 
  2468 as well as indirectly recursive datatypes such as
  2469 
  2470   datatype
  2471     ('a, 'b) term = Var 'a
  2472                   | App 'b ((('a, 'b) term) list)
  2473 
  2474 The new tactic  mutual_induct_tac [<var_1>, ..., <var_n>] i  performs
  2475 induction on mutually / indirectly recursive datatypes.
  2476 
  2477 Primrec equations are now stored in theory and can be accessed via
  2478 <function_name>.simps.
  2479 
  2480 INCOMPATIBILITIES:
  2481 
  2482   - Theories using datatypes must now have theory Datatype as an
  2483     ancestor.
  2484   - The specific <typename>.induct_tac no longer exists - use the
  2485     generic induct_tac instead.
  2486   - natE has been renamed to nat.exhaust - use exhaust_tac
  2487     instead of res_inst_tac ... natE. Note that the variable
  2488     names in nat.exhaust differ from the names in natE, this
  2489     may cause some "fragile" proofs to fail.
  2490   - The theorems split_<typename>_case and split_<typename>_case_asm
  2491     have been renamed to <typename>.split and <typename>.split_asm.
  2492   - Since default sorts of type variables are now handled correctly,
  2493     some datatype definitions may have to be annotated with explicit
  2494     sort constraints.
  2495   - Primrec definitions no longer require function name and type
  2496     of recursive argument.
  2497 
  2498 Consider using isatool fixdatatype to adapt your theories and proof
  2499 scripts to the new package (backup your sources first!).
  2500 
  2501 
  2502 * HOL/record package: considerably improved implementation; now
  2503 includes concrete syntax for record types, terms, updates; theorems
  2504 for surjective pairing and splitting !!-bound record variables; proof
  2505 support is as follows:
  2506 
  2507   1) standard conversions (selectors or updates applied to record
  2508 constructor terms) are part of the standard simpset;
  2509 
  2510   2) inject equations of the form ((x, y) = (x', y')) == x=x' & y=y' are
  2511 made part of standard simpset and claset via addIffs;
  2512 
  2513   3) a tactic for record field splitting (record_split_tac) is part of
  2514 the standard claset (addSWrapper);
  2515 
  2516 To get a better idea about these rules you may retrieve them via
  2517 something like 'thms "foo.simps"' or 'thms "foo.iffs"', where "foo" is
  2518 the name of your record type.
  2519 
  2520 The split tactic 3) conceptually simplifies by the following rule:
  2521 
  2522   "(!!x. PROP ?P x) == (!!a b. PROP ?P (a, b))"
  2523 
  2524 Thus any record variable that is bound by meta-all will automatically
  2525 blow up into some record constructor term, consequently the
  2526 simplifications of 1), 2) apply.  Thus force_tac, auto_tac etc. shall
  2527 solve record problems automatically.
  2528 
  2529 
  2530 * reorganized the main HOL image: HOL/Integ and String loaded by
  2531 default; theory Main includes everything;
  2532 
  2533 * automatic simplification of integer sums and comparisons, using cancellation;
  2534 
  2535 * added option_map_eq_Some and not_Some_eq to the default simpset and claset;
  2536 
  2537 * added disj_not1 = "(~P | Q) = (P --> Q)" to the default simpset;
  2538 
  2539 * many new identities for unions, intersections, set difference, etc.;
  2540 
  2541 * expand_if, expand_split, expand_sum_case and expand_nat_case are now
  2542 called split_if, split_split, split_sum_case and split_nat_case (to go
  2543 with add/delsplits);
  2544 
  2545 * HOL/Prod introduces simplification procedure unit_eq_proc rewriting
  2546 (?x::unit) = (); this is made part of the default simpset, which COULD
  2547 MAKE EXISTING PROOFS FAIL under rare circumstances (consider
  2548 'Delsimprocs [unit_eq_proc];' as last resort); also note that
  2549 unit_abs_eta_conv is added in order to counter the effect of
  2550 unit_eq_proc on (%u::unit. f u), replacing it by f rather than by
  2551 %u.f();
  2552 
  2553 * HOL/Fun INCOMPATIBILITY: `inj_onto' is now called `inj_on' (which
  2554 makes more sense);
  2555 
  2556 * HOL/Set INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
  2557   It and 'sym RS equals0D' are now in the default  claset, giving automatic
  2558   disjointness reasoning but breaking a few old proofs.
