NEWS
author wenzelm
Wed Jun 22 19:48:20 2005 +0200 (2005-06-22)
changeset 16547 09f7a953d2d6
parent 16506 b2687ce38433
child 16563 a92f96951355
permissions -rw-r--r--
* Pure: the Isar proof context type is already defined early in Pure
as Context.proof;
     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 
   346 *** HOLCF ***
   347 
   348 * HOLCF: discontinued special version of 'constdefs' (which used to
   349 support continuous functions) in favor of the general Pure one with
   350 full type-inference.
   351 
   352 
   353 *** ZF ***
   354 
   355 * ZF/ex: theories Group and Ring provide examples in abstract algebra,
   356 including the First Isomorphism Theorem (on quotienting by the kernel
   357 of a homomorphism).
   358 
   359 * ZF/Simplifier: install second copy of type solver that actually
   360 makes use of TC rules declared to Isar proof contexts (or locales);
   361 the old version is still required for ML proof scripts.
   362 
   363 
   364 *** ML ***
   365 
   366 * Pure/library.ML no longer defines its own option datatype, but uses
   367 that of the SML basis, which has constructors NONE and SOME instead of
   368 None and Some, as well as exception Option.Option instead of OPTION.
   369 The functions the, if_none, is_some, is_none have been adapted
   370 accordingly, while Option.map replaces apsome.
   371 
   372 * The exception LIST has been given up in favour of the standard
   373 exceptions Empty and Subscript, as well as Library.UnequalLengths.
   374 Function like Library.hd and Library.tl are superceded by the standard
   375 hd and tl functions etc.
   376 
   377 A number of basic functions are now no longer exported to the ML
   378 toplevel, as they are variants of standard functions.  The following
   379 suggests how one can translate existing code:
   380 
   381     rev_append xs ys = List.revAppend (xs, ys)
   382     nth_elem (i, xs) = List.nth (xs, i)
   383     last_elem xs = List.last xs
   384     flat xss = List.concat xss
   385     seq fs = List.app fs
   386     partition P xs = List.partition P xs
   387     filter P xs = List.filter P xs
   388     mapfilter f xs = List.mapPartial f xs
   389 
   390 * Pure: output via the Isabelle channels of writeln/warning/error
   391 etc. is now passed through Output.output, with a hook for arbitrary
   392 transformations depending on the print_mode (cf. Output.add_mode --
   393 the first active mode that provides a output function wins).  Already
   394 formatted output may be embedded into further text via Output.raw; the
   395 result of Pretty.string_of/str_of and derived functions
   396 (string_of_term/cterm/thm etc.) is already marked raw to accommodate
   397 easy composition of diagnostic messages etc.  Programmers rarely need
   398 to care about Output.output or Output.raw at all, with some notable
   399 exceptions: Output.output is required when bypassing the standard
   400 channels (writeln etc.), or in token translations to produce properly
   401 formatted results; Output.raw is required when capturing already
   402 output material that will eventually be presented to the user a second
   403 time.  For the default print mode, both Output.output and Output.raw
   404 have no effect.
   405 
   406 * Pure: print_tac now outputs the goal through the trace channel.
   407 
   408 * Isar debugging: new reference Toplevel.debug; default false.  Set to
   409 make printing of exceptions THM, TERM, TYPE and THEORY more verbose.
   410 
   411 * Pure: name spaces have been refined, with significant changes of the
   412 internal interfaces -- INCOMPATIBILITY.  Renamed cond_extern(_table)
   413 to extern(_table).  The plain name entry path is superceded by a
   414 general 'naming' context, which also includes the 'policy' to produce
   415 a fully qualified name and external accesses of a fully qualified
   416 name; NameSpace.extend is superceded by context dependent
   417 Sign.declare_name.  Several theory and proof context operations modify
   418 the naming context.  Especially note Theory.restore_naming and
   419 ProofContext.restore_naming to get back to a sane state; note that
   420 Theory.add_path is no longer sufficient to recover from
   421 Theory.absolute_path in particular.
   422 
   423 * Pure: new flags short_names (default false) and unique_names
   424 (default true) for controlling output of qualified names.  If
   425 short_names is set, names are printed unqualified.  If unique_names is
   426 reset, the name prefix is reduced to the minimum required to achieve
   427 the original result when interning again, even if there is an overlap
   428 with earlier declarations.
