NEWS
author wenzelm
Wed Jul 13 16:07:26 2005 +0200 (2005-07-13)
changeset 16805 fadf80952202
parent 16799 978dcf30c3dd
child 16856 6468a5d6a16e
permissions -rw-r--r--
open ReconPrelim Recon_Transfer;
     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 * Isar session: The initial use of ROOT.ML is now always timed,
   420 i.e. the log will show the actual process times, in contrast to the
   421 elapsed wall-clock time that the outer shell wrapper produces.
   422  
   423 * Pure: structure OrdList (cf. Pure/General/ord_list.ML) provides a
   424 reasonably efficient light-weight implementation of sets as lists.
   425 
   426 * Pure: more efficient orders for basic syntactic entities: added
   427 fast_string_ord, fast_indexname_ord, fast_term_ord; changed sort_ord
   428 and typ_ord to use fast_string_ord and fast_indexname_ord (term_ord is
   429 NOT affected); structures Symtab, Vartab, Typtab, Termtab use the fast
   430 orders now -- potential INCOMPATIBILITY for code that depends on a
   431 particular order for Symtab.keys, Symtab.dest, etc. (consider using
   432 Library.sort_strings on result).
   433 
   434 * Pure: name spaces have been refined, with significant changes of the
   435 internal interfaces -- INCOMPATIBILITY.  Renamed cond_extern(_table)
   436 to extern(_table).  The plain name entry path is superceded by a
   437 general 'naming' context, which also includes the 'policy' to produce
   438 a fully qualified name and external accesses of a fully qualified
   439 name; NameSpace.extend is superceded by context dependent
   440 Sign.declare_name.  Several theory and proof context operations modify
   441 the naming context.  Especially note Theory.restore_naming and
   442 ProofContext.restore_naming to get back to a sane state; note that
   443 Theory.add_path is no longer sufficient to recover from
   444 Theory.absolute_path in particular.
   445 
   446 * Pure: new flags short_names (default false) and unique_names
   447 (default true) for controlling output of qualified names.  If
   448 short_names is set, names are printed unqualified.  If unique_names is
   449 reset, the name prefix is reduced to the minimum required to achieve
   450 the original result when interning again, even if there is an overlap
   451 with earlier declarations.
   452 
   453 * Pure/TheoryDataFun: change of the argument structure; 'prep_ext' is
   454 now 'extend', and 'merge' gets an additional Pretty.pp argument
   455 (useful for printing error messages).  INCOMPATIBILITY.
   456 
   457 * Pure: major reorganization of the theory context.  Type Sign.sg and
   458 Theory.theory are now identified, referring to the universal
   459 Context.theory (see Pure/context.ML).  Actual signature and theory
   460 content is managed as theory data.  The old code and interfaces were
   461 spread over many files and structures; the new arrangement introduces
   462 considerable INCOMPATIBILITY to gain more clarity:
   463 
   464   Context -- theory management operations (name, identity, inclusion,
   465     parents, ancestors, merge, etc.), plus generic theory data;
   466 
   467   Sign -- logical signature and syntax operations (declaring consts,
   468     types, etc.), plus certify/read for common entities;
   469 
   470   Theory -- logical theory operations (stating axioms, definitions,
   471     oracles), plus a copy of logical signature operations (consts,
   472     types, etc.); also a few basic management operations (Theory.copy,
   473     Theory.merge, etc.)
   474 
   475 The most basic sign_of operations (Theory.sign_of, Thm.sign_of_thm
   476 etc.) as well as the sign field in Thm.rep_thm etc. have been retained
   477 for convenience -- they merely return the theory.
   478 
   479 * Pure: the Isar proof context type is already defined early in Pure
   480 as Context.proof (note that ProofContext.context and Proof.context are
   481 aliases, where the latter is the preferred name).  This enables other
   482 Isabelle components to refer to that type even before Isar is present.
   483 
   484 * Pure/sign/theory: discontinued named name spaces (i.e. classK,
   485 typeK, constK, axiomK, oracleK), but provide explicit operations for
   486 any of these kinds.  For example, Sign.intern typeK is now
   487 Sign.intern_type, Theory.hide_space Sign.typeK is now
   488 Theory.hide_types.  Also note that former
   489 Theory.hide_classes/types/consts are now
   490 Theory.hide_classes_i/types_i/consts_i, while the non '_i' versions
   491 internalize their arguments!  INCOMPATIBILITY.
   492 
   493 * Pure: get_thm interface (of PureThy and ProofContext) expects
   494 datatype thmref (with constructors Name and NameSelection) instead of
   495 plain string -- INCOMPATIBILITY;
   496 
   497 * Pure: cases produced by proof methods specify options, where NONE
   498 means to remove case bindings -- INCOMPATIBILITY in
   499 (RAW_)METHOD_CASES.
   500 
   501 * Pure: the following operations retrieve axioms or theorems from a
   502 theory node or theory hierarchy, respectively:
   503 
   504   Theory.axioms_of: theory -> (string * term) list
   505   Theory.all_axioms_of: theory -> (string * term) list
   506   PureThy.thms_of: theory -> (string * thm) list
   507   PureThy.all_thms_of: theory -> (string * thm) list
   508 
   509 * Pure: print_tac now outputs the goal through the trace channel.
   510 
   511 * Provers: Simplifier and Classical Reasoner now support proof context
   512 dependent plug-ins (simprocs, solvers, wrappers etc.).  These extra
   513 components are stored in the theory and patched into the
   514 simpset/claset when used in an Isar proof context.  Context dependent
   515 components are maintained by the following theory operations:
   516 
   517   Simplifier.add_context_simprocs
   518   Simplifier.del_context_simprocs
   519   Simplifier.set_context_subgoaler
   520   Simplifier.reset_context_subgoaler
   521   Simplifier.add_context_looper
   522   Simplifier.del_context_looper
   523   Simplifier.add_context_unsafe_solver
   524   Simplifier.add_context_safe_solver
   525 
   526   Classical.add_context_safe_wrapper
   527   Classical.del_context_safe_wrapper
   528   Classical.add_context_unsafe_wrapper
   529   Classical.del_context_unsafe_wrapper
   530 
   531 IMPORTANT NOTE: proof tools (methods etc.) need to use
   532 local_simpset_of and local_claset_of to instead of the primitive
   533 Simplifier.get_local_simpset and Classical.get_local_claset,
   534 respectively, in order to see the context dependent fields!
   535 
   536 * File.sysify_path and File.quote_sysify path have been replaced by
   537 File.platform_path and File.shell_path (with appropriate hooks).  This
   538 provides a clean interface for unusual systems where the internal and
   539 external process view of file names are different.
   540 
   541 
   542 *** System ***
   543 
   544 * Allow symlinks to all proper Isabelle executables (Isabelle,
   545 isabelle, isatool etc.).
   546 
   547 * ISABELLE_DOC_FORMAT setting specifies preferred document format (for
   548 isatool doc, isatool mkdir, display_drafts etc.).
   549 
   550 * isatool usedir: option -f allows specification of the ML file to be
   551 used by Isabelle; default is ROOT.ML.
   552 
   553 * New isatool version outputs the version identifier of the Isabelle
   554 distribution being used.
   555 
   556 * HOL: new isatool dimacs2hol converts files in DIMACS CNF format
   557 (containing Boolean satisfiability problems) into Isabelle/HOL
   558 theories.
   559 
   560 
   561 
   562 New in Isabelle2004 (April 2004)
   563 --------------------------------
   564 
   565 *** General ***
   566 
   567 * Provers/order.ML:  new efficient reasoner for partial and linear orders.
   568   Replaces linorder.ML.
   569 
   570 * Pure: Greek letters (except small lambda, \<lambda>), as well as Gothic
   571   (\<aa>...\<zz>\<AA>...\<ZZ>), calligraphic (\<A>...\<Z>), and Euler
   572   (\<a>...\<z>), are now considered normal letters, and can therefore
   573   be used anywhere where an ASCII letter (a...zA...Z) has until
   574   now. COMPATIBILITY: This obviously changes the parsing of some
   575   terms, especially where a symbol has been used as a binder, say
   576   '\<Pi>x. ...', which is now a type error since \<Pi>x will be parsed
   577   as an identifier.  Fix it by inserting a space around former
   578   symbols.  Call 'isatool fixgreek' to try to fix parsing errors in
   579   existing theory and ML files.
   580 
   581 * Pure: Macintosh and Windows line-breaks are now allowed in theory files.
   582 
   583 * Pure: single letter sub/superscripts (\<^isub> and \<^isup>) are now
   584   allowed in identifiers. Similar to Greek letters \<^isub> is now considered
   585   a normal (but invisible) letter. For multiple letter subscripts repeat
   586   \<^isub> like this: x\<^isub>1\<^isub>2.
   587 
   588 * Pure: There are now sub-/superscripts that can span more than one
   589   character. Text between \<^bsub> and \<^esub> is set in subscript in
   590   ProofGeneral and LaTeX, text between \<^bsup> and \<^esup> in
   591   superscript. The new control characters are not identifier parts.
   592 
   593 * Pure: Control-symbols of the form \<^raw:...> will literally print the
   594   content of "..." to the latex file instead of \isacntrl... . The "..."
   595   may consist of any printable characters excluding the end bracket >.
   596 
   597 * Pure: Using new Isar command "finalconsts" (or the ML functions
   598   Theory.add_finals or Theory.add_finals_i) it is now possible to
   599   declare constants "final", which prevents their being given a definition
   600   later.  It is useful for constants whose behaviour is fixed axiomatically
   601   rather than definitionally, such as the meta-logic connectives.
   602 
   603 * Pure: 'instance' now handles general arities with general sorts
   604   (i.e. intersections of classes),
   605 
   606 * Presentation: generated HTML now uses a CSS style sheet to make layout
   607   (somewhat) independent of content. It is copied from lib/html/isabelle.css.
   608   It can be changed to alter the colors/layout of generated pages.
   609 
   610 
   611 *** Isar ***
   612 
   613 * Tactic emulation methods rule_tac, erule_tac, drule_tac, frule_tac,
   614   cut_tac, subgoal_tac and thin_tac:
   615   - Now understand static (Isar) contexts.  As a consequence, users of Isar
   616     locales are no longer forced to write Isar proof scripts.
   617     For details see Isar Reference Manual, paragraph 4.3.2: Further tactic
   618     emulations.
   619   - INCOMPATIBILITY: names of variables to be instantiated may no
   620     longer be enclosed in quotes.  Instead, precede variable name with `?'.
   621     This is consistent with the instantiation attribute "where".
   622 
   623 * Attributes "where" and "of":
   624   - Now take type variables of instantiated theorem into account when reading
   625     the instantiation string.  This fixes a bug that caused instantiated
   626     theorems to have too special types in some circumstances.
   627   - "where" permits explicit instantiations of type variables.
   628 
   629 * Calculation commands "moreover" and "also" no longer interfere with
   630   current facts ("this"), admitting arbitrary combinations with "then"
   631   and derived forms.
   632 
   633 * Locales:
   634   - Goal statements involving the context element "includes" no longer
   635     generate theorems with internal delta predicates (those ending on
   636     "_axioms") in the premise.
   637     Resolve particular premise with <locale>.intro to obtain old form.
   638   - Fixed bug in type inference ("unify_frozen") that prevented mix of target
   639     specification and "includes" elements in goal statement.
   640   - Rule sets <locale>.intro and <locale>.axioms no longer declared as
   641     [intro?] and [elim?] (respectively) by default.
   642   - Experimental command for instantiation of locales in proof contexts:
   643         instantiate <label>[<attrs>]: <loc>
   644     Instantiates locale <loc> and adds all its theorems to the current context
   645     taking into account their attributes.  Label and attrs are optional
   646     modifiers, like in theorem declarations.  If present, names of
   647     instantiated theorems are qualified with <label>, and the attributes
   648     <attrs> are applied after any attributes these theorems might have already.
   649       If the locale has assumptions, a chained fact of the form
   650     "<loc> t1 ... tn" is expected from which instantiations of the parameters
   651     are derived.  The command does not support old-style locales declared
   652     with "locale (open)".
   653       A few (very simple) examples can be found in FOL/ex/LocaleInst.thy.
   654 
   655 * HOL: Tactic emulation methods induct_tac and case_tac understand static
   656   (Isar) contexts.
   657 
   658 
   659 *** HOL ***
   660 
   661 * Proof import: new image HOL4 contains the imported library from
   662   the HOL4 system with about 2500 theorems. It is imported by
   663   replaying proof terms produced by HOL4 in Isabelle. The HOL4 image
   664   can be used like any other Isabelle image.  See
   665   HOL/Import/HOL/README for more information.
   666 
   667 * Simplifier:
   668   - Much improved handling of linear and partial orders.
   669     Reasoners for linear and partial orders are set up for type classes
   670     "linorder" and "order" respectively, and are added to the default simpset
   671     as solvers.  This means that the simplifier can build transitivity chains
   672     to solve goals from the assumptions.
   673   - INCOMPATIBILITY: old proofs break occasionally.  Typically, applications
   674     of blast or auto after simplification become unnecessary because the goal
   675     is solved by simplification already.
   676 
   677 * Numerics: new theory Ring_and_Field contains over 250 basic numerical laws,
   678     all proved in axiomatic type classes for semirings, rings and fields.
   679 
   680 * Numerics:
   681   - Numeric types (nat, int, and in HOL-Complex rat, real, complex, etc.) are
   682     now formalized using the Ring_and_Field theory mentioned above.
   683   - INCOMPATIBILITY: simplification and arithmetic behaves somewhat differently
   684     than before, because now they are set up once in a generic manner.
   685   - INCOMPATIBILITY: many type-specific arithmetic laws have gone.
   686     Look for the general versions in Ring_and_Field (and Power if they concern
   687     exponentiation).
   688 
   689 * Type "rat" of the rational numbers is now available in HOL-Complex.
   690 
   691 * Records:
   692   - Record types are now by default printed with their type abbreviation
   693     instead of the list of all field types. This can be configured via
   694     the reference "print_record_type_abbr".
   695   - Simproc "record_upd_simproc" for simplification of multiple updates added
   696     (not enabled by default).
   697   - Simproc "record_ex_sel_eq_simproc" to simplify EX x. sel r = x resp.
   698     EX x. x = sel r to True (not enabled by default).
   699   - Tactic "record_split_simp_tac" to split and simplify records added.
   700 
   701 * 'specification' command added, allowing for definition by
   702   specification.  There is also an 'ax_specification' command that
   703   introduces the new constants axiomatically.
   704 
   705 * arith(_tac) is now able to generate counterexamples for reals as well.
   706 
   707 * HOL-Algebra: new locale "ring" for non-commutative rings.
   708 
   709 * HOL-ex: InductiveInvariant_examples illustrates advanced recursive function
   710   definitions, thanks to Sava Krsti\'{c} and John Matthews.
   711 
   712 * HOL-Matrix: a first theory for matrices in HOL with an application of
   713   matrix theory to linear programming.
   714 
   715 * Unions and Intersections:
   716   The latex output syntax of UN and INT has been changed
   717   from "\Union x \in A. B" to "\Union_{x \in A} B"
   718   i.e. the index formulae has become a subscript.
   719   Similarly for "\Union x. B", and for \Inter instead of \Union.
   720 
   721 * Unions and Intersections over Intervals:
   722   There is new short syntax "UN i<=n. A" for "UN i:{0..n}. A". There is
   723   also an x-symbol version with subscripts "\<Union>\<^bsub>i <= n\<^esub>. A"
   724   like in normal math, and corresponding versions for < and for intersection.
   725 
   726 * HOL/List: Ordering "lexico" is renamed "lenlex" and the standard
   727   lexicographic dictonary ordering has been added as "lexord".
   728 
   729 * ML: the legacy theory structures Int and List have been removed. They had
   730   conflicted with ML Basis Library structures having the same names.
   731 
   732 * 'refute' command added to search for (finite) countermodels.  Only works
   733   for a fragment of HOL.  The installation of an external SAT solver is
   734   highly recommended.  See "HOL/Refute.thy" for details.