  2559 
  2560 * HOL/Relation INCOMPATIBILITY: renamed the relational operator r^-1
  2561 to 'converse' from 'inverse' (for compatibility with ZF and some
  2562 literature);
  2563 
  2564 * HOL/recdef can now declare non-recursive functions, with {} supplied as
  2565 the well-founded relation;
  2566 
  2567 * HOL/Set INCOMPATIBILITY: the complement of set A is now written -A instead of
  2568     Compl A.  The "Compl" syntax remains available as input syntax for this
  2569     release ONLY.
  2570 
  2571 * HOL/Update: new theory of function updates:
  2572     f(a:=b) == %x. if x=a then b else f x
  2573 may also be iterated as in f(a:=b,c:=d,...);
  2574 
  2575 * HOL/Vimage: new theory for inverse image of a function, syntax f-``B;
  2576 
  2577 * HOL/List:
  2578   - new function list_update written xs[i:=v] that updates the i-th
  2579     list position. May also be iterated as in xs[i:=a,j:=b,...].
  2580   - new function `upt' written [i..j(] which generates the list
  2581     [i,i+1,...,j-1], i.e. the upper bound is excluded. To include the upper
  2582     bound write [i..j], which is a shorthand for [i..j+1(].
  2583   - new lexicographic orderings and corresponding wellfoundedness theorems.
  2584 
  2585 * HOL/Arith:
  2586   - removed 'pred' (predecessor) function;
  2587   - generalized some theorems about n-1;
  2588   - many new laws about "div" and "mod";
  2589   - new laws about greatest common divisors (see theory ex/Primes);
  2590 
  2591 * HOL/Relation: renamed the relational operator r^-1 "converse"
  2592 instead of "inverse";
  2593 
  2594 * HOL/Induct/Multiset: a theory of multisets, including the wellfoundedness
  2595   of the multiset ordering;
  2596 
  2597 * directory HOL/Real: a construction of the reals using Dedekind cuts
  2598   (not included by default);
  2599 
  2600 * directory HOL/UNITY: Chandy and Misra's UNITY formalism;
  2601 
  2602 * directory HOL/Hoare: a new version of Hoare logic which permits many-sorted
  2603   programs, i.e. different program variables may have different types.
  2604 
  2605 * calling (stac rew i) now fails if "rew" has no effect on the goal
  2606   [previously, this check worked only if the rewrite rule was unconditional]
  2607   Now rew can involve either definitions or equalities (either == or =).
  2608 
  2609 
  2610 *** ZF ***
  2611 
  2612 * theory Main includes everything; INCOMPATIBILITY: theory ZF.thy contains
  2613   only the theorems proved on ZF.ML;
  2614 
  2615 * ZF INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
  2616   It and 'sym RS equals0D' are now in the default  claset, giving automatic
  2617   disjointness reasoning but breaking a few old proofs.
  2618 
  2619 * ZF/Update: new theory of function updates
  2620     with default rewrite rule  f(x:=y) ` z = if(z=x, y, f`z)
  2621   may also be iterated as in f(a:=b,c:=d,...);
  2622 
  2623 * in  let x=t in u(x), neither t nor u(x) has to be an FOL term.