   429 
   430 * Pure/TheoryDataFun: change of the argument structure; 'prep_ext' is
   431 now 'extend', and 'merge' gets an additional Pretty.pp argument
   432 (useful for printing error messages).  INCOMPATIBILITY.
   433 
   434 * Pure: major reorganization of the theory context.  Type Sign.sg and
   435 Theory.theory are now identified, referring to the universal
   436 Context.theory (see Pure/context.ML).  Actual signature and theory
   437 content is managed as theory data.  The old code and interfaces were
   438 spread over many files and structures; the new arrangement introduces
   439 considerable INCOMPATIBILITY to gain more clarity:
   440 
   441   Context -- theory management operations (name, identity, inclusion,
   442     parents, ancestors, merge, etc.), plus generic theory data;
   443 
   444   Sign -- logical signature and syntax operations (declaring consts,
   445     types, etc.), plus certify/read for common entities;
   446 
   447   Theory -- logical theory operations (stating axioms, definitions,
   448     oracles), plus a copy of logical signature operations (consts,
   449     types, etc.); also a few basic management operations (Theory.copy,
   450     Theory.merge, etc.)
   451 
   452 The most basic sign_of operations (Theory.sign_of, Thm.sign_of_thm
   453 etc.) as well as the sign field in Thm.rep_thm etc. have been retained
   454 for convenience -- they merely return the theory.
   455 
   456 * Pure: the Isar proof context type is already defined early in Pure
   457 as Context.proof (note that ProofContext.context and Proof.context are
   458 aliases, where the latter is the preferred name).  This enables other
   459 Isabelle components to refer to that type even before Isar is present.
   460 
   461 * Pure/sign/theory: discontinued named name spaces (i.e. classK,
   462 typeK, constK, axiomK, oracleK), but provide explicit operations for
   463 any of these kinds.  For example, Sign.intern typeK is now
   464 Sign.intern_type, Theory.hide_space Sign.typeK is now
   465 Theory.hide_types.  Also note that former
   466 Theory.hide_classes/types/consts are now
   467 Theory.hide_classes_i/types_i/consts_i, while the non '_i' versions
   468 internalize their arguments!  INCOMPATIBILITY.
   469 
   470 * Pure: get_thm interface (of PureThy and ProofContext) expects
   471 datatype thmref (with constructors Name and NameSelection) instead of
   472 plain string -- INCOMPATIBILITY;
   473 
   474 * Pure: cases produced by proof methods specify options, where NONE
   475 means to remove case bindings -- INCOMPATIBILITY in
   476 (RAW_)METHOD_CASES.
   477 
   478 * Pure: the following operations retrieve axioms or theorems from a
   479 theory node or theory hierarchy, respectively:
   480 
   481   Theory.axioms_of: theory -> (string * term) list
   482   Theory.all_axioms_of: theory -> (string * term) list
   483   PureThy.thms_of: theory -> (string * thm) list
   484   PureThy.all_thms_of: theory -> (string * thm) list
   485 
   486 * Provers: Simplifier and Classical Reasoner now support proof context
   487 dependent plug-ins (simprocs, solvers, wrappers etc.).  These extra
   488 components are stored in the theory and patched into the
   489 simpset/claset when used in an Isar proof context.  Context dependent
   490 components are maintained by the following theory operations:
   491 
   492   Simplifier.add_context_simprocs
   493   Simplifier.del_context_simprocs
   494   Simplifier.set_context_subgoaler
   495   Simplifier.reset_context_subgoaler
   496   Simplifier.add_context_looper
   497   Simplifier.del_context_looper
   498   Simplifier.add_context_unsafe_solver
   499   Simplifier.add_context_safe_solver
   500 
   501   Classical.add_context_safe_wrapper
   502   Classical.del_context_safe_wrapper
   503   Classical.add_context_unsafe_wrapper
   504   Classical.del_context_unsafe_wrapper
   505 
   506 IMPORTANT NOTE: proof tools (methods etc.) need to use
   507 local_simpset_of and local_claset_of to instead of the primitive
   508 Simplifier.get_local_simpset and Classical.get_local_claset,
   509 respectively, in order to see the context dependent fields!