   735 
   736 * 'quickcheck' command: Allows to find counterexamples by evaluating
   737   formulae under an assignment of free variables to random values.
   738   In contrast to 'refute', it can deal with inductive datatypes,
   739   but cannot handle quantifiers. See "HOL/ex/Quickcheck_Examples.thy"
   740   for examples.
   741 
   742 
   743 *** HOLCF ***
   744 
   745 * Streams now come with concatenation and are part of the HOLCF image
   746 
   747 
   748 
   749 New in Isabelle2003 (May 2003)
   750 ------------------------------
   751 
   752 *** General ***
   753 
   754 * Provers/simplifier:
   755 
   756   - Completely reimplemented method simp (ML: Asm_full_simp_tac):
   757     Assumptions are now subject to complete mutual simplification,
   758     not just from left to right. The simplifier now preserves
   759     the order of assumptions.
   760 
   761     Potential INCOMPATIBILITY:
   762 
   763     -- simp sometimes diverges where the old version did
   764        not, e.g. invoking simp on the goal
   765 
   766         [| P (f x); y = x; f x = f y |] ==> Q
   767 
   768        now gives rise to the infinite reduction sequence
   769 
   770         P(f x) --(f x = f y)--> P(f y) --(y = x)--> P(f x) --(f x = f y)--> ...
   771 
   772        Using "simp (asm_lr)" (ML: Asm_lr_simp_tac) instead often solves this
   773        kind of problem.
   774 
   775     -- Tactics combining classical reasoner and simplification (such as auto)
   776        are also affected by this change, because many of them rely on
   777        simp. They may sometimes diverge as well or yield a different numbers
   778        of subgoals. Try to use e.g. force, fastsimp, or safe instead of auto
   779        in case of problems. Sometimes subsequent calls to the classical
   780        reasoner will fail because a preceeding call to the simplifier too
   781        eagerly simplified the goal, e.g. deleted redundant premises.
   782 
   783   - The simplifier trace now shows the names of the applied rewrite rules
   784 
   785   - You can limit the number of recursive invocations of the simplifier
   786     during conditional rewriting (where the simplifie tries to solve the
   787     conditions before applying the rewrite rule):
   788     ML "simp_depth_limit := n"
   789     where n is an integer. Thus you can force termination where previously
   790     the simplifier would diverge.
   791 
   792   - Accepts free variables as head terms in congruence rules.  Useful in Isar.
   793 
   794   - No longer aborts on failed congruence proof.  Instead, the
   795     congruence is ignored.
   796 
   797 * Pure: New generic framework for extracting programs from constructive
   798   proofs. See HOL/Extraction.thy for an example instantiation, as well
   799   as HOL/Extraction for some case studies.
   800 
   801 * Pure: The main goal of the proof state is no longer shown by default, only
   802 the subgoals. This behaviour is controlled by a new flag.
   803    PG menu: Isabelle/Isar -> Settings -> Show Main Goal
   804 (ML: Proof.show_main_goal).
   805 
   806 * Pure: You can find all matching introduction rules for subgoal 1, i.e. all
   807 rules whose conclusion matches subgoal 1:
   808       PG menu: Isabelle/Isar -> Show me -> matching rules
   809 The rules are ordered by how closely they match the subgoal.
   810 In particular, rules that solve a subgoal outright are displayed first
   811 (or rather last, the way they are printed).
   812 (ML: ProofGeneral.print_intros())
   813 
   814 * Pure: New flag trace_unify_fail causes unification to print
   815 diagnostic information (PG: in trace buffer) when it fails. This is
   816 useful for figuring out why single step proofs like rule, erule or
   817 assumption failed.
   818 
   819 * Pure: Locale specifications now produce predicate definitions
   820 according to the body of text (covering assumptions modulo local
   821 definitions); predicate "loc_axioms" covers newly introduced text,
   822 while "loc" is cumulative wrt. all included locale expressions; the
   823 latter view is presented only on export into the global theory
   824 context; potential INCOMPATIBILITY, use "(open)" option to fall back
   825 on the old view without predicates;
   826 
   827 * Pure: predefined locales "var" and "struct" are useful for sharing
   828 parameters (as in CASL, for example); just specify something like
   829 ``var x + var y + struct M'' as import;
   830 
   831 * Pure: improved thms_containing: proper indexing of facts instead of
   832 raw theorems; check validity of results wrt. current name space;
   833 include local facts of proof configuration (also covers active
   834 locales), cover fixed variables in index; may use "_" in term
   835 specification; an optional limit for the number of printed facts may
   836 be given (the default is 40);
   837 
   838 * Pure: disallow duplicate fact bindings within new-style theory files
   839 (batch-mode only);
   840 
   841 * Provers: improved induct method: assumptions introduced by case
   842 "foo" are split into "foo.hyps" (from the rule) and "foo.prems" (from
   843 the goal statement); "foo" still refers to all facts collectively;
   844 
   845 * Provers: the function blast.overloaded has been removed: all constants
   846 are regarded as potentially overloaded, which improves robustness in exchange
   847 for slight decrease in efficiency;
   848 
   849 * Provers/linorder: New generic prover for transitivity reasoning over
   850 linear orders.  Note: this prover is not efficient!
   851 
   852 * Isar: preview of problems to finish 'show' now produce an error
   853 rather than just a warning (in interactive mode);
   854 
   855 
   856 *** HOL ***
   857 
   858 * arith(_tac)
   859 
   860  - Produces a counter example if it cannot prove a goal.
   861    Note that the counter example may be spurious if the goal is not a formula
   862    of quantifier-free linear arithmetic.
   863    In ProofGeneral the counter example appears in the trace buffer.
   864 
   865  - Knows about div k and mod k where k is a numeral of type nat or int.
   866 
   867  - Calls full Presburger arithmetic (by Amine Chaieb) if quantifier-free
   868    linear arithmetic fails. This takes account of quantifiers and divisibility.
   869    Presburger arithmetic can also be called explicitly via presburger(_tac).
   870 
   871 * simp's arithmetic capabilities have been enhanced a bit: it now
   872 takes ~= in premises into account (by performing a case split);
   873 
   874 * simp reduces "m*(n div m) + n mod m" to n, even if the two summands
   875 are distributed over a sum of terms;
   876 
   877 * New tactic "trans_tac" and method "trans" instantiate
   878 Provers/linorder.ML for axclasses "order" and "linorder" (predicates
   879 "<=", "<" and "=").
   880 
   881 * function INCOMPATIBILITIES: Pi-sets have been redefined and moved from main
   882 HOL to Library/FuncSet; constant "Fun.op o" is now called "Fun.comp";
   883 
   884 * 'typedef' command has new option "open" to suppress the set
   885 definition;
   886 
   887 * functions Min and Max on finite sets have been introduced (theory
   888 Finite_Set);
   889 
   890 * attribute [symmetric] now works for relations as well; it turns
   891 (x,y) : R^-1 into (y,x) : R, and vice versa;
   892 
   893 * induct over a !!-quantified statement (say !!x1..xn):
   894   each "case" automatically performs "fix x1 .. xn" with exactly those names.
   895 
   896 * Map: `empty' is no longer a constant but a syntactic abbreviation for
   897 %x. None. Warning: empty_def now refers to the previously hidden definition
   898 of the empty set.
   899 
   900 * Algebra: formalization of classical algebra.  Intended as base for
   901 any algebraic development in Isabelle.  Currently covers group theory
   902 (up to Sylow's theorem) and ring theory (Universal Property of
   903 Univariate Polynomials).  Contributions welcome;
   904 
   905 * GroupTheory: deleted, since its material has been moved to Algebra;
   906 
   907 * Complex: new directory of the complex numbers with numeric constants,
   908 nonstandard complex numbers, and some complex analysis, standard and
   909 nonstandard (Jacques Fleuriot);
   910 
   911 * HOL-Complex: new image for analysis, replacing HOL-Real and HOL-Hyperreal;
   912 
   913 * Hyperreal: introduced Gauge integration and hyperreal logarithms (Jacques
   914 Fleuriot);
   915 
   916 * Real/HahnBanach: updated and adapted to locales;
   917 
   918 * NumberTheory: added Gauss's law of quadratic reciprocity (by Avigad,
   919 Gray and Kramer);
   920 
   921 * UNITY: added the Meier-Sanders theory of progress sets;
   922 
   923 * MicroJava: bytecode verifier and lightweight bytecode verifier
   924 as abstract algorithms, instantiated to the JVM;
   925 
   926 * Bali: Java source language formalization. Type system, operational
   927 semantics, axiomatic semantics. Supported language features:
   928 classes, interfaces, objects,virtual methods, static methods,
   929 static/instance fields, arrays, access modifiers, definite
   930 assignment, exceptions.
   931 
   932 
   933 *** ZF ***
   934 
   935 * ZF/Constructible: consistency proof for AC (Gdel's constructible
   936 universe, etc.);
   937 
   938 * Main ZF: virtually all theories converted to new-style format;
   939 
   940 
   941 *** ML ***
   942 
   943 * Pure: Tactic.prove provides sane interface for internal proofs;
   944 omits the infamous "standard" operation, so this is more appropriate
   945 than prove_goalw_cterm in many situations (e.g. in simprocs);
   946 
   947 * Pure: improved error reporting of simprocs;
   948 
   949 * Provers: Simplifier.simproc(_i) provides sane interface for setting
   950 up simprocs;
   951 
   952 
   953 *** Document preparation ***
   954 
   955 * uses \par instead of \\ for line breaks in theory text. This may
   956 shift some page breaks in large documents. To get the old behaviour
   957 use \renewcommand{\isanewline}{\mbox{}\\\mbox{}} in root.tex.
   958 
   959 * minimized dependencies of isabelle.sty and isabellesym.sty on
   960 other packages
   961 
   962 * \<euro> now needs package babel/greek instead of marvosym (which
   963 broke \Rightarrow)
   964 
   965 * normal size for \<zero>...\<nine> (uses \mathbf instead of
   966 textcomp package)
   967 
   968 
   969 
   970 New in Isabelle2002 (March 2002)
   971 --------------------------------
   972 
   973 *** Document preparation ***
   974 
   975 * greatly simplified document preparation setup, including more
   976 graceful interpretation of isatool usedir -i/-d/-D options, and more
   977 instructive isatool mkdir; users should basically be able to get
   978 started with "isatool mkdir HOL Test && isatool make"; alternatively,
   979 users may run a separate document processing stage manually like this:
   980 "isatool usedir -D output HOL Test && isatool document Test/output";
   981 
   982 * theory dependency graph may now be incorporated into documents;
   983 isatool usedir -g true will produce session_graph.eps/.pdf for use
   984 with \includegraphics of LaTeX;
   985 
   986 * proper spacing of consecutive markup elements, especially text
   987 blocks after section headings;
   988 
   989 * support bold style (for single symbols only), input syntax is like
   990 this: "\<^bold>\<alpha>" or "\<^bold>A";
   991 
   992 * \<bullet> is now output as bold \cdot by default, which looks much
   993 better in printed text;
   994 
   995 * added default LaTeX bindings for \<tturnstile> and \<TTurnstile>;
   996 note that these symbols are currently unavailable in Proof General /
   997 X-Symbol; new symbols \<zero>, \<one>, ..., \<nine>, and \<euro>;
   998 
   999 * isatool latex no longer depends on changed TEXINPUTS, instead
  1000 isatool document copies the Isabelle style files to the target
  1001 location;
  1002 
  1003 
  1004 *** Isar ***
  1005 
  1006 * Pure/Provers: improved proof by cases and induction;
  1007   - 'case' command admits impromptu naming of parameters (such as
  1008     "case (Suc n)");
  1009   - 'induct' method divinates rule instantiation from the inductive
  1010     claim; no longer requires excessive ?P bindings for proper
  1011     instantiation of cases;
  1012   - 'induct' method properly enumerates all possibilities of set/type
  1013     rules; as a consequence facts may be also passed through *type*
  1014     rules without further ado;
  1015   - 'induct' method now derives symbolic cases from the *rulified*
  1016     rule (before it used to rulify cases stemming from the internal
  1017     atomized version); this means that the context of a non-atomic
  1018     statement becomes is included in the hypothesis, avoiding the
  1019     slightly cumbersome show "PROP ?case" form;
  1020   - 'induct' may now use elim-style induction rules without chaining
  1021     facts, using ``missing'' premises from the goal state; this allows
  1022     rules stemming from inductive sets to be applied in unstructured
  1023     scripts, while still benefitting from proper handling of non-atomic
  1024     statements; NB: major inductive premises need to be put first, all
  1025     the rest of the goal is passed through the induction;
  1026   - 'induct' proper support for mutual induction involving non-atomic
  1027     rule statements (uses the new concept of simultaneous goals, see
  1028     below);
  1029   - append all possible rule selections, but only use the first
  1030     success (no backtracking);
  1031   - removed obsolete "(simplified)" and "(stripped)" options of methods;
  1032   - undeclared rule case names default to numbers 1, 2, 3, ...;
  1033   - added 'print_induct_rules' (covered by help item in recent Proof
  1034     General versions);
  1035   - moved induct/cases attributes to Pure, methods to Provers;
  1036   - generic method setup instantiated for FOL and HOL;
  1037 
  1038 * Pure: support multiple simultaneous goal statements, for example
  1039 "have a: A and b: B" (same for 'theorem' etc.); being a pure
  1040 meta-level mechanism, this acts as if several individual goals had
  1041 been stated separately; in particular common proof methods need to be
  1042 repeated in order to cover all claims; note that a single elimination
  1043 step is *not* sufficient to establish the two conjunctions, so this
  1044 fails:
  1045 
  1046   assume "A & B" then have A and B ..   (*".." fails*)
  1047 
  1048 better use "obtain" in situations as above; alternative refer to
  1049 multi-step methods like 'auto', 'simp_all', 'blast+' etc.;
  1050 
  1051 * Pure: proper integration with ``locales''; unlike the original
  1052 version by Florian Kammller, Isar locales package high-level proof
  1053 contexts rather than raw logical ones (e.g. we admit to include
  1054 attributes everywhere); operations on locales include merge and
  1055 rename; support for implicit arguments (``structures''); simultaneous
  1056 type-inference over imports and text; see also HOL/ex/Locales.thy for
  1057 some examples;
  1058 
  1059 * Pure: the following commands have been ``localized'', supporting a
  1060 target locale specification "(in name)": 'lemma', 'theorem',
  1061 'corollary', 'lemmas', 'theorems', 'declare'; the results will be
  1062 stored both within the locale and at the theory level (exported and
  1063 qualified by the locale name);
  1064 
  1065 * Pure: theory goals may now be specified in ``long'' form, with
  1066 ad-hoc contexts consisting of arbitrary locale elements. for example
  1067 ``lemma foo: fixes x assumes "A x" shows "B x"'' (local syntax and
  1068 definitions may be given, too); the result is a meta-level rule with
  1069 the context elements being discharged in the obvious way;
  1070 
  1071 * Pure: new proof command 'using' allows to augment currently used
  1072 facts after a goal statement ('using' is syntactically analogous to
  1073 'apply', but acts on the goal's facts only); this allows chained facts
  1074 to be separated into parts given before and after a claim, as in
  1075 ``from a and b have C using d and e <proof>'';
  1076 
  1077 * Pure: renamed "antecedent" case to "rule_context";
  1078 
  1079 * Pure: new 'judgment' command records explicit information about the
  1080 object-logic embedding (used by several tools internally); no longer
  1081 use hard-wired "Trueprop";
  1082 
  1083 * Pure: added 'corollary' command;
  1084 
  1085 * Pure: fixed 'token_translation' command;
  1086 
  1087 * Pure: removed obsolete 'exported' attribute;
  1088 
  1089 * Pure: dummy pattern "_" in is/let is now automatically lifted over
  1090 bound variables: "ALL x. P x --> Q x" (is "ALL x. _ --> ?C x")
  1091 supersedes more cumbersome ... (is "ALL x. _ x --> ?C x");
  1092 
  1093 * Pure: method 'atomize' presents local goal premises as object-level
  1094 statements (atomic meta-level propositions); setup controlled via
  1095 rewrite rules declarations of 'atomize' attribute; example
  1096 application: 'induct' method with proper rule statements in improper
  1097 proof *scripts*;
  1098 
  1099 * Pure: emulation of instantiation tactics (rule_tac, cut_tac, etc.)