  2624 
  2625 * calling (stac rew i) now fails if "rew" has no effect on the goal
  2626   [previously, this check worked only if the rewrite rule was unconditional]
  2627   Now rew can involve either definitions or equalities (either == or =).
  2628 
  2629 * case_tac provided for compatibility with HOL
  2630     (like the old excluded_middle_tac, but with subgoals swapped)
  2631 
  2632 
  2633 *** Internal programming interfaces ***
  2634 
  2635 * Pure: several new basic modules made available for general use, see
  2636 also src/Pure/README;
  2637 
  2638 * improved the theory data mechanism to support encapsulation (data
  2639 kind name replaced by private Object.kind, acting as authorization
  2640 key); new type-safe user interface via functor TheoryDataFun; generic
  2641 print_data function becomes basically useless;
  2642 
  2643 * removed global_names compatibility flag -- all theory declarations
  2644 are qualified by default;
  2645 
  2646 * module Pure/Syntax now offers quote / antiquote translation
  2647 functions (useful for Hoare logic etc. with implicit dependencies);
  2648 see HOL/ex/Antiquote for an example use;
  2649 
  2650 * Simplifier now offers conversions (asm_)(full_)rewrite: simpset ->
  2651 cterm -> thm;
  2652 
  2653 * new tactical CHANGED_GOAL for checking that a tactic modifies a
  2654 subgoal;
  2655 
  2656 * Display.print_goals function moved to Locale.print_goals;
  2657 
  2658 * standard print function for goals supports current_goals_markers
  2659 variable for marking begin of proof, end of proof, start of goal; the
  2660 default is ("", "", ""); setting current_goals_markers := ("<proof>",
  2661 "</proof>", "<goal>") causes SGML like tagged proof state printing,
  2662 for example;
  2663 
  2664 
  2665 
  2666 New in Isabelle98 (January 1998)
  2667 --------------------------------
  2668 
  2669 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  2670 
  2671 * changed lexical syntax of terms / types: dots made part of long
  2672 identifiers, e.g. "%x.x" no longer possible, should be "%x. x";
  2673 
  2674 * simpset (and claset) reference variable replaced by functions
  2675 simpset / simpset_ref;
  2676 
  2677 * no longer supports theory aliases (via merge) and non-trivial
  2678 implicit merge of thms' signatures;
  2679 
  2680 * most internal names of constants changed due to qualified names;
  2681 
  2682 * changed Pure/Sequence interface (see Pure/seq.ML);
  2683 
  2684 
  2685 *** General Changes ***
  2686 
  2687 * hierachically structured name spaces (for consts, types, axms, thms
  2688 etc.); new lexical class 'longid' (e.g. Foo.bar.x) may render much of
  2689 old input syntactically incorrect (e.g. "%x.x"); COMPATIBILITY:
  2690 isatool fixdots ensures space after dots (e.g. "%x. x"); set
  2691 long_names for fully qualified output names; NOTE: ML programs
  2692 (special tactics, packages etc.) referring to internal names may have
  2693 to be adapted to cope with fully qualified names; in case of severe
  2694 backward campatibility problems try setting 'global_names' at compile
  2695 time to have enrything declared within a flat name space; one may also
  2696 fine tune name declarations in theories via the 'global' and 'local'
  2697 section;
  2698 
  2699 * reimplemented the implicit simpset and claset using the new anytype
  2700 data filed in signatures; references simpset:simpset ref etc. are
  2701 replaced by functions simpset:unit->simpset and
  2702 simpset_ref:unit->simpset ref; COMPATIBILITY: use isatool fixclasimp
  2703 to patch your ML files accordingly;
  2704 
  2705 * HTML output now includes theory graph data for display with Java
  2706 applet or isatool browser; data generated automatically via isatool
  2707 usedir (see -i option, ISABELLE_USEDIR_OPTIONS);
  2708 
  2709 * defs may now be conditional; improved rewrite_goals_tac to handle
  2710 conditional equations;
  2711 
  2712 * defs now admits additional type arguments, using TYPE('a) syntax;
  2713 
  2714 * theory aliases via merge (e.g. M=A+B+C) no longer supported, always
  2715 creates a new theory node; implicit merge of thms' signatures is
  2716 restricted to 'trivial' ones; COMPATIBILITY: one may have to use
