NEWS
author wenzelm
Tue Jul 05 15:39:48 2005 +0200 (2005-07-05)
changeset 16690 b8b2579a2509
parent 16689 05b986733a59
child 16717 710a7a7a2b65
permissions -rw-r--r--
tuned;
     1 Isabelle NEWS -- history user-relevant changes
     2 ==============================================
     3 
     4 New in this Isabelle release
     5 ----------------------------
     6 
     7 *** General ***
     8 
     9 * Theory headers: the new header syntax for Isar theories is
    10 
    11   theory <name>
    12   imports <theory1> ... <theoryN>
    13   uses <file1> ... <fileM>
    14   begin
    15 
    16 where the 'uses' part is optional.  The previous syntax
    17 
    18   theory <name> = <theory1> + ... + <theoryN>:
    19 
    20 will disappear in the next release.  Note that there is no change in
    21 ancient non-Isar theories.
    22 
    23 * Theory loader: parent theories can now also be referred to via
    24 relative and absolute paths.
    25 
    26 * Improved version of thms_containing searches for a list of criteria
    27 instead of a list of constants. Known criteria are: intro, elim, dest,
    28 name:string, simp:term, and any term. Criteria can be preceded by '-'
    29 to select theorems that do not match. Intro, elim, dest select
    30 theorems that match the current goal, name:s selects theorems whose
    31 fully qualified name contain s, and simp:term selects all
    32 simplification rules whose lhs match term.  Any other term is
    33 interpreted as pattern and selects all theorems matching the
    34 pattern. Available in ProofGeneral under 'ProofGeneral -> Find
    35 Theorems' or C-c C-f.  Example:
    36 
    37   C-c C-f (100) "(_::nat) + _ + _" intro -name:"HOL."
    38 
    39 prints the last 100 theorems matching the pattern "(_::nat) + _ + _",
    40 matching the current goal as introduction rule and not having "HOL."
    41 in their name (i.e. not being defined in theory HOL).
    42 
    43 
    44 *** Document preparation ***
    45 
    46 * Commands 'display_drafts' and 'print_drafts' perform simple output
    47 of raw sources.  Only those symbols that do not require additional
    48 LaTeX packages (depending on comments in isabellesym.sty) are
    49 displayed properly, everything else is left verbatim.  isatool display
    50 and isatool print are used as front ends (these are subject to the
    51 DVI/PDF_VIEWER and PRINT_COMMAND settings, respectively).
    52 
    53 * There is now a flag to control hiding of proofs and some other
    54 commands (such as 'ML' or 'parse/print_translation') in document
    55 output.  Hiding is enabled by default, and can be disabled by the
    56 option '-H false' of isatool usedir or by resetting the reference
    57 variable IsarOutput.hide_commands in ML.  Additional commands to be
    58 hidden may be declared using IsarOutput.add_hidden_commands.
    59 
    60 * Several new antiquotation:
    61 
    62   @{term_type term} prints a term with its type annotated;
    63 
    64   @{typeof term} prints the type of a term;
    65 
    66   @{const const} is the same as @{term const}, but checks that the
    67   argument is a known logical constant;
    68 
    69   @{term_style style term} and @{thm_style style thm} print a term or
    70   theorem applying a "style" to it
    71 
    72 Predefined styles are 'lhs' and 'rhs' printing the lhs/rhs of
    73 definitions, equations, inequations etc., 'concl' printing only the
    74 conclusion of a meta-logical statement theorem, and 'prem1' .. 'prem9'
    75 to print the specified premise.  TermStyle.add_style provides an ML
    76 interface for introducing further styles.  See also the "LaTeX Sugar"
    77 document practical applications.
    78 
    79 
    80 *** Pure ***
    81 
    82 * Considerably improved version of 'constdefs' command.  Now performs
    83 automatic type-inference of declared constants; additional support for
    84 local structure declarations (cf. locales and HOL records), see also
    85 isar-ref manual.  Potential INCOMPATIBILITY: need to observe strictly
    86 sequential dependencies of definitions within a single 'constdefs'
    87 section; moreover, the declared name needs to be an identifier.  If
    88 all fails, consider to fall back on 'consts' and 'defs' separately.
    89 
    90 * Improved indexed syntax and implicit structures.  First of all,
    91 indexed syntax provides a notational device for subscripted
    92 application, using the new syntax \<^bsub>term\<^esub> for arbitrary
    93 expressions.  Secondly, in a local context with structure
    94 declarations, number indexes \<^sub>n or the empty index (default
    95 number 1) refer to a certain fixed variable implicitly; option
    96 show_structs controls printing of implicit structures.  Typical
    97 applications of these concepts involve record types and locales.
    98 
    99 * New command 'no_syntax' removes grammar declarations (and
   100 translations) resulting from the given syntax specification, which is
   101 interpreted in the same manner as for the 'syntax' command.
   102 
   103 * 'Advanced' translation functions (parse_translation etc.) may depend
   104 on the signature of the theory context being presently used for
   105 parsing/printing, see also isar-ref manual.
   106 
   107 * Improved internal renaming of symbolic identifiers -- attach primes
   108 instead of base 26 numbers.
   109 
   110 * New flag show_question_marks controls printing of leading question
   111 marks in schematic variable names.
   112 
   113 * In schematic variable names, *any* symbol following \<^isub> or
   114 \<^isup> is now treated as part of the base name.  For example, the
   115 following works without printing of awkward ".0" indexes:
   116 
   117   lemma "x\<^isub>1 = x\<^isub>2 ==> x\<^isub>2 = x\<^isub>1"
   118     by simp
   119 
   120 * Inner syntax includes (*(*nested*) comments*).
   121 
   122 * Pretty pinter now supports unbreakable blocks, specified in mixfix
   123 annotations as "(00...)".
   124 
   125 * Clear separation of logical types and nonterminals, where the latter
   126 may only occur in 'syntax' specifications or type abbreviations.
   127 Before that distinction was only partially implemented via type class
   128 "logic" vs. "{}".  Potential INCOMPATIBILITY in rare cases of improper
   129 use of 'types'/'consts' instead of 'nonterminals'/'syntax'.  Some very
   130 exotic syntax specifications may require further adaption
   131 (e.g. Cube/Base.thy).
   132 
   133 * Removed obsolete type class "logic", use the top sort {} instead.
   134 Note that non-logical types should be declared as 'nonterminals'
   135 rather than 'types'.  INCOMPATIBILITY for new object-logic
   136 specifications.
   137 
   138 * Simplifier: can now control the depth to which conditional rewriting
   139 is traced via the PG menu Isabelle -> Settings -> Trace Simp Depth
   140 Limit.
   141 
   142 * Simplifier: simplification procedures may now take the current
   143 simpset into account (cf. Simplifier.simproc(_i) / mk_simproc
   144 interface), which is very useful for calling the Simplifier
   145 recursively.  Minor INCOMPATIBILITY: the 'prems' argument of simprocs
   146 is gone -- use prems_of_ss on the simpset instead.  Moreover, the
   147 low-level mk_simproc no longer applies Logic.varify internally, to
   148 allow for use in a context of fixed variables.
   149 
   150 * thin_tac now works even if the assumption being deleted contains !!
   151 or ==>.  More generally, erule now works even if the major premise of
   152 the elimination rule contains !! or ==>.
   153 
   154 * Reorganized bootstrapping of the Pure theories; CPure is now derived
   155 from Pure, which contains all common declarations already.  Both
   156 theories are defined via plain Isabelle/Isar .thy files.
   157 INCOMPATIBILITY: elements of CPure (such as the CPure.intro /
   158 CPure.elim / CPure.dest attributes) now appear in the Pure name space;
   159 use isatool fixcpure to adapt your theory and ML sources.
   160 
   161 * New syntax 'name(i-j, i-, i, ...)' for referring to specific
   162 selections of theorems in named facts via index ranges.
   163 
   164 * More efficient treatment of intermediate checkpoints in interactive
   165 theory development.
   166 
   167 
   168 *** Locales ***
   169   
   170 * New commands for the interpretation of locale expressions in
   171 theories ('interpretation') and proof contexts ('interpret').  These
   172 take an instantiation of the locale parameters and compute proof
   173 obligations from the instantiated specification.  After the
   174 obligations have been discharged, the instantiated theorems of the
   175 locale are added to the theory or proof context.  Interpretation is
   176 smart in that already active interpretations do not occur in proof
   177 obligations, neither are instantiated theorems stored in duplicate.
   178 Use print_interps to inspect active interpretations of a particular
   179 locale.  For details, see the Isar Reference manual.
   180 
   181 INCOMPATIBILITY: former 'instantiate' has been withdrawn, use
   182 'interpret' instead.
   183 
   184 * Proper static binding of attribute syntax -- i.e. types / terms /
   185 facts mentioned as arguments are always those of the locale definition
   186 context, independently of the context of later invocations.  Moreover,
   187 locale operations (renaming and type / term instantiation) are applied
   188 to attribute arguments as expected.
   189 
   190 INCOMPATIBILITY of the ML interface: always pass Attrib.src instead of
   191 actual attributes; rare situations may require Attrib.attribute to
   192 embed those attributes into Attrib.src that lack concrete syntax.
   193 Attribute implementations need to cooperate properly with the static
   194 binding mechanism.  Basic parsers Args.XXX_typ/term/prop and
   195 Attrib.XXX_thm etc. already do the right thing without further
   196 intervention.  Only unusual applications -- such as "where" or "of"
   197 (cf. src/Pure/Isar/attrib.ML), which process arguments depending both
   198 on the context and the facts involved -- may have to assign parsed
   199 values to argument tokens explicitly.
   200 
   201 * New context element "constrains" adds type constraints to parameters --
   202 there is no logical significance.
   203 
   204 * Context expressions: renaming parameters permits syntax
   205 redeclaration as well.
   206 
   207 * Locale definition: 'includes' now disallowed.
   208 
   209 * Changed parameter management in theorem generation for long goal
   210 statements with 'includes'.  INCOMPATIBILITY: produces a different
   211 theorem statement in rare situations.
   212 
   213 * Attributes 'induct' and 'cases': type or set names may now be
   214 locally fixed variables as well.
   215 
   216 * Antiquotations now provide the option 'locale=NAME' to specify an
   217 alternative context used for evaluating and printing the subsequent
   218 argument, as in @{thm [locale=LC] fold_commute}, for example.
   219 
   220 
   221 *** Provers ***
   222 
   223 * Provers/hypsubst.ML: improved version of the subst method, for
   224 single-step rewriting: it now works in bound variable contexts. New is
   225 'subst (asm)', for rewriting an assumption.  INCOMPATIBILITY: may
   226 rewrite a different subterm than the original subst method, which is
   227 still available as 'simplesubst'.
   228 
   229 * Provers/quasi.ML: new transitivity reasoners for transitivity only
   230 and quasi orders.
   231 
   232 * Provers/trancl.ML: new transitivity reasoner for transitive and
   233 reflexive-transitive closure of relations.
   234 
   235 * Provers/blast.ML: new reference depth_limit to make blast's depth
   236 limit (previously hard-coded with a value of 20) user-definable.
   237 
   238 * Provers/simplifier.ML has been moved to Pure, where Simplifier.setup
   239 is peformed already.  Object-logics merely need to finish their
   240 initial simpset configuration as before.  INCOMPATIBILITY.
   241 
   242 
   243 *** HOL ***
   244 
   245 * Symbolic syntax of Hilbert Choice Operator is now as follows:
   246 
   247   syntax (epsilon)
   248     "_Eps" :: "[pttrn, bool] => 'a"    ("(3\<some>_./ _)" [0, 10] 10)
   249 
   250 The symbol \<some> is displayed as the alternative epsilon of LaTeX
   251 and x-symbol; use option '-m epsilon' to get it actually printed.
   252 Moreover, the mathematically important symbolic identifier \<epsilon>
   253 becomes available as variable, constant etc.  INCOMPATIBILITY,
   254 
   255 * "x > y" abbreviates "y < x" and "x >= y" abbreviates "y <= x".
   256 Similarly for all quantifiers: "ALL x > y" etc.  The x-symbol for >=
   257 is \<ge>.
   258 
   259 * "{x:A. P}" abbreviates "{x. x:A & P}", and similarly for "\<in>"
   260 instead of ":".
   261 
   262 * theory SetInterval: changed the syntax for open intervals:
   263 
   264   Old       New
   265   {..n(}    {..<n}
   266   {)n..}    {n<..}
   267   {m..n(}   {m..<n}
   268   {)m..n}   {m<..n}
   269   {)m..n(}  {m<..<n}
   270 
   271 The old syntax is still supported but will disappear in the next
   272 release.  For conversion use the following Emacs search and replace
   273 patterns (these are not perfect but work quite well):
   274 
   275   {)\([^\.]*\)\.\.  ->  {\1<\.\.}
   276   \.\.\([^(}]*\)(}  ->  \.\.<\1}
   277 
   278 * theory Finite_Set: changed the syntax for 'setsum', summation over
   279 finite sets: "setsum (%x. e) A", which used to be "\<Sum>x:A. e", is
   280 now either "SUM x:A. e" or "\<Sum>x \<in> A. e".
   281 
   282 Some new syntax forms are available:
   283 
   284   "\<Sum>x | P. e"      for     "setsum (%x. e) {x. P}"
   285   "\<Sum>x = a..b. e"   for     "setsum (%x. e) {a..b}"
   286   "\<Sum>x = a..<b. e"  for     "setsum (%x. e) {a..<b}"
   287   "\<Sum>x < k. e"      for     "setsum (%x. e) {..<k}"
   288 
   289 The latter form "\<Sum>x < k. e" used to be based on a separate
   290 function "Summation", which has been discontinued.
   291 
   292 * theory Finite_Set: in structured induction proofs, the insert case
   293 is now 'case (insert x F)' instead of the old counterintuitive 'case
   294 (insert F x)'.
   295 
   296 * The 'refute' command has been extended to support a much larger
   297 fragment of HOL, including axiomatic type classes, constdefs and
   298 typedefs, inductive datatypes and recursion.
   299 
   300 * Datatype induction via method 'induct' now preserves the name of the
   301 induction variable. For example, when proving P(xs::'a list) by
   302 induction on xs, the induction step is now P(xs) ==> P(a#xs) rather
   303 than P(list) ==> P(a#list) as previously.  Potential INCOMPATIBILITY
   304 in unstructured proof scripts.
   305 
   306 * Reworked implementation of records.  Improved scalability for
   307 records with many fields, avoiding performance problems for type
   308 inference. Records are no longer composed of nested field types, but
   309 of nested extension types. Therefore the record type only grows linear
   310 in the number of extensions and not in the number of fields.  The
   311 top-level (users) view on records is preserved.  Potential
   312 INCOMPATIBILITY only in strange cases, where the theory depends on the
   313 old record representation. The type generated for a record is called
   314 <record_name>_ext_type.
   315 
   316 Flag record_quick_and_dirty_sensitive can be enabled to skip the
   317 proofs triggered by a record definition or a simproc (if
   318 quick_and_dirty is enabled).  Definitions of large records can take
   319 quite long.
   320 
   321 New simproc record_upd_simproc for simplification of multiple record
   322 updates enabled by default.  Moreover, trivial updates are also
   323 removed: r(|x := x r|) = r.  INCOMPATIBILITY: old proofs break
   324 occasionally, since simplification is more powerful by default.
   325 
   326 * Simplifier: automatically reasons about transitivity chains
   327 involving "trancl" (r^+) and "rtrancl" (r^*) by setting up tactics
   328 provided by Provers/trancl.ML as additional solvers.  INCOMPATIBILITY:
   329 old proofs break occasionally as simplification may now solve more
   330 goals than previously.
   331 
   332 * Simplifier: converts x <= y into x = y if assumption y <= x is
   333 present.  Works for all partial orders (class "order"), in particular
   334 numbers and sets.  For linear orders (e.g. numbers) it treats ~ x < y
   335 just like y <= x.
   336 
   337 * Simplifier: new simproc for "let x = a in f x".  If a is a free or
   338 bound variable or a constant then the let is unfolded.  Otherwise
   339 first a is simplified to b, and then f b is simplified to g. If
   340 possible we abstract b from g arriving at "let x = b in h x",
   341 otherwise we unfold the let and arrive at g.  The simproc can be
   342 enabled/disabled by the reference use_let_simproc.  Potential
   343 INCOMPATIBILITY since simplification is more powerful by default.
   344 
   345 * Classical reasoning: the meson method now accepts theorems as arguments.
   346 
   347 
   348 *** HOLCF ***
   349 
   350 * HOLCF: discontinued special version of 'constdefs' (which used to
   351 support continuous functions) in favor of the general Pure one with
   352 full type-inference.
   353 
   354 
   355 *** ZF ***
   356 
   357 * ZF/ex: theories Group and Ring provide examples in abstract algebra,
   358 including the First Isomorphism Theorem (on quotienting by the kernel
   359 of a homomorphism).
   360 
   361 * ZF/Simplifier: install second copy of type solver that actually
   362 makes use of TC rules declared to Isar proof contexts (or locales);
   363 the old version is still required for ML proof scripts.
   364 
   365 
   366 *** ML ***
   367 
   368 * Pure/library.ML no longer defines its own option datatype, but uses
   369 that of the SML basis, which has constructors NONE and SOME instead of
   370 None and Some, as well as exception Option.Option instead of OPTION.
   371 The functions the, if_none, is_some, is_none have been adapted
   372 accordingly, while Option.map replaces apsome.
   373 
   374 * The exception LIST has been given up in favour of the standard
   375 exceptions Empty and Subscript, as well as Library.UnequalLengths.
   376 Function like Library.hd and Library.tl are superceded by the standard
   377 hd and tl functions etc.