  1100 now consider the syntactic context of assumptions, giving a better
  1101 chance to get type-inference of the arguments right (this is
  1102 especially important for locales);
  1103 
  1104 * Pure: "sorry" no longer requires quick_and_dirty in interactive
  1105 mode;
  1106 
  1107 * Pure/obtain: the formal conclusion "thesis", being marked as
  1108 ``internal'', may no longer be reference directly in the text;
  1109 potential INCOMPATIBILITY, may need to use "?thesis" in rare
  1110 situations;
  1111 
  1112 * Pure: generic 'sym' attribute which declares a rule both as pure
  1113 'elim?' and for the 'symmetric' operation;
  1114 
  1115 * Pure: marginal comments ``--'' may now occur just anywhere in the
  1116 text; the fixed correlation with particular command syntax has been
  1117 discontinued;
  1118 
  1119 * Pure: new method 'rules' is particularly well-suited for proof
  1120 search in intuitionistic logic; a bit slower than 'blast' or 'fast',
  1121 but often produces more compact proof terms with less detours;
  1122 
  1123 * Pure/Provers/classical: simplified integration with pure rule
  1124 attributes and methods; the classical "intro?/elim?/dest?"
  1125 declarations coincide with the pure ones; the "rule" method no longer
  1126 includes classically swapped intros; "intro" and "elim" methods no
  1127 longer pick rules from the context; also got rid of ML declarations
  1128 AddXIs/AddXEs/AddXDs; all of this has some potential for
  1129 INCOMPATIBILITY;
  1130 
  1131 * Provers/classical: attribute 'swapped' produces classical inversions
  1132 of introduction rules;
  1133 
  1134 * Provers/simplifier: 'simplified' attribute may refer to explicit
  1135 rules instead of full simplifier context; 'iff' attribute handles
  1136 conditional rules;
  1137 
  1138 * HOL: 'typedef' now allows alternative names for Rep/Abs morphisms;
  1139 
  1140 * HOL: 'recdef' now fails on unfinished automated proofs, use
  1141 "(permissive)" option to recover old behavior;
  1142 
  1143 * HOL: 'inductive' no longer features separate (collective) attributes
  1144 for 'intros' (was found too confusing);
  1145 
  1146 * HOL: properly declared induction rules less_induct and
  1147 wf_induct_rule;
  1148 
  1149 
  1150 *** HOL ***
  1151 
  1152 * HOL: moved over to sane numeral syntax; the new policy is as
  1153 follows:
  1154 
  1155   - 0 and 1 are polymorphic constants, which are defined on any
  1156   numeric type (nat, int, real etc.);
  1157 
  1158   - 2, 3, 4, ... and -1, -2, -3, ... are polymorphic numerals, based
  1159   binary representation internally;
  1160 
  1161   - type nat has special constructor Suc, and generally prefers Suc 0
  1162   over 1::nat and Suc (Suc 0) over 2::nat;
  1163 
  1164 This change may cause significant problems of INCOMPATIBILITY; here
  1165 are some hints on converting existing sources:
  1166 
  1167   - due to the new "num" token, "-0" and "-1" etc. are now atomic
  1168   entities, so expressions involving "-" (unary or binary minus) need
  1169   to be spaced properly;
  1170 
  1171   - existing occurrences of "1" may need to be constraint "1::nat" or
  1172   even replaced by Suc 0; similar for old "2";
  1173 
  1174   - replace "#nnn" by "nnn", and "#-nnn" by "-nnn";
  1175 
  1176   - remove all special provisions on numerals in proofs;
  1177 
  1178 * HOL: simp rules nat_number expand numerals on nat to Suc/0
  1179 representation (depends on bin_arith_simps in the default context);
  1180 
  1181 * HOL: symbolic syntax for x^2 (numeral 2);
  1182 
  1183 * HOL: the class of all HOL types is now called "type" rather than
  1184 "term"; INCOMPATIBILITY, need to adapt references to this type class
  1185 in axclass/classes, instance/arities, and (usually rare) occurrences
  1186 in typings (of consts etc.); internally the class is called
  1187 "HOL.type", ML programs should refer to HOLogic.typeS;
  1188 
  1189 * HOL/record package improvements:
  1190   - new derived operations "fields" to build a partial record section,
  1191     "extend" to promote a fixed record to a record scheme, and
  1192     "truncate" for the reverse; cf. theorems "xxx.defs", which are *not*
  1193     declared as simp by default;
  1194   - shared operations ("more", "fields", etc.) now need to be always
  1195     qualified) --- potential INCOMPATIBILITY;
  1196   - removed "make_scheme" operations (use "make" with "extend") --
  1197     INCOMPATIBILITY;
  1198   - removed "more" class (simply use "term") -- INCOMPATIBILITY;
  1199   - provides cases/induct rules for use with corresponding Isar
  1200     methods (for concrete records, record schemes, concrete more
  1201     parts, and schematic more parts -- in that order);
  1202   - internal definitions directly based on a light-weight abstract
  1203     theory of product types over typedef rather than datatype;
  1204 
  1205 * HOL: generic code generator for generating executable ML code from
  1206 specifications; specific support for HOL constructs such as inductive
  1207 datatypes and sets, as well as recursive functions; can be invoked
  1208 via 'generate_code' theory section;
  1209 
  1210 * HOL: canonical cases/induct rules for n-tuples (n = 3..7);
  1211 
  1212 * HOL: consolidated and renamed several theories.  In particular:
  1213         Ord.thy has been absorbed into HOL.thy
  1214         String.thy has been absorbed into List.thy
  1215 
  1216 * HOL: concrete setsum syntax "\<Sum>i:A. b" == "setsum (%i. b) A"
  1217 (beware of argument permutation!);
  1218 
  1219 * HOL: linorder_less_split superseded by linorder_cases;
  1220 
  1221 * HOL/List: "nodups" renamed to "distinct";
  1222 
  1223 * HOL: added "The" definite description operator; move Hilbert's "Eps"
  1224 to peripheral theory "Hilbert_Choice"; some INCOMPATIBILITIES:
  1225   - Ex_def has changed, now need to use some_eq_ex
  1226 
  1227 * HOL: made split_all_tac safe; EXISTING PROOFS MAY FAIL OR LOOP, so
  1228 in this (rare) case use:
  1229 
  1230   delSWrapper "split_all_tac"
  1231   addSbefore ("unsafe_split_all_tac", unsafe_split_all_tac)
  1232 
  1233 * HOL: added safe wrapper "split_conv_tac" to claset; EXISTING PROOFS
  1234 MAY FAIL;
  1235 
  1236 * HOL: introduced f^n = f o ... o f; warning: due to the limits of
  1237 Isabelle's type classes, ^ on functions and relations has too general
  1238 a domain, namely ('a * 'b) set and 'a => 'b; this means that it may be
  1239 necessary to attach explicit type constraints;
  1240 
  1241 * HOL/Relation: the prefix name of the infix "O" has been changed from
  1242 "comp" to "rel_comp"; INCOMPATIBILITY: a few theorems have been
  1243 renamed accordingly (eg "compI" -> "rel_compI").
  1244 
  1245 * HOL: syntax translations now work properly with numerals and records
  1246 expressions;
  1247 
  1248 * HOL: bounded abstraction now uses syntax "%" / "\<lambda>" instead
  1249 of "lam" -- INCOMPATIBILITY;
  1250 
  1251 * HOL: got rid of some global declarations (potential INCOMPATIBILITY
  1252 for ML tools): const "()" renamed "Product_Type.Unity", type "unit"
  1253 renamed "Product_Type.unit";
  1254 
  1255 * HOL: renamed rtrancl_into_rtrancl2 to converse_rtrancl_into_rtrancl
  1256 
  1257 * HOL: removed obsolete theorem "optionE" (use "option.exhaust", or
  1258 the "cases" method);
  1259 
  1260 * HOL/GroupTheory: group theory examples including Sylow's theorem (by
  1261 Florian Kammller);
  1262 
  1263 * HOL/IMP: updated and converted to new-style theory format; several
  1264 parts turned into readable document, with proper Isar proof texts and
  1265 some explanations (by Gerwin Klein);
  1266 
  1267 * HOL-Real: added Complex_Numbers (by Gertrud Bauer);
  1268 
  1269 * HOL-Hyperreal is now a logic image;
  1270 
  1271 
  1272 *** HOLCF ***
  1273 
  1274 * Isar: consts/constdefs supports mixfix syntax for continuous
  1275 operations;
  1276 
  1277 * Isar: domain package adapted to new-style theory format, e.g. see
  1278 HOLCF/ex/Dnat.thy;
  1279 
  1280 * theory Lift: proper use of rep_datatype lift instead of ML hacks --
  1281 potential INCOMPATIBILITY; now use plain induct_tac instead of former
  1282 lift.induct_tac, always use UU instead of Undef;
  1283 
  1284 * HOLCF/IMP: updated and converted to new-style theory;
  1285 
  1286 
  1287 *** ZF ***
  1288 
  1289 * Isar: proper integration of logic-specific tools and packages,
  1290 including theory commands '(co)inductive', '(co)datatype',
  1291 'rep_datatype', 'inductive_cases', as well as methods 'ind_cases',
  1292 'induct_tac', 'case_tac', and 'typecheck' (with attribute 'TC');
  1293 
  1294 * theory Main no longer includes AC; for the Axiom of Choice, base
  1295 your theory on Main_ZFC;
  1296 
  1297 * the integer library now covers quotients and remainders, with many
  1298 laws relating division to addition, multiplication, etc.;
  1299 
  1300 * ZF/UNITY: Chandy and Misra's UNITY is now available in ZF, giving a
  1301 typeless version of the formalism;
  1302 
  1303 * ZF/AC, Coind, IMP, Resid: updated and converted to new-style theory
  1304 format;
  1305 
  1306 * ZF/Induct: new directory for examples of inductive definitions,
  1307 including theory Multiset for multiset orderings; converted to
  1308 new-style theory format;
  1309 
  1310 * ZF: many new theorems about lists, ordinals, etc.;
  1311 
  1312 
  1313 *** General ***
  1314 
  1315 * Pure/kernel: meta-level proof terms (by Stefan Berghofer); reference
  1316 variable proof controls level of detail: 0 = no proofs (only oracle
  1317 dependencies), 1 = lemma dependencies, 2 = compact proof terms; see
  1318 also ref manual for further ML interfaces;
  1319 
  1320 * Pure/axclass: removed obsolete ML interface
  1321 goal_subclass/goal_arity;
  1322 
  1323 * Pure/syntax: new token syntax "num" for plain numerals (without "#"
  1324 of "xnum"); potential INCOMPATIBILITY, since -0, -1 etc. are now
  1325 separate tokens, so expressions involving minus need to be spaced
  1326 properly;
  1327 
  1328 * Pure/syntax: support non-oriented infixes, using keyword "infix"
  1329 rather than "infixl" or "infixr";
  1330 
  1331 * Pure/syntax: concrete syntax for dummy type variables admits genuine
  1332 sort constraint specifications in type inference; e.g. "x::_::foo"
  1333 ensures that the type of "x" is of sort "foo" (but not necessarily a
  1334 type variable);
  1335 
  1336 * Pure/syntax: print modes "type_brackets" and "no_type_brackets"
  1337 control output of nested => (types); the default behavior is
  1338 "type_brackets";
  1339 
  1340 * Pure/syntax: builtin parse translation for "_constify" turns valued
  1341 tokens into AST constants;
  1342 
  1343 * Pure/syntax: prefer later declarations of translations and print
  1344 translation functions; potential INCOMPATIBILITY: need to reverse
  1345 multiple declarations for same syntax element constant;
  1346 
  1347 * Pure/show_hyps reset by default (in accordance to existing Isar
  1348 practice);
  1349 
  1350 * Provers/classical: renamed addaltern to addafter, addSaltern to
  1351 addSafter;
  1352 
  1353 * Provers/clasimp: ``iff'' declarations now handle conditional rules
  1354 as well;
  1355 
  1356 * system: tested support for MacOS X; should be able to get Isabelle +
  1357 Proof General to work in a plain Terminal after installing Poly/ML
  1358 (e.g. from the Isabelle distribution area) and GNU bash alone
  1359 (e.g. from http://www.apple.com); full X11, XEmacs and X-Symbol
  1360 support requires further installations, e.g. from
  1361 http://fink.sourceforge.net/);
  1362 
  1363 * system: support Poly/ML 4.1.1 (able to manage larger heaps);
  1364 
  1365 * system: reduced base memory usage by Poly/ML (approx. 20 MB instead
  1366 of 40 MB), cf. ML_OPTIONS;
  1367 
  1368 * system: Proof General keywords specification is now part of the
  1369 Isabelle distribution (see etc/isar-keywords.el);
  1370 
  1371 * system: support for persistent Proof General sessions (refrain from
  1372 outdating all loaded theories on startup); user may create writable
  1373 logic images like this: ``isabelle -q HOL Test'';
  1374 
  1375 * system: smart selection of Isabelle process versus Isabelle
  1376 interface, accommodates case-insensitive file systems (e.g. HFS+); may
  1377 run both "isabelle" and "Isabelle" even if file names are badly
  1378 damaged (executable inspects the case of the first letter of its own
  1379 name); added separate "isabelle-process" and "isabelle-interface";
  1380 
  1381 * system: refrain from any attempt at filtering input streams; no
  1382 longer support ``8bit'' encoding of old isabelle font, instead proper
  1383 iso-latin characters may now be used; the related isatools
  1384 "symbolinput" and "nonascii" have disappeared as well;
  1385 
  1386 * system: removed old "xterm" interface (the print modes "xterm" and
  1387 "xterm_color" are still available for direct use in a suitable
  1388 terminal);
  1389 
  1390 
  1391 
  1392 New in Isabelle99-2 (February 2001)
  1393 -----------------------------------
  1394 
  1395 *** Overview of INCOMPATIBILITIES ***
  1396 
  1397 * HOL: please note that theories in the Library and elsewhere often use the
  1398 new-style (Isar) format; to refer to their theorems in an ML script you must
  1399 bind them to ML identifers by e.g.      val thm_name = thm "thm_name";
  1400 
  1401 * HOL: inductive package no longer splits induction rule aggressively,
  1402 but only as far as specified by the introductions given; the old
  1403 format may be recovered via ML function complete_split_rule or attribute
  1404 'split_rule (complete)';
  1405 
  1406 * HOL: induct renamed to lfp_induct, lfp_Tarski to lfp_unfold,
  1407 gfp_Tarski to gfp_unfold;
  1408 
  1409 * HOL: contrapos, contrapos2 renamed to contrapos_nn, contrapos_pp;
  1410 
  1411 * HOL: infix "dvd" now has priority 50 rather than 70 (because it is a
  1412 relation); infix "^^" has been renamed "``"; infix "``" has been
  1413 renamed "`"; "univalent" has been renamed "single_valued";
  1414 
  1415 * HOL/Real: "rinv" and "hrinv" replaced by overloaded "inverse"
  1416 operation;
  1417 
  1418 * HOLCF: infix "`" has been renamed "$"; the symbol syntax is \<cdot>;
  1419 
  1420 * Isar: 'obtain' no longer declares "that" fact as simp/intro;
  1421 
  1422 * Isar/HOL: method 'induct' now handles non-atomic goals; as a
  1423 consequence, it is no longer monotonic wrt. the local goal context
  1424 (which is now passed through the inductive cases);
  1425 
  1426 * Document preparation: renamed standard symbols \<ll> to \<lless> and
  1427 \<gg> to \<ggreater>;
  1428 
  1429 
  1430 *** Document preparation ***
  1431 
  1432 * \isabellestyle{NAME} selects version of Isabelle output (currently
  1433 available: are "it" for near math-mode best-style output, "sl" for
  1434 slanted text style, and "tt" for plain type-writer; if no
  1435 \isabellestyle command is given, output is according to slanted
  1436 type-writer);
  1437 
  1438 * support sub/super scripts (for single symbols only), input syntax is
  1439 like this: "A\<^sup>*" or "A\<^sup>\<star>";
  1440 
  1441 * some more standard symbols; see Appendix A of the system manual for
  1442 the complete list of symbols defined in isabellesym.sty;
  1443 
  1444 * improved isabelle style files; more abstract symbol implementation
  1445 (should now use \isamath{...} and \isatext{...} in custom symbol
  1446 definitions);
  1447 
  1448 * antiquotation @{goals} and @{subgoals} for output of *dynamic* goals
  1449 state; Note that presentation of goal states does not conform to
  1450 actual human-readable proof documents.  Please do not include goal
  1451 states into document output unless you really know what you are doing!