   510 
   511 * File.sysify_path and File.quote_sysify path have been replaced by
   512 File.platform_path and File.shell_path (with appropriate hooks).  This
   513 provides a clean interface for unusual systems where the internal and
   514 external process view of file names are different.
   515 
   516 
   517 *** System ***
   518 
   519 * Allow symlinks to all proper Isabelle executables (Isabelle,
   520 isabelle, isatool etc.).
   521 
   522 * ISABELLE_DOC_FORMAT setting specifies preferred document format (for
   523 isatool doc, isatool mkdir, display_drafts etc.).
   524 
   525 * isatool usedir: option -f allows specification of the ML file to be
   526 used by Isabelle; default is ROOT.ML.
   527 
   528 * New isatool version outputs the version identifier of the Isabelle
   529 distribution being used.
   530 
   531 * HOL: new isatool dimacs2hol converts files in DIMACS CNF format
   532 (containing Boolean satisfiability problems) into Isabelle/HOL
   533 theories.
   534 
   535 
   536 
   537 New in Isabelle2004 (April 2004)
   538 --------------------------------
   539 
   540 *** General ***
   541 
   542 * Provers/order.ML:  new efficient reasoner for partial and linear orders.
   543   Replaces linorder.ML.
   544 
   545 * Pure: Greek letters (except small lambda, \<lambda>), as well as Gothic
   546   (\<aa>...\<zz>\<AA>...\<ZZ>), calligraphic (\<A>...\<Z>), and Euler
   547   (\<a>...\<z>), are now considered normal letters, and can therefore
   548   be used anywhere where an ASCII letter (a...zA...Z) has until
   549   now. COMPATIBILITY: This obviously changes the parsing of some
   550   terms, especially where a symbol has been used as a binder, say
   551   '\<Pi>x. ...', which is now a type error since \<Pi>x will be parsed
   552   as an identifier.  Fix it by inserting a space around former
   553   symbols.  Call 'isatool fixgreek' to try to fix parsing errors in
   554   existing theory and ML files.
   555 
   556 * Pure: Macintosh and Windows line-breaks are now allowed in theory files.
   557 
   558 * Pure: single letter sub/superscripts (\<^isub> and \<^isup>) are now
   559   allowed in identifiers. Similar to Greek letters \<^isub> is now considered
   560   a normal (but invisible) letter. For multiple letter subscripts repeat
   561   \<^isub> like this: x\<^isub>1\<^isub>2.
   562 
   563 * Pure: There are now sub-/superscripts that can span more than one
   564   character. Text between \<^bsub> and \<^esub> is set in subscript in
   565   ProofGeneral and LaTeX, text between \<^bsup> and \<^esup> in
   566   superscript. The new control characters are not identifier parts.
   567 
   568 * Pure: Control-symbols of the form \<^raw:...> will literally print the
   569   content of "..." to the latex file instead of \isacntrl... . The "..."
   570   may consist of any printable characters excluding the end bracket >.
   571 
   572 * Pure: Using new Isar command "finalconsts" (or the ML functions
   573   Theory.add_finals or Theory.add_finals_i) it is now possible to
   574   declare constants "final", which prevents their being given a definition
   575   later.  It is useful for constants whose behaviour is fixed axiomatically
   576   rather than definitionally, such as the meta-logic connectives.
   577 
   578 * Pure: 'instance' now handles general arities with general sorts
   579   (i.e. intersections of classes),
   580 
   581 * Presentation: generated HTML now uses a CSS style sheet to make layout
   582   (somewhat) independent of content. It is copied from lib/html/isabelle.css.
   583   It can be changed to alter the colors/layout of generated pages.
   584 
   585 
   586 *** Isar ***
   587 
   588 * Tactic emulation methods rule_tac, erule_tac, drule_tac, frule_tac,
   589   cut_tac, subgoal_tac and thin_tac:
   590   - Now understand static (Isar) contexts.  As a consequence, users of Isar
   591     locales are no longer forced to write Isar proof scripts.