   378 
   379 A number of basic functions are now no longer exported to the ML
   380 toplevel, as they are variants of standard functions.  The following
   381 suggests how one can translate existing code:
   382 
   383     rev_append xs ys = List.revAppend (xs, ys)
   384     nth_elem (i, xs) = List.nth (xs, i)
   385     last_elem xs = List.last xs
   386     flat xss = List.concat xss
   387     seq fs = List.app fs
   388     partition P xs = List.partition P xs
   389     filter P xs = List.filter P xs
   390     mapfilter f xs = List.mapPartial f xs
   391 
   392 * Pure: output via the Isabelle channels of writeln/warning/error
   393 etc. is now passed through Output.output, with a hook for arbitrary
   394 transformations depending on the print_mode (cf. Output.add_mode --
   395 the first active mode that provides a output function wins).  Already
   396 formatted output may be embedded into further text via Output.raw; the
   397 result of Pretty.string_of/str_of and derived functions
   398 (string_of_term/cterm/thm etc.) is already marked raw to accommodate
   399 easy composition of diagnostic messages etc.  Programmers rarely need
   400 to care about Output.output or Output.raw at all, with some notable
   401 exceptions: Output.output is required when bypassing the standard
   402 channels (writeln etc.), or in token translations to produce properly
   403 formatted results; Output.raw is required when capturing already
   404 output material that will eventually be presented to the user a second
   405 time.  For the default print mode, both Output.output and Output.raw
   406 have no effect.
   407 
   408 * Pure: print_tac now outputs the goal through the trace channel.
   409 
   410 * Isar debugging: new reference Toplevel.debug (default false).  Set
   411 to make printing of exceptions THM, TERM, TYPE and THEORY more
   412 verbose.
   413 
   414 * Isar profiling: new reference Toplevel.profiling (default 0).  For
   415 Poly/ML, set to 1 to profile time, 2 to profile space (which increases
   416 the runtime).
   417 
   418 * Pure: structure OrdList (cf. Pure/General/ord_list.ML) provides a
   419 reasonably efficient light-weight implementation of sets as lists.
   420 
   421 * Pure: more efficient orders for basic syntactic entities: added
   422 fast_string_ord, fast_indexname_ord, fast_term_ord; changed sort_ord
   423 and typ_ord to use fast_string_ord and fast_indexname_ord (term_ord is
   424 NOT affected); structures Symtab, Vartab, Typtab, Termtab use the fast
   425 orders now -- potential INCOMPATIBILITY for code that depends on a
   426 particular order for Symtab.keys, Symtab.dest, etc. (consider using
   427 Library.sort_strings on result).
   428 
   429 * Pure: name spaces have been refined, with significant changes of the
   430 internal interfaces -- INCOMPATIBILITY.  Renamed cond_extern(_table)
   431 to extern(_table).  The plain name entry path is superceded by a
   432 general 'naming' context, which also includes the 'policy' to produce
   433 a fully qualified name and external accesses of a fully qualified
   434 name; NameSpace.extend is superceded by context dependent
   435 Sign.declare_name.  Several theory and proof context operations modify
   436 the naming context.  Especially note Theory.restore_naming and
   437 ProofContext.restore_naming to get back to a sane state; note that
   438 Theory.add_path is no longer sufficient to recover from
   439 Theory.absolute_path in particular.
   440 
   441 * Pure: new flags short_names (default false) and unique_names
   442 (default true) for controlling output of qualified names.  If
   443 short_names is set, names are printed unqualified.  If unique_names is
   444 reset, the name prefix is reduced to the minimum required to achieve
   445 the original result when interning again, even if there is an overlap
   446 with earlier declarations.
   447 
   448 * Pure/TheoryDataFun: change of the argument structure; 'prep_ext' is
   449 now 'extend', and 'merge' gets an additional Pretty.pp argument
   450 (useful for printing error messages).  INCOMPATIBILITY.
   451 
   452 * Pure: major reorganization of the theory context.  Type Sign.sg and
   453 Theory.theory are now identified, referring to the universal
   454 Context.theory (see Pure/context.ML).  Actual signature and theory
   455 content is managed as theory data.  The old code and interfaces were
   456 spread over many files and structures; the new arrangement introduces
   457 considerable INCOMPATIBILITY to gain more clarity:
   458 
   459   Context -- theory management operations (name, identity, inclusion,
   460     parents, ancestors, merge, etc.), plus generic theory data;
   461 
   462   Sign -- logical signature and syntax operations (declaring consts,
   463     types, etc.), plus certify/read for common entities;
   464 
   465   Theory -- logical theory operations (stating axioms, definitions,
   466     oracles), plus a copy of logical signature operations (consts,
   467     types, etc.); also a few basic management operations (Theory.copy,
   468     Theory.merge, etc.)
   469 
   470 The most basic sign_of operations (Theory.sign_of, Thm.sign_of_thm
   471 etc.) as well as the sign field in Thm.rep_thm etc. have been retained
   472 for convenience -- they merely return the theory.
   473 
   474 * Pure: the Isar proof context type is already defined early in Pure
   475 as Context.proof (note that ProofContext.context and Proof.context are
   476 aliases, where the latter is the preferred name).  This enables other
   477 Isabelle components to refer to that type even before Isar is present.
   478 
   479 * Pure/sign/theory: discontinued named name spaces (i.e. classK,
   480 typeK, constK, axiomK, oracleK), but provide explicit operations for
   481 any of these kinds.  For example, Sign.intern typeK is now
   482 Sign.intern_type, Theory.hide_space Sign.typeK is now
   483 Theory.hide_types.  Also note that former
   484 Theory.hide_classes/types/consts are now
   485 Theory.hide_classes_i/types_i/consts_i, while the non '_i' versions
   486 internalize their arguments!  INCOMPATIBILITY.
   487 
   488 * Pure: get_thm interface (of PureThy and ProofContext) expects
   489 datatype thmref (with constructors Name and NameSelection) instead of
   490 plain string -- INCOMPATIBILITY;
   491 
   492 * Pure: cases produced by proof methods specify options, where NONE
   493 means to remove case bindings -- INCOMPATIBILITY in
   494 (RAW_)METHOD_CASES.
   495 
   496 * Pure: the following operations retrieve axioms or theorems from a
   497 theory node or theory hierarchy, respectively:
   498 
   499   Theory.axioms_of: theory -> (string * term) list
   500   Theory.all_axioms_of: theory -> (string * term) list
   501   PureThy.thms_of: theory -> (string * thm) list
   502   PureThy.all_thms_of: theory -> (string * thm) list
   503 
   504 * Provers: Simplifier and Classical Reasoner now support proof context
   505 dependent plug-ins (simprocs, solvers, wrappers etc.).  These extra
   506 components are stored in the theory and patched into the
   507 simpset/claset when used in an Isar proof context.  Context dependent
   508 components are maintained by the following theory operations:
   509 
   510   Simplifier.add_context_simprocs
   511   Simplifier.del_context_simprocs
   512   Simplifier.set_context_subgoaler
   513   Simplifier.reset_context_subgoaler
   514   Simplifier.add_context_looper
   515   Simplifier.del_context_looper
   516   Simplifier.add_context_unsafe_solver
   517   Simplifier.add_context_safe_solver
   518 
   519   Classical.add_context_safe_wrapper
   520   Classical.del_context_safe_wrapper
   521   Classical.add_context_unsafe_wrapper
   522   Classical.del_context_unsafe_wrapper
   523 
   524 IMPORTANT NOTE: proof tools (methods etc.) need to use
   525 local_simpset_of and local_claset_of to instead of the primitive
   526 Simplifier.get_local_simpset and Classical.get_local_claset,
   527 respectively, in order to see the context dependent fields!
   528 
   529 * File.sysify_path and File.quote_sysify path have been replaced by
   530 File.platform_path and File.shell_path (with appropriate hooks).  This
   531 provides a clean interface for unusual systems where the internal and
   532 external process view of file names are different.
   533 
   534 
   535 *** System ***
   536 
   537 * Allow symlinks to all proper Isabelle executables (Isabelle,
   538 isabelle, isatool etc.).
   539 
   540 * ISABELLE_DOC_FORMAT setting specifies preferred document format (for
   541 isatool doc, isatool mkdir, display_drafts etc.).
   542 
   543 * isatool usedir: option -f allows specification of the ML file to be
   544 used by Isabelle; default is ROOT.ML.
   545 
   546 * New isatool version outputs the version identifier of the Isabelle
   547 distribution being used.
   548 
   549 * HOL: new isatool dimacs2hol converts files in DIMACS CNF format
   550 (containing Boolean satisfiability problems) into Isabelle/HOL
   551 theories.
   552 
   553 
   554 
   555 New in Isabelle2004 (April 2004)
   556 --------------------------------
   557 
   558 *** General ***
   559 
   560 * Provers/order.ML:  new efficient reasoner for partial and linear orders.
   561   Replaces linorder.ML.
   562 
   563 * Pure: Greek letters (except small lambda, \<lambda>), as well as Gothic
   564   (\<aa>...\<zz>\<AA>...\<ZZ>), calligraphic (\<A>...\<Z>), and Euler
   565   (\<a>...\<z>), are now considered normal letters, and can therefore
   566   be used anywhere where an ASCII letter (a...zA...Z) has until
   567   now. COMPATIBILITY: This obviously changes the parsing of some
   568   terms, especially where a symbol has been used as a binder, say
   569   '\<Pi>x. ...', which is now a type error since \<Pi>x will be parsed
   570   as an identifier.  Fix it by inserting a space around former
   571   symbols.  Call 'isatool fixgreek' to try to fix parsing errors in
   572   existing theory and ML files.
   573 
   574 * Pure: Macintosh and Windows line-breaks are now allowed in theory files.
   575 
   576 * Pure: single letter sub/superscripts (\<^isub> and \<^isup>) are now
   577   allowed in identifiers. Similar to Greek letters \<^isub> is now considered
   578   a normal (but invisible) letter. For multiple letter subscripts repeat
   579   \<^isub> like this: x\<^isub>1\<^isub>2.
   580 
   581 * Pure: There are now sub-/superscripts that can span more than one
   582   character. Text between \<^bsub> and \<^esub> is set in subscript in
   583   ProofGeneral and LaTeX, text between \<^bsup> and \<^esup> in
   584   superscript. The new control characters are not identifier parts.
   585 
   586 * Pure: Control-symbols of the form \<^raw:...> will literally print the
   587   content of "..." to the latex file instead of \isacntrl... . The "..."
   588   may consist of any printable characters excluding the end bracket >.
   589 
   590 * Pure: Using new Isar command "finalconsts" (or the ML functions
   591   Theory.add_finals or Theory.add_finals_i) it is now possible to
   592   declare constants "final", which prevents their being given a definition
   593   later.  It is useful for constants whose behaviour is fixed axiomatically
   594   rather than definitionally, such as the meta-logic connectives.
   595 
   596 * Pure: 'instance' now handles general arities with general sorts
   597   (i.e. intersections of classes),
   598 
   599 * Presentation: generated HTML now uses a CSS style sheet to make layout
   600   (somewhat) independent of content. It is copied from lib/html/isabelle.css.
   601   It can be changed to alter the colors/layout of generated pages.
   602 
   603 
   604 *** Isar ***
   605 
   606 * Tactic emulation methods rule_tac, erule_tac, drule_tac, frule_tac,
   607   cut_tac, subgoal_tac and thin_tac:
   608   - Now understand static (Isar) contexts.  As a consequence, users of Isar
   609     locales are no longer forced to write Isar proof scripts.
   610     For details see Isar Reference Manual, paragraph 4.3.2: Further tactic
   611     emulations.
   612   - INCOMPATIBILITY: names of variables to be instantiated may no
   613     longer be enclosed in quotes.  Instead, precede variable name with `?'.
   614     This is consistent with the instantiation attribute "where".
   615 
   616 * Attributes "where" and "of":
   617   - Now take type variables of instantiated theorem into account when reading
   618     the instantiation string.  This fixes a bug that caused instantiated
   619     theorems to have too special types in some circumstances.
   620   - "where" permits explicit instantiations of type variables.
   621 
   622 * Calculation commands "moreover" and "also" no longer interfere with
   623   current facts ("this"), admitting arbitrary combinations with "then"
   624   and derived forms.
   625 
   626 * Locales:
   627   - Goal statements involving the context element "includes" no longer
   628     generate theorems with internal delta predicates (those ending on
   629     "_axioms") in the premise.
   630     Resolve particular premise with <locale>.intro to obtain old form.
   631   - Fixed bug in type inference ("unify_frozen") that prevented mix of target
   632     specification and "includes" elements in goal statement.
   633   - Rule sets <locale>.intro and <locale>.axioms no longer declared as
   634     [intro?] and [elim?] (respectively) by default.
   635   - Experimental command for instantiation of locales in proof contexts:
   636         instantiate <label>[<attrs>]: <loc>
   637     Instantiates locale <loc> and adds all its theorems to the current context
   638     taking into account their attributes.  Label and attrs are optional
   639     modifiers, like in theorem declarations.  If present, names of
   640     instantiated theorems are qualified with <label>, and the attributes
   641     <attrs> are applied after any attributes these theorems might have already.
   642       If the locale has assumptions, a chained fact of the form
   643     "<loc> t1 ... tn" is expected from which instantiations of the parameters
   644     are derived.  The command does not support old-style locales declared
   645     with "locale (open)".
   646       A few (very simple) examples can be found in FOL/ex/LocaleInst.thy.
   647 
   648 * HOL: Tactic emulation methods induct_tac and case_tac understand static
   649   (Isar) contexts.
   650 
   651 
   652 *** HOL ***
   653 
   654 * Proof import: new image HOL4 contains the imported library from
   655   the HOL4 system with about 2500 theorems. It is imported by
   656   replaying proof terms produced by HOL4 in Isabelle. The HOL4 image
   657   can be used like any other Isabelle image.  See
   658   HOL/Import/HOL/README for more information.
   659 
   660 * Simplifier:
   661   - Much improved handling of linear and partial orders.
   662     Reasoners for linear and partial orders are set up for type classes
   663     "linorder" and "order" respectively, and are added to the default simpset
   664     as solvers.  This means that the simplifier can build transitivity chains
   665     to solve goals from the assumptions.
   666   - INCOMPATIBILITY: old proofs break occasionally.  Typically, applications
   667     of blast or auto after simplification become unnecessary because the goal
   668     is solved by simplification already.
   669 
   670 * Numerics: new theory Ring_and_Field contains over 250 basic numerical laws,
   671     all proved in axiomatic type classes for semirings, rings and fields.
   672 
   673 * Numerics:
   674   - Numeric types (nat, int, and in HOL-Complex rat, real, complex, etc.) are
   675     now formalized using the Ring_and_Field theory mentioned above.
   676   - INCOMPATIBILITY: simplification and arithmetic behaves somewhat differently
   677     than before, because now they are set up once in a generic manner.
   678   - INCOMPATIBILITY: many type-specific arithmetic laws have gone.
   679     Look for the general versions in Ring_and_Field (and Power if they concern
   680     exponentiation).
   681 
   682 * Type "rat" of the rational numbers is now available in HOL-Complex.
   683 
   684 * Records:
   685   - Record types are now by default printed with their type abbreviation
   686     instead of the list of all field types. This can be configured via
   687     the reference "print_record_type_abbr".
   688   - Simproc "record_upd_simproc" for simplification of multiple updates added
   689     (not enabled by default).
   690   - Simproc "record_ex_sel_eq_simproc" to simplify EX x. sel r = x resp.
   691     EX x. x = sel r to True (not enabled by default).
   692   - Tactic "record_split_simp_tac" to split and simplify records added.
   693 
   694 * 'specification' command added, allowing for definition by
   695   specification.  There is also an 'ax_specification' command that
   696   introduces the new constants axiomatically.
   697 
   698 * arith(_tac) is now able to generate counterexamples for reals as well.
   699 
   700 * HOL-Algebra: new locale "ring" for non-commutative rings.
   701 
   702 * HOL-ex: InductiveInvariant_examples illustrates advanced recursive function
   703   definitions, thanks to Sava Krsti\'{c} and John Matthews.
   704 
   705 * HOL-Matrix: a first theory for matrices in HOL with an application of
   706   matrix theory to linear programming.
   707 
   708 * Unions and Intersections:
   709   The latex output syntax of UN and INT has been changed
   710   from "\Union x \in A. B" to "\Union_{x \in A} B"
   711   i.e. the index formulae has become a subscript.
   712   Similarly for "\Union x. B", and for \Inter instead of \Union.
   713 
   714 * Unions and Intersections over Intervals:
   715   There is new short syntax "UN i<=n. A" for "UN i:{0..n}. A". There is
   716   also an x-symbol version with subscripts "\<Union>\<^bsub>i <= n\<^esub>. A"
   717   like in normal math, and corresponding versions for < and for intersection.
   718 
   719 * HOL/List: Ordering "lexico" is renamed "lenlex" and the standard
   720   lexicographic dictonary ordering has been added as "lexord".
   721 
   722 * ML: the legacy theory structures Int and List have been removed. They had
   723   conflicted with ML Basis Library structures having the same names.
   724 
   725 * 'refute' command added to search for (finite) countermodels.  Only works
   726   for a fragment of HOL.  The installation of an external SAT solver is
   727   highly recommended.  See "HOL/Refute.thy" for details.
   728 
   729 * 'quickcheck' command: Allows to find counterexamples by evaluating
   730   formulae under an assignment of free variables to random values.
   731   In contrast to 'refute', it can deal with inductive datatypes,
   732   but cannot handle quantifiers. See "HOL/ex/Quickcheck_Examples.thy"
   733   for examples.
   734 
   735 
   736 *** HOLCF ***
   737 
   738 * Streams now come with concatenation and are part of the HOLCF image
   739 
   740 
   741 
   742 New in Isabelle2003 (May 2003)
   743 ------------------------------
   744 
   745 *** General ***
   746 
   747 * Provers/simplifier:
   748 
   749   - Completely reimplemented method simp (ML: Asm_full_simp_tac):
   750     Assumptions are now subject to complete mutual simplification,
   751     not just from left to right. The simplifier now preserves
   752     the order of assumptions.
   753 
   754     Potential INCOMPATIBILITY:
   755 
   756     -- simp sometimes diverges where the old version did
   757        not, e.g. invoking simp on the goal
   758 
   759         [| P (f x); y = x; f x = f y |] ==> Q
   760 
   761        now gives rise to the infinite reduction sequence
   762 
   763         P(f x) --(f x = f y)--> P(f y) --(y = x)--> P(f x) --(f x = f y)--> ...
   764 
   765        Using "simp (asm_lr)" (ML: Asm_lr_simp_tac) instead often solves this
   766        kind of problem.