  1452 
  1453 * proper indentation of antiquoted output with proportional LaTeX
  1454 fonts;
  1455 
  1456 * no_document ML operator temporarily disables LaTeX document
  1457 generation;
  1458 
  1459 * isatool unsymbolize tunes sources for plain ASCII communication;
  1460 
  1461 
  1462 *** Isar ***
  1463 
  1464 * Pure: Isar now suffers initial goal statements to contain unbound
  1465 schematic variables (this does not conform to actual readable proof
  1466 documents, due to unpredictable outcome and non-compositional proof
  1467 checking); users who know what they are doing may use schematic goals
  1468 for Prolog-style synthesis of proven results;
  1469 
  1470 * Pure: assumption method (an implicit finishing) now handles actual
  1471 rules as well;
  1472 
  1473 * Pure: improved 'obtain' --- moved to Pure, insert "that" into
  1474 initial goal, declare "that" only as Pure intro (only for single
  1475 steps); the "that" rule assumption may now be involved in implicit
  1476 finishing, thus ".." becomes a feasible for trivial obtains;
  1477 
  1478 * Pure: default proof step now includes 'intro_classes'; thus trivial
  1479 instance proofs may be performed by "..";
  1480 
  1481 * Pure: ?thesis / ?this / "..." now work for pure meta-level
  1482 statements as well;
  1483 
  1484 * Pure: more robust selection of calculational rules;
  1485 
  1486 * Pure: the builtin notion of 'finished' goal now includes the ==-refl
  1487 rule (as well as the assumption rule);
  1488 
  1489 * Pure: 'thm_deps' command visualizes dependencies of theorems and
  1490 lemmas, using the graph browser tool;
  1491 
  1492 * Pure: predict failure of "show" in interactive mode;
  1493 
  1494 * Pure: 'thms_containing' now takes actual terms as arguments;
  1495 
  1496 * HOL: improved method 'induct' --- now handles non-atomic goals
  1497 (potential INCOMPATIBILITY); tuned error handling;
  1498 
  1499 * HOL: cases and induct rules now provide explicit hints about the
  1500 number of facts to be consumed (0 for "type" and 1 for "set" rules);
  1501 any remaining facts are inserted into the goal verbatim;
  1502 
  1503 * HOL: local contexts (aka cases) may now contain term bindings as
  1504 well; the 'cases' and 'induct' methods new provide a ?case binding for
  1505 the result to be shown in each case;
  1506 
  1507 * HOL: added 'recdef_tc' command;
  1508 
  1509 * isatool convert assists in eliminating legacy ML scripts;
  1510 
  1511 
  1512 *** HOL ***
  1513 
  1514 * HOL/Library: a collection of generic theories to be used together
  1515 with main HOL; the theory loader path already includes this directory
  1516 by default; the following existing theories have been moved here:
  1517 HOL/Induct/Multiset, HOL/Induct/Acc (as Accessible_Part), HOL/While
  1518 (as While_Combinator), HOL/Lex/Prefix (as List_Prefix);
  1519 
  1520 * HOL/Unix: "Some aspects of Unix file-system security", a typical
  1521 modelling and verification task performed in Isabelle/HOL +
  1522 Isabelle/Isar + Isabelle document preparation (by Markus Wenzel).
  1523 
  1524 * HOL/Algebra: special summation operator SUM no longer exists, it has
  1525 been replaced by setsum; infix 'assoc' now has priority 50 (like
  1526 'dvd'); axiom 'one_not_zero' has been moved from axclass 'ring' to
  1527 'domain', this makes the theory consistent with mathematical
  1528 literature;
  1529 
  1530 * HOL basics: added overloaded operations "inverse" and "divide"
  1531 (infix "/"), syntax for generic "abs" operation, generic summation
  1532 operator \<Sum>;
  1533 
  1534 * HOL/typedef: simplified package, provide more useful rules (see also
  1535 HOL/subset.thy);
  1536 
  1537 * HOL/datatype: induction rule for arbitrarily branching datatypes is
  1538 now expressed as a proper nested rule (old-style tactic scripts may
  1539 require atomize_strip_tac to cope with non-atomic premises);
  1540 
  1541 * HOL: renamed theory "Prod" to "Product_Type", renamed "split" rule
  1542 to "split_conv" (old name still available for compatibility);
  1543 
  1544 * HOL: improved concrete syntax for strings (e.g. allows translation
  1545 rules with string literals);
  1546 
  1547 * HOL-Real-Hyperreal: this extends HOL-Real with the hyperreals
  1548  and Fleuriot's mechanization of analysis, including the transcendental
  1549  functions for the reals;
  1550 
  1551 * HOL/Real, HOL/Hyperreal: improved arithmetic simplification;
  1552 
  1553 
  1554 *** CTT ***
  1555 
  1556 * CTT: x-symbol support for Pi, Sigma, -->, : (membership); note that
  1557 "lam" is displayed as TWO lambda-symbols
  1558 
  1559 * CTT: theory Main now available, containing everything (that is, Bool
  1560 and Arith);
  1561 
  1562 
  1563 *** General ***
  1564 
  1565 * Pure: the Simplifier has been implemented properly as a derived rule
  1566 outside of the actual kernel (at last!); the overall performance
  1567 penalty in practical applications is about 50%, while reliability of
  1568 the Isabelle inference kernel has been greatly improved;
  1569 
  1570 * print modes "brackets" and "no_brackets" control output of nested =>
  1571 (types) and ==> (props); the default behaviour is "brackets";
  1572 
  1573 * Provers: fast_tac (and friends) now handle actual object-logic rules
  1574 as assumptions as well;
  1575 
  1576 * system: support Poly/ML 4.0;
  1577 
  1578 * system: isatool install handles KDE version 1 or 2;
  1579 
  1580 
  1581 
  1582 New in Isabelle99-1 (October 2000)
  1583 ----------------------------------
  1584 
  1585 *** Overview of INCOMPATIBILITIES ***
  1586 
  1587 * HOL: simplification of natural numbers is much changed; to partly
  1588 recover the old behaviour (e.g. to prevent n+n rewriting to #2*n)
  1589 issue the following ML commands:
  1590 
  1591   Delsimprocs Nat_Numeral_Simprocs.cancel_numerals;
  1592   Delsimprocs [Nat_Numeral_Simprocs.combine_numerals];
  1593 
  1594 * HOL: simplification no longer dives into case-expressions; this is
  1595 controlled by "t.weak_case_cong" for each datatype t;
  1596 
  1597 * HOL: nat_less_induct renamed to less_induct;
  1598 
  1599 * HOL: systematic renaming of the SOME (Eps) rules, may use isatool
  1600 fixsome to patch .thy and .ML sources automatically;
  1601 
  1602   select_equality  -> some_equality
  1603   select_eq_Ex     -> some_eq_ex
  1604   selectI2EX       -> someI2_ex
  1605   selectI2         -> someI2
  1606   selectI          -> someI
  1607   select1_equality -> some1_equality
  1608   Eps_sym_eq       -> some_sym_eq_trivial
  1609   Eps_eq           -> some_eq_trivial
  1610 
  1611 * HOL: exhaust_tac on datatypes superceded by new generic case_tac;
  1612 
  1613 * HOL: removed obsolete theorem binding expand_if (refer to split_if
  1614 instead);
  1615 
  1616 * HOL: the recursion equations generated by 'recdef' are now called
  1617 f.simps instead of f.rules;
  1618 
  1619 * HOL: qed_spec_mp now also handles bounded ALL as well;
  1620 
  1621 * HOL: 0 is now overloaded, so the type constraint ":: nat" may
  1622 sometimes be needed;
  1623 
  1624 * HOL: the constant for "f``x" is now "image" rather than "op ``";
  1625 
  1626 * HOL: the constant for "f-``x" is now "vimage" rather than "op -``";
  1627 
  1628 * HOL: the disjoint sum is now "<+>" instead of "Plus"; the cartesian
  1629 product is now "<*>" instead of "Times"; the lexicographic product is
  1630 now "<*lex*>" instead of "**";
  1631 
  1632 * HOL: theory Sexp is now in HOL/Induct examples (it used to be part
  1633 of main HOL, but was unused); better use HOL's datatype package;
  1634 
  1635 * HOL: removed "symbols" syntax for constant "override" of theory Map;
  1636 the old syntax may be recovered as follows:
  1637 
  1638   syntax (symbols)
  1639     override  :: "('a ~=> 'b) => ('a ~=> 'b) => ('a ~=> 'b)"
  1640       (infixl "\\<oplus>" 100)
  1641 
  1642 * HOL/Real: "rabs" replaced by overloaded "abs" function;
  1643 
  1644 * HOL/ML: even fewer consts are declared as global (see theories Ord,
  1645 Lfp, Gfp, WF); this only affects ML packages that refer to const names
  1646 internally;
  1647 
  1648 * HOL and ZF: syntax for quotienting wrt an equivalence relation
  1649 changed from A/r to A//r;
  1650 
  1651 * ZF: new treatment of arithmetic (nat & int) may break some old
  1652 proofs;
  1653 
  1654 * Isar: renamed some attributes (RS -> THEN, simplify -> simplified,
  1655 rulify -> rule_format, elimify -> elim_format, ...);
  1656 
  1657 * Isar/Provers: intro/elim/dest attributes changed; renamed
  1658 intro/intro!/intro!! flags to intro!/intro/intro? (in most cases, one
  1659 should have to change intro!! to intro? only); replaced "delrule" by
  1660 "rule del";
  1661 
  1662 * Isar/HOL: renamed "intrs" to "intros" in inductive definitions;
  1663 
  1664 * Provers: strengthened force_tac by using new first_best_tac;
  1665 
  1666 * LaTeX document preparation: several changes of isabelle.sty (see
  1667 lib/texinputs);
  1668 
  1669 
  1670 *** Document preparation ***
  1671 
  1672 * formal comments (text blocks etc.) in new-style theories may now
  1673 contain antiquotations of thm/prop/term/typ/text to be presented
  1674 according to latex print mode; concrete syntax is like this:
  1675 @{term[show_types] "f(x) = a + x"};
  1676 
  1677 * isatool mkdir provides easy setup of Isabelle session directories,
  1678 including proper document sources;
  1679 
  1680 * generated LaTeX sources are now deleted after successful run
  1681 (isatool document -c); may retain a copy somewhere else via -D option
  1682 of isatool usedir;
  1683 
  1684 * isatool usedir -D now lets isatool latex -o sty update the Isabelle
  1685 style files, achieving self-contained LaTeX sources and simplifying
  1686 LaTeX debugging;
  1687 
  1688 * old-style theories now produce (crude) LaTeX output as well;
  1689 
  1690 * browser info session directories are now self-contained (may be put
  1691 on WWW server seperately); improved graphs of nested sessions; removed
  1692 graph for 'all sessions';
  1693 
  1694 * several improvements in isabelle style files; \isabellestyle{it}
  1695 produces fake math mode output; \isamarkupheader is now \section by
  1696 default; see lib/texinputs/isabelle.sty etc.;
  1697 
  1698 
  1699 *** Isar ***
  1700 
  1701 * Isar/Pure: local results and corresponding term bindings are now
  1702 subject to Hindley-Milner polymorphism (similar to ML); this
  1703 accommodates incremental type-inference very nicely;
  1704 
  1705 * Isar/Pure: new derived language element 'obtain' supports
  1706 generalized existence reasoning;
  1707 
  1708 * Isar/Pure: new calculational elements 'moreover' and 'ultimately'
  1709 support accumulation of results, without applying any rules yet;
  1710 useful to collect intermediate results without explicit name
  1711 references, and for use with transitivity rules with more than 2
  1712 premises;
  1713 
  1714 * Isar/Pure: scalable support for case-analysis type proofs: new
  1715 'case' language element refers to local contexts symbolically, as
  1716 produced by certain proof methods; internally, case names are attached
  1717 to theorems as "tags";
  1718 
  1719 * Isar/Pure: theory command 'hide' removes declarations from
  1720 class/type/const name spaces;
  1721 
  1722 * Isar/Pure: theory command 'defs' supports option "(overloaded)" to
  1723 indicate potential overloading;
  1724 
  1725 * Isar/Pure: changed syntax of local blocks from {{ }} to { };
  1726 
  1727 * Isar/Pure: syntax of sorts made 'inner', i.e. have to write
  1728 "{a,b,c}" instead of {a,b,c};
  1729 
  1730 * Isar/Pure now provides its own version of intro/elim/dest
  1731 attributes; useful for building new logics, but beware of confusion
  1732 with the version in Provers/classical;
  1733 
  1734 * Isar/Pure: the local context of (non-atomic) goals is provided via
  1735 case name 'antecedent';
  1736 
  1737 * Isar/Pure: removed obsolete 'transfer' attribute (transfer of thms
  1738 to the current context is now done automatically);
  1739 
  1740 * Isar/Pure: theory command 'method_setup' provides a simple interface
  1741 for definining proof methods in ML;
  1742 
  1743 * Isar/Provers: intro/elim/dest attributes changed; renamed
  1744 intro/intro!/intro!! flags to intro!/intro/intro? (INCOMPATIBILITY, in
  1745 most cases, one should have to change intro!! to intro? only);
  1746 replaced "delrule" by "rule del";
  1747 
  1748 * Isar/Provers: new 'hypsubst' method, plain 'subst' method and
  1749 'symmetric' attribute (the latter supercedes [RS sym]);
  1750 
  1751 * Isar/Provers: splitter support (via 'split' attribute and 'simp'
  1752 method modifier); 'simp' method: 'only:' modifier removes loopers as
  1753 well (including splits);
  1754 
  1755 * Isar/Provers: Simplifier and Classical methods now support all kind
  1756 of modifiers used in the past, including 'cong', 'iff', etc.