  2717 transfer:theory->thm->thm in (rare) cases;
  2718 
  2719 * improved handling of draft signatures / theories; draft thms (and
  2720 ctyps, cterms) are automatically promoted to real ones;
  2721 
  2722 * slightly changed interfaces for oracles: admit many per theory, named
  2723 (e.g. oracle foo = mlfun), additional name argument for invoke_oracle;
  2724 
  2725 * print_goals: optional output of const types (set show_consts and
  2726 show_types);
  2727 
  2728 * improved output of warnings (###) and errors (***);
  2729 
  2730 * subgoal_tac displays a warning if the new subgoal has type variables;
  2731 
  2732 * removed old README and Makefiles;
  2733 
  2734 * replaced print_goals_ref hook by print_current_goals_fn and result_error_fn;
  2735 
  2736 * removed obsolete init_pps and init_database;
  2737 
  2738 * deleted the obsolete tactical STATE, which was declared by
  2739     fun STATE tacfun st = tacfun st st;
  2740 
  2741 * cd and use now support path variables, e.g. $ISABELLE_HOME, or ~
  2742 (which abbreviates $HOME);
  2743 
  2744 * changed Pure/Sequence interface (see Pure/seq.ML); COMPATIBILITY:
  2745 use isatool fixseq to adapt your ML programs (this works for fully
  2746 qualified references to the Sequence structure only!);
  2747 
  2748 * use_thy no longer requires writable current directory; it always
  2749 reloads .ML *and* .thy file, if either one is out of date;
  2750 
  2751 
  2752 *** Classical Reasoner ***
  2753 
  2754 * Clarify_tac, clarify_tac, clarify_step_tac, Clarify_step_tac: new
  2755 tactics that use classical reasoning to simplify a subgoal without
  2756 splitting it into several subgoals;
  2757 
  2758 * Safe_tac: like safe_tac but uses the default claset;
  2759 
  2760 
  2761 *** Simplifier ***
  2762 
  2763 * added simplification meta rules:
  2764     (asm_)(full_)simplify: simpset -> thm -> thm;
  2765 
  2766 * simplifier.ML no longer part of Pure -- has to be loaded by object
  2767 logics (again);
  2768 
  2769 * added prems argument to simplification procedures;
  2770 
  2771 * HOL, FOL, ZF: added infix function `addsplits':
  2772   instead of `<simpset> setloop (split_tac <thms>)'
  2773   you can simply write `<simpset> addsplits <thms>'
  2774 
  2775 
  2776 *** Syntax ***
  2777 
  2778 * TYPE('a) syntax for type reflection terms;
  2779 
  2780 * no longer handles consts with name "" -- declare as 'syntax' instead;
  2781 
  2782 * pretty printer: changed order of mixfix annotation preference (again!);
  2783 
  2784 * Pure: fixed idt/idts vs. pttrn/pttrns syntactic categories;
  2785 
  2786 
  2787 *** HOL ***
  2788 
  2789 * HOL: there is a new splitter `split_asm_tac' that can be used e.g.
  2790   with `addloop' of the simplifier to faciliate case splitting in premises.
  2791 
  2792 * HOL/TLA: Stephan Merz's formalization of Lamport's Temporal Logic of Actions;
  2793 
  2794 * HOL/Auth: new protocol proofs including some for the Internet
  2795   protocol TLS;
  2796 
  2797 * HOL/Map: new theory of `maps' a la VDM;
  2798 
  2799 * HOL/simplifier: simplification procedures nat_cancel_sums for
  2800 cancelling out common nat summands from =, <, <= (in)equalities, or
  2801 differences; simplification procedures nat_cancel_factor for
  2802 cancelling common factor from =, <, <= (in)equalities over natural
  2803 sums; nat_cancel contains both kinds of procedures, it is installed by
  2804 default in Arith.thy -- this COULD MAKE EXISTING PROOFS FAIL;
  2805 
  2806 * HOL/simplifier: terms of the form
  2807   `? x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x)'  (or t=x)
  2808   are rewritten to
  2809   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t)',
  2810   and those of the form
  2811   `! x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x) --> R(x)'  (or t=x)
  2812   are rewritten to
  2813   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t) --> R(t)',
  2814 
  2815 * HOL/datatype
  2816   Each datatype `t' now comes with a theorem `split_t_case' of the form
  2817 
  2818   P(t_case f1 ... fn x) =
  2819      ( (!y1 ... ym1. x = C1 y1 ... ym1 --> P(f1 y1 ... ym1)) &
  2820         ...