   767 
   768     -- Tactics combining classical reasoner and simplification (such as auto)
   769        are also affected by this change, because many of them rely on
   770        simp. They may sometimes diverge as well or yield a different numbers
   771        of subgoals. Try to use e.g. force, fastsimp, or safe instead of auto
   772        in case of problems. Sometimes subsequent calls to the classical
   773        reasoner will fail because a preceeding call to the simplifier too
   774        eagerly simplified the goal, e.g. deleted redundant premises.
   775 
   776   - The simplifier trace now shows the names of the applied rewrite rules
   777 
   778   - You can limit the number of recursive invocations of the simplifier
   779     during conditional rewriting (where the simplifie tries to solve the
   780     conditions before applying the rewrite rule):
   781     ML "simp_depth_limit := n"
   782     where n is an integer. Thus you can force termination where previously
   783     the simplifier would diverge.
   784 
   785   - Accepts free variables as head terms in congruence rules.  Useful in Isar.
   786 
   787   - No longer aborts on failed congruence proof.  Instead, the
   788     congruence is ignored.
   789 
   790 * Pure: New generic framework for extracting programs from constructive
   791   proofs. See HOL/Extraction.thy for an example instantiation, as well
   792   as HOL/Extraction for some case studies.
   793 
   794 * Pure: The main goal of the proof state is no longer shown by default, only
   795 the subgoals. This behaviour is controlled by a new flag.
   796    PG menu: Isabelle/Isar -> Settings -> Show Main Goal
   797 (ML: Proof.show_main_goal).
   798 
   799 * Pure: You can find all matching introduction rules for subgoal 1, i.e. all
   800 rules whose conclusion matches subgoal 1:
   801       PG menu: Isabelle/Isar -> Show me -> matching rules
   802 The rules are ordered by how closely they match the subgoal.
   803 In particular, rules that solve a subgoal outright are displayed first
   804 (or rather last, the way they are printed).
   805 (ML: ProofGeneral.print_intros())
   806 
   807 * Pure: New flag trace_unify_fail causes unification to print
   808 diagnostic information (PG: in trace buffer) when it fails. This is
   809 useful for figuring out why single step proofs like rule, erule or
   810 assumption failed.
   811 
   812 * Pure: Locale specifications now produce predicate definitions
   813 according to the body of text (covering assumptions modulo local
   814 definitions); predicate "loc_axioms" covers newly introduced text,
   815 while "loc" is cumulative wrt. all included locale expressions; the
   816 latter view is presented only on export into the global theory
   817 context; potential INCOMPATIBILITY, use "(open)" option to fall back
   818 on the old view without predicates;
   819 
   820 * Pure: predefined locales "var" and "struct" are useful for sharing
   821 parameters (as in CASL, for example); just specify something like
   822 ``var x + var y + struct M'' as import;
   823 
   824 * Pure: improved thms_containing: proper indexing of facts instead of
   825 raw theorems; check validity of results wrt. current name space;
   826 include local facts of proof configuration (also covers active
   827 locales), cover fixed variables in index; may use "_" in term
   828 specification; an optional limit for the number of printed facts may
   829 be given (the default is 40);
   830 
   831 * Pure: disallow duplicate fact bindings within new-style theory files
   832 (batch-mode only);
   833 
   834 * Provers: improved induct method: assumptions introduced by case
   835 "foo" are split into "foo.hyps" (from the rule) and "foo.prems" (from
   836 the goal statement); "foo" still refers to all facts collectively;
   837 
   838 * Provers: the function blast.overloaded has been removed: all constants
   839 are regarded as potentially overloaded, which improves robustness in exchange
   840 for slight decrease in efficiency;
   841 
   842 * Provers/linorder: New generic prover for transitivity reasoning over
   843 linear orders.  Note: this prover is not efficient!
   844 
   845 * Isar: preview of problems to finish 'show' now produce an error
   846 rather than just a warning (in interactive mode);
   847 
   848 
   849 *** HOL ***
   850 
   851 * arith(_tac)
   852 
   853  - Produces a counter example if it cannot prove a goal.
   854    Note that the counter example may be spurious if the goal is not a formula
   855    of quantifier-free linear arithmetic.
   856    In ProofGeneral the counter example appears in the trace buffer.
   857 
   858  - Knows about div k and mod k where k is a numeral of type nat or int.
   859 
   860  - Calls full Presburger arithmetic (by Amine Chaieb) if quantifier-free
   861    linear arithmetic fails. This takes account of quantifiers and divisibility.
   862    Presburger arithmetic can also be called explicitly via presburger(_tac).
   863 
   864 * simp's arithmetic capabilities have been enhanced a bit: it now
   865 takes ~= in premises into account (by performing a case split);
   866 
   867 * simp reduces "m*(n div m) + n mod m" to n, even if the two summands
   868 are distributed over a sum of terms;
   869 
   870 * New tactic "trans_tac" and method "trans" instantiate
   871 Provers/linorder.ML for axclasses "order" and "linorder" (predicates
   872 "<=", "<" and "=").
   873 
   874 * function INCOMPATIBILITIES: Pi-sets have been redefined and moved from main
   875 HOL to Library/FuncSet; constant "Fun.op o" is now called "Fun.comp";
   876 
   877 * 'typedef' command has new option "open" to suppress the set
   878 definition;
   879 
   880 * functions Min and Max on finite sets have been introduced (theory
   881 Finite_Set);
   882 
   883 * attribute [symmetric] now works for relations as well; it turns
   884 (x,y) : R^-1 into (y,x) : R, and vice versa;
   885 
   886 * induct over a !!-quantified statement (say !!x1..xn):
   887   each "case" automatically performs "fix x1 .. xn" with exactly those names.
   888 
   889 * Map: `empty' is no longer a constant but a syntactic abbreviation for
   890 %x. None. Warning: empty_def now refers to the previously hidden definition
   891 of the empty set.
   892 
   893 * Algebra: formalization of classical algebra.  Intended as base for
   894 any algebraic development in Isabelle.  Currently covers group theory
   895 (up to Sylow's theorem) and ring theory (Universal Property of
   896 Univariate Polynomials).  Contributions welcome;
   897 
   898 * GroupTheory: deleted, since its material has been moved to Algebra;
   899 
   900 * Complex: new directory of the complex numbers with numeric constants,
   901 nonstandard complex numbers, and some complex analysis, standard and
   902 nonstandard (Jacques Fleuriot);
   903 
   904 * HOL-Complex: new image for analysis, replacing HOL-Real and HOL-Hyperreal;
   905 
   906 * Hyperreal: introduced Gauge integration and hyperreal logarithms (Jacques
   907 Fleuriot);
   908 
   909 * Real/HahnBanach: updated and adapted to locales;
   910 
   911 * NumberTheory: added Gauss's law of quadratic reciprocity (by Avigad,
   912 Gray and Kramer);
   913 
   914 * UNITY: added the Meier-Sanders theory of progress sets;
   915 
   916 * MicroJava: bytecode verifier and lightweight bytecode verifier
   917 as abstract algorithms, instantiated to the JVM;
   918 
   919 * Bali: Java source language formalization. Type system, operational
   920 semantics, axiomatic semantics. Supported language features:
   921 classes, interfaces, objects,virtual methods, static methods,
   922 static/instance fields, arrays, access modifiers, definite
   923 assignment, exceptions.
   924 
   925 
   926 *** ZF ***
   927 
   928 * ZF/Constructible: consistency proof for AC (Gdel's constructible
   929 universe, etc.);
   930 
   931 * Main ZF: virtually all theories converted to new-style format;
   932 
   933 
   934 *** ML ***
   935 
   936 * Pure: Tactic.prove provides sane interface for internal proofs;
   937 omits the infamous "standard" operation, so this is more appropriate
   938 than prove_goalw_cterm in many situations (e.g. in simprocs);
   939 
   940 * Pure: improved error reporting of simprocs;
   941 
   942 * Provers: Simplifier.simproc(_i) provides sane interface for setting
   943 up simprocs;
   944 
   945 
   946 *** Document preparation ***
   947 
   948 * uses \par instead of \\ for line breaks in theory text. This may
   949 shift some page breaks in large documents. To get the old behaviour
   950 use \renewcommand{\isanewline}{\mbox{}\\\mbox{}} in root.tex.
   951 
   952 * minimized dependencies of isabelle.sty and isabellesym.sty on
   953 other packages
   954 
   955 * \<euro> now needs package babel/greek instead of marvosym (which
   956 broke \Rightarrow)
   957 
   958 * normal size for \<zero>...\<nine> (uses \mathbf instead of
   959 textcomp package)
   960 
   961 
   962 
   963 New in Isabelle2002 (March 2002)
   964 --------------------------------
   965 
   966 *** Document preparation ***
   967 
   968 * greatly simplified document preparation setup, including more
   969 graceful interpretation of isatool usedir -i/-d/-D options, and more
   970 instructive isatool mkdir; users should basically be able to get
   971 started with "isatool mkdir HOL Test && isatool make"; alternatively,
   972 users may run a separate document processing stage manually like this:
   973 "isatool usedir -D output HOL Test && isatool document Test/output";
   974 
   975 * theory dependency graph may now be incorporated into documents;
   976 isatool usedir -g true will produce session_graph.eps/.pdf for use
   977 with \includegraphics of LaTeX;
   978 
   979 * proper spacing of consecutive markup elements, especially text
   980 blocks after section headings;
   981 
   982 * support bold style (for single symbols only), input syntax is like
   983 this: "\<^bold>\<alpha>" or "\<^bold>A";
   984 
   985 * \<bullet> is now output as bold \cdot by default, which looks much
   986 better in printed text;
   987 
   988 * added default LaTeX bindings for \<tturnstile> and \<TTurnstile>;
   989 note that these symbols are currently unavailable in Proof General /
   990 X-Symbol; new symbols \<zero>, \<one>, ..., \<nine>, and \<euro>;
   991 
   992 * isatool latex no longer depends on changed TEXINPUTS, instead
   993 isatool document copies the Isabelle style files to the target
   994 location;
   995 
   996 
   997 *** Isar ***
   998 
   999 * Pure/Provers: improved proof by cases and induction;
  1000   - 'case' command admits impromptu naming of parameters (such as
  1001     "case (Suc n)");
  1002   - 'induct' method divinates rule instantiation from the inductive
  1003     claim; no longer requires excessive ?P bindings for proper
  1004     instantiation of cases;
  1005   - 'induct' method properly enumerates all possibilities of set/type
  1006     rules; as a consequence facts may be also passed through *type*
  1007     rules without further ado;
  1008   - 'induct' method now derives symbolic cases from the *rulified*
  1009     rule (before it used to rulify cases stemming from the internal
  1010     atomized version); this means that the context of a non-atomic
  1011     statement becomes is included in the hypothesis, avoiding the
  1012     slightly cumbersome show "PROP ?case" form;
  1013   - 'induct' may now use elim-style induction rules without chaining
  1014     facts, using ``missing'' premises from the goal state; this allows
  1015     rules stemming from inductive sets to be applied in unstructured
  1016     scripts, while still benefitting from proper handling of non-atomic
  1017     statements; NB: major inductive premises need to be put first, all
  1018     the rest of the goal is passed through the induction;
  1019   - 'induct' proper support for mutual induction involving non-atomic
  1020     rule statements (uses the new concept of simultaneous goals, see
  1021     below);
  1022   - append all possible rule selections, but only use the first
  1023     success (no backtracking);
  1024   - removed obsolete "(simplified)" and "(stripped)" options of methods;
  1025   - undeclared rule case names default to numbers 1, 2, 3, ...;
  1026   - added 'print_induct_rules' (covered by help item in recent Proof
  1027     General versions);
  1028   - moved induct/cases attributes to Pure, methods to Provers;
  1029   - generic method setup instantiated for FOL and HOL;
  1030 
  1031 * Pure: support multiple simultaneous goal statements, for example
  1032 "have a: A and b: B" (same for 'theorem' etc.); being a pure
  1033 meta-level mechanism, this acts as if several individual goals had
  1034 been stated separately; in particular common proof methods need to be
  1035 repeated in order to cover all claims; note that a single elimination
  1036 step is *not* sufficient to establish the two conjunctions, so this
  1037 fails:
  1038 
  1039   assume "A & B" then have A and B ..   (*".." fails*)
  1040 
  1041 better use "obtain" in situations as above; alternative refer to
  1042 multi-step methods like 'auto', 'simp_all', 'blast+' etc.;
  1043 
  1044 * Pure: proper integration with ``locales''; unlike the original
  1045 version by Florian Kammller, Isar locales package high-level proof
  1046 contexts rather than raw logical ones (e.g. we admit to include
  1047 attributes everywhere); operations on locales include merge and
  1048 rename; support for implicit arguments (``structures''); simultaneous
  1049 type-inference over imports and text; see also HOL/ex/Locales.thy for
  1050 some examples;
  1051 
  1052 * Pure: the following commands have been ``localized'', supporting a
  1053 target locale specification "(in name)": 'lemma', 'theorem',
  1054 'corollary', 'lemmas', 'theorems', 'declare'; the results will be
  1055 stored both within the locale and at the theory level (exported and
  1056 qualified by the locale name);
  1057 
  1058 * Pure: theory goals may now be specified in ``long'' form, with
  1059 ad-hoc contexts consisting of arbitrary locale elements. for example
  1060 ``lemma foo: fixes x assumes "A x" shows "B x"'' (local syntax and
  1061 definitions may be given, too); the result is a meta-level rule with
  1062 the context elements being discharged in the obvious way;
  1063 
  1064 * Pure: new proof command 'using' allows to augment currently used
  1065 facts after a goal statement ('using' is syntactically analogous to
  1066 'apply', but acts on the goal's facts only); this allows chained facts
  1067 to be separated into parts given before and after a claim, as in
  1068 ``from a and b have C using d and e <proof>'';
  1069 
  1070 * Pure: renamed "antecedent" case to "rule_context";
  1071 
  1072 * Pure: new 'judgment' command records explicit information about the
  1073 object-logic embedding (used by several tools internally); no longer
  1074 use hard-wired "Trueprop";
  1075 
  1076 * Pure: added 'corollary' command;
  1077 
  1078 * Pure: fixed 'token_translation' command;
  1079 
  1080 * Pure: removed obsolete 'exported' attribute;
  1081 
  1082 * Pure: dummy pattern "_" in is/let is now automatically lifted over
  1083 bound variables: "ALL x. P x --> Q x" (is "ALL x. _ --> ?C x")
  1084 supersedes more cumbersome ... (is "ALL x. _ x --> ?C x");
  1085 
  1086 * Pure: method 'atomize' presents local goal premises as object-level
  1087 statements (atomic meta-level propositions); setup controlled via
  1088 rewrite rules declarations of 'atomize' attribute; example
  1089 application: 'induct' method with proper rule statements in improper
  1090 proof *scripts*;
  1091 
  1092 * Pure: emulation of instantiation tactics (rule_tac, cut_tac, etc.)
  1093 now consider the syntactic context of assumptions, giving a better
  1094 chance to get type-inference of the arguments right (this is
  1095 especially important for locales);
  1096 
  1097 * Pure: "sorry" no longer requires quick_and_dirty in interactive
  1098 mode;
  1099 
  1100 * Pure/obtain: the formal conclusion "thesis", being marked as
  1101 ``internal'', may no longer be reference directly in the text;
  1102 potential INCOMPATIBILITY, may need to use "?thesis" in rare
  1103 situations;
  1104 
  1105 * Pure: generic 'sym' attribute which declares a rule both as pure
  1106 'elim?' and for the 'symmetric' operation;
  1107 
  1108 * Pure: marginal comments ``--'' may now occur just anywhere in the
  1109 text; the fixed correlation with particular command syntax has been
  1110 discontinued;
  1111 
  1112 * Pure: new method 'rules' is particularly well-suited for proof
  1113 search in intuitionistic logic; a bit slower than 'blast' or 'fast',
  1114 but often produces more compact proof terms with less detours;
  1115 
  1116 * Pure/Provers/classical: simplified integration with pure rule
  1117 attributes and methods; the classical "intro?/elim?/dest?"