  1757 
  1758 * Isar/Provers: added 'fastsimp' and 'clarsimp' methods (combination
  1759 of Simplifier and Classical reasoner);
  1760 
  1761 * Isar/HOL: new proof method 'cases' and improved version of 'induct'
  1762 now support named cases; major packages (inductive, datatype, primrec,
  1763 recdef) support case names and properly name parameters;
  1764 
  1765 * Isar/HOL: new transitivity rules for substitution in inequalities --
  1766 monotonicity conditions are extracted to be proven at end of
  1767 calculations;
  1768 
  1769 * Isar/HOL: removed 'case_split' thm binding, should use 'cases' proof
  1770 method anyway;
  1771 
  1772 * Isar/HOL: removed old expand_if = split_if; theorems if_splits =
  1773 split_if split_if_asm; datatype package provides theorems foo.splits =
  1774 foo.split foo.split_asm for each datatype;
  1775 
  1776 * Isar/HOL: tuned inductive package, rename "intrs" to "intros"
  1777 (potential INCOMPATIBILITY), emulation of mk_cases feature for proof
  1778 scripts: new 'inductive_cases' command and 'ind_cases' method; (Note:
  1779 use "(cases (simplified))" method in proper proof texts);
  1780 
  1781 * Isar/HOL: added global 'arith_split' attribute for 'arith' method;
  1782 
  1783 * Isar: names of theorems etc. may be natural numbers as well;
  1784 
  1785 * Isar: 'pr' command: optional arguments for goals_limit and
  1786 ProofContext.prems_limit; no longer prints theory contexts, but only
  1787 proof states;
  1788 
  1789 * Isar: diagnostic commands 'pr', 'thm', 'prop', 'term', 'typ' admit
  1790 additional print modes to be specified; e.g. "pr(latex)" will print
  1791 proof state according to the Isabelle LaTeX style;
  1792 
  1793 * Isar: improved support for emulating tactic scripts, including proof
  1794 methods 'rule_tac' etc., 'cut_tac', 'thin_tac', 'subgoal_tac',
  1795 'rename_tac', 'rotate_tac', 'tactic', and 'case_tac' / 'induct_tac'
  1796 (for HOL datatypes);
  1797 
  1798 * Isar: simplified (more robust) goal selection of proof methods: 1st
  1799 goal, all goals, or explicit goal specifier (tactic emulation); thus
  1800 'proof method scripts' have to be in depth-first order;
  1801 
  1802 * Isar: tuned 'let' syntax: replaced 'as' keyword by 'and';
  1803 
  1804 * Isar: removed 'help' command, which hasn't been too helpful anyway;
  1805 should instead use individual commands for printing items
  1806 (print_commands, print_methods etc.);
  1807 
  1808 * Isar: added 'nothing' --- the empty list of theorems;
  1809 
  1810 
  1811 *** HOL ***
  1812 
  1813 * HOL/MicroJava: formalization of a fragment of Java, together with a
  1814 corresponding virtual machine and a specification of its bytecode
  1815 verifier and a lightweight bytecode verifier, including proofs of
  1816 type-safety; by Gerwin Klein, Tobias Nipkow, David von Oheimb, and
  1817 Cornelia Pusch (see also the homepage of project Bali at
  1818 http://isabelle.in.tum.de/Bali/);
  1819 
  1820 * HOL/Algebra: new theory of rings and univariate polynomials, by
  1821 Clemens Ballarin;
  1822 
  1823 * HOL/NumberTheory: fundamental Theorem of Arithmetic, Chinese
  1824 Remainder Theorem, Fermat/Euler Theorem, Wilson's Theorem, by Thomas M
  1825 Rasmussen;
  1826 
  1827 * HOL/Lattice: fundamental concepts of lattice theory and order
  1828 structures, including duals, properties of bounds versus algebraic
  1829 laws, lattice operations versus set-theoretic ones, the Knaster-Tarski
  1830 Theorem for complete lattices etc.; may also serve as a demonstration
  1831 for abstract algebraic reasoning using axiomatic type classes, and
  1832 mathematics-style proof in Isabelle/Isar; by Markus Wenzel;
  1833 
  1834 * HOL/Prolog: a (bare-bones) implementation of Lambda-Prolog, by David
  1835 von Oheimb;
  1836 
  1837 * HOL/IMPP: extension of IMP with local variables and mutually
  1838 recursive procedures, by David von Oheimb;
  1839 
  1840 * HOL/Lambda: converted into new-style theory and document;
  1841 
  1842 * HOL/ex/Multiquote: example of multiple nested quotations and
  1843 anti-quotations -- basically a generalized version of de-Bruijn
  1844 representation; very useful in avoiding lifting of operations;
  1845 
  1846 * HOL/record: added general record equality rule to simpset; fixed
  1847 select-update simplification procedure to handle extended records as
  1848 well; admit "r" as field name;
  1849 
  1850 * HOL: 0 is now overloaded over the new sort "zero", allowing its use with
  1851 other numeric types and also as the identity of groups, rings, etc.;
  1852 
  1853 * HOL: new axclass plus_ac0 for addition with the AC-laws and 0 as identity.
  1854 Types nat and int belong to this axclass;
  1855 
  1856 * HOL: greatly improved simplification involving numerals of type nat, int, real:
  1857    (i + #8 + j) = Suc k simplifies to  #7 + (i + j) = k
  1858    i*j + k + j*#3*i     simplifies to  #4*(i*j) + k
  1859   two terms #m*u and #n*u are replaced by #(m+n)*u
  1860     (where #m, #n and u can implicitly be 1; this is simproc combine_numerals)
  1861   and the term/formula #m*u+x ~~ #n*u+y simplifies simplifies to #(m-n)+x ~~ y
  1862     or x ~~ #(n-m)+y, where ~~ is one of = < <= or - (simproc cancel_numerals);
  1863 
  1864 * HOL: meson_tac is available (previously in ex/meson.ML); it is a
  1865 powerful prover for predicate logic but knows nothing of clasets; see
  1866 ex/mesontest.ML and ex/mesontest2.ML for example applications;
  1867 
  1868 * HOL: new version of "case_tac" subsumes both boolean case split and
  1869 "exhaust_tac" on datatypes; INCOMPATIBILITY: exhaust_tac no longer
  1870 exists, may define val exhaust_tac = case_tac for ad-hoc portability;
  1871 
  1872 * HOL: simplification no longer dives into case-expressions: only the
  1873 selector expression is simplified, but not the remaining arms; to
  1874 enable full simplification of case-expressions for datatype t, you may
  1875 remove t.weak_case_cong from the simpset, either globally (Delcongs
  1876 [thm"t.weak_case_cong"];) or locally (delcongs [...]).
  1877 
  1878 * HOL/recdef: the recursion equations generated by 'recdef' for
  1879 function 'f' are now called f.simps instead of f.rules; if all
  1880 termination conditions are proved automatically, these simplification
  1881 rules are added to the simpset, as in primrec; rules may be named
  1882 individually as well, resulting in a separate list of theorems for
  1883 each equation;
  1884 
  1885 * HOL/While is a new theory that provides a while-combinator. It
  1886 permits the definition of tail-recursive functions without the
  1887 provision of a termination measure. The latter is necessary once the
  1888 invariant proof rule for while is applied.
  1889 
  1890 * HOL: new (overloaded) notation for the set of elements below/above
  1891 some element: {..u}, {..u(}, {l..}, {)l..}. See theory SetInterval.
  1892 
  1893 * HOL: theorems impI, allI, ballI bound as "strip";
  1894 
  1895 * HOL: new tactic induct_thm_tac: thm -> string -> int -> tactic
  1896 induct_tac th "x1 ... xn" expects th to have a conclusion of the form
  1897 P v1 ... vn and abbreviates res_inst_tac [("v1","x1"),...,("vn","xn")] th;
  1898 
  1899 * HOL/Real: "rabs" replaced by overloaded "abs" function;
  1900 
  1901 * HOL: theory Sexp now in HOL/Induct examples (it used to be part of
  1902 main HOL, but was unused);
  1903 
  1904 * HOL: fewer consts declared as global (e.g. have to refer to
  1905 "Lfp.lfp" instead of "lfp" internally; affects ML packages only);
  1906 
  1907 * HOL: tuned AST representation of nested pairs, avoiding bogus output
  1908 in case of overlap with user translations (e.g. judgements over
  1909 tuples); (note that the underlying logical represenation is still
  1910 bogus);
  1911 
  1912 
  1913 *** ZF ***
  1914 
  1915 * ZF: simplification automatically cancels common terms in arithmetic
  1916 expressions over nat and int;
  1917 
  1918 * ZF: new treatment of nat to minimize type-checking: all operators
  1919 coerce their operands to a natural number using the function natify,
  1920 making the algebraic laws unconditional;
  1921 
  1922 * ZF: as above, for int: operators coerce their operands to an integer
  1923 using the function intify;
  1924 
  1925 * ZF: the integer library now contains many of the usual laws for the
  1926 orderings, including $<=, and monotonicity laws for $+ and $*;
  1927 
  1928 * ZF: new example ZF/ex/NatSum to demonstrate integer arithmetic
  1929 simplification;
  1930 
  1931 * FOL and ZF: AddIffs now available, giving theorems of the form P<->Q
  1932 to the simplifier and classical reasoner simultaneously;
  1933 
  1934 
  1935 *** General ***
  1936 
  1937 * Provers: blast_tac now handles actual object-logic rules as
  1938 assumptions; note that auto_tac uses blast_tac internally as well;
  1939 
  1940 * Provers: new functions rulify/rulify_no_asm: thm -> thm for turning
  1941 outer -->/All/Ball into ==>/!!; qed_spec_mp now uses rulify_no_asm;
  1942 
  1943 * Provers: delrules now handles destruct rules as well (no longer need
  1944 explicit make_elim);
  1945 
  1946 * Provers: Blast_tac now warns of and ignores "weak elimination rules" e.g.
  1947   [| inj ?f;          ?f ?x = ?f ?y; ?x = ?y ==> ?W |] ==> ?W
  1948 use instead the strong form,
  1949   [| inj ?f; ~ ?W ==> ?f ?x = ?f ?y; ?x = ?y ==> ?W |] ==> ?W
  1950 in HOL, FOL and ZF the function cla_make_elim will create such rules
  1951 from destruct-rules;
  1952 
  1953 * Provers: Simplifier.easy_setup provides a fast path to basic
  1954 Simplifier setup for new object-logics;
  1955 
  1956 * Pure: AST translation rules no longer require constant head on LHS;
  1957 
  1958 * Pure: improved name spaces: ambiguous output is qualified; support
  1959 for hiding of names;
  1960 
  1961 * system: smart setup of canonical ML_HOME, ISABELLE_INTERFACE, and
  1962 XSYMBOL_HOME; no longer need to do manual configuration in most
  1963 situations;
  1964 
  1965 * system: compression of ML heaps images may now be controlled via -c
  1966 option of isabelle and isatool usedir (currently only observed by
  1967 Poly/ML);
  1968 
  1969 * system: isatool installfonts may handle X-Symbol fonts as well (very
  1970 useful for remote X11);
  1971 
  1972 * system: provide TAGS file for Isabelle sources;
  1973 
  1974 * ML: infix 'OF' is a version of 'MRS' with more appropriate argument
  1975 order;
  1976 
  1977 * ML: renamed flags Syntax.trace_norm_ast to Syntax.trace_ast; global
  1978 timing flag supersedes proof_timing and Toplevel.trace;
  1979 
  1980 * ML: new combinators |>> and |>>> for incremental transformations
  1981 with secondary results (e.g. certain theory extensions):
  1982 
  1983 * ML: PureThy.add_defs gets additional argument to indicate potential
  1984 overloading (usually false);
  1985 
  1986 * ML: PureThy.add_thms/add_axioms/add_defs now return theorems as
  1987 results;
  1988 
  1989 
  1990 
  1991 New in Isabelle99 (October 1999)
  1992 --------------------------------
  1993 
  1994 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  1995 
  1996 * HOL: The THEN and ELSE parts of conditional expressions (if P then x else y)
  1997 are no longer simplified.  (This allows the simplifier to unfold recursive
  1998 functional programs.)  To restore the old behaviour, declare
  1999 
  2000     Delcongs [if_weak_cong];
  2001 
  2002 * HOL: Removed the obsolete syntax "Compl A"; use -A for set
  2003 complement;
  2004 
  2005 * HOL: the predicate "inj" is now defined by translation to "inj_on";
  2006 
  2007 * HOL/datatype: mutual_induct_tac no longer exists --
  2008   use induct_tac "x_1 ... x_n" instead of mutual_induct_tac ["x_1", ..., "x_n"]
  2009 
  2010 * HOL/typedef: fixed type inference for representing set; type
  2011 arguments now have to occur explicitly on the rhs as type constraints;
  2012 
  2013 * ZF: The con_defs part of an inductive definition may no longer refer
  2014 to constants declared in the same theory;
  2015 
  2016 * HOL, ZF: the function mk_cases, generated by the inductive
  2017 definition package, has lost an argument.  To simplify its result, it
  2018 uses the default simpset instead of a supplied list of theorems.
  2019 
  2020 * HOL/List: the constructors of type list are now Nil and Cons;
  2021 
  2022 * Simplifier: the type of the infix ML functions
  2023         setSSolver addSSolver setSolver addSolver
  2024 is now  simpset * solver -> simpset  where `solver' is a new abstract type
  2025 for packaging solvers. A solver is created via
  2026         mk_solver: string -> (thm list -> int -> tactic) -> solver
  2027 where the string argument is only a comment.
  2028 
  2029 
  2030 *** Proof tools ***
  2031 
  2032 * Provers/Arith/fast_lin_arith.ML contains a functor for creating a
  2033 decision procedure for linear arithmetic. Currently it is used for
  2034 types `nat', `int', and `real' in HOL (see below); it can, should and
  2035 will be instantiated for other types and logics as well.
  2036 
  2037 * The simplifier now accepts rewrite rules with flexible heads, eg
  2038      hom ?f ==> ?f(?x+?y) = ?f ?x + ?f ?y
  2039   They are applied like any rule with a non-pattern lhs, i.e. by first-order
  2040   matching.
  2041 
  2042 
  2043 *** General ***
  2044 
  2045 * New Isabelle/Isar subsystem provides an alternative to traditional
  2046 tactical theorem proving; together with the ProofGeneral/isar user
  2047 interface it offers an interactive environment for developing human
  2048 readable proof documents (Isar == Intelligible semi-automated
  2049 reasoning); for further information see isatool doc isar-ref,
  2050 src/HOL/Isar_examples and http://isabelle.in.tum.de/Isar/
  2051 
  2052 * improved and simplified presentation of theories: better HTML markup
  2053 (including colors), graph views in several sizes; isatool usedir now
  2054 provides a proper interface for user theories (via -P option); actual
  2055 document preparation based on (PDF)LaTeX is available as well (for
  2056 new-style theories only); see isatool doc system for more information;
  2057 
  2058 * native support for Proof General, both for classic Isabelle and
  2059 Isabelle/Isar;
  2060 
  2061 * ML function thm_deps visualizes dependencies of theorems and lemmas,
  2062 using the graph browser tool;
  2063 
  2064 * Isabelle manuals now also available as PDF;
  2065 
  2066 * theory loader rewritten from scratch (may not be fully
  2067 bug-compatible); old loadpath variable has been replaced by show_path,
  2068 add_path, del_path, reset_path functions; new operations such as
  2069 update_thy, touch_thy, remove_thy, use/update_thy_only (see also
  2070 isatool doc ref);
  2071 
  2072 * improved isatool install: option -k creates KDE application icon,
  2073 option -p DIR installs standalone binaries;
  2074 
  2075 * added ML_PLATFORM setting (useful for cross-platform installations);
  2076 more robust handling of platform specific ML images for SML/NJ;
  2077 
  2078 * the settings environment is now statically scoped, i.e. it is never
  2079 created again in sub-processes invoked from isabelle, isatool, or
  2080 Isabelle;
  2081 
  2082 * path element specification '~~' refers to '$ISABELLE_HOME';
  2083 
  2084 * in locales, the "assumes" and "defines" parts may be omitted if
  2085 empty;
  2086 
  2087 * new print_mode "xsymbols" for extended symbol support (e.g. genuine
  2088 long arrows);
  2089 
  2090 * new print_mode "HTML";
  2091 
  2092 * new flag show_tags controls display of tags of theorems (which are
  2093 basically just comments that may be attached by some tools);
  2094 
  2095 * Isamode 2.6 requires patch to accomodate change of Isabelle font
  2096 mode and goal output format:
  2097 
  2098 diff -r Isamode-2.6/elisp/isa-load.el Isamode/elisp/isa-load.el
  2099 244c244
  2100 <       (list (isa-getenv "ISABELLE") "-msymbols" logic-name)
  2101 ---
  2102 >       (list (isa-getenv "ISABELLE") "-misabelle_font" "-msymbols" logic-name)
  2103 diff -r Isabelle-2.6/elisp/isa-proofstate.el Isamode/elisp/isa-proofstate.el
  2104 181c181
  2105 < (defconst proofstate-proofstart-regexp "^Level [0-9]+$"
  2106 ---
  2107 > (defconst proofstate-proofstart-regexp "^Level [0-9]+"
  2108 
  2109 * function bind_thms stores lists of theorems (cf. bind_thm);
  2110 
  2111 * new shorthand tactics ftac, eatac, datac, fatac;
  2112 
  2113 * qed (and friends) now accept "" as result name; in that case the
  2114 theorem is not stored, but proper checks and presentation of the
  2115 result still apply;
  2116 
  2117 * theorem database now also indexes constants "Trueprop", "all",
  2118 "==>", "=="; thus thms_containing, findI etc. may retrieve more rules;
  2119 
  2120 
  2121 *** HOL ***
  2122 
  2123 ** HOL arithmetic **
  2124 
  2125 * There are now decision procedures for linear arithmetic over nat and
  2126 int:
  2127 
  2128 1. arith_tac copes with arbitrary formulae involving `=', `<', `<=',
  2129 `+', `-', `Suc', `min', `max' and numerical constants; other subterms
  2130 are treated as atomic; subformulae not involving type `nat' or `int'
  2131 are ignored; quantified subformulae are ignored unless they are
  2132 positive universal or negative existential. The tactic has to be
  2133 invoked by hand and can be a little bit slow. In particular, the
  2134 running time is exponential in the number of occurrences of `min' and
  2135 `max', and `-' on `nat'.