  2821        (!y1 ... ymn. x = Cn y1 ... ymn --> P(f1 y1 ... ymn))
  2822      )
  2823 
  2824   and a theorem `split_t_case_asm' of the form
  2825 
  2826   P(t_case f1 ... fn x) =
  2827     ~( (? y1 ... ym1. x = C1 y1 ... ym1 & ~P(f1 y1 ... ym1)) |
  2828         ...
  2829        (? y1 ... ymn. x = Cn y1 ... ymn & ~P(f1 y1 ... ymn))
  2830      )
  2831   which can be added to a simpset via `addsplits'. The existing theorems
  2832   expand_list_case and expand_option_case have been renamed to
  2833   split_list_case and split_option_case.
  2834 
  2835 * HOL/Arithmetic:
  2836   - `pred n' is automatically converted to `n-1'.
  2837     Users are strongly encouraged not to use `pred' any longer,
  2838     because it will disappear altogether at some point.
  2839   - Users are strongly encouraged to write "0 < n" rather than
  2840     "n ~= 0". Theorems and proof tools have been modified towards this
  2841     `standard'.
  2842 
  2843 * HOL/Lists:
  2844   the function "set_of_list" has been renamed "set" (and its theorems too);
  2845   the function "nth" now takes its arguments in the reverse order and
  2846   has acquired the infix notation "!" as in "xs!n".
  2847 
  2848 * HOL/Set: UNIV is now a constant and is no longer translated to Compl{};
  2849 
  2850 * HOL/Set: The operator (UN x.B x) now abbreviates (UN x:UNIV. B x) and its
  2851   specialist theorems (like UN1_I) are gone.  Similarly for (INT x.B x);
  2852 
  2853 * HOL/record: extensible records with schematic structural subtyping
  2854 (single inheritance); EXPERIMENTAL version demonstrating the encoding,
  2855 still lacks various theorems and concrete record syntax;
  2856 
  2857 
  2858 *** HOLCF ***
  2859 
  2860 * removed "axioms" and "generated by" sections;
  2861 
  2862 * replaced "ops" section by extended "consts" section, which is capable of
  2863   handling the continuous function space "->" directly;
  2864 
  2865 * domain package:
  2866   . proves theorems immediately and stores them in the theory,
  2867   . creates hierachical name space,
  2868   . now uses normal mixfix annotations (instead of cinfix...),
  2869   . minor changes to some names and values (for consistency),
  2870   . e.g. cases -> casedist, dists_eq -> dist_eqs, [take_lemma] -> take_lemmas,
  2871   . separator between mutual domain defs: changed "," to "and",
  2872   . improved handling of sort constraints;  now they have to
  2873     appear on the left-hand side of the equations only;
  2874 
  2875 * fixed LAM <x,y,zs>.b syntax;
  2876 
  2877 * added extended adm_tac to simplifier in HOLCF -- can now discharge
  2878 adm (%x. P (t x)), where P is chainfinite and t continuous;
  2879 
  2880 
  2881 *** FOL and ZF ***
  2882 
  2883 * FOL: there is a new splitter `split_asm_tac' that can be used e.g.
  2884   with `addloop' of the simplifier to faciliate case splitting in premises.