  1118 declarations coincide with the pure ones; the "rule" method no longer
  1119 includes classically swapped intros; "intro" and "elim" methods no
  1120 longer pick rules from the context; also got rid of ML declarations
  1121 AddXIs/AddXEs/AddXDs; all of this has some potential for
  1122 INCOMPATIBILITY;
  1123 
  1124 * Provers/classical: attribute 'swapped' produces classical inversions
  1125 of introduction rules;
  1126 
  1127 * Provers/simplifier: 'simplified' attribute may refer to explicit
  1128 rules instead of full simplifier context; 'iff' attribute handles
  1129 conditional rules;
  1130 
  1131 * HOL: 'typedef' now allows alternative names for Rep/Abs morphisms;
  1132 
  1133 * HOL: 'recdef' now fails on unfinished automated proofs, use
  1134 "(permissive)" option to recover old behavior;
  1135 
  1136 * HOL: 'inductive' no longer features separate (collective) attributes
  1137 for 'intros' (was found too confusing);
  1138 
  1139 * HOL: properly declared induction rules less_induct and
  1140 wf_induct_rule;
  1141 
  1142 
  1143 *** HOL ***
  1144 
  1145 * HOL: moved over to sane numeral syntax; the new policy is as
  1146 follows:
  1147 
  1148   - 0 and 1 are polymorphic constants, which are defined on any
  1149   numeric type (nat, int, real etc.);
  1150 
  1151   - 2, 3, 4, ... and -1, -2, -3, ... are polymorphic numerals, based
  1152   binary representation internally;
  1153 
  1154   - type nat has special constructor Suc, and generally prefers Suc 0
  1155   over 1::nat and Suc (Suc 0) over 2::nat;
  1156 
  1157 This change may cause significant problems of INCOMPATIBILITY; here
  1158 are some hints on converting existing sources:
  1159 
  1160   - due to the new "num" token, "-0" and "-1" etc. are now atomic
  1161   entities, so expressions involving "-" (unary or binary minus) need
  1162   to be spaced properly;
  1163 
  1164   - existing occurrences of "1" may need to be constraint "1::nat" or
  1165   even replaced by Suc 0; similar for old "2";
  1166 
  1167   - replace "#nnn" by "nnn", and "#-nnn" by "-nnn";
  1168 
  1169   - remove all special provisions on numerals in proofs;
  1170 
  1171 * HOL: simp rules nat_number expand numerals on nat to Suc/0
  1172 representation (depends on bin_arith_simps in the default context);
  1173 
  1174 * HOL: symbolic syntax for x^2 (numeral 2);
  1175 
  1176 * HOL: the class of all HOL types is now called "type" rather than
  1177 "term"; INCOMPATIBILITY, need to adapt references to this type class
  1178 in axclass/classes, instance/arities, and (usually rare) occurrences
  1179 in typings (of consts etc.); internally the class is called
  1180 "HOL.type", ML programs should refer to HOLogic.typeS;
  1181 
  1182 * HOL/record package improvements:
  1183   - new derived operations "fields" to build a partial record section,
  1184     "extend" to promote a fixed record to a record scheme, and
  1185     "truncate" for the reverse; cf. theorems "xxx.defs", which are *not*
  1186     declared as simp by default;
  1187   - shared operations ("more", "fields", etc.) now need to be always
  1188     qualified) --- potential INCOMPATIBILITY;
  1189   - removed "make_scheme" operations (use "make" with "extend") --
  1190     INCOMPATIBILITY;
  1191   - removed "more" class (simply use "term") -- INCOMPATIBILITY;
  1192   - provides cases/induct rules for use with corresponding Isar
  1193     methods (for concrete records, record schemes, concrete more
  1194     parts, and schematic more parts -- in that order);
  1195   - internal definitions directly based on a light-weight abstract
  1196     theory of product types over typedef rather than datatype;
  1197 
  1198 * HOL: generic code generator for generating executable ML code from
  1199 specifications; specific support for HOL constructs such as inductive
  1200 datatypes and sets, as well as recursive functions; can be invoked
  1201 via 'generate_code' theory section;
  1202 
  1203 * HOL: canonical cases/induct rules for n-tuples (n = 3..7);
  1204 
  1205 * HOL: consolidated and renamed several theories.  In particular:
  1206         Ord.thy has been absorbed into HOL.thy
  1207         String.thy has been absorbed into List.thy
  1208 
  1209 * HOL: concrete setsum syntax "\<Sum>i:A. b" == "setsum (%i. b) A"
  1210 (beware of argument permutation!);
  1211 
  1212 * HOL: linorder_less_split superseded by linorder_cases;
  1213 
  1214 * HOL/List: "nodups" renamed to "distinct";
  1215 
  1216 * HOL: added "The" definite description operator; move Hilbert's "Eps"
  1217 to peripheral theory "Hilbert_Choice"; some INCOMPATIBILITIES:
  1218   - Ex_def has changed, now need to use some_eq_ex
  1219 
  1220 * HOL: made split_all_tac safe; EXISTING PROOFS MAY FAIL OR LOOP, so
  1221 in this (rare) case use:
  1222 
  1223   delSWrapper "split_all_tac"
  1224   addSbefore ("unsafe_split_all_tac", unsafe_split_all_tac)
  1225 
  1226 * HOL: added safe wrapper "split_conv_tac" to claset; EXISTING PROOFS
  1227 MAY FAIL;
  1228 
  1229 * HOL: introduced f^n = f o ... o f; warning: due to the limits of
  1230 Isabelle's type classes, ^ on functions and relations has too general
  1231 a domain, namely ('a * 'b) set and 'a => 'b; this means that it may be
  1232 necessary to attach explicit type constraints;
  1233 
  1234 * HOL/Relation: the prefix name of the infix "O" has been changed from
  1235 "comp" to "rel_comp"; INCOMPATIBILITY: a few theorems have been
  1236 renamed accordingly (eg "compI" -> "rel_compI").
  1237 
  1238 * HOL: syntax translations now work properly with numerals and records
  1239 expressions;
  1240 
  1241 * HOL: bounded abstraction now uses syntax "%" / "\<lambda>" instead
  1242 of "lam" -- INCOMPATIBILITY;
  1243 
  1244 * HOL: got rid of some global declarations (potential INCOMPATIBILITY
  1245 for ML tools): const "()" renamed "Product_Type.Unity", type "unit"
  1246 renamed "Product_Type.unit";
  1247 
  1248 * HOL: renamed rtrancl_into_rtrancl2 to converse_rtrancl_into_rtrancl
  1249 
  1250 * HOL: removed obsolete theorem "optionE" (use "option.exhaust", or
  1251 the "cases" method);
  1252 
  1253 * HOL/GroupTheory: group theory examples including Sylow's theorem (by
  1254 Florian Kammller);
  1255 
  1256 * HOL/IMP: updated and converted to new-style theory format; several
  1257 parts turned into readable document, with proper Isar proof texts and
  1258 some explanations (by Gerwin Klein);
  1259 
  1260 * HOL-Real: added Complex_Numbers (by Gertrud Bauer);
  1261 
  1262 * HOL-Hyperreal is now a logic image;
  1263 
  1264 
  1265 *** HOLCF ***
  1266 
  1267 * Isar: consts/constdefs supports mixfix syntax for continuous
  1268 operations;
  1269 
  1270 * Isar: domain package adapted to new-style theory format, e.g. see
  1271 HOLCF/ex/Dnat.thy;
  1272 
  1273 * theory Lift: proper use of rep_datatype lift instead of ML hacks --
  1274 potential INCOMPATIBILITY; now use plain induct_tac instead of former
  1275 lift.induct_tac, always use UU instead of Undef;
  1276 
  1277 * HOLCF/IMP: updated and converted to new-style theory;
  1278 
  1279 
  1280 *** ZF ***
  1281 
  1282 * Isar: proper integration of logic-specific tools and packages,
  1283 including theory commands '(co)inductive', '(co)datatype',
  1284 'rep_datatype', 'inductive_cases', as well as methods 'ind_cases',
  1285 'induct_tac', 'case_tac', and 'typecheck' (with attribute 'TC');
  1286 
  1287 * theory Main no longer includes AC; for the Axiom of Choice, base
  1288 your theory on Main_ZFC;
  1289 
  1290 * the integer library now covers quotients and remainders, with many
  1291 laws relating division to addition, multiplication, etc.;
  1292 
  1293 * ZF/UNITY: Chandy and Misra's UNITY is now available in ZF, giving a
  1294 typeless version of the formalism;
  1295 
  1296 * ZF/AC, Coind, IMP, Resid: updated and converted to new-style theory
  1297 format;
  1298 
  1299 * ZF/Induct: new directory for examples of inductive definitions,
  1300 including theory Multiset for multiset orderings; converted to
  1301 new-style theory format;
  1302 
  1303 * ZF: many new theorems about lists, ordinals, etc.;
  1304 
  1305 
  1306 *** General ***
  1307 
  1308 * Pure/kernel: meta-level proof terms (by Stefan Berghofer); reference
  1309 variable proof controls level of detail: 0 = no proofs (only oracle
  1310 dependencies), 1 = lemma dependencies, 2 = compact proof terms; see
  1311 also ref manual for further ML interfaces;
  1312 
  1313 * Pure/axclass: removed obsolete ML interface
  1314 goal_subclass/goal_arity;
  1315 
  1316 * Pure/syntax: new token syntax "num" for plain numerals (without "#"
  1317 of "xnum"); potential INCOMPATIBILITY, since -0, -1 etc. are now
  1318 separate tokens, so expressions involving minus need to be spaced
  1319 properly;
  1320 
  1321 * Pure/syntax: support non-oriented infixes, using keyword "infix"
  1322 rather than "infixl" or "infixr";
  1323 
  1324 * Pure/syntax: concrete syntax for dummy type variables admits genuine
  1325 sort constraint specifications in type inference; e.g. "x::_::foo"
  1326 ensures that the type of "x" is of sort "foo" (but not necessarily a
  1327 type variable);
  1328 
  1329 * Pure/syntax: print modes "type_brackets" and "no_type_brackets"
  1330 control output of nested => (types); the default behavior is
  1331 "type_brackets";
  1332 
  1333 * Pure/syntax: builtin parse translation for "_constify" turns valued
  1334 tokens into AST constants;
  1335 
  1336 * Pure/syntax: prefer later declarations of translations and print
  1337 translation functions; potential INCOMPATIBILITY: need to reverse
  1338 multiple declarations for same syntax element constant;
  1339 
  1340 * Pure/show_hyps reset by default (in accordance to existing Isar
  1341 practice);
  1342 
  1343 * Provers/classical: renamed addaltern to addafter, addSaltern to
  1344 addSafter;
  1345 
  1346 * Provers/clasimp: ``iff'' declarations now handle conditional rules
  1347 as well;
  1348 
  1349 * system: tested support for MacOS X; should be able to get Isabelle +
  1350 Proof General to work in a plain Terminal after installing Poly/ML
  1351 (e.g. from the Isabelle distribution area) and GNU bash alone
  1352 (e.g. from http://www.apple.com); full X11, XEmacs and X-Symbol
  1353 support requires further installations, e.g. from
  1354 http://fink.sourceforge.net/);
  1355 
  1356 * system: support Poly/ML 4.1.1 (able to manage larger heaps);
  1357 
  1358 * system: reduced base memory usage by Poly/ML (approx. 20 MB instead
  1359 of 40 MB), cf. ML_OPTIONS;
  1360 
  1361 * system: Proof General keywords specification is now part of the
  1362 Isabelle distribution (see etc/isar-keywords.el);
  1363 
  1364 * system: support for persistent Proof General sessions (refrain from
  1365 outdating all loaded theories on startup); user may create writable
  1366 logic images like this: ``isabelle -q HOL Test'';
  1367 
  1368 * system: smart selection of Isabelle process versus Isabelle
  1369 interface, accommodates case-insensitive file systems (e.g. HFS+); may
  1370 run both "isabelle" and "Isabelle" even if file names are badly
  1371 damaged (executable inspects the case of the first letter of its own
  1372 name); added separate "isabelle-process" and "isabelle-interface";
  1373 
  1374 * system: refrain from any attempt at filtering input streams; no
  1375 longer support ``8bit'' encoding of old isabelle font, instead proper
  1376 iso-latin characters may now be used; the related isatools
  1377 "symbolinput" and "nonascii" have disappeared as well;
  1378 
  1379 * system: removed old "xterm" interface (the print modes "xterm" and
  1380 "xterm_color" are still available for direct use in a suitable
  1381 terminal);
  1382 
  1383 
  1384 
  1385 New in Isabelle99-2 (February 2001)
  1386 -----------------------------------
  1387 
  1388 *** Overview of INCOMPATIBILITIES ***
  1389 
  1390 * HOL: please note that theories in the Library and elsewhere often use the
  1391 new-style (Isar) format; to refer to their theorems in an ML script you must
  1392 bind them to ML identifers by e.g.      val thm_name = thm "thm_name";
  1393 
  1394 * HOL: inductive package no longer splits induction rule aggressively,
  1395 but only as far as specified by the introductions given; the old
  1396 format may be recovered via ML function complete_split_rule or attribute
  1397 'split_rule (complete)';
  1398 
  1399 * HOL: induct renamed to lfp_induct, lfp_Tarski to lfp_unfold,
  1400 gfp_Tarski to gfp_unfold;
  1401 
  1402 * HOL: contrapos, contrapos2 renamed to contrapos_nn, contrapos_pp;
  1403 
  1404 * HOL: infix "dvd" now has priority 50 rather than 70 (because it is a
  1405 relation); infix "^^" has been renamed "``"; infix "``" has been
  1406 renamed "`"; "univalent" has been renamed "single_valued";
  1407 
  1408 * HOL/Real: "rinv" and "hrinv" replaced by overloaded "inverse"
  1409 operation;
  1410 
  1411 * HOLCF: infix "`" has been renamed "$"; the symbol syntax is \<cdot>;
  1412 
  1413 * Isar: 'obtain' no longer declares "that" fact as simp/intro;
  1414 
  1415 * Isar/HOL: method 'induct' now handles non-atomic goals; as a
  1416 consequence, it is no longer monotonic wrt. the local goal context
  1417 (which is now passed through the inductive cases);
  1418 
  1419 * Document preparation: renamed standard symbols \<ll> to \<lless> and
  1420 \<gg> to \<ggreater>;
  1421 
  1422 
  1423 *** Document preparation ***
  1424 
  1425 * \isabellestyle{NAME} selects version of Isabelle output (currently
  1426 available: are "it" for near math-mode best-style output, "sl" for
  1427 slanted text style, and "tt" for plain type-writer; if no
  1428 \isabellestyle command is given, output is according to slanted
  1429 type-writer);
  1430 
  1431 * support sub/super scripts (for single symbols only), input syntax is
  1432 like this: "A\<^sup>*" or "A\<^sup>\<star>";
  1433 
  1434 * some more standard symbols; see Appendix A of the system manual for
  1435 the complete list of symbols defined in isabellesym.sty;
  1436 
  1437 * improved isabelle style files; more abstract symbol implementation
  1438 (should now use \isamath{...} and \isatext{...} in custom symbol
  1439 definitions);
  1440 
  1441 * antiquotation @{goals} and @{subgoals} for output of *dynamic* goals
  1442 state; Note that presentation of goal states does not conform to
  1443 actual human-readable proof documents.  Please do not include goal
  1444 states into document output unless you really know what you are doing!
  1445 
  1446 * proper indentation of antiquoted output with proportional LaTeX
  1447 fonts;
  1448 
  1449 * no_document ML operator temporarily disables LaTeX document
  1450 generation;
  1451 
  1452 * isatool unsymbolize tunes sources for plain ASCII communication;
  1453 
  1454 
  1455 *** Isar ***
  1456 
  1457 * Pure: Isar now suffers initial goal statements to contain unbound
  1458 schematic variables (this does not conform to actual readable proof
  1459 documents, due to unpredictable outcome and non-compositional proof
  1460 checking); users who know what they are doing may use schematic goals
  1461 for Prolog-style synthesis of proven results;
  1462 
  1463 * Pure: assumption method (an implicit finishing) now handles actual
  1464 rules as well;
  1465 
  1466 * Pure: improved 'obtain' --- moved to Pure, insert "that" into
  1467 initial goal, declare "that" only as Pure intro (only for single
  1468 steps); the "that" rule assumption may now be involved in implicit
  1469 finishing, thus ".." becomes a feasible for trivial obtains;
  1470 
  1471 * Pure: default proof step now includes 'intro_classes'; thus trivial
  1472 instance proofs may be performed by "..";
  1473 
  1474 * Pure: ?thesis / ?this / "..." now work for pure meta-level
  1475 statements as well;
  1476 
  1477 * Pure: more robust selection of calculational rules;
  1478 
  1479 * Pure: the builtin notion of 'finished' goal now includes the ==-refl
  1480 rule (as well as the assumption rule);
  1481 
  1482 * Pure: 'thm_deps' command visualizes dependencies of theorems and
  1483 lemmas, using the graph browser tool;
  1484 
  1485 * Pure: predict failure of "show" in interactive mode;
  1486 
  1487 * Pure: 'thms_containing' now takes actual terms as arguments;
  1488 
  1489 * HOL: improved method 'induct' --- now handles non-atomic goals
  1490 (potential INCOMPATIBILITY); tuned error handling;
  1491 
  1492 * HOL: cases and induct rules now provide explicit hints about the
  1493 number of facts to be consumed (0 for "type" and 1 for "set" rules);
  1494 any remaining facts are inserted into the goal verbatim;
  1495 
  1496 * HOL: local contexts (aka cases) may now contain term bindings as
  1497 well; the 'cases' and 'induct' methods new provide a ?case binding for
  1498 the result to be shown in each case;
  1499 
  1500 * HOL: added 'recdef_tc' command;
  1501 
  1502 * isatool convert assists in eliminating legacy ML scripts;
  1503 
  1504 
  1505 *** HOL ***
  1506 
  1507 * HOL/Library: a collection of generic theories to be used together
  1508 with main HOL; the theory loader path already includes this directory
  1509 by default; the following existing theories have been moved here:
  1510 HOL/Induct/Multiset, HOL/Induct/Acc (as Accessible_Part), HOL/While
  1511 (as While_Combinator), HOL/Lex/Prefix (as List_Prefix);