  2136 
  2137 2. fast_arith_tac is a cut-down version of arith_tac: it only takes
  2138 (negated) (in)equalities among the premises and the conclusion into
  2139 account (i.e. no compound formulae) and does not know about `min' and
  2140 `max', and `-' on `nat'. It is fast and is used automatically by the
  2141 simplifier.
  2142 
  2143 NB: At the moment, these decision procedures do not cope with mixed
  2144 nat/int formulae where the two parts interact, such as `m < n ==>
  2145 int(m) < int(n)'.
  2146 
  2147 * HOL/Numeral provides a generic theory of numerals (encoded
  2148 efficiently as bit strings); setup for types nat/int/real is in place;
  2149 INCOMPATIBILITY: since numeral syntax is now polymorphic, rather than
  2150 int, existing theories and proof scripts may require a few additional
  2151 type constraints;
  2152 
  2153 * integer division and remainder can now be performed on constant
  2154 arguments;
  2155 
  2156 * many properties of integer multiplication, division and remainder
  2157 are now available;
  2158 
  2159 * An interface to the Stanford Validity Checker (SVC) is available through the
  2160 tactic svc_tac.  Propositional tautologies and theorems of linear arithmetic
  2161 are proved automatically.  SVC must be installed separately, and its results
  2162 must be TAKEN ON TRUST (Isabelle does not check the proofs, but tags any
  2163 invocation of the underlying oracle).  For SVC see
  2164   http://verify.stanford.edu/SVC
  2165 
  2166 * IsaMakefile: the HOL-Real target now builds an actual image;
  2167 
  2168 
  2169 ** HOL misc **
  2170 
  2171 * HOL/Real/HahnBanach: the Hahn-Banach theorem for real vector spaces
  2172 (in Isabelle/Isar) -- by Gertrud Bauer;
  2173 
  2174 * HOL/BCV: generic model of bytecode verification, i.e. data-flow
  2175 analysis for assembly languages with subtypes;
  2176 
  2177 * HOL/TLA (Lamport's Temporal Logic of Actions): major reorganization
  2178 -- avoids syntactic ambiguities and treats state, transition, and
  2179 temporal levels more uniformly; introduces INCOMPATIBILITIES due to
  2180 changed syntax and (many) tactics;
  2181 
  2182 * HOL/inductive: Now also handles more general introduction rules such
  2183   as "ALL y. (y, x) : r --> y : acc r ==> x : acc r"; monotonicity
  2184   theorems are now maintained within the theory (maintained via the
  2185   "mono" attribute);
  2186 
  2187 * HOL/datatype: Now also handles arbitrarily branching datatypes
  2188   (using function types) such as
  2189 
  2190   datatype 'a tree = Atom 'a | Branch "nat => 'a tree"
  2191 
  2192 * HOL/record: record_simproc (part of the default simpset) takes care
  2193 of selectors applied to updated records; record_split_tac is no longer
  2194 part of the default claset; update_defs may now be removed from the
  2195 simpset in many cases; COMPATIBILITY: old behavior achieved by
  2196 
  2197   claset_ref () := claset() addSWrapper record_split_wrapper;
  2198   Delsimprocs [record_simproc]
  2199 
  2200 * HOL/typedef: fixed type inference for representing set; type
  2201 arguments now have to occur explicitly on the rhs as type constraints;
  2202 
  2203 * HOL/recdef (TFL): 'congs' syntax now expects comma separated list of theorem
  2204 names rather than an ML expression;
  2205 
  2206 * HOL/defer_recdef (TFL): like recdef but the well-founded relation can be
  2207 supplied later.  Program schemes can be defined, such as
  2208     "While B C s = (if B s then While B C (C s) else s)"
  2209 where the well-founded relation can be chosen after B and C have been given.
  2210 
  2211 * HOL/List: the constructors of type list are now Nil and Cons;
  2212 INCOMPATIBILITY: while [] and infix # syntax is still there, of
  2213 course, ML tools referring to List.list.op # etc. have to be adapted;
  2214 
  2215 * HOL_quantifiers flag superseded by "HOL" print mode, which is
  2216 disabled by default; run isabelle with option -m HOL to get back to
  2217 the original Gordon/HOL-style output;
  2218 
  2219 * HOL/Ord.thy: new bounded quantifier syntax (input only): ALL x<y. P,
  2220 ALL x<=y. P, EX x<y. P, EX x<=y. P;
  2221 
  2222 * HOL basic syntax simplified (more orthogonal): all variants of
  2223 All/Ex now support plain / symbolic / HOL notation; plain syntax for
  2224 Eps operator is provided as well: "SOME x. P[x]";
  2225 
  2226 * HOL/Sum.thy: sum_case has been moved to HOL/Datatype;
  2227 
  2228 * HOL/Univ.thy: infix syntax <*>, <+>, <**>, <+> eliminated and made
  2229 thus available for user theories;
  2230 
  2231 * HOLCF/IOA/Sequents: renamed 'Cons' to 'Consq' to avoid clash with
  2232 HOL/List; hardly an INCOMPATIBILITY since '>>' syntax is used all the
  2233 time;
  2234 
  2235 * HOL: new tactic smp_tac: int -> int -> tactic, which applies spec
  2236 several times and then mp;
  2237 
  2238 
  2239 *** LK ***
  2240 
  2241 * the notation <<...>> is now available as a notation for sequences of
  2242 formulas;
  2243 
  2244 * the simplifier is now installed
  2245 
  2246 * the axiom system has been generalized (thanks to Soren Heilmann)
  2247 
  2248 * the classical reasoner now has a default rule database
  2249 
  2250 
  2251 *** ZF ***
  2252 
  2253 * new primrec section allows primitive recursive functions to be given
  2254 directly (as in HOL) over datatypes and the natural numbers;
  2255 
  2256 * new tactics induct_tac and exhaust_tac for induction (or case
  2257 analysis) over datatypes and the natural numbers;
  2258 
  2259 * the datatype declaration of type T now defines the recursor T_rec;
  2260 
  2261 * simplification automatically does freeness reasoning for datatype
  2262 constructors;
  2263 
  2264 * automatic type-inference, with AddTCs command to insert new
  2265 type-checking rules;
  2266 
  2267 * datatype introduction rules are now added as Safe Introduction rules
  2268 to the claset;
  2269 
  2270 * the syntax "if P then x else y" is now available in addition to
  2271 if(P,x,y);
  2272 
  2273 
  2274 *** Internal programming interfaces ***
  2275 
  2276 * tuned simplifier trace output; new flag debug_simp;
  2277 
  2278 * structures Vartab / Termtab (instances of TableFun) offer efficient
  2279 tables indexed by indexname_ord / term_ord (compatible with aconv);
  2280 
  2281 * AxClass.axclass_tac lost the theory argument;
  2282 
  2283 * tuned current_goals_markers semantics: begin / end goal avoids
  2284 printing empty lines;
  2285 
  2286 * removed prs and prs_fn hook, which was broken because it did not
  2287 include \n in its semantics, forcing writeln to add one
  2288 uncoditionally; replaced prs_fn by writeln_fn; consider std_output:
  2289 string -> unit if you really want to output text without newline;
  2290 
  2291 * Symbol.output subject to print mode; INCOMPATIBILITY: defaults to
  2292 plain output, interface builders may have to enable 'isabelle_font'
  2293 mode to get Isabelle font glyphs as before;
  2294 
  2295 * refined token_translation interface; INCOMPATIBILITY: output length
  2296 now of type real instead of int;
  2297 
  2298 * theory loader actions may be traced via new ThyInfo.add_hook
  2299 interface (see src/Pure/Thy/thy_info.ML); example application: keep
  2300 your own database of information attached to *whole* theories -- as
  2301 opposed to intra-theory data slots offered via TheoryDataFun;
  2302 
  2303 * proper handling of dangling sort hypotheses (at last!);
  2304 Thm.strip_shyps and Drule.strip_shyps_warning take care of removing
  2305 extra sort hypotheses that can be witnessed from the type signature;
  2306 the force_strip_shyps flag is gone, any remaining shyps are simply
  2307 left in the theorem (with a warning issued by strip_shyps_warning);
  2308 
  2309 
  2310 
  2311 New in Isabelle98-1 (October 1998)
  2312 ----------------------------------
  2313 
  2314 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  2315 
  2316 * several changes of automated proof tools;
  2317 
  2318 * HOL: major changes to the inductive and datatype packages, including
  2319 some minor incompatibilities of theory syntax;
  2320 
  2321 * HOL: renamed r^-1 to 'converse' from 'inverse'; 'inj_onto' is now
  2322 called `inj_on';
  2323 
  2324 * HOL: removed duplicate thms in Arith:
  2325   less_imp_add_less  should be replaced by  trans_less_add1
  2326   le_imp_add_le      should be replaced by  trans_le_add1
  2327 
  2328 * HOL: unary minus is now overloaded (new type constraints may be
  2329 required);
  2330 
  2331 * HOL and ZF: unary minus for integers is now #- instead of #~.  In
  2332 ZF, expressions such as n#-1 must be changed to n#- 1, since #-1 is
  2333 now taken as an integer constant.
  2334 
  2335 * Pure: ML function 'theory_of' renamed to 'theory';
  2336 
  2337 
  2338 *** Proof tools ***
  2339 
  2340 * Simplifier:
  2341   1. Asm_full_simp_tac is now more aggressive.
  2342      1. It will sometimes reorient premises if that increases their power to
  2343         simplify.
  2344      2. It does no longer proceed strictly from left to right but may also
  2345         rotate premises to achieve further simplification.
  2346      For compatibility reasons there is now Asm_lr_simp_tac which is like the
  2347      old Asm_full_simp_tac in that it does not rotate premises.
  2348   2. The simplifier now knows a little bit about nat-arithmetic.
  2349 
  2350 * Classical reasoner: wrapper mechanism for the classical reasoner now
  2351 allows for selected deletion of wrappers, by introduction of names for
  2352 wrapper functionals.  This implies that addbefore, addSbefore,
  2353 addaltern, and addSaltern now take a pair (name, tactic) as argument,
  2354 and that adding two tactics with the same name overwrites the first
  2355 one (emitting a warning).
  2356   type wrapper = (int -> tactic) -> (int -> tactic)
  2357   setWrapper, setSWrapper, compWrapper and compSWrapper are replaced by
  2358   addWrapper, addSWrapper: claset * (string * wrapper) -> claset
  2359   delWrapper, delSWrapper: claset *  string            -> claset
  2360   getWrapper is renamed to appWrappers, getSWrapper to appSWrappers;
  2361 
  2362 * Classical reasoner: addbefore/addSbefore now have APPEND/ORELSE
  2363 semantics; addbefore now affects only the unsafe part of step_tac
  2364 etc.; this affects addss/auto_tac/force_tac, so EXISTING PROOFS MAY
  2365 FAIL, but proofs should be fixable easily, e.g. by replacing Auto_tac
  2366 by Force_tac;
  2367 
  2368 * Classical reasoner: setwrapper to setWrapper and compwrapper to
  2369 compWrapper; added safe wrapper (and access functions for it);
  2370 
  2371 * HOL/split_all_tac is now much faster and fails if there is nothing
  2372 to split.  Some EXISTING PROOFS MAY REQUIRE ADAPTION because the order
  2373 and the names of the automatically generated variables have changed.
  2374 split_all_tac has moved within claset() from unsafe wrappers to safe
  2375 wrappers, which means that !!-bound variables are split much more
  2376 aggressively, and safe_tac and clarify_tac now split such variables.
  2377 If this splitting is not appropriate, use delSWrapper "split_all_tac".
  2378 Note: the same holds for record_split_tac, which does the job of
  2379 split_all_tac for record fields.
  2380 
  2381 * HOL/Simplifier: Rewrite rules for case distinctions can now be added
  2382 permanently to the default simpset using Addsplits just like
  2383 Addsimps. They can be removed via Delsplits just like
  2384 Delsimps. Lower-case versions are also available.
  2385 
  2386 * HOL/Simplifier: The rule split_if is now part of the default
  2387 simpset. This means that the simplifier will eliminate all occurrences
  2388 of if-then-else in the conclusion of a goal. To prevent this, you can
  2389 either remove split_if completely from the default simpset by
  2390 `Delsplits [split_if]' or remove it in a specific call of the
  2391 simplifier using `... delsplits [split_if]'.  You can also add/delete
  2392 other case splitting rules to/from the default simpset: every datatype
  2393 generates suitable rules `split_t_case' and `split_t_case_asm' (where
  2394 t is the name of the datatype).
  2395 
  2396 * Classical reasoner / Simplifier combination: new force_tac (and
  2397 derivatives Force_tac, force) combines rewriting and classical
  2398 reasoning (and whatever other tools) similarly to auto_tac, but is
  2399 aimed to solve the given subgoal completely.
  2400 
  2401 
  2402 *** General ***
  2403 
  2404 * new top-level commands `Goal' and `Goalw' that improve upon `goal'
  2405 and `goalw': the theory is no longer needed as an explicit argument -
  2406 the current theory context is used; assumptions are no longer returned
  2407 at the ML-level unless one of them starts with ==> or !!; it is
  2408 recommended to convert to these new commands using isatool fixgoal
  2409 (backup your sources first!);
  2410 
  2411 * new top-level commands 'thm' and 'thms' for retrieving theorems from
  2412 the current theory context, and 'theory' to lookup stored theories;
  2413 
  2414 * new theory section 'locale' for declaring constants, assumptions and
  2415 definitions that have local scope;
  2416 
  2417 * new theory section 'nonterminals' for purely syntactic types;
  2418 
  2419 * new theory section 'setup' for generic ML setup functions
  2420 (e.g. package initialization);
  2421 
  2422 * the distribution now includes Isabelle icons: see
  2423 lib/logo/isabelle-{small,tiny}.xpm;
  2424 
  2425 * isatool install - install binaries with absolute references to
  2426 ISABELLE_HOME/bin;
  2427 
  2428 * isatool logo -- create instances of the Isabelle logo (as EPS);
  2429 
  2430 * print mode 'emacs' reserved for Isamode;
  2431 
  2432 * support multiple print (ast) translations per constant name;
  2433 
  2434 * theorems involving oracles are now printed with a suffixed [!];
  2435 
  2436 
  2437 *** HOL ***
  2438 
  2439 * there is now a tutorial on Isabelle/HOL (do 'isatool doc tutorial');
  2440 
  2441 * HOL/inductive package reorganized and improved: now supports mutual
  2442 definitions such as
  2443 
  2444   inductive EVEN ODD
  2445     intrs
  2446       null "0 : EVEN"
  2447       oddI "n : EVEN ==> Suc n : ODD"
  2448       evenI "n : ODD ==> Suc n : EVEN"
  2449 
  2450 new theorem list "elims" contains an elimination rule for each of the
  2451 recursive sets; inductive definitions now handle disjunctive premises
  2452 correctly (also ZF);
  2453 
  2454 INCOMPATIBILITIES: requires Inductive as an ancestor; component
  2455 "mutual_induct" no longer exists - the induction rule is always
  2456 contained in "induct";
  2457 
  2458 
  2459 * HOL/datatype package re-implemented and greatly improved: now
  2460 supports mutually recursive datatypes such as
  2461 
  2462   datatype
  2463     'a aexp = IF_THEN_ELSE ('a bexp) ('a aexp) ('a aexp)
  2464             | SUM ('a aexp) ('a aexp)
  2465             | DIFF ('a aexp) ('a aexp)
  2466             | NUM 'a
  2467   and
  2468     'a bexp = LESS ('a aexp) ('a aexp)
  2469             | AND ('a bexp) ('a bexp)
  2470             | OR ('a bexp) ('a bexp)
  2471 
  2472 as well as indirectly recursive datatypes such as
  2473 
  2474   datatype
  2475     ('a, 'b) term = Var 'a
  2476                   | App 'b ((('a, 'b) term) list)
  2477 
  2478 The new tactic  mutual_induct_tac [<var_1>, ..., <var_n>] i  performs
  2479 induction on mutually / indirectly recursive datatypes.