  2885 
  2886 * qed_spec_mp, qed_goal_spec_mp, qed_goalw_spec_mp are available, as
  2887 in HOL, they strip ALL and --> from proved theorems;
  2888 
  2889 
  2890 
  2891 New in Isabelle94-8 (May 1997)
  2892 ------------------------------
  2893 
  2894 *** General Changes ***
  2895 
  2896 * new utilities to build / run / maintain Isabelle etc. (in parts
  2897 still somewhat experimental); old Makefiles etc. still functional;
  2898 
  2899 * new 'Isabelle System Manual';
  2900 
  2901 * INSTALL text, together with ./configure and ./build scripts;
  2902 
  2903 * reimplemented type inference for greater efficiency, better error
  2904 messages and clean internal interface;
  2905 
  2906 * prlim command for dealing with lots of subgoals (an easier way of
  2907 setting goals_limit);
  2908 
  2909 
  2910 *** Syntax ***
  2911 
  2912 * supports alternative (named) syntax tables (parser and pretty
  2913 printer); internal interface is provided by add_modesyntax(_i);
  2914 
  2915 * Pure, FOL, ZF, HOL, HOLCF now support symbolic input and output; to
  2916 be used in conjunction with the Isabelle symbol font; uses the
  2917 "symbols" syntax table;
  2918 
  2919 * added token_translation interface (may translate name tokens in
  2920 arbitrary ways, dependent on their type (free, bound, tfree, ...) and
  2921 the current print_mode); IMPORTANT: user print translation functions
  2922 are responsible for marking newly introduced bounds
  2923 (Syntax.mark_boundT);
  2924 
  2925 * token translations for modes "xterm" and "xterm_color" that display
  2926 names in bold, underline etc. or colors (which requires a color
  2927 version of xterm);
  2928 
  2929 * infixes may now be declared with names independent of their syntax;
  2930 
  2931 * added typed_print_translation (like print_translation, but may
  2932 access type of constant);
  2933 
  2934 
  2935 *** Classical Reasoner ***
  2936 
  2937 Blast_tac: a new tactic!  It is often more powerful than fast_tac, but has
  2938 some limitations.  Blast_tac...
  2939   + ignores addss, addbefore, addafter; this restriction is intrinsic
  2940   + ignores elimination rules that don't have the correct format
  2941         (the conclusion MUST be a formula variable)
  2942   + ignores types, which can make HOL proofs fail
  2943   + rules must not require higher-order unification, e.g. apply_type in ZF
  2944     [message "Function Var's argument not a bound variable" relates to this]
  2945   + its proof strategy is more general but can actually be slower
  2946 
  2947 * substitution with equality assumptions no longer permutes other
  2948 assumptions;
  2949 
  2950 * minor changes in semantics of addafter (now called addaltern); renamed
  2951 setwrapper to setWrapper and compwrapper to compWrapper; added safe wrapper
  2952 (and access functions for it);
  2953 
  2954 * improved combination of classical reasoner and simplifier:
  2955   + functions for handling clasimpsets
  2956   + improvement of addss: now the simplifier is called _after_ the
  2957     safe steps.
  2958   + safe variant of addss called addSss: uses safe simplifications
  2959     _during_ the safe steps. It is more complete as it allows multiple
  2960     instantiations of unknowns (e.g. with slow_tac).
  2961 
  2962 *** Simplifier ***
  2963 
  2964 * added interface for simplification procedures (functions that
  2965 produce *proven* rewrite rules on the fly, depending on current
  2966 redex);
  2967 
  2968 * ordering on terms as parameter (used for ordered rewriting);
  2969 
  2970 * new functions delcongs, deleqcongs, and Delcongs. richer rep_ss;
  2971 
  2972 * the solver is now split into a safe and an unsafe part.