  1512 
  1513 * HOL/Unix: "Some aspects of Unix file-system security", a typical
  1514 modelling and verification task performed in Isabelle/HOL +
  1515 Isabelle/Isar + Isabelle document preparation (by Markus Wenzel).
  1516 
  1517 * HOL/Algebra: special summation operator SUM no longer exists, it has
  1518 been replaced by setsum; infix 'assoc' now has priority 50 (like
  1519 'dvd'); axiom 'one_not_zero' has been moved from axclass 'ring' to
  1520 'domain', this makes the theory consistent with mathematical
  1521 literature;
  1522 
  1523 * HOL basics: added overloaded operations "inverse" and "divide"
  1524 (infix "/"), syntax for generic "abs" operation, generic summation
  1525 operator \<Sum>;
  1526 
  1527 * HOL/typedef: simplified package, provide more useful rules (see also
  1528 HOL/subset.thy);
  1529 
  1530 * HOL/datatype: induction rule for arbitrarily branching datatypes is
  1531 now expressed as a proper nested rule (old-style tactic scripts may
  1532 require atomize_strip_tac to cope with non-atomic premises);
  1533 
  1534 * HOL: renamed theory "Prod" to "Product_Type", renamed "split" rule
  1535 to "split_conv" (old name still available for compatibility);
  1536 
  1537 * HOL: improved concrete syntax for strings (e.g. allows translation
  1538 rules with string literals);
  1539 
  1540 * HOL-Real-Hyperreal: this extends HOL-Real with the hyperreals
  1541  and Fleuriot's mechanization of analysis, including the transcendental
  1542  functions for the reals;
  1543 
  1544 * HOL/Real, HOL/Hyperreal: improved arithmetic simplification;
  1545 
  1546 
  1547 *** CTT ***
  1548 
  1549 * CTT: x-symbol support for Pi, Sigma, -->, : (membership); note that
  1550 "lam" is displayed as TWO lambda-symbols
  1551 
  1552 * CTT: theory Main now available, containing everything (that is, Bool
  1553 and Arith);
  1554 
  1555 
  1556 *** General ***
  1557 
  1558 * Pure: the Simplifier has been implemented properly as a derived rule
  1559 outside of the actual kernel (at last!); the overall performance
  1560 penalty in practical applications is about 50%, while reliability of
  1561 the Isabelle inference kernel has been greatly improved;
  1562 
  1563 * print modes "brackets" and "no_brackets" control output of nested =>
  1564 (types) and ==> (props); the default behaviour is "brackets";
  1565 
  1566 * Provers: fast_tac (and friends) now handle actual object-logic rules
  1567 as assumptions as well;
  1568 
  1569 * system: support Poly/ML 4.0;
  1570 
  1571 * system: isatool install handles KDE version 1 or 2;
  1572 
  1573 
  1574 
  1575 New in Isabelle99-1 (October 2000)
  1576 ----------------------------------
  1577 
  1578 *** Overview of INCOMPATIBILITIES ***
  1579 
  1580 * HOL: simplification of natural numbers is much changed; to partly
  1581 recover the old behaviour (e.g. to prevent n+n rewriting to #2*n)
  1582 issue the following ML commands:
  1583 
  1584   Delsimprocs Nat_Numeral_Simprocs.cancel_numerals;
  1585   Delsimprocs [Nat_Numeral_Simprocs.combine_numerals];
  1586 
  1587 * HOL: simplification no longer dives into case-expressions; this is
  1588 controlled by "t.weak_case_cong" for each datatype t;
  1589 
  1590 * HOL: nat_less_induct renamed to less_induct;
  1591 
  1592 * HOL: systematic renaming of the SOME (Eps) rules, may use isatool
  1593 fixsome to patch .thy and .ML sources automatically;
  1594 
  1595   select_equality  -> some_equality
  1596   select_eq_Ex     -> some_eq_ex
  1597   selectI2EX       -> someI2_ex
  1598   selectI2         -> someI2
  1599   selectI          -> someI
  1600   select1_equality -> some1_equality
  1601   Eps_sym_eq       -> some_sym_eq_trivial
  1602   Eps_eq           -> some_eq_trivial
  1603 
  1604 * HOL: exhaust_tac on datatypes superceded by new generic case_tac;
  1605 
  1606 * HOL: removed obsolete theorem binding expand_if (refer to split_if
  1607 instead);
  1608 
  1609 * HOL: the recursion equations generated by 'recdef' are now called
  1610 f.simps instead of f.rules;
  1611 
  1612 * HOL: qed_spec_mp now also handles bounded ALL as well;
  1613 
  1614 * HOL: 0 is now overloaded, so the type constraint ":: nat" may
  1615 sometimes be needed;
  1616 
  1617 * HOL: the constant for "f``x" is now "image" rather than "op ``";
  1618 
  1619 * HOL: the constant for "f-``x" is now "vimage" rather than "op -``";
  1620 
  1621 * HOL: the disjoint sum is now "<+>" instead of "Plus"; the cartesian
  1622 product is now "<*>" instead of "Times"; the lexicographic product is
  1623 now "<*lex*>" instead of "**";
  1624 
  1625 * HOL: theory Sexp is now in HOL/Induct examples (it used to be part
  1626 of main HOL, but was unused); better use HOL's datatype package;
  1627 
  1628 * HOL: removed "symbols" syntax for constant "override" of theory Map;
  1629 the old syntax may be recovered as follows:
  1630 
  1631   syntax (symbols)
  1632     override  :: "('a ~=> 'b) => ('a ~=> 'b) => ('a ~=> 'b)"
  1633       (infixl "\\<oplus>" 100)
  1634 
  1635 * HOL/Real: "rabs" replaced by overloaded "abs" function;
  1636 
  1637 * HOL/ML: even fewer consts are declared as global (see theories Ord,
  1638 Lfp, Gfp, WF); this only affects ML packages that refer to const names
  1639 internally;
  1640 
  1641 * HOL and ZF: syntax for quotienting wrt an equivalence relation
  1642 changed from A/r to A//r;
  1643 
  1644 * ZF: new treatment of arithmetic (nat & int) may break some old
  1645 proofs;
  1646 
  1647 * Isar: renamed some attributes (RS -> THEN, simplify -> simplified,
  1648 rulify -> rule_format, elimify -> elim_format, ...);
  1649 
  1650 * Isar/Provers: intro/elim/dest attributes changed; renamed
  1651 intro/intro!/intro!! flags to intro!/intro/intro? (in most cases, one
  1652 should have to change intro!! to intro? only); replaced "delrule" by
  1653 "rule del";
  1654 
  1655 * Isar/HOL: renamed "intrs" to "intros" in inductive definitions;
  1656 
  1657 * Provers: strengthened force_tac by using new first_best_tac;
  1658 
  1659 * LaTeX document preparation: several changes of isabelle.sty (see
  1660 lib/texinputs);
  1661 
  1662 
  1663 *** Document preparation ***
  1664 
  1665 * formal comments (text blocks etc.) in new-style theories may now
  1666 contain antiquotations of thm/prop/term/typ/text to be presented
  1667 according to latex print mode; concrete syntax is like this:
  1668 @{term[show_types] "f(x) = a + x"};
  1669 
  1670 * isatool mkdir provides easy setup of Isabelle session directories,
  1671 including proper document sources;
  1672 
  1673 * generated LaTeX sources are now deleted after successful run
  1674 (isatool document -c); may retain a copy somewhere else via -D option
  1675 of isatool usedir;
  1676 
  1677 * isatool usedir -D now lets isatool latex -o sty update the Isabelle
  1678 style files, achieving self-contained LaTeX sources and simplifying
  1679 LaTeX debugging;
  1680 
  1681 * old-style theories now produce (crude) LaTeX output as well;
  1682 
  1683 * browser info session directories are now self-contained (may be put
  1684 on WWW server seperately); improved graphs of nested sessions; removed
  1685 graph for 'all sessions';
  1686 
  1687 * several improvements in isabelle style files; \isabellestyle{it}
  1688 produces fake math mode output; \isamarkupheader is now \section by
  1689 default; see lib/texinputs/isabelle.sty etc.;
  1690 
  1691 
  1692 *** Isar ***
  1693 
  1694 * Isar/Pure: local results and corresponding term bindings are now
  1695 subject to Hindley-Milner polymorphism (similar to ML); this
  1696 accommodates incremental type-inference very nicely;
  1697 
  1698 * Isar/Pure: new derived language element 'obtain' supports
  1699 generalized existence reasoning;
  1700 
  1701 * Isar/Pure: new calculational elements 'moreover' and 'ultimately'
  1702 support accumulation of results, without applying any rules yet;
  1703 useful to collect intermediate results without explicit name
  1704 references, and for use with transitivity rules with more than 2
  1705 premises;
  1706 
  1707 * Isar/Pure: scalable support for case-analysis type proofs: new
  1708 'case' language element refers to local contexts symbolically, as
  1709 produced by certain proof methods; internally, case names are attached
  1710 to theorems as "tags";
  1711 
  1712 * Isar/Pure: theory command 'hide' removes declarations from
  1713 class/type/const name spaces;
  1714 
  1715 * Isar/Pure: theory command 'defs' supports option "(overloaded)" to
  1716 indicate potential overloading;
  1717 
  1718 * Isar/Pure: changed syntax of local blocks from {{ }} to { };
  1719 
  1720 * Isar/Pure: syntax of sorts made 'inner', i.e. have to write
  1721 "{a,b,c}" instead of {a,b,c};
  1722 
  1723 * Isar/Pure now provides its own version of intro/elim/dest
  1724 attributes; useful for building new logics, but beware of confusion
  1725 with the version in Provers/classical;
  1726 
  1727 * Isar/Pure: the local context of (non-atomic) goals is provided via
  1728 case name 'antecedent';
  1729 
  1730 * Isar/Pure: removed obsolete 'transfer' attribute (transfer of thms
  1731 to the current context is now done automatically);
  1732 
  1733 * Isar/Pure: theory command 'method_setup' provides a simple interface
  1734 for definining proof methods in ML;
  1735 
  1736 * Isar/Provers: intro/elim/dest attributes changed; renamed
  1737 intro/intro!/intro!! flags to intro!/intro/intro? (INCOMPATIBILITY, in
  1738 most cases, one should have to change intro!! to intro? only);
  1739 replaced "delrule" by "rule del";
  1740 
  1741 * Isar/Provers: new 'hypsubst' method, plain 'subst' method and
  1742 'symmetric' attribute (the latter supercedes [RS sym]);
  1743 
  1744 * Isar/Provers: splitter support (via 'split' attribute and 'simp'
  1745 method modifier); 'simp' method: 'only:' modifier removes loopers as
  1746 well (including splits);
  1747 
  1748 * Isar/Provers: Simplifier and Classical methods now support all kind
  1749 of modifiers used in the past, including 'cong', 'iff', etc.
  1750 
  1751 * Isar/Provers: added 'fastsimp' and 'clarsimp' methods (combination
  1752 of Simplifier and Classical reasoner);
  1753 
  1754 * Isar/HOL: new proof method 'cases' and improved version of 'induct'
  1755 now support named cases; major packages (inductive, datatype, primrec,
  1756 recdef) support case names and properly name parameters;
  1757 
  1758 * Isar/HOL: new transitivity rules for substitution in inequalities --
  1759 monotonicity conditions are extracted to be proven at end of
  1760 calculations;
  1761 
  1762 * Isar/HOL: removed 'case_split' thm binding, should use 'cases' proof
  1763 method anyway;
  1764 
  1765 * Isar/HOL: removed old expand_if = split_if; theorems if_splits =
  1766 split_if split_if_asm; datatype package provides theorems foo.splits =
  1767 foo.split foo.split_asm for each datatype;
  1768 
  1769 * Isar/HOL: tuned inductive package, rename "intrs" to "intros"
  1770 (potential INCOMPATIBILITY), emulation of mk_cases feature for proof
  1771 scripts: new 'inductive_cases' command and 'ind_cases' method; (Note:
  1772 use "(cases (simplified))" method in proper proof texts);
  1773 
  1774 * Isar/HOL: added global 'arith_split' attribute for 'arith' method;
  1775 
  1776 * Isar: names of theorems etc. may be natural numbers as well;
  1777 
  1778 * Isar: 'pr' command: optional arguments for goals_limit and
  1779 ProofContext.prems_limit; no longer prints theory contexts, but only
  1780 proof states;
  1781 
  1782 * Isar: diagnostic commands 'pr', 'thm', 'prop', 'term', 'typ' admit
  1783 additional print modes to be specified; e.g. "pr(latex)" will print
  1784 proof state according to the Isabelle LaTeX style;
  1785 
  1786 * Isar: improved support for emulating tactic scripts, including proof
  1787 methods 'rule_tac' etc., 'cut_tac', 'thin_tac', 'subgoal_tac',
  1788 'rename_tac', 'rotate_tac', 'tactic', and 'case_tac' / 'induct_tac'
  1789 (for HOL datatypes);
  1790 
  1791 * Isar: simplified (more robust) goal selection of proof methods: 1st
  1792 goal, all goals, or explicit goal specifier (tactic emulation); thus
  1793 'proof method scripts' have to be in depth-first order;
  1794 
  1795 * Isar: tuned 'let' syntax: replaced 'as' keyword by 'and';
  1796 
  1797 * Isar: removed 'help' command, which hasn't been too helpful anyway;
  1798 should instead use individual commands for printing items
  1799 (print_commands, print_methods etc.);
  1800 
  1801 * Isar: added 'nothing' --- the empty list of theorems;
  1802 
  1803 
  1804 *** HOL ***
  1805 
  1806 * HOL/MicroJava: formalization of a fragment of Java, together with a
  1807 corresponding virtual machine and a specification of its bytecode
  1808 verifier and a lightweight bytecode verifier, including proofs of
  1809 type-safety; by Gerwin Klein, Tobias Nipkow, David von Oheimb, and
  1810 Cornelia Pusch (see also the homepage of project Bali at
  1811 http://isabelle.in.tum.de/Bali/);
  1812 
  1813 * HOL/Algebra: new theory of rings and univariate polynomials, by
  1814 Clemens Ballarin;
  1815 
  1816 * HOL/NumberTheory: fundamental Theorem of Arithmetic, Chinese
  1817 Remainder Theorem, Fermat/Euler Theorem, Wilson's Theorem, by Thomas M
  1818 Rasmussen;
  1819 
  1820 * HOL/Lattice: fundamental concepts of lattice theory and order
  1821 structures, including duals, properties of bounds versus algebraic
  1822 laws, lattice operations versus set-theoretic ones, the Knaster-Tarski
  1823 Theorem for complete lattices etc.; may also serve as a demonstration
  1824 for abstract algebraic reasoning using axiomatic type classes, and
  1825 mathematics-style proof in Isabelle/Isar; by Markus Wenzel;
  1826 
  1827 * HOL/Prolog: a (bare-bones) implementation of Lambda-Prolog, by David
  1828 von Oheimb;
  1829 
  1830 * HOL/IMPP: extension of IMP with local variables and mutually
  1831 recursive procedures, by David von Oheimb;
  1832 
  1833 * HOL/Lambda: converted into new-style theory and document;
  1834 
  1835 * HOL/ex/Multiquote: example of multiple nested quotations and
  1836 anti-quotations -- basically a generalized version of de-Bruijn
  1837 representation; very useful in avoiding lifting of operations;
  1838 
  1839 * HOL/record: added general record equality rule to simpset; fixed
  1840 select-update simplification procedure to handle extended records as
  1841 well; admit "r" as field name;
  1842 
  1843 * HOL: 0 is now overloaded over the new sort "zero", allowing its use with
  1844 other numeric types and also as the identity of groups, rings, etc.;
  1845 
  1846 * HOL: new axclass plus_ac0 for addition with the AC-laws and 0 as identity.
  1847 Types nat and int belong to this axclass;
  1848 
  1849 * HOL: greatly improved simplification involving numerals of type nat, int, real:
  1850    (i + #8 + j) = Suc k simplifies to  #7 + (i + j) = k
  1851    i*j + k + j*#3*i     simplifies to  #4*(i*j) + k
  1852   two terms #m*u and #n*u are replaced by #(m+n)*u
  1853     (where #m, #n and u can implicitly be 1; this is simproc combine_numerals)
  1854   and the term/formula #m*u+x ~~ #n*u+y simplifies simplifies to #(m-n)+x ~~ y
  1855     or x ~~ #(n-m)+y, where ~~ is one of = < <= or - (simproc cancel_numerals);
  1856 
  1857 * HOL: meson_tac is available (previously in ex/meson.ML); it is a
  1858 powerful prover for predicate logic but knows nothing of clasets; see
  1859 ex/mesontest.ML and ex/mesontest2.ML for example applications;
  1860 
  1861 * HOL: new version of "case_tac" subsumes both boolean case split and
  1862 "exhaust_tac" on datatypes; INCOMPATIBILITY: exhaust_tac no longer
  1863 exists, may define val exhaust_tac = case_tac for ad-hoc portability;
  1864 
  1865 * HOL: simplification no longer dives into case-expressions: only the
  1866 selector expression is simplified, but not the remaining arms; to
  1867 enable full simplification of case-expressions for datatype t, you may
  1868 remove t.weak_case_cong from the simpset, either globally (Delcongs
  1869 [thm"t.weak_case_cong"];) or locally (delcongs [...]).
  1870 
  1871 * HOL/recdef: the recursion equations generated by 'recdef' for
  1872 function 'f' are now called f.simps instead of f.rules; if all
  1873 termination conditions are proved automatically, these simplification
  1874 rules are added to the simpset, as in primrec; rules may be named
  1875 individually as well, resulting in a separate list of theorems for
  1876 each equation;
  1877 
  1878 * HOL/While is a new theory that provides a while-combinator. It
  1879 permits the definition of tail-recursive functions without the
  1880 provision of a termination measure. The latter is necessary once the
  1881 invariant proof rule for while is applied.
  1882 
  1883 * HOL: new (overloaded) notation for the set of elements below/above
  1884 some element: {..u}, {..u(}, {l..}, {)l..}. See theory SetInterval.
  1885 
  1886 * HOL: theorems impI, allI, ballI bound as "strip";
  1887 
  1888 * HOL: new tactic induct_thm_tac: thm -> string -> int -> tactic
  1889 induct_tac th "x1 ... xn" expects th to have a conclusion of the form
  1890 P v1 ... vn and abbreviates res_inst_tac [("v1","x1"),...,("vn","xn")] th;
  1891 
  1892 * HOL/Real: "rabs" replaced by overloaded "abs" function;
  1893 
  1894 * HOL: theory Sexp now in HOL/Induct examples (it used to be part of
  1895 main HOL, but was unused);
  1896 
  1897 * HOL: fewer consts declared as global (e.g. have to refer to
  1898 "Lfp.lfp" instead of "lfp" internally; affects ML packages only);
  1899 
  1900 * HOL: tuned AST representation of nested pairs, avoiding bogus output
  1901 in case of overlap with user translations (e.g. judgements over
  1902 tuples); (note that the underlying logical represenation is still
  1903 bogus);
  1904 
  1905 
  1906 *** ZF ***
  1907 
  1908 * ZF: simplification automatically cancels common terms in arithmetic
  1909 expressions over nat and int;
  1910 
  1911 * ZF: new treatment of nat to minimize type-checking: all operators
  1912 coerce their operands to a natural number using the function natify,
  1913 making the algebraic laws unconditional;
  1914 
  1915 * ZF: as above, for int: operators coerce their operands to an integer
  1916 using the function intify;
  1917 
  1918 * ZF: the integer library now contains many of the usual laws for the
  1919 orderings, including $<=, and monotonicity laws for $+ and $*;
  1920 
  1921 * ZF: new example ZF/ex/NatSum to demonstrate integer arithmetic
  1922 simplification;
  1923 
  1924 * FOL and ZF: AddIffs now available, giving theorems of the form P<->Q
  1925 to the simplifier and classical reasoner simultaneously;
  1926 
  1927 
  1928 *** General ***
  1929 
  1930 * Provers: blast_tac now handles actual object-logic rules as
  1931 assumptions; note that auto_tac uses blast_tac internally as well;
  1932 
  1933 * Provers: new functions rulify/rulify_no_asm: thm -> thm for turning
  1934 outer -->/All/Ball into ==>/!!; qed_spec_mp now uses rulify_no_asm;
  1935 
  1936 * Provers: delrules now handles destruct rules as well (no longer need
  1937 explicit make_elim);
  1938 
  1939 * Provers: Blast_tac now warns of and ignores "weak elimination rules" e.g.