  2480 
  2481 Primrec equations are now stored in theory and can be accessed via
  2482 <function_name>.simps.
  2483 
  2484 INCOMPATIBILITIES:
  2485 
  2486   - Theories using datatypes must now have theory Datatype as an
  2487     ancestor.
  2488   - The specific <typename>.induct_tac no longer exists - use the
  2489     generic induct_tac instead.
  2490   - natE has been renamed to nat.exhaust - use exhaust_tac
  2491     instead of res_inst_tac ... natE. Note that the variable
  2492     names in nat.exhaust differ from the names in natE, this
  2493     may cause some "fragile" proofs to fail.
  2494   - The theorems split_<typename>_case and split_<typename>_case_asm
  2495     have been renamed to <typename>.split and <typename>.split_asm.
  2496   - Since default sorts of type variables are now handled correctly,
  2497     some datatype definitions may have to be annotated with explicit
  2498     sort constraints.
  2499   - Primrec definitions no longer require function name and type
  2500     of recursive argument.
  2501 
  2502 Consider using isatool fixdatatype to adapt your theories and proof
  2503 scripts to the new package (backup your sources first!).
  2504 
  2505 
  2506 * HOL/record package: considerably improved implementation; now
  2507 includes concrete syntax for record types, terms, updates; theorems
  2508 for surjective pairing and splitting !!-bound record variables; proof
  2509 support is as follows:
  2510 
  2511   1) standard conversions (selectors or updates applied to record
  2512 constructor terms) are part of the standard simpset;
  2513 
  2514   2) inject equations of the form ((x, y) = (x', y')) == x=x' & y=y' are
  2515 made part of standard simpset and claset via addIffs;
  2516 
  2517   3) a tactic for record field splitting (record_split_tac) is part of
  2518 the standard claset (addSWrapper);
  2519 
  2520 To get a better idea about these rules you may retrieve them via
  2521 something like 'thms "foo.simps"' or 'thms "foo.iffs"', where "foo" is
  2522 the name of your record type.
  2523 
  2524 The split tactic 3) conceptually simplifies by the following rule:
  2525 
  2526   "(!!x. PROP ?P x) == (!!a b. PROP ?P (a, b))"
  2527 
  2528 Thus any record variable that is bound by meta-all will automatically
  2529 blow up into some record constructor term, consequently the
  2530 simplifications of 1), 2) apply.  Thus force_tac, auto_tac etc. shall
  2531 solve record problems automatically.
  2532 
  2533 
  2534 * reorganized the main HOL image: HOL/Integ and String loaded by
  2535 default; theory Main includes everything;
  2536 
  2537 * automatic simplification of integer sums and comparisons, using cancellation;
  2538 
  2539 * added option_map_eq_Some and not_Some_eq to the default simpset and claset;
  2540 
  2541 * added disj_not1 = "(~P | Q) = (P --> Q)" to the default simpset;
  2542 
  2543 * many new identities for unions, intersections, set difference, etc.;
  2544 
  2545 * expand_if, expand_split, expand_sum_case and expand_nat_case are now
  2546 called split_if, split_split, split_sum_case and split_nat_case (to go
  2547 with add/delsplits);
  2548 
  2549 * HOL/Prod introduces simplification procedure unit_eq_proc rewriting
  2550 (?x::unit) = (); this is made part of the default simpset, which COULD
  2551 MAKE EXISTING PROOFS FAIL under rare circumstances (consider
  2552 'Delsimprocs [unit_eq_proc];' as last resort); also note that
  2553 unit_abs_eta_conv is added in order to counter the effect of
  2554 unit_eq_proc on (%u::unit. f u), replacing it by f rather than by
  2555 %u.f();
  2556 
  2557 * HOL/Fun INCOMPATIBILITY: `inj_onto' is now called `inj_on' (which
  2558 makes more sense);
  2559 
  2560 * HOL/Set INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
  2561   It and 'sym RS equals0D' are now in the default  claset, giving automatic
  2562   disjointness reasoning but breaking a few old proofs.
  2563 
  2564 * HOL/Relation INCOMPATIBILITY: renamed the relational operator r^-1
  2565 to 'converse' from 'inverse' (for compatibility with ZF and some
  2566 literature);
  2567 
  2568 * HOL/recdef can now declare non-recursive functions, with {} supplied as
  2569 the well-founded relation;
  2570 
  2571 * HOL/Set INCOMPATIBILITY: the complement of set A is now written -A instead of
  2572     Compl A.  The "Compl" syntax remains available as input syntax for this
  2573     release ONLY.
  2574 
  2575 * HOL/Update: new theory of function updates:
  2576     f(a:=b) == %x. if x=a then b else f x
  2577 may also be iterated as in f(a:=b,c:=d,...);
  2578 
  2579 * HOL/Vimage: new theory for inverse image of a function, syntax f-``B;
  2580 
  2581 * HOL/List:
  2582   - new function list_update written xs[i:=v] that updates the i-th
  2583     list position. May also be iterated as in xs[i:=a,j:=b,...].
  2584   - new function `upt' written [i..j(] which generates the list
  2585     [i,i+1,...,j-1], i.e. the upper bound is excluded. To include the upper
  2586     bound write [i..j], which is a shorthand for [i..j+1(].
  2587   - new lexicographic orderings and corresponding wellfoundedness theorems.
  2588 
  2589 * HOL/Arith:
  2590   - removed 'pred' (predecessor) function;
  2591   - generalized some theorems about n-1;
  2592   - many new laws about "div" and "mod";
  2593   - new laws about greatest common divisors (see theory ex/Primes);
  2594 
  2595 * HOL/Relation: renamed the relational operator r^-1 "converse"
  2596 instead of "inverse";
  2597 
  2598 * HOL/Induct/Multiset: a theory of multisets, including the wellfoundedness
  2599   of the multiset ordering;
  2600 
  2601 * directory HOL/Real: a construction of the reals using Dedekind cuts
  2602   (not included by default);
  2603 
  2604 * directory HOL/UNITY: Chandy and Misra's UNITY formalism;
  2605 
  2606 * directory HOL/Hoare: a new version of Hoare logic which permits many-sorted
  2607   programs, i.e. different program variables may have different types.
  2608 
  2609 * calling (stac rew i) now fails if "rew" has no effect on the goal
  2610   [previously, this check worked only if the rewrite rule was unconditional]
  2611   Now rew can involve either definitions or equalities (either == or =).
  2612 
  2613 
  2614 *** ZF ***
  2615 
  2616 * theory Main includes everything; INCOMPATIBILITY: theory ZF.thy contains
  2617   only the theorems proved on ZF.ML;
  2618 
  2619 * ZF INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
  2620   It and 'sym RS equals0D' are now in the default  claset, giving automatic
  2621   disjointness reasoning but breaking a few old proofs.
  2622 
  2623 * ZF/Update: new theory of function updates
  2624     with default rewrite rule  f(x:=y) ` z = if(z=x, y, f`z)
  2625   may also be iterated as in f(a:=b,c:=d,...);
  2626 
  2627 * in  let x=t in u(x), neither t nor u(x) has to be an FOL term.
  2628 
  2629 * calling (stac rew i) now fails if "rew" has no effect on the goal
  2630   [previously, this check worked only if the rewrite rule was unconditional]
  2631   Now rew can involve either definitions or equalities (either == or =).
  2632 
  2633 * case_tac provided for compatibility with HOL
  2634     (like the old excluded_middle_tac, but with subgoals swapped)
  2635 
  2636 
  2637 *** Internal programming interfaces ***
  2638 
  2639 * Pure: several new basic modules made available for general use, see
  2640 also src/Pure/README;
  2641 
  2642 * improved the theory data mechanism to support encapsulation (data
  2643 kind name replaced by private Object.kind, acting as authorization
  2644 key); new type-safe user interface via functor TheoryDataFun; generic
  2645 print_data function becomes basically useless;
  2646 
  2647 * removed global_names compatibility flag -- all theory declarations
  2648 are qualified by default;
  2649 
  2650 * module Pure/Syntax now offers quote / antiquote translation
  2651 functions (useful for Hoare logic etc. with implicit dependencies);
  2652 see HOL/ex/Antiquote for an example use;
  2653 
  2654 * Simplifier now offers conversions (asm_)(full_)rewrite: simpset ->
  2655 cterm -> thm;
  2656 
  2657 * new tactical CHANGED_GOAL for checking that a tactic modifies a
  2658 subgoal;
  2659 
  2660 * Display.print_goals function moved to Locale.print_goals;
  2661 
  2662 * standard print function for goals supports current_goals_markers
  2663 variable for marking begin of proof, end of proof, start of goal; the
  2664 default is ("", "", ""); setting current_goals_markers := ("<proof>",
  2665 "</proof>", "<goal>") causes SGML like tagged proof state printing,
  2666 for example;
  2667 
  2668 
  2669 
  2670 New in Isabelle98 (January 1998)
  2671 --------------------------------
  2672 
  2673 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  2674 
  2675 * changed lexical syntax of terms / types: dots made part of long
  2676 identifiers, e.g. "%x.x" no longer possible, should be "%x. x";
  2677 
  2678 * simpset (and claset) reference variable replaced by functions
  2679 simpset / simpset_ref;
  2680 
  2681 * no longer supports theory aliases (via merge) and non-trivial
  2682 implicit merge of thms' signatures;
  2683 
  2684 * most internal names of constants changed due to qualified names;
  2685 
  2686 * changed Pure/Sequence interface (see Pure/seq.ML);
  2687 
  2688 
  2689 *** General Changes ***
  2690 
  2691 * hierachically structured name spaces (for consts, types, axms, thms
  2692 etc.); new lexical class 'longid' (e.g. Foo.bar.x) may render much of
  2693 old input syntactically incorrect (e.g. "%x.x"); COMPATIBILITY:
  2694 isatool fixdots ensures space after dots (e.g. "%x. x"); set
  2695 long_names for fully qualified output names; NOTE: ML programs
  2696 (special tactics, packages etc.) referring to internal names may have
  2697 to be adapted to cope with fully qualified names; in case of severe
  2698 backward campatibility problems try setting 'global_names' at compile
  2699 time to have enrything declared within a flat name space; one may also
  2700 fine tune name declarations in theories via the 'global' and 'local'
  2701 section;
  2702 
  2703 * reimplemented the implicit simpset and claset using the new anytype
  2704 data filed in signatures; references simpset:simpset ref etc. are
  2705 replaced by functions simpset:unit->simpset and
  2706 simpset_ref:unit->simpset ref; COMPATIBILITY: use isatool fixclasimp
  2707 to patch your ML files accordingly;
  2708 
  2709 * HTML output now includes theory graph data for display with Java
  2710 applet or isatool browser; data generated automatically via isatool
  2711 usedir (see -i option, ISABELLE_USEDIR_OPTIONS);
  2712 
  2713 * defs may now be conditional; improved rewrite_goals_tac to handle
  2714 conditional equations;
  2715 
  2716 * defs now admits additional type arguments, using TYPE('a) syntax;
  2717 
  2718 * theory aliases via merge (e.g. M=A+B+C) no longer supported, always
  2719 creates a new theory node; implicit merge of thms' signatures is
  2720 restricted to 'trivial' ones; COMPATIBILITY: one may have to use
  2721 transfer:theory->thm->thm in (rare) cases;
  2722 
  2723 * improved handling of draft signatures / theories; draft thms (and
  2724 ctyps, cterms) are automatically promoted to real ones;
  2725 
  2726 * slightly changed interfaces for oracles: admit many per theory, named
  2727 (e.g. oracle foo = mlfun), additional name argument for invoke_oracle;
  2728 
  2729 * print_goals: optional output of const types (set show_consts and
  2730 show_types);
  2731 
  2732 * improved output of warnings (###) and errors (***);
  2733 
  2734 * subgoal_tac displays a warning if the new subgoal has type variables;
  2735 
  2736 * removed old README and Makefiles;
  2737 
  2738 * replaced print_goals_ref hook by print_current_goals_fn and result_error_fn;
  2739 
  2740 * removed obsolete init_pps and init_database;
  2741 
  2742 * deleted the obsolete tactical STATE, which was declared by
  2743     fun STATE tacfun st = tacfun st st;
  2744 
  2745 * cd and use now support path variables, e.g. $ISABELLE_HOME, or ~
  2746 (which abbreviates $HOME);
  2747 
  2748 * changed Pure/Sequence interface (see Pure/seq.ML); COMPATIBILITY:
  2749 use isatool fixseq to adapt your ML programs (this works for fully
  2750 qualified references to the Sequence structure only!);
  2751 
  2752 * use_thy no longer requires writable current directory; it always
  2753 reloads .ML *and* .thy file, if either one is out of date;
  2754 
  2755 
  2756 *** Classical Reasoner ***
  2757 
  2758 * Clarify_tac, clarify_tac, clarify_step_tac, Clarify_step_tac: new
  2759 tactics that use classical reasoning to simplify a subgoal without
  2760 splitting it into several subgoals;
  2761 
  2762 * Safe_tac: like safe_tac but uses the default claset;
  2763 
  2764 
  2765 *** Simplifier ***
  2766 
  2767 * added simplification meta rules:
  2768     (asm_)(full_)simplify: simpset -> thm -> thm;
  2769 
  2770 * simplifier.ML no longer part of Pure -- has to be loaded by object
  2771 logics (again);
  2772 
  2773 * added prems argument to simplification procedures;
  2774 
  2775 * HOL, FOL, ZF: added infix function `addsplits':
  2776   instead of `<simpset> setloop (split_tac <thms>)'
  2777   you can simply write `<simpset> addsplits <thms>'
  2778 
  2779 
  2780 *** Syntax ***
  2781 
  2782 * TYPE('a) syntax for type reflection terms;
  2783 
  2784 * no longer handles consts with name "" -- declare as 'syntax' instead;
  2785 
  2786 * pretty printer: changed order of mixfix annotation preference (again!);
  2787 
  2788 * Pure: fixed idt/idts vs. pttrn/pttrns syntactic categories;
  2789 
  2790 
  2791 *** HOL ***
  2792 
  2793 * HOL: there is a new splitter `split_asm_tac' that can be used e.g.
  2794   with `addloop' of the simplifier to faciliate case splitting in premises.