  2973 This should be invisible for the normal user, except that the
  2974 functions setsolver and addsolver have been renamed to setSolver and
  2975 addSolver; added safe_asm_full_simp_tac;
  2976 
  2977 
  2978 *** HOL ***
  2979 
  2980 * a generic induction tactic `induct_tac' which works for all datatypes and
  2981 also for type `nat';
  2982 
  2983 * a generic case distinction tactic `exhaust_tac' which works for all
  2984 datatypes and also for type `nat';
  2985 
  2986 * each datatype comes with a function `size';
  2987 
  2988 * patterns in case expressions allow tuple patterns as arguments to
  2989 constructors, for example `case x of [] => ... | (x,y,z)#ps => ...';
  2990 
  2991 * primrec now also works with type nat;
  2992 
  2993 * recdef: a new declaration form, allows general recursive functions to be
  2994 defined in theory files.  See HOL/ex/Fib, HOL/ex/Primes, HOL/Subst/Unify.
  2995 
  2996 * the constant for negation has been renamed from "not" to "Not" to
  2997 harmonize with FOL, ZF, LK, etc.;
  2998 
  2999 * HOL/ex/LFilter theory of a corecursive "filter" functional for
  3000 infinite lists;
  3001 
  3002 * HOL/Modelcheck demonstrates invocation of model checker oracle;
  3003 
  3004 * HOL/ex/Ring.thy declares cring_simp, which solves equational
  3005 problems in commutative rings, using axiomatic type classes for + and *;
  3006 
  3007 * more examples in HOL/MiniML and HOL/Auth;
  3008 
  3009 * more default rewrite rules for quantifiers, union/intersection;
  3010 
  3011 * a new constant `arbitrary == @x.False';
  3012 
  3013 * HOLCF/IOA replaces old HOL/IOA;
  3014 
  3015 * HOLCF changes: derived all rules and arities
  3016   + axiomatic type classes instead of classes
  3017   + typedef instead of faking type definitions
  3018   + eliminated the internal constants less_fun, less_cfun, UU_fun, UU_cfun etc.
  3019   + new axclasses cpo, chfin, flat with flat < chfin < pcpo < cpo < po
  3020   + eliminated the types void, one, tr
  3021   + use unit lift and bool lift (with translations) instead of one and tr
  3022   + eliminated blift from Lift3.thy (use Def instead of blift)
  3023   all eliminated rules are derived as theorems --> no visible changes ;
  3024 
  3025 
  3026 *** ZF ***
  3027 
  3028 * ZF now has Fast_tac, Simp_tac and Auto_tac.  Union_iff is a now a default
  3029 rewrite rule; this may affect some proofs.  eq_cs is gone but can be put back
  3030 as ZF_cs addSIs [equalityI];
  3031 
  3032 
  3033 
  3034 New in Isabelle94-7 (November 96)
  3035 ---------------------------------
  3036 
  3037 * allowing negative levels (as offsets) in prlev and choplev;
  3038 
  3039 * super-linear speedup for large simplifications;
  3040 
  3041 * FOL, ZF and HOL now use miniscoping: rewriting pushes
  3042 quantifications in as far as possible (COULD MAKE EXISTING PROOFS
  3043 FAIL); can suppress it using the command Delsimps (ex_simps @
  3044 all_simps); De Morgan laws are also now included, by default;
  3045 
  3046 * improved printing of ==>  :  ~:
  3047 
  3048 * new object-logic "Sequents" adds linear logic, while replacing LK
  3049 and Modal (thanks to Sara Kalvala);
  3050 
  3051 * HOL/Auth: correctness proofs for authentication protocols;
  3052 
  3053 * HOL: new auto_tac combines rewriting and classical reasoning (many
  3054 examples on HOL/Auth);
  3055 
  3056 * HOL: new command AddIffs for declaring theorems of the form P=Q to
  3057 the rewriter and classical reasoner simultaneously;
  3058 
  3059 * function uresult no longer returns theorems in "standard" format;
  3060 regain previous version by: val uresult = standard o uresult;
  3061 
  3062 
  3063 
  3064 New in Isabelle94-6
  3065 -------------------
  3066 
  3067 * oracles -- these establish an interface between Isabelle and trusted