  1940   [| inj ?f;          ?f ?x = ?f ?y; ?x = ?y ==> ?W |] ==> ?W
  1941 use instead the strong form,
  1942   [| inj ?f; ~ ?W ==> ?f ?x = ?f ?y; ?x = ?y ==> ?W |] ==> ?W
  1943 in HOL, FOL and ZF the function cla_make_elim will create such rules
  1944 from destruct-rules;
  1945 
  1946 * Provers: Simplifier.easy_setup provides a fast path to basic
  1947 Simplifier setup for new object-logics;
  1948 
  1949 * Pure: AST translation rules no longer require constant head on LHS;
  1950 
  1951 * Pure: improved name spaces: ambiguous output is qualified; support
  1952 for hiding of names;
  1953 
  1954 * system: smart setup of canonical ML_HOME, ISABELLE_INTERFACE, and
  1955 XSYMBOL_HOME; no longer need to do manual configuration in most
  1956 situations;
  1957 
  1958 * system: compression of ML heaps images may now be controlled via -c
  1959 option of isabelle and isatool usedir (currently only observed by
  1960 Poly/ML);
  1961 
  1962 * system: isatool installfonts may handle X-Symbol fonts as well (very
  1963 useful for remote X11);
  1964 
  1965 * system: provide TAGS file for Isabelle sources;
  1966 
  1967 * ML: infix 'OF' is a version of 'MRS' with more appropriate argument
  1968 order;
  1969 
  1970 * ML: renamed flags Syntax.trace_norm_ast to Syntax.trace_ast; global
  1971 timing flag supersedes proof_timing and Toplevel.trace;
  1972 
  1973 * ML: new combinators |>> and |>>> for incremental transformations
  1974 with secondary results (e.g. certain theory extensions):
  1975 
  1976 * ML: PureThy.add_defs gets additional argument to indicate potential
  1977 overloading (usually false);
  1978 
  1979 * ML: PureThy.add_thms/add_axioms/add_defs now return theorems as
  1980 results;
  1981 
  1982 
  1983 
  1984 New in Isabelle99 (October 1999)
  1985 --------------------------------
  1986 
  1987 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  1988 
  1989 * HOL: The THEN and ELSE parts of conditional expressions (if P then x else y)
  1990 are no longer simplified.  (This allows the simplifier to unfold recursive
  1991 functional programs.)  To restore the old behaviour, declare
  1992 
  1993     Delcongs [if_weak_cong];
  1994 
  1995 * HOL: Removed the obsolete syntax "Compl A"; use -A for set
  1996 complement;
  1997 
  1998 * HOL: the predicate "inj" is now defined by translation to "inj_on";
  1999 
  2000 * HOL/datatype: mutual_induct_tac no longer exists --
  2001   use induct_tac "x_1 ... x_n" instead of mutual_induct_tac ["x_1", ..., "x_n"]
  2002 
  2003 * HOL/typedef: fixed type inference for representing set; type
  2004 arguments now have to occur explicitly on the rhs as type constraints;
  2005 
  2006 * ZF: The con_defs part of an inductive definition may no longer refer
  2007 to constants declared in the same theory;
  2008 
  2009 * HOL, ZF: the function mk_cases, generated by the inductive
  2010 definition package, has lost an argument.  To simplify its result, it
  2011 uses the default simpset instead of a supplied list of theorems.
  2012 
  2013 * HOL/List: the constructors of type list are now Nil and Cons;
  2014 
  2015 * Simplifier: the type of the infix ML functions
  2016         setSSolver addSSolver setSolver addSolver
  2017 is now  simpset * solver -> simpset  where `solver' is a new abstract type
  2018 for packaging solvers. A solver is created via
  2019         mk_solver: string -> (thm list -> int -> tactic) -> solver
  2020 where the string argument is only a comment.
  2021 
  2022 
  2023 *** Proof tools ***
  2024 
  2025 * Provers/Arith/fast_lin_arith.ML contains a functor for creating a
  2026 decision procedure for linear arithmetic. Currently it is used for
  2027 types `nat', `int', and `real' in HOL (see below); it can, should and
  2028 will be instantiated for other types and logics as well.
  2029 
  2030 * The simplifier now accepts rewrite rules with flexible heads, eg
  2031      hom ?f ==> ?f(?x+?y) = ?f ?x + ?f ?y
  2032   They are applied like any rule with a non-pattern lhs, i.e. by first-order
  2033   matching.
  2034 
  2035 
  2036 *** General ***
  2037 
  2038 * New Isabelle/Isar subsystem provides an alternative to traditional
  2039 tactical theorem proving; together with the ProofGeneral/isar user
  2040 interface it offers an interactive environment for developing human
  2041 readable proof documents (Isar == Intelligible semi-automated
  2042 reasoning); for further information see isatool doc isar-ref,
  2043 src/HOL/Isar_examples and http://isabelle.in.tum.de/Isar/
  2044 
  2045 * improved and simplified presentation of theories: better HTML markup
  2046 (including colors), graph views in several sizes; isatool usedir now
  2047 provides a proper interface for user theories (via -P option); actual
  2048 document preparation based on (PDF)LaTeX is available as well (for
  2049 new-style theories only); see isatool doc system for more information;
  2050 
  2051 * native support for Proof General, both for classic Isabelle and
  2052 Isabelle/Isar;
  2053 
  2054 * ML function thm_deps visualizes dependencies of theorems and lemmas,
  2055 using the graph browser tool;
  2056 
  2057 * Isabelle manuals now also available as PDF;
  2058 
  2059 * theory loader rewritten from scratch (may not be fully
  2060 bug-compatible); old loadpath variable has been replaced by show_path,
  2061 add_path, del_path, reset_path functions; new operations such as
  2062 update_thy, touch_thy, remove_thy, use/update_thy_only (see also
  2063 isatool doc ref);
  2064 
  2065 * improved isatool install: option -k creates KDE application icon,
  2066 option -p DIR installs standalone binaries;
  2067 
  2068 * added ML_PLATFORM setting (useful for cross-platform installations);
  2069 more robust handling of platform specific ML images for SML/NJ;
  2070 
  2071 * the settings environment is now statically scoped, i.e. it is never
  2072 created again in sub-processes invoked from isabelle, isatool, or
  2073 Isabelle;
  2074 
  2075 * path element specification '~~' refers to '$ISABELLE_HOME';
  2076 
  2077 * in locales, the "assumes" and "defines" parts may be omitted if
  2078 empty;
  2079 
  2080 * new print_mode "xsymbols" for extended symbol support (e.g. genuine
  2081 long arrows);
  2082 
  2083 * new print_mode "HTML";
  2084 
  2085 * new flag show_tags controls display of tags of theorems (which are
  2086 basically just comments that may be attached by some tools);
  2087 
  2088 * Isamode 2.6 requires patch to accomodate change of Isabelle font
  2089 mode and goal output format:
  2090 
  2091 diff -r Isamode-2.6/elisp/isa-load.el Isamode/elisp/isa-load.el
  2092 244c244
  2093 <       (list (isa-getenv "ISABELLE") "-msymbols" logic-name)
  2094 ---
  2095 >       (list (isa-getenv "ISABELLE") "-misabelle_font" "-msymbols" logic-name)
  2096 diff -r Isabelle-2.6/elisp/isa-proofstate.el Isamode/elisp/isa-proofstate.el
  2097 181c181
  2098 < (defconst proofstate-proofstart-regexp "^Level [0-9]+$"
  2099 ---
  2100 > (defconst proofstate-proofstart-regexp "^Level [0-9]+"
  2101 
  2102 * function bind_thms stores lists of theorems (cf. bind_thm);
  2103 
  2104 * new shorthand tactics ftac, eatac, datac, fatac;
  2105 
  2106 * qed (and friends) now accept "" as result name; in that case the
  2107 theorem is not stored, but proper checks and presentation of the
  2108 result still apply;
  2109 
  2110 * theorem database now also indexes constants "Trueprop", "all",
  2111 "==>", "=="; thus thms_containing, findI etc. may retrieve more rules;
  2112 
  2113 
  2114 *** HOL ***
  2115 
  2116 ** HOL arithmetic **
  2117 
  2118 * There are now decision procedures for linear arithmetic over nat and
  2119 int:
  2120 
  2121 1. arith_tac copes with arbitrary formulae involving `=', `<', `<=',
  2122 `+', `-', `Suc', `min', `max' and numerical constants; other subterms
  2123 are treated as atomic; subformulae not involving type `nat' or `int'
  2124 are ignored; quantified subformulae are ignored unless they are
  2125 positive universal or negative existential. The tactic has to be
  2126 invoked by hand and can be a little bit slow. In particular, the
  2127 running time is exponential in the number of occurrences of `min' and
  2128 `max', and `-' on `nat'.
  2129 
  2130 2. fast_arith_tac is a cut-down version of arith_tac: it only takes
  2131 (negated) (in)equalities among the premises and the conclusion into
  2132 account (i.e. no compound formulae) and does not know about `min' and
  2133 `max', and `-' on `nat'. It is fast and is used automatically by the
  2134 simplifier.
  2135 
  2136 NB: At the moment, these decision procedures do not cope with mixed
  2137 nat/int formulae where the two parts interact, such as `m < n ==>
  2138 int(m) < int(n)'.
  2139 
  2140 * HOL/Numeral provides a generic theory of numerals (encoded
  2141 efficiently as bit strings); setup for types nat/int/real is in place;
  2142 INCOMPATIBILITY: since numeral syntax is now polymorphic, rather than
  2143 int, existing theories and proof scripts may require a few additional
  2144 type constraints;
  2145 
  2146 * integer division and remainder can now be performed on constant
  2147 arguments;
  2148 
  2149 * many properties of integer multiplication, division and remainder
  2150 are now available;
  2151 
  2152 * An interface to the Stanford Validity Checker (SVC) is available through the
  2153 tactic svc_tac.  Propositional tautologies and theorems of linear arithmetic
  2154 are proved automatically.  SVC must be installed separately, and its results
  2155 must be TAKEN ON TRUST (Isabelle does not check the proofs, but tags any
  2156 invocation of the underlying oracle).  For SVC see
  2157   http://verify.stanford.edu/SVC
  2158 
  2159 * IsaMakefile: the HOL-Real target now builds an actual image;
  2160 
  2161 
  2162 ** HOL misc **
  2163 
  2164 * HOL/Real/HahnBanach: the Hahn-Banach theorem for real vector spaces
  2165 (in Isabelle/Isar) -- by Gertrud Bauer;
  2166 
  2167 * HOL/BCV: generic model of bytecode verification, i.e. data-flow
  2168 analysis for assembly languages with subtypes;
  2169 
  2170 * HOL/TLA (Lamport's Temporal Logic of Actions): major reorganization
  2171 -- avoids syntactic ambiguities and treats state, transition, and
  2172 temporal levels more uniformly; introduces INCOMPATIBILITIES due to
  2173 changed syntax and (many) tactics;
  2174 
  2175 * HOL/inductive: Now also handles more general introduction rules such
  2176   as "ALL y. (y, x) : r --> y : acc r ==> x : acc r"; monotonicity
  2177   theorems are now maintained within the theory (maintained via the
  2178   "mono" attribute);
  2179 
  2180 * HOL/datatype: Now also handles arbitrarily branching datatypes
  2181   (using function types) such as
  2182 
  2183   datatype 'a tree = Atom 'a | Branch "nat => 'a tree"
  2184 
  2185 * HOL/record: record_simproc (part of the default simpset) takes care
  2186 of selectors applied to updated records; record_split_tac is no longer
  2187 part of the default claset; update_defs may now be removed from the
  2188 simpset in many cases; COMPATIBILITY: old behavior achieved by
  2189 
  2190   claset_ref () := claset() addSWrapper record_split_wrapper;
  2191   Delsimprocs [record_simproc]
  2192 
  2193 * HOL/typedef: fixed type inference for representing set; type
  2194 arguments now have to occur explicitly on the rhs as type constraints;
  2195 
  2196 * HOL/recdef (TFL): 'congs' syntax now expects comma separated list of theorem
  2197 names rather than an ML expression;
  2198 
  2199 * HOL/defer_recdef (TFL): like recdef but the well-founded relation can be
  2200 supplied later.  Program schemes can be defined, such as
  2201     "While B C s = (if B s then While B C (C s) else s)"
  2202 where the well-founded relation can be chosen after B and C have been given.
  2203 
  2204 * HOL/List: the constructors of type list are now Nil and Cons;
  2205 INCOMPATIBILITY: while [] and infix # syntax is still there, of
  2206 course, ML tools referring to List.list.op # etc. have to be adapted;
  2207 
  2208 * HOL_quantifiers flag superseded by "HOL" print mode, which is
  2209 disabled by default; run isabelle with option -m HOL to get back to
  2210 the original Gordon/HOL-style output;
  2211 
  2212 * HOL/Ord.thy: new bounded quantifier syntax (input only): ALL x<y. P,
  2213 ALL x<=y. P, EX x<y. P, EX x<=y. P;
  2214 
  2215 * HOL basic syntax simplified (more orthogonal): all variants of
  2216 All/Ex now support plain / symbolic / HOL notation; plain syntax for
  2217 Eps operator is provided as well: "SOME x. P[x]";
  2218 
  2219 * HOL/Sum.thy: sum_case has been moved to HOL/Datatype;
  2220 
  2221 * HOL/Univ.thy: infix syntax <*>, <+>, <**>, <+> eliminated and made
  2222 thus available for user theories;
  2223 
  2224 * HOLCF/IOA/Sequents: renamed 'Cons' to 'Consq' to avoid clash with
  2225 HOL/List; hardly an INCOMPATIBILITY since '>>' syntax is used all the
  2226 time;
  2227 
  2228 * HOL: new tactic smp_tac: int -> int -> tactic, which applies spec
  2229 several times and then mp;
  2230 
  2231 
  2232 *** LK ***
  2233 
  2234 * the notation <<...>> is now available as a notation for sequences of
  2235 formulas;
  2236 
  2237 * the simplifier is now installed
  2238 
  2239 * the axiom system has been generalized (thanks to Soren Heilmann)
  2240 
  2241 * the classical reasoner now has a default rule database
  2242 
  2243 
  2244 *** ZF ***
  2245 
  2246 * new primrec section allows primitive recursive functions to be given
  2247 directly (as in HOL) over datatypes and the natural numbers;
  2248 
  2249 * new tactics induct_tac and exhaust_tac for induction (or case
  2250 analysis) over datatypes and the natural numbers;
  2251 
  2252 * the datatype declaration of type T now defines the recursor T_rec;
  2253 
  2254 * simplification automatically does freeness reasoning for datatype
  2255 constructors;
  2256 
  2257 * automatic type-inference, with AddTCs command to insert new
  2258 type-checking rules;
  2259 
  2260 * datatype introduction rules are now added as Safe Introduction rules
  2261 to the claset;
  2262 
  2263 * the syntax "if P then x else y" is now available in addition to
  2264 if(P,x,y);
  2265 
  2266 
  2267 *** Internal programming interfaces ***
  2268 
  2269 * tuned simplifier trace output; new flag debug_simp;
  2270 
  2271 * structures Vartab / Termtab (instances of TableFun) offer efficient
  2272 tables indexed by indexname_ord / term_ord (compatible with aconv);
  2273 
  2274 * AxClass.axclass_tac lost the theory argument;
  2275 
  2276 * tuned current_goals_markers semantics: begin / end goal avoids
  2277 printing empty lines;
  2278 
  2279 * removed prs and prs_fn hook, which was broken because it did not
  2280 include \n in its semantics, forcing writeln to add one
  2281 uncoditionally; replaced prs_fn by writeln_fn; consider std_output:
  2282 string -> unit if you really want to output text without newline;
  2283 
  2284 * Symbol.output subject to print mode; INCOMPATIBILITY: defaults to
  2285 plain output, interface builders may have to enable 'isabelle_font'
  2286 mode to get Isabelle font glyphs as before;
  2287 
  2288 * refined token_translation interface; INCOMPATIBILITY: output length
  2289 now of type real instead of int;
  2290 
  2291 * theory loader actions may be traced via new ThyInfo.add_hook
  2292 interface (see src/Pure/Thy/thy_info.ML); example application: keep
  2293 your own database of information attached to *whole* theories -- as
  2294 opposed to intra-theory data slots offered via TheoryDataFun;
  2295 
  2296 * proper handling of dangling sort hypotheses (at last!);
  2297 Thm.strip_shyps and Drule.strip_shyps_warning take care of removing
  2298 extra sort hypotheses that can be witnessed from the type signature;
  2299 the force_strip_shyps flag is gone, any remaining shyps are simply
  2300 left in the theorem (with a warning issued by strip_shyps_warning);
  2301 
  2302 
  2303 
  2304 New in Isabelle98-1 (October 1998)
  2305 ----------------------------------
  2306 
  2307 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  2308 
  2309 * several changes of automated proof tools;
  2310 
  2311 * HOL: major changes to the inductive and datatype packages, including
  2312 some minor incompatibilities of theory syntax;
  2313 
  2314 * HOL: renamed r^-1 to 'converse' from 'inverse'; 'inj_onto' is now
  2315 called `inj_on';
  2316 
  2317 * HOL: removed duplicate thms in Arith:
  2318   less_imp_add_less  should be replaced by  trans_less_add1
  2319   le_imp_add_le      should be replaced by  trans_le_add1
  2320 
  2321 * HOL: unary minus is now overloaded (new type constraints may be
  2322 required);
  2323 
  2324 * HOL and ZF: unary minus for integers is now #- instead of #~.  In
  2325 ZF, expressions such as n#-1 must be changed to n#- 1, since #-1 is
  2326 now taken as an integer constant.
  2327 
  2328 * Pure: ML function 'theory_of' renamed to 'theory';
  2329 
  2330 
  2331 *** Proof tools ***
  2332 
  2333 * Simplifier:
  2334   1. Asm_full_simp_tac is now more aggressive.
  2335      1. It will sometimes reorient premises if that increases their power to
  2336         simplify.
  2337      2. It does no longer proceed strictly from left to right but may also
  2338         rotate premises to achieve further simplification.
  2339      For compatibility reasons there is now Asm_lr_simp_tac which is like the
  2340      old Asm_full_simp_tac in that it does not rotate premises.
  2341   2. The simplifier now knows a little bit about nat-arithmetic.