  2795 
  2796 * HOL/TLA: Stephan Merz's formalization of Lamport's Temporal Logic of Actions;
  2797 
  2798 * HOL/Auth: new protocol proofs including some for the Internet
  2799   protocol TLS;
  2800 
  2801 * HOL/Map: new theory of `maps' a la VDM;
  2802 
  2803 * HOL/simplifier: simplification procedures nat_cancel_sums for
  2804 cancelling out common nat summands from =, <, <= (in)equalities, or
  2805 differences; simplification procedures nat_cancel_factor for
  2806 cancelling common factor from =, <, <= (in)equalities over natural
  2807 sums; nat_cancel contains both kinds of procedures, it is installed by
  2808 default in Arith.thy -- this COULD MAKE EXISTING PROOFS FAIL;
  2809 
  2810 * HOL/simplifier: terms of the form
  2811   `? x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x)'  (or t=x)
  2812   are rewritten to
  2813   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t)',
  2814   and those of the form
  2815   `! x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x) --> R(x)'  (or t=x)
  2816   are rewritten to
  2817   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t) --> R(t)',
  2818 
  2819 * HOL/datatype
  2820   Each datatype `t' now comes with a theorem `split_t_case' of the form
  2821 
  2822   P(t_case f1 ... fn x) =
  2823      ( (!y1 ... ym1. x = C1 y1 ... ym1 --> P(f1 y1 ... ym1)) &
  2824         ...
  2825        (!y1 ... ymn. x = Cn y1 ... ymn --> P(f1 y1 ... ymn))
  2826      )
  2827 
  2828   and a theorem `split_t_case_asm' of the form
  2829 
  2830   P(t_case f1 ... fn x) =
  2831     ~( (? y1 ... ym1. x = C1 y1 ... ym1 & ~P(f1 y1 ... ym1)) |
  2832         ...
  2833        (? y1 ... ymn. x = Cn y1 ... ymn & ~P(f1 y1 ... ymn))
  2834      )
  2835   which can be added to a simpset via `addsplits'. The existing theorems
  2836   expand_list_case and expand_option_case have been renamed to
  2837   split_list_case and split_option_case.
  2838 
  2839 * HOL/Arithmetic:
  2840   - `pred n' is automatically converted to `n-1'.
  2841     Users are strongly encouraged not to use `pred' any longer,
  2842     because it will disappear altogether at some point.
  2843   - Users are strongly encouraged to write "0 < n" rather than
  2844     "n ~= 0". Theorems and proof tools have been modified towards this
  2845     `standard'.
  2846 
  2847 * HOL/Lists:
  2848   the function "set_of_list" has been renamed "set" (and its theorems too);
  2849   the function "nth" now takes its arguments in the reverse order and
  2850   has acquired the infix notation "!" as in "xs!n".
  2851 
  2852 * HOL/Set: UNIV is now a constant and is no longer translated to Compl{};
  2853 
  2854 * HOL/Set: The operator (UN x.B x) now abbreviates (UN x:UNIV. B x) and its
  2855   specialist theorems (like UN1_I) are gone.  Similarly for (INT x.B x);
  2856 
  2857 * HOL/record: extensible records with schematic structural subtyping
  2858 (single inheritance); EXPERIMENTAL version demonstrating the encoding,
  2859 still lacks various theorems and concrete record syntax;
  2860 
  2861 
  2862 *** HOLCF ***
  2863 
  2864 * removed "axioms" and "generated by" sections;
  2865 
  2866 * replaced "ops" section by extended "consts" section, which is capable of
  2867   handling the continuous function space "->" directly;
  2868 
  2869 * domain package:
  2870   . proves theorems immediately and stores them in the theory,
  2871   . creates hierachical name space,
  2872   . now uses normal mixfix annotations (instead of cinfix...),
  2873   . minor changes to some names and values (for consistency),
  2874   . e.g. cases -> casedist, dists_eq -> dist_eqs, [take_lemma] -> take_lemmas,
  2875   . separator between mutual domain defs: changed "," to "and",
  2876   . improved handling of sort constraints;  now they have to
  2877     appear on the left-hand side of the equations only;
  2878 
  2879 * fixed LAM <x,y,zs>.b syntax;
  2880 
  2881 * added extended adm_tac to simplifier in HOLCF -- can now discharge
  2882 adm (%x. P (t x)), where P is chainfinite and t continuous;
  2883 
  2884 
  2885 *** FOL and ZF ***
  2886 
  2887 * FOL: there is a new splitter `split_asm_tac' that can be used e.g.
  2888   with `addloop' of the simplifier to faciliate case splitting in premises.
  2889 
  2890 * qed_spec_mp, qed_goal_spec_mp, qed_goalw_spec_mp are available, as
  2891 in HOL, they strip ALL and --> from proved theorems;
  2892 
  2893 
  2894 
  2895 New in Isabelle94-8 (May 1997)
  2896 ------------------------------
  2897 
  2898 *** General Changes ***
  2899 
  2900 * new utilities to build / run / maintain Isabelle etc. (in parts
  2901 still somewhat experimental); old Makefiles etc. still functional;
  2902 
  2903 * new 'Isabelle System Manual';
  2904 
  2905 * INSTALL text, together with ./configure and ./build scripts;
  2906 
  2907 * reimplemented type inference for greater efficiency, better error
  2908 messages and clean internal interface;
  2909 
  2910 * prlim command for dealing with lots of subgoals (an easier way of
  2911 setting goals_limit);
  2912 
  2913 
  2914 *** Syntax ***
  2915 
  2916 * supports alternative (named) syntax tables (parser and pretty
  2917 printer); internal interface is provided by add_modesyntax(_i);
  2918 
  2919 * Pure, FOL, ZF, HOL, HOLCF now support symbolic input and output; to
  2920 be used in conjunction with the Isabelle symbol font; uses the
  2921 "symbols" syntax table;
  2922 
  2923 * added token_translation interface (may translate name tokens in
  2924 arbitrary ways, dependent on their type (free, bound, tfree, ...) and
  2925 the current print_mode); IMPORTANT: user print translation functions
  2926 are responsible for marking newly introduced bounds
  2927 (Syntax.mark_boundT);
  2928 
  2929 * token translations for modes "xterm" and "xterm_color" that display
  2930 names in bold, underline etc. or colors (which requires a color
  2931 version of xterm);
  2932 
  2933 * infixes may now be declared with names independent of their syntax;
  2934 
  2935 * added typed_print_translation (like print_translation, but may
  2936 access type of constant);
  2937 
  2938 
  2939 *** Classical Reasoner ***
  2940 
  2941 Blast_tac: a new tactic!  It is often more powerful than fast_tac, but has
  2942 some limitations.  Blast_tac...
  2943   + ignores addss, addbefore, addafter; this restriction is intrinsic
  2944   + ignores elimination rules that don't have the correct format
  2945         (the conclusion MUST be a formula variable)
  2946   + ignores types, which can make HOL proofs fail
  2947   + rules must not require higher-order unification, e.g. apply_type in ZF
  2948     [message "Function Var's argument not a bound variable" relates to this]
  2949   + its proof strategy is more general but can actually be slower
  2950 
  2951 * substitution with equality assumptions no longer permutes other
  2952 assumptions;
  2953 
  2954 * minor changes in semantics of addafter (now called addaltern); renamed
  2955 setwrapper to setWrapper and compwrapper to compWrapper; added safe wrapper
  2956 (and access functions for it);
  2957 
  2958 * improved combination of classical reasoner and simplifier:
  2959   + functions for handling clasimpsets
  2960   + improvement of addss: now the simplifier is called _after_ the
  2961     safe steps.
  2962   + safe variant of addss called addSss: uses safe simplifications
  2963     _during_ the safe steps. It is more complete as it allows multiple
  2964     instantiations of unknowns (e.g. with slow_tac).
  2965 
  2966 *** Simplifier ***
  2967 
  2968 * added interface for simplification procedures (functions that
  2969 produce *proven* rewrite rules on the fly, depending on current
  2970 redex);
  2971 
  2972 * ordering on terms as parameter (used for ordered rewriting);
  2973 
  2974 * new functions delcongs, deleqcongs, and Delcongs. richer rep_ss;
  2975 
  2976 * the solver is now split into a safe and an unsafe part.
  2977 This should be invisible for the normal user, except that the
  2978 functions setsolver and addsolver have been renamed to setSolver and
  2979 addSolver; added safe_asm_full_simp_tac;
  2980 
  2981 
  2982 *** HOL ***
  2983 
  2984 * a generic induction tactic `induct_tac' which works for all datatypes and
  2985 also for type `nat';
  2986 
  2987 * a generic case distinction tactic `exhaust_tac' which works for all
  2988 datatypes and also for type `nat';
  2989 
  2990 * each datatype comes with a function `size';
  2991 
  2992 * patterns in case expressions allow tuple patterns as arguments to
  2993 constructors, for example `case x of [] => ... | (x,y,z)#ps => ...';
  2994 
  2995 * primrec now also works with type nat;
  2996 
  2997 * recdef: a new declaration form, allows general recursive functions to be
  2998 defined in theory files.  See HOL/ex/Fib, HOL/ex/Primes, HOL/Subst/Unify.
  2999 
  3000 * the constant for negation has been renamed from "not" to "Not" to
  3001 harmonize with FOL, ZF, LK, etc.;
  3002 
  3003 * HOL/ex/LFilter theory of a corecursive "filter" functional for
  3004 infinite lists;
  3005 
  3006 * HOL/Modelcheck demonstrates invocation of model checker oracle;
  3007 
  3008 * HOL/ex/Ring.thy declares cring_simp, which solves equational
  3009 problems in commutative rings, using axiomatic type classes for + and *;
  3010 
  3011 * more examples in HOL/MiniML and HOL/Auth;
  3012 
  3013 * more default rewrite rules for quantifiers, union/intersection;
  3014 
  3015 * a new constant `arbitrary == @x.False';
  3016 
  3017 * HOLCF/IOA replaces old HOL/IOA;
  3018 
  3019 * HOLCF changes: derived all rules and arities
  3020   + axiomatic type classes instead of classes
  3021   + typedef instead of faking type definitions
  3022   + eliminated the internal constants less_fun, less_cfun, UU_fun, UU_cfun etc.
  3023   + new axclasses cpo, chfin, flat with flat < chfin < pcpo < cpo < po
  3024   + eliminated the types void, one, tr
  3025   + use unit lift and bool lift (with translations) instead of one and tr
  3026   + eliminated blift from Lift3.thy (use Def instead of blift)
  3027   all eliminated rules are derived as theorems --> no visible changes ;
  3028 
  3029 
  3030 *** ZF ***
  3031 
  3032 * ZF now has Fast_tac, Simp_tac and Auto_tac.  Union_iff is a now a default
  3033 rewrite rule; this may affect some proofs.  eq_cs is gone but can be put back
  3034 as ZF_cs addSIs [equalityI];
  3035 
  3036 
  3037 
  3038 New in Isabelle94-7 (November 96)
  3039 ---------------------------------
  3040 
  3041 * allowing negative levels (as offsets) in prlev and choplev;
  3042 
  3043 * super-linear speedup for large simplifications;
  3044 
  3045 * FOL, ZF and HOL now use miniscoping: rewriting pushes
  3046 quantifications in as far as possible (COULD MAKE EXISTING PROOFS
  3047 FAIL); can suppress it using the command Delsimps (ex_simps @
  3048 all_simps); De Morgan laws are also now included, by default;
  3049 
  3050 * improved printing of ==>  :  ~:
  3051 
  3052 * new object-logic "Sequents" adds linear logic, while replacing LK
  3053 and Modal (thanks to Sara Kalvala);
  3054 
  3055 * HOL/Auth: correctness proofs for authentication protocols;
  3056 
  3057 * HOL: new auto_tac combines rewriting and classical reasoning (many
  3058 examples on HOL/Auth);
  3059 
  3060 * HOL: new command AddIffs for declaring theorems of the form P=Q to
  3061 the rewriter and classical reasoner simultaneously;
  3062 
  3063 * function uresult no longer returns theorems in "standard" format;
  3064 regain previous version by: val uresult = standard o uresult;
  3065 
  3066 
  3067 
  3068 New in Isabelle94-6
  3069 -------------------
  3070 
  3071 * oracles -- these establish an interface between Isabelle and trusted
  3072 external reasoners, which may deliver results as theorems;
  3073 
  3074 * proof objects (in particular record all uses of oracles);
  3075 
  3076 * Simp_tac, Fast_tac, etc. that refer to implicit simpset / claset;
  3077 
  3078 * "constdefs" section in theory files;
  3079 
  3080 * "primrec" section (HOL) no longer requires names;
  3081 
  3082 * internal type "tactic" now simply "thm -> thm Sequence.seq";
  3083 
  3084 
  3085 
  3086 New in Isabelle94-5
  3087 -------------------
  3088 
  3089 * reduced space requirements;
  3090 
  3091 * automatic HTML generation from theories;
  3092 
  3093 * theory files no longer require "..." (quotes) around most types;
  3094 
  3095 * new examples, including two proofs of the Church-Rosser theorem;
  3096 
  3097 * non-curried (1994) version of HOL is no longer distributed;
  3098 
  3099 
  3100 
  3101 New in Isabelle94-4
  3102 -------------------
  3103 
  3104 * greatly reduced space requirements;
  3105 
  3106 * theory files (.thy) no longer require \...\ escapes at line breaks;
  3107 
  3108 * searchable theorem database (see the section "Retrieving theorems" on
  3109 page 8 of the Reference Manual);
  3110 
  3111 * new examples, including Grabczewski's monumental case study of the
  3112 Axiom of Choice;
  3113 
  3114 * The previous version of HOL renamed to Old_HOL;
  3115 
  3116 * The new version of HOL (previously called CHOL) uses a curried syntax
  3117 for functions.  Application looks like f a b instead of f(a,b);
  3118 
  3119 * Mutually recursive inductive definitions finally work in HOL;
  3120 
  3121 * In ZF, pattern-matching on tuples is now available in all abstractions and
  3122 translates to the operator "split";
  3123 
  3124 
  3125 
  3126 New in Isabelle94-3
  3127 -------------------
  3128 
  3129 * new infix operator, addss, allowing the classical reasoner to
  3130 perform simplification at each step of its search.  Example:
  3131         fast_tac (cs addss ss)
  3132 
  3133 * a new logic, CHOL, the same as HOL, but with a curried syntax
  3134 for functions.  Application looks like f a b instead of f(a,b).  Also pairs
  3135 look like (a,b) instead of <a,b>;
  3136 
  3137 * PLEASE NOTE: CHOL will eventually replace HOL!
  3138 
  3139 * In CHOL, pattern-matching on tuples is now available in all abstractions.
  3140 It translates to the operator "split".  A new theory of integers is available;
  3141 
  3142 * In ZF, integer numerals now denote two's-complement binary integers.
  3143 Arithmetic operations can be performed by rewriting.  See ZF/ex/Bin.ML;
  3144 
  3145 * Many new examples: I/O automata, Church-Rosser theorem, equivalents
  3146 of the Axiom of Choice;
  3147 
  3148 
  3149 
  3150 New in Isabelle94-2
  3151 -------------------
  3152 
  3153 * Significantly faster resolution;
  3154 
  3155 * the different sections in a .thy file can now be mixed and repeated
  3156 freely;
  3157 
  3158 * Database of theorems for FOL, HOL and ZF.  New
  3159 commands including qed, qed_goal and bind_thm store theorems in the database.
  3160 
  3161 * Simple database queries: return a named theorem (get_thm) or all theorems of
  3162 a given theory (thms_of), or find out what theory a theorem was proved in
  3163 (theory_of_thm);
  3164 
  3165 * Bugs fixed in the inductive definition and datatype packages;
  3166 
  3167 * The classical reasoner provides deepen_tac and depth_tac, making FOL_dup_cs
  3168 and HOL_dup_cs obsolete;
  3169 
  3170 * Syntactic ambiguities caused by the new treatment of syntax in Isabelle94-1
  3171 have been removed;
  3172 
  3173 * Simpler definition of function space in ZF;
  3174 
  3175 * new results about cardinal and ordinal arithmetic in ZF;
  3176 
  3177 * 'subtype' facility in HOL for introducing new types as subsets of existing
  3178 types;
  3179 
  3180 
  3181 $Id$