  3068 external reasoners, which may deliver results as theorems;
  3069 
  3070 * proof objects (in particular record all uses of oracles);
  3071 
  3072 * Simp_tac, Fast_tac, etc. that refer to implicit simpset / claset;
  3073 
  3074 * "constdefs" section in theory files;
  3075 
  3076 * "primrec" section (HOL) no longer requires names;
  3077 
  3078 * internal type "tactic" now simply "thm -> thm Sequence.seq";
  3079 
  3080 
  3081 
  3082 New in Isabelle94-5
  3083 -------------------
  3084 
  3085 * reduced space requirements;
  3086 
  3087 * automatic HTML generation from theories;
  3088 
  3089 * theory files no longer require "..." (quotes) around most types;
  3090 
  3091 * new examples, including two proofs of the Church-Rosser theorem;
  3092 
  3093 * non-curried (1994) version of HOL is no longer distributed;
  3094 
  3095 
  3096 
  3097 New in Isabelle94-4
  3098 -------------------
  3099 
  3100 * greatly reduced space requirements;
  3101 
  3102 * theory files (.thy) no longer require \...\ escapes at line breaks;
  3103 
  3104 * searchable theorem database (see the section "Retrieving theorems" on
  3105 page 8 of the Reference Manual);
  3106 
  3107 * new examples, including Grabczewski's monumental case study of the
  3108 Axiom of Choice;
  3109 
  3110 * The previous version of HOL renamed to Old_HOL;
  3111 
  3112 * The new version of HOL (previously called CHOL) uses a curried syntax
  3113 for functions.  Application looks like f a b instead of f(a,b);
  3114 
  3115 * Mutually recursive inductive definitions finally work in HOL;
  3116 
  3117 * In ZF, pattern-matching on tuples is now available in all abstractions and
  3118 translates to the operator "split";
  3119 
  3120 
  3121 
  3122 New in Isabelle94-3
  3123 -------------------
  3124 
  3125 * new infix operator, addss, allowing the classical reasoner to
  3126 perform simplification at each step of its search.  Example:
  3127         fast_tac (cs addss ss)
  3128 
  3129 * a new logic, CHOL, the same as HOL, but with a curried syntax
  3130 for functions.  Application looks like f a b instead of f(a,b).  Also pairs
  3131 look like (a,b) instead of <a,b>;
  3132 
  3133 * PLEASE NOTE: CHOL will eventually replace HOL!
  3134 
  3135 * In CHOL, pattern-matching on tuples is now available in all abstractions.
  3136 It translates to the operator "split".  A new theory of integers is available;
  3137 
  3138 * In ZF, integer numerals now denote two's-complement binary integers.
  3139 Arithmetic operations can be performed by rewriting.  See ZF/ex/Bin.ML;
  3140 
  3141 * Many new examples: I/O automata, Church-Rosser theorem, equivalents
  3142 of the Axiom of Choice;
  3143 
  3144 
  3145 
  3146 New in Isabelle94-2
  3147 -------------------
  3148 
  3149 * Significantly faster resolution;
  3150 
  3151 * the different sections in a .thy file can now be mixed and repeated
  3152 freely;
  3153 
  3154 * Database of theorems for FOL, HOL and ZF.  New
  3155 commands including qed, qed_goal and bind_thm store theorems in the database.
  3156 
  3157 * Simple database queries: return a named theorem (get_thm) or all theorems of
  3158 a given theory (thms_of), or find out what theory a theorem was proved in
  3159 (theory_of_thm);
  3160 
  3161 * Bugs fixed in the inductive definition and datatype packages;
  3162 
  3163 * The classical reasoner provides deepen_tac and depth_tac, making FOL_dup_cs
  3164 and HOL_dup_cs obsolete;
  3165 
  3166 * Syntactic ambiguities caused by the new treatment of syntax in Isabelle94-1
  3167 have been removed;
  3168 
  3169 * Simpler definition of function space in ZF;
  3170 
  3171 * new results about cardinal and ordinal arithmetic in ZF;
  3172 
  3173 * 'subtype' facility in HOL for introducing new types as subsets of existing
  3174 types;
  3175 
  3176 
  3177 $Id$