  2342 
  2343 * Classical reasoner: wrapper mechanism for the classical reasoner now
  2344 allows for selected deletion of wrappers, by introduction of names for
  2345 wrapper functionals.  This implies that addbefore, addSbefore,
  2346 addaltern, and addSaltern now take a pair (name, tactic) as argument,
  2347 and that adding two tactics with the same name overwrites the first
  2348 one (emitting a warning).
  2349   type wrapper = (int -> tactic) -> (int -> tactic)
  2350   setWrapper, setSWrapper, compWrapper and compSWrapper are replaced by
  2351   addWrapper, addSWrapper: claset * (string * wrapper) -> claset
  2352   delWrapper, delSWrapper: claset *  string            -> claset
  2353   getWrapper is renamed to appWrappers, getSWrapper to appSWrappers;
  2354 
  2355 * Classical reasoner: addbefore/addSbefore now have APPEND/ORELSE
  2356 semantics; addbefore now affects only the unsafe part of step_tac
  2357 etc.; this affects addss/auto_tac/force_tac, so EXISTING PROOFS MAY
  2358 FAIL, but proofs should be fixable easily, e.g. by replacing Auto_tac
  2359 by Force_tac;
  2360 
  2361 * Classical reasoner: setwrapper to setWrapper and compwrapper to
  2362 compWrapper; added safe wrapper (and access functions for it);
  2363 
  2364 * HOL/split_all_tac is now much faster and fails if there is nothing
  2365 to split.  Some EXISTING PROOFS MAY REQUIRE ADAPTION because the order
  2366 and the names of the automatically generated variables have changed.
  2367 split_all_tac has moved within claset() from unsafe wrappers to safe
  2368 wrappers, which means that !!-bound variables are split much more
  2369 aggressively, and safe_tac and clarify_tac now split such variables.
  2370 If this splitting is not appropriate, use delSWrapper "split_all_tac".
  2371 Note: the same holds for record_split_tac, which does the job of
  2372 split_all_tac for record fields.
  2373 
  2374 * HOL/Simplifier: Rewrite rules for case distinctions can now be added
  2375 permanently to the default simpset using Addsplits just like
  2376 Addsimps. They can be removed via Delsplits just like
  2377 Delsimps. Lower-case versions are also available.
  2378 
  2379 * HOL/Simplifier: The rule split_if is now part of the default
  2380 simpset. This means that the simplifier will eliminate all occurrences
  2381 of if-then-else in the conclusion of a goal. To prevent this, you can
  2382 either remove split_if completely from the default simpset by
  2383 `Delsplits [split_if]' or remove it in a specific call of the
  2384 simplifier using `... delsplits [split_if]'.  You can also add/delete
  2385 other case splitting rules to/from the default simpset: every datatype
  2386 generates suitable rules `split_t_case' and `split_t_case_asm' (where
  2387 t is the name of the datatype).
  2388 
  2389 * Classical reasoner / Simplifier combination: new force_tac (and
  2390 derivatives Force_tac, force) combines rewriting and classical
  2391 reasoning (and whatever other tools) similarly to auto_tac, but is
  2392 aimed to solve the given subgoal completely.
  2393 
  2394 
  2395 *** General ***
  2396 
  2397 * new top-level commands `Goal' and `Goalw' that improve upon `goal'
  2398 and `goalw': the theory is no longer needed as an explicit argument -
  2399 the current theory context is used; assumptions are no longer returned
  2400 at the ML-level unless one of them starts with ==> or !!; it is
  2401 recommended to convert to these new commands using isatool fixgoal
  2402 (backup your sources first!);
  2403 
  2404 * new top-level commands 'thm' and 'thms' for retrieving theorems from
  2405 the current theory context, and 'theory' to lookup stored theories;
  2406 
  2407 * new theory section 'locale' for declaring constants, assumptions and
  2408 definitions that have local scope;
  2409 
  2410 * new theory section 'nonterminals' for purely syntactic types;
  2411 
  2412 * new theory section 'setup' for generic ML setup functions
  2413 (e.g. package initialization);
  2414 
  2415 * the distribution now includes Isabelle icons: see
  2416 lib/logo/isabelle-{small,tiny}.xpm;
  2417 
  2418 * isatool install - install binaries with absolute references to
  2419 ISABELLE_HOME/bin;
  2420 
  2421 * isatool logo -- create instances of the Isabelle logo (as EPS);
  2422 
  2423 * print mode 'emacs' reserved for Isamode;
  2424 
  2425 * support multiple print (ast) translations per constant name;
  2426 
  2427 * theorems involving oracles are now printed with a suffixed [!];
  2428 
  2429 
  2430 *** HOL ***
  2431 
  2432 * there is now a tutorial on Isabelle/HOL (do 'isatool doc tutorial');
  2433 
  2434 * HOL/inductive package reorganized and improved: now supports mutual
  2435 definitions such as
  2436 
  2437   inductive EVEN ODD
  2438     intrs
  2439       null "0 : EVEN"
  2440       oddI "n : EVEN ==> Suc n : ODD"
  2441       evenI "n : ODD ==> Suc n : EVEN"
  2442 
  2443 new theorem list "elims" contains an elimination rule for each of the
  2444 recursive sets; inductive definitions now handle disjunctive premises
  2445 correctly (also ZF);
  2446 
  2447 INCOMPATIBILITIES: requires Inductive as an ancestor; component
  2448 "mutual_induct" no longer exists - the induction rule is always
  2449 contained in "induct";
  2450 
  2451 
  2452 * HOL/datatype package re-implemented and greatly improved: now
  2453 supports mutually recursive datatypes such as
  2454 
  2455   datatype
  2456     'a aexp = IF_THEN_ELSE ('a bexp) ('a aexp) ('a aexp)
  2457             | SUM ('a aexp) ('a aexp)
  2458             | DIFF ('a aexp) ('a aexp)
  2459             | NUM 'a
  2460   and
  2461     'a bexp = LESS ('a aexp) ('a aexp)
  2462             | AND ('a bexp) ('a bexp)
  2463             | OR ('a bexp) ('a bexp)
  2464 
  2465 as well as indirectly recursive datatypes such as
  2466 
  2467   datatype
  2468     ('a, 'b) term = Var 'a
  2469                   | App 'b ((('a, 'b) term) list)
  2470 
  2471 The new tactic  mutual_induct_tac [<var_1>, ..., <var_n>] i  performs
  2472 induction on mutually / indirectly recursive datatypes.
  2473 
  2474 Primrec equations are now stored in theory and can be accessed via
  2475 <function_name>.simps.
  2476 
  2477 INCOMPATIBILITIES:
  2478 
  2479   - Theories using datatypes must now have theory Datatype as an
  2480     ancestor.
  2481   - The specific <typename>.induct_tac no longer exists - use the
  2482     generic induct_tac instead.
  2483   - natE has been renamed to nat.exhaust - use exhaust_tac
  2484     instead of res_inst_tac ... natE. Note that the variable
  2485     names in nat.exhaust differ from the names in natE, this
  2486     may cause some "fragile" proofs to fail.
  2487   - The theorems split_<typename>_case and split_<typename>_case_asm
  2488     have been renamed to <typename>.split and <typename>.split_asm.
  2489   - Since default sorts of type variables are now handled correctly,
  2490     some datatype definitions may have to be annotated with explicit
  2491     sort constraints.
  2492   - Primrec definitions no longer require function name and type
  2493     of recursive argument.
  2494 
  2495 Consider using isatool fixdatatype to adapt your theories and proof
  2496 scripts to the new package (backup your sources first!).
  2497 
  2498 
  2499 * HOL/record package: considerably improved implementation; now
  2500 includes concrete syntax for record types, terms, updates; theorems
  2501 for surjective pairing and splitting !!-bound record variables; proof
  2502 support is as follows:
  2503 
  2504   1) standard conversions (selectors or updates applied to record
  2505 constructor terms) are part of the standard simpset;
  2506 
  2507   2) inject equations of the form ((x, y) = (x', y')) == x=x' & y=y' are
  2508 made part of standard simpset and claset via addIffs;
  2509 
  2510   3) a tactic for record field splitting (record_split_tac) is part of
  2511 the standard claset (addSWrapper);
  2512 
  2513 To get a better idea about these rules you may retrieve them via
  2514 something like 'thms "foo.simps"' or 'thms "foo.iffs"', where "foo" is
  2515 the name of your record type.
  2516 
  2517 The split tactic 3) conceptually simplifies by the following rule:
  2518 
  2519   "(!!x. PROP ?P x) == (!!a b. PROP ?P (a, b))"
  2520 
  2521 Thus any record variable that is bound by meta-all will automatically
  2522 blow up into some record constructor term, consequently the
  2523 simplifications of 1), 2) apply.  Thus force_tac, auto_tac etc. shall
  2524 solve record problems automatically.
  2525 
  2526 
  2527 * reorganized the main HOL image: HOL/Integ and String loaded by
  2528 default; theory Main includes everything;
  2529 
  2530 * automatic simplification of integer sums and comparisons, using cancellation;
  2531 
  2532 * added option_map_eq_Some and not_Some_eq to the default simpset and claset;
  2533 
  2534 * added disj_not1 = "(~P | Q) = (P --> Q)" to the default simpset;
  2535 
  2536 * many new identities for unions, intersections, set difference, etc.;
  2537 
  2538 * expand_if, expand_split, expand_sum_case and expand_nat_case are now
  2539 called split_if, split_split, split_sum_case and split_nat_case (to go
  2540 with add/delsplits);
  2541 
  2542 * HOL/Prod introduces simplification procedure unit_eq_proc rewriting
  2543 (?x::unit) = (); this is made part of the default simpset, which COULD
  2544 MAKE EXISTING PROOFS FAIL under rare circumstances (consider
  2545 'Delsimprocs [unit_eq_proc];' as last resort); also note that
  2546 unit_abs_eta_conv is added in order to counter the effect of
  2547 unit_eq_proc on (%u::unit. f u), replacing it by f rather than by
  2548 %u.f();
  2549 
  2550 * HOL/Fun INCOMPATIBILITY: `inj_onto' is now called `inj_on' (which
  2551 makes more sense);
  2552 
  2553 * HOL/Set INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
  2554   It and 'sym RS equals0D' are now in the default  claset, giving automatic
  2555   disjointness reasoning but breaking a few old proofs.
  2556 
  2557 * HOL/Relation INCOMPATIBILITY: renamed the relational operator r^-1
  2558 to 'converse' from 'inverse' (for compatibility with ZF and some
  2559 literature);
  2560 
  2561 * HOL/recdef can now declare non-recursive functions, with {} supplied as
  2562 the well-founded relation;
  2563 
  2564 * HOL/Set INCOMPATIBILITY: the complement of set A is now written -A instead of
  2565     Compl A.  The "Compl" syntax remains available as input syntax for this
  2566     release ONLY.
  2567 
  2568 * HOL/Update: new theory of function updates:
  2569     f(a:=b) == %x. if x=a then b else f x
  2570 may also be iterated as in f(a:=b,c:=d,...);
  2571 
  2572 * HOL/Vimage: new theory for inverse image of a function, syntax f-``B;
  2573 
  2574 * HOL/List:
  2575   - new function list_update written xs[i:=v] that updates the i-th
  2576     list position. May also be iterated as in xs[i:=a,j:=b,...].
  2577   - new function `upt' written [i..j(] which generates the list
  2578     [i,i+1,...,j-1], i.e. the upper bound is excluded. To include the upper
  2579     bound write [i..j], which is a shorthand for [i..j+1(].
  2580   - new lexicographic orderings and corresponding wellfoundedness theorems.
  2581 
  2582 * HOL/Arith:
  2583   - removed 'pred' (predecessor) function;
  2584   - generalized some theorems about n-1;
  2585   - many new laws about "div" and "mod";
  2586   - new laws about greatest common divisors (see theory ex/Primes);
  2587 
  2588 * HOL/Relation: renamed the relational operator r^-1 "converse"
  2589 instead of "inverse";
  2590 
  2591 * HOL/Induct/Multiset: a theory of multisets, including the wellfoundedness
  2592   of the multiset ordering;
  2593 
  2594 * directory HOL/Real: a construction of the reals using Dedekind cuts
  2595   (not included by default);
  2596 
  2597 * directory HOL/UNITY: Chandy and Misra's UNITY formalism;
  2598 
  2599 * directory HOL/Hoare: a new version of Hoare logic which permits many-sorted
  2600   programs, i.e. different program variables may have different types.
  2601 
  2602 * calling (stac rew i) now fails if "rew" has no effect on the goal
  2603   [previously, this check worked only if the rewrite rule was unconditional]
  2604   Now rew can involve either definitions or equalities (either == or =).
  2605 
  2606 
  2607 *** ZF ***
  2608 
  2609 * theory Main includes everything; INCOMPATIBILITY: theory ZF.thy contains
  2610   only the theorems proved on ZF.ML;
  2611 
  2612 * ZF INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
  2613   It and 'sym RS equals0D' are now in the default  claset, giving automatic
  2614   disjointness reasoning but breaking a few old proofs.
  2615 
  2616 * ZF/Update: new theory of function updates
  2617     with default rewrite rule  f(x:=y) ` z = if(z=x, y, f`z)
  2618   may also be iterated as in f(a:=b,c:=d,...);
  2619 
  2620 * in  let x=t in u(x), neither t nor u(x) has to be an FOL term.
  2621 
  2622 * calling (stac rew i) now fails if "rew" has no effect on the goal
  2623   [previously, this check worked only if the rewrite rule was unconditional]
  2624   Now rew can involve either definitions or equalities (either == or =).
  2625 
  2626 * case_tac provided for compatibility with HOL
  2627     (like the old excluded_middle_tac, but with subgoals swapped)
  2628 
  2629 
  2630 *** Internal programming interfaces ***
  2631 
  2632 * Pure: several new basic modules made available for general use, see
  2633 also src/Pure/README;
  2634 
  2635 * improved the theory data mechanism to support encapsulation (data
  2636 kind name replaced by private Object.kind, acting as authorization
  2637 key); new type-safe user interface via functor TheoryDataFun; generic
  2638 print_data function becomes basically useless;
  2639 
  2640 * removed global_names compatibility flag -- all theory declarations
  2641 are qualified by default;
  2642 
  2643 * module Pure/Syntax now offers quote / antiquote translation
  2644 functions (useful for Hoare logic etc. with implicit dependencies);
  2645 see HOL/ex/Antiquote for an example use;
  2646 
  2647 * Simplifier now offers conversions (asm_)(full_)rewrite: simpset ->
  2648 cterm -> thm;
  2649 
  2650 * new tactical CHANGED_GOAL for checking that a tactic modifies a
  2651 subgoal;
  2652 
  2653 * Display.print_goals function moved to Locale.print_goals;
  2654 
  2655 * standard print function for goals supports current_goals_markers
  2656 variable for marking begin of proof, end of proof, start of goal; the
  2657 default is ("", "", ""); setting current_goals_markers := ("<proof>",
  2658 "</proof>", "<goal>") causes SGML like tagged proof state printing,
  2659 for example;
  2660 
  2661 
  2662 
  2663 New in Isabelle98 (January 1998)
  2664 --------------------------------
  2665 
  2666 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  2667 
  2668 * changed lexical syntax of terms / types: dots made part of long
  2669 identifiers, e.g. "%x.x" no longer possible, should be "%x. x";
  2670 
  2671 * simpset (and claset) reference variable replaced by functions
  2672 simpset / simpset_ref;
  2673 
  2674 * no longer supports theory aliases (via merge) and non-trivial
  2675 implicit merge of thms' signatures;
  2676 
  2677 * most internal names of constants changed due to qualified names;
  2678 
  2679 * changed Pure/Sequence interface (see Pure/seq.ML);
  2680 
  2681 
  2682 *** General Changes ***
  2683 
  2684 * hierachically structured name spaces (for consts, types, axms, thms
  2685 etc.); new lexical class 'longid' (e.g. Foo.bar.x) may render much of
  2686 old input syntactically incorrect (e.g. "%x.x"); COMPATIBILITY:
  2687 isatool fixdots ensures space after dots (e.g. "%x. x"); set
  2688 long_names for fully qualified output names; NOTE: ML programs
  2689 (special tactics, packages etc.) referring to internal names may have
  2690 to be adapted to cope with fully qualified names; in case of severe
  2691 backward campatibility problems try setting 'global_names' at compile
  2692 time to have enrything declared within a flat name space; one may also
  2693 fine tune name declarations in theories via the 'global' and 'local'
  2694 section;
  2695 
  2696 * reimplemented the implicit simpset and claset using the new anytype
  2697 data filed in signatures; references simpset:simpset ref etc. are
  2698 replaced by functions simpset:unit->simpset and
  2699 simpset_ref:unit->simpset ref; COMPATIBILITY: use isatool fixclasimp
  2700 to patch your ML files accordingly;
  2701 
  2702 * HTML output now includes theory graph data for display with Java
  2703 applet or isatool browser; data generated automatically via isatool
  2704 usedir (see -i option, ISABELLE_USEDIR_OPTIONS);
  2705 
  2706 * defs may now be conditional; improved rewrite_goals_tac to handle
  2707 conditional equations;
  2708 
  2709 * defs now admits additional type arguments, using TYPE('a) syntax;
  2710 
  2711 * theory aliases via merge (e.g. M=A+B+C) no longer supported, always
  2712 creates a new theory node; implicit merge of thms' signatures is
  2713 restricted to 'trivial' ones; COMPATIBILITY: one may have to use
  2714 transfer:theory->thm->thm in (rare) cases;
  2715 
  2716 * improved handling of draft signatures / theories; draft thms (and
  2717 ctyps, cterms) are automatically promoted to real ones;
  2718 
  2719 * slightly changed interfaces for oracles: admit many per theory, named
  2720 (e.g. oracle foo = mlfun), additional name argument for invoke_oracle;
  2721 
  2722 * print_goals: optional output of const types (set show_consts and
  2723 show_types);
  2724 
  2725 * improved output of warnings (###) and errors (***);
  2726 
  2727 * subgoal_tac displays a warning if the new subgoal has type variables;
  2728 
  2729 * removed old README and Makefiles;
  2730 
  2731 * replaced print_goals_ref hook by print_current_goals_fn and result_error_fn;
  2732 
  2733 * removed obsolete init_pps and init_database;
  2734 
  2735 * deleted the obsolete tactical STATE, which was declared by
  2736     fun STATE tacfun st = tacfun st st;
  2737 
  2738 * cd and use now support path variables, e.g. $ISABELLE_HOME, or ~
  2739 (which abbreviates $HOME);
  2740 
  2741 * changed Pure/Sequence interface (see Pure/seq.ML); COMPATIBILITY:
  2742 use isatool fixseq to adapt your ML programs (this works for fully
  2743 qualified references to the Sequence structure only!);
  2744 
  2745 * use_thy no longer requires writable current directory; it always
  2746 reloads .ML *and* .thy file, if either one is out of date;
  2747 
  2748 
  2749 *** Classical Reasoner ***
  2750 
  2751 * Clarify_tac, clarify_tac, clarify_step_tac, Clarify_step_tac: new
  2752 tactics that use classical reasoning to simplify a subgoal without
  2753 splitting it into several subgoals;
  2754 
  2755 * Safe_tac: like safe_tac but uses the default claset;
  2756 
  2757 
  2758 *** Simplifier ***
  2759 
  2760 * added simplification meta rules:
  2761     (asm_)(full_)simplify: simpset -> thm -> thm;
  2762 
  2763 * simplifier.ML no longer part of Pure -- has to be loaded by object
  2764 logics (again);
  2765 
  2766 * added prems argument to simplification procedures;
  2767 
  2768 * HOL, FOL, ZF: added infix function `addsplits':
  2769   instead of `<simpset> setloop (split_tac <thms>)'
  2770   you can simply write `<simpset> addsplits <thms>'
  2771 
  2772 
  2773 *** Syntax ***
  2774 
  2775 * TYPE('a) syntax for type reflection terms;
  2776 
  2777 * no longer handles consts with name "" -- declare as 'syntax' instead;
  2778 
  2779 * pretty printer: changed order of mixfix annotation preference (again!);
  2780 
  2781 * Pure: fixed idt/idts vs. pttrn/pttrns syntactic categories;
  2782 
  2783 
  2784 *** HOL ***
  2785 
  2786 * HOL: there is a new splitter `split_asm_tac' that can be used e.g.
  2787   with `addloop' of the simplifier to faciliate case splitting in premises.
  2788 
  2789 * HOL/TLA: Stephan Merz's formalization of Lamport's Temporal Logic of Actions;
  2790 
  2791 * HOL/Auth: new protocol proofs including some for the Internet
  2792   protocol TLS;
  2793 
  2794 * HOL/Map: new theory of `maps' a la VDM;
  2795 
  2796 * HOL/simplifier: simplification procedures nat_cancel_sums for
  2797 cancelling out common nat summands from =, <, <= (in)equalities, or
  2798 differences; simplification procedures nat_cancel_factor for
  2799 cancelling common factor from =, <, <= (in)equalities over natural
  2800 sums; nat_cancel contains both kinds of procedures, it is installed by
  2801 default in Arith.thy -- this COULD MAKE EXISTING PROOFS FAIL;
  2802 
  2803 * HOL/simplifier: terms of the form
  2804   `? x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x)'  (or t=x)
  2805   are rewritten to
  2806   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t)',
  2807   and those of the form
  2808   `! x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x) --> R(x)'  (or t=x)
  2809   are rewritten to
  2810   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t) --> R(t)',
  2811 
  2812 * HOL/datatype
  2813   Each datatype `t' now comes with a theorem `split_t_case' of the form
  2814 
  2815   P(t_case f1 ... fn x) =
  2816      ( (!y1 ... ym1. x = C1 y1 ... ym1 --> P(f1 y1 ... ym1)) &
  2817         ...
  2818        (!y1 ... ymn. x = Cn y1 ... ymn --> P(f1 y1 ... ymn))
  2819      )
  2820 
  2821   and a theorem `split_t_case_asm' of the form
  2822 
  2823   P(t_case f1 ... fn x) =
  2824     ~( (? y1 ... ym1. x = C1 y1 ... ym1 & ~P(f1 y1 ... ym1)) |
  2825         ...
  2826        (? y1 ... ymn. x = Cn y1 ... ymn & ~P(f1 y1 ... ymn))
  2827      )
  2828   which can be added to a simpset via `addsplits'. The existing theorems
  2829   expand_list_case and expand_option_case have been renamed to
  2830   split_list_case and split_option_case.
  2831 
  2832 * HOL/Arithmetic:
  2833   - `pred n' is automatically converted to `n-1'.
  2834     Users are strongly encouraged not to use `pred' any longer,
  2835     because it will disappear altogether at some point.
  2836   - Users are strongly encouraged to write "0 < n" rather than
  2837     "n ~= 0". Theorems and proof tools have been modified towards this
  2838     `standard'.
  2839 
  2840 * HOL/Lists:
  2841   the function "set_of_list" has been renamed "set" (and its theorems too);
  2842   the function "nth" now takes its arguments in the reverse order and
  2843   has acquired the infix notation "!" as in "xs!n".
  2844 
  2845 * HOL/Set: UNIV is now a constant and is no longer translated to Compl{};
  2846 
  2847 * HOL/Set: The operator (UN x.B x) now abbreviates (UN x:UNIV. B x) and its
  2848   specialist theorems (like UN1_I) are gone.  Similarly for (INT x.B x);
  2849 
  2850 * HOL/record: extensible records with schematic structural subtyping
  2851 (single inheritance); EXPERIMENTAL version demonstrating the encoding,
  2852 still lacks various theorems and concrete record syntax;
  2853 
  2854 
  2855 *** HOLCF ***
  2856 
  2857 * removed "axioms" and "generated by" sections;
  2858 
  2859 * replaced "ops" section by extended "consts" section, which is capable of
  2860   handling the continuous function space "->" directly;
  2861 
  2862 * domain package:
  2863   . proves theorems immediately and stores them in the theory,
  2864   . creates hierachical name space,
  2865   . now uses normal mixfix annotations (instead of cinfix...),
  2866   . minor changes to some names and values (for consistency),
  2867   . e.g. cases -> casedist, dists_eq -> dist_eqs, [take_lemma] -> take_lemmas,
  2868   . separator between mutual domain defs: changed "," to "and",
  2869   . improved handling of sort constraints;  now they have to
  2870     appear on the left-hand side of the equations only;
  2871 
  2872 * fixed LAM <x,y,zs>.b syntax;
  2873 
  2874 * added extended adm_tac to simplifier in HOLCF -- can now discharge
  2875 adm (%x. P (t x)), where P is chainfinite and t continuous;
  2876 
  2877 
  2878 *** FOL and ZF ***
  2879 
  2880 * FOL: there is a new splitter `split_asm_tac' that can be used e.g.
  2881   with `addloop' of the simplifier to faciliate case splitting in premises.
  2882 
  2883 * qed_spec_mp, qed_goal_spec_mp, qed_goalw_spec_mp are available, as
  2884 in HOL, they strip ALL and --> from proved theorems;
  2885 
  2886 
  2887 
  2888 New in Isabelle94-8 (May 1997)
  2889 ------------------------------
  2890 
  2891 *** General Changes ***
  2892 
  2893 * new utilities to build / run / maintain Isabelle etc. (in parts
  2894 still somewhat experimental); old Makefiles etc. still functional;
  2895 
  2896 * new 'Isabelle System Manual';
  2897 
  2898 * INSTALL text, together with ./configure and ./build scripts;
  2899 
  2900 * reimplemented type inference for greater efficiency, better error
  2901 messages and clean internal interface;
  2902 
  2903 * prlim command for dealing with lots of subgoals (an easier way of
  2904 setting goals_limit);
  2905 
  2906 
  2907 *** Syntax ***
  2908 
  2909 * supports alternative (named) syntax tables (parser and pretty
  2910 printer); internal interface is provided by add_modesyntax(_i);
  2911 
  2912 * Pure, FOL, ZF, HOL, HOLCF now support symbolic input and output; to
  2913 be used in conjunction with the Isabelle symbol font; uses the
  2914 "symbols" syntax table;
  2915 
  2916 * added token_translation interface (may translate name tokens in
  2917 arbitrary ways, dependent on their type (free, bound, tfree, ...) and
  2918 the current print_mode); IMPORTANT: user print translation functions
  2919 are responsible for marking newly introduced bounds
  2920 (Syntax.mark_boundT);
  2921 
  2922 * token translations for modes "xterm" and "xterm_color" that display
  2923 names in bold, underline etc. or colors (which requires a color
  2924 version of xterm);
  2925 
  2926 * infixes may now be declared with names independent of their syntax;
  2927 
  2928 * added typed_print_translation (like print_translation, but may
  2929 access type of constant);
  2930 
  2931 
  2932 *** Classical Reasoner ***
  2933 
  2934 Blast_tac: a new tactic!  It is often more powerful than fast_tac, but has
  2935 some limitations.  Blast_tac...
  2936   + ignores addss, addbefore, addafter; this restriction is intrinsic
  2937   + ignores elimination rules that don't have the correct format
  2938         (the conclusion MUST be a formula variable)
  2939   + ignores types, which can make HOL proofs fail
  2940   + rules must not require higher-order unification, e.g. apply_type in ZF
  2941     [message "Function Var's argument not a bound variable" relates to this]
  2942   + its proof strategy is more general but can actually be slower
  2943 
  2944 * substitution with equality assumptions no longer permutes other
  2945 assumptions;
  2946 
  2947 * minor changes in semantics of addafter (now called addaltern); renamed
  2948 setwrapper to setWrapper and compwrapper to compWrapper; added safe wrapper
  2949 (and access functions for it);
  2950 
  2951 * improved combination of classical reasoner and simplifier:
  2952   + functions for handling clasimpsets
  2953   + improvement of addss: now the simplifier is called _after_ the
  2954     safe steps.
  2955   + safe variant of addss called addSss: uses safe simplifications
  2956     _during_ the safe steps. It is more complete as it allows multiple
  2957     instantiations of unknowns (e.g. with slow_tac).
  2958 
  2959 *** Simplifier ***
  2960 
  2961 * added interface for simplification procedures (functions that
  2962 produce *proven* rewrite rules on the fly, depending on current
  2963 redex);
  2964 
  2965 * ordering on terms as parameter (used for ordered rewriting);
  2966 
  2967 * new functions delcongs, deleqcongs, and Delcongs. richer rep_ss;
  2968 
  2969 * the solver is now split into a safe and an unsafe part.
  2970 This should be invisible for the normal user, except that the
  2971 functions setsolver and addsolver have been renamed to setSolver and
  2972 addSolver; added safe_asm_full_simp_tac;
  2973 
  2974 
  2975 *** HOL ***
  2976 
  2977 * a generic induction tactic `induct_tac' which works for all datatypes and
  2978 also for type `nat';
  2979 
  2980 * a generic case distinction tactic `exhaust_tac' which works for all
  2981 datatypes and also for type `nat';
  2982 
  2983 * each datatype comes with a function `size';
  2984 
  2985 * patterns in case expressions allow tuple patterns as arguments to
  2986 constructors, for example `case x of [] => ... | (x,y,z)#ps => ...';
  2987 
  2988 * primrec now also works with type nat;
  2989 
  2990 * recdef: a new declaration form, allows general recursive functions to be
  2991 defined in theory files.  See HOL/ex/Fib, HOL/ex/Primes, HOL/Subst/Unify.
  2992 
  2993 * the constant for negation has been renamed from "not" to "Not" to
  2994 harmonize with FOL, ZF, LK, etc.;
  2995 
  2996 * HOL/ex/LFilter theory of a corecursive "filter" functional for
  2997 infinite lists;
  2998 
  2999 * HOL/Modelcheck demonstrates invocation of model checker oracle;
  3000 
  3001 * HOL/ex/Ring.thy declares cring_simp, which solves equational
  3002 problems in commutative rings, using axiomatic type classes for + and *;
  3003 
  3004 * more examples in HOL/MiniML and HOL/Auth;
  3005 
  3006 * more default rewrite rules for quantifiers, union/intersection;
  3007 
  3008 * a new constant `arbitrary == @x.False';
  3009 
  3010 * HOLCF/IOA replaces old HOL/IOA;
  3011 
  3012 * HOLCF changes: derived all rules and arities
  3013   + axiomatic type classes instead of classes
  3014   + typedef instead of faking type definitions
  3015   + eliminated the internal constants less_fun, less_cfun, UU_fun, UU_cfun etc.
  3016   + new axclasses cpo, chfin, flat with flat < chfin < pcpo < cpo < po
  3017   + eliminated the types void, one, tr
  3018   + use unit lift and bool lift (with translations) instead of one and tr
  3019   + eliminated blift from Lift3.thy (use Def instead of blift)
  3020   all eliminated rules are derived as theorems --> no visible changes ;
  3021 
  3022 
  3023 *** ZF ***
  3024 
  3025 * ZF now has Fast_tac, Simp_tac and Auto_tac.  Union_iff is a now a default
  3026 rewrite rule; this may affect some proofs.  eq_cs is gone but can be put back
  3027 as ZF_cs addSIs [equalityI];
  3028 
  3029 
  3030 
  3031 New in Isabelle94-7 (November 96)
  3032 ---------------------------------
  3033 
  3034 * allowing negative levels (as offsets) in prlev and choplev;
  3035 
  3036 * super-linear speedup for large simplifications;
  3037 
  3038 * FOL, ZF and HOL now use miniscoping: rewriting pushes
  3039 quantifications in as far as possible (COULD MAKE EXISTING PROOFS
  3040 FAIL); can suppress it using the command Delsimps (ex_simps @
  3041 all_simps); De Morgan laws are also now included, by default;
  3042 
  3043 * improved printing of ==>  :  ~:
  3044 
  3045 * new object-logic "Sequents" adds linear logic, while replacing LK
  3046 and Modal (thanks to Sara Kalvala);
  3047 
  3048 * HOL/Auth: correctness proofs for authentication protocols;
  3049 
  3050 * HOL: new auto_tac combines rewriting and classical reasoning (many
  3051 examples on HOL/Auth);
  3052 
  3053 * HOL: new command AddIffs for declaring theorems of the form P=Q to
  3054 the rewriter and classical reasoner simultaneously;
  3055 
  3056 * function uresult no longer returns theorems in "standard" format;
  3057 regain previous version by: val uresult = standard o uresult;
  3058 
  3059 
  3060 
  3061 New in Isabelle94-6
  3062 -------------------
  3063 
  3064 * oracles -- these establish an interface between Isabelle and trusted
  3065 external reasoners, which may deliver results as theorems;
  3066 
  3067 * proof objects (in particular record all uses of oracles);
  3068 
  3069 * Simp_tac, Fast_tac, etc. that refer to implicit simpset / claset;
  3070 
  3071 * "constdefs" section in theory files;
  3072 
  3073 * "primrec" section (HOL) no longer requires names;
  3074 
  3075 * internal type "tactic" now simply "thm -> thm Sequence.seq";
  3076 
  3077 
  3078 
  3079 New in Isabelle94-5
  3080 -------------------
  3081 
  3082 * reduced space requirements;
  3083 
  3084 * automatic HTML generation from theories;
  3085 
  3086 * theory files no longer require "..." (quotes) around most types;
  3087 
  3088 * new examples, including two proofs of the Church-Rosser theorem;
  3089 
  3090 * non-curried (1994) version of HOL is no longer distributed;
  3091 
  3092 
  3093 
  3094 New in Isabelle94-4
  3095 -------------------
  3096 
  3097 * greatly reduced space requirements;
  3098 
  3099 * theory files (.thy) no longer require \...\ escapes at line breaks;
  3100 
  3101 * searchable theorem database (see the section "Retrieving theorems" on
  3102 page 8 of the Reference Manual);
  3103 
  3104 * new examples, including Grabczewski's monumental case study of the
  3105 Axiom of Choice;
  3106 
  3107 * The previous version of HOL renamed to Old_HOL;
  3108 
  3109 * The new version of HOL (previously called CHOL) uses a curried syntax
  3110 for functions.  Application looks like f a b instead of f(a,b);
  3111 
  3112 * Mutually recursive inductive definitions finally work in HOL;
  3113 
  3114 * In ZF, pattern-matching on tuples is now available in all abstractions and
  3115 translates to the operator "split";
  3116 
  3117 
  3118 
  3119 New in Isabelle94-3
  3120 -------------------
  3121 
  3122 * new infix operator, addss, allowing the classical reasoner to
  3123 perform simplification at each step of its search.  Example:
  3124         fast_tac (cs addss ss)
  3125 
  3126 * a new logic, CHOL, the same as HOL, but with a curried syntax
  3127 for functions.  Application looks like f a b instead of f(a,b).  Also pairs
  3128 look like (a,b) instead of <a,b>;
  3129 
  3130 * PLEASE NOTE: CHOL will eventually replace HOL!
  3131 
  3132 * In CHOL, pattern-matching on tuples is now available in all abstractions.
  3133 It translates to the operator "split".  A new theory of integers is available;
  3134 
  3135 * In ZF, integer numerals now denote two's-complement binary integers.
  3136 Arithmetic operations can be performed by rewriting.  See ZF/ex/Bin.ML;
  3137 
  3138 * Many new examples: I/O automata, Church-Rosser theorem, equivalents
  3139 of the Axiom of Choice;
  3140 
  3141 
  3142 
  3143 New in Isabelle94-2
  3144 -------------------
  3145 
  3146 * Significantly faster resolution;
  3147 
  3148 * the different sections in a .thy file can now be mixed and repeated
  3149 freely;
  3150 
  3151 * Database of theorems for FOL, HOL and ZF.  New
  3152 commands including qed, qed_goal and bind_thm store theorems in the database.
  3153 
  3154 * Simple database queries: return a named theorem (get_thm) or all theorems of
  3155 a given theory (thms_of), or find out what theory a theorem was proved in
  3156 (theory_of_thm);
  3157 
  3158 * Bugs fixed in the inductive definition and datatype packages;
  3159 
  3160 * The classical reasoner provides deepen_tac and depth_tac, making FOL_dup_cs
  3161 and HOL_dup_cs obsolete;
  3162 
  3163 * Syntactic ambiguities caused by the new treatment of syntax in Isabelle94-1
  3164 have been removed;
  3165 
  3166 * Simpler definition of function space in ZF;
  3167 
  3168 * new results about cardinal and ordinal arithmetic in ZF;
  3169 
  3170 * 'subtype' facility in HOL for introducing new types as subsets of existing
  3171 types;
  3172 
  3173 
  3174 $Id$