   592     For details see Isar Reference Manual, paragraph 4.3.2: Further tactic
   593     emulations.
   594   - INCOMPATIBILITY: names of variables to be instantiated may no
   595     longer be enclosed in quotes.  Instead, precede variable name with `?'.
   596     This is consistent with the instantiation attribute "where".
   597 
   598 * Attributes "where" and "of":
   599   - Now take type variables of instantiated theorem into account when reading
   600     the instantiation string.  This fixes a bug that caused instantiated
   601     theorems to have too special types in some circumstances.
   602   - "where" permits explicit instantiations of type variables.
   603 
   604 * Calculation commands "moreover" and "also" no longer interfere with
   605   current facts ("this"), admitting arbitrary combinations with "then"
   606   and derived forms.
   607 
   608 * Locales:
   609   - Goal statements involving the context element "includes" no longer
   610     generate theorems with internal delta predicates (those ending on
   611     "_axioms") in the premise.
   612     Resolve particular premise with <locale>.intro to obtain old form.
   613   - Fixed bug in type inference ("unify_frozen") that prevented mix of target
   614     specification and "includes" elements in goal statement.
   615   - Rule sets <locale>.intro and <locale>.axioms no longer declared as
   616     [intro?] and [elim?] (respectively) by default.
   617   - Experimental command for instantiation of locales in proof contexts:
   618         instantiate <label>[<attrs>]: <loc>
   619     Instantiates locale <loc> and adds all its theorems to the current context
   620     taking into account their attributes.  Label and attrs are optional
   621     modifiers, like in theorem declarations.  If present, names of
   622     instantiated theorems are qualified with <label>, and the attributes
   623     <attrs> are applied after any attributes these theorems might have already.
   624       If the locale has assumptions, a chained fact of the form
   625     "<loc> t1 ... tn" is expected from which instantiations of the parameters
   626     are derived.  The command does not support old-style locales declared
   627     with "locale (open)".
   628       A few (very simple) examples can be found in FOL/ex/LocaleInst.thy.
   629 
   630 * HOL: Tactic emulation methods induct_tac and case_tac understand static
   631   (Isar) contexts.
   632 
   633 
   634 *** HOL ***
   635 
   636 * Proof import: new image HOL4 contains the imported library from
   637   the HOL4 system with about 2500 theorems. It is imported by
   638   replaying proof terms produced by HOL4 in Isabelle. The HOL4 image
   639   can be used like any other Isabelle image.  See
   640   HOL/Import/HOL/README for more information.
   641 
   642 * Simplifier:
   643   - Much improved handling of linear and partial orders.
   644     Reasoners for linear and partial orders are set up for type classes
   645     "linorder" and "order" respectively, and are added to the default simpset
   646     as solvers.  This means that the simplifier can build transitivity chains
   647     to solve goals from the assumptions.
   648   - INCOMPATIBILITY: old proofs break occasionally.  Typically, applications
   649     of blast or auto after simplification become unnecessary because the goal
   650     is solved by simplification already.
   651 
   652 * Numerics: new theory Ring_and_Field contains over 250 basic numerical laws,
   653     all proved in axiomatic type classes for semirings, rings and fields.
   654 
   655 * Numerics:
   656   - Numeric types (nat, int, and in HOL-Complex rat, real, complex, etc.) are
   657     now formalized using the Ring_and_Field theory mentioned above.
   658   - INCOMPATIBILITY: simplification and arithmetic behaves somewhat differently
   659     than before, because now they are set up once in a generic manner.
   660   - INCOMPATIBILITY: many type-specific arithmetic laws have gone.
   661     Look for the general versions in Ring_and_Field (and Power if they concern
   662     exponentiation).
   663 
   664 * Type "rat" of the rational numbers is now available in HOL-Complex.
   665 
   666 * Records:
   667   - Record types are now by default printed with their type abbreviation
   668     instead of the list of all field types. This can be configured via
   669     the reference "print_record_type_abbr".
   670   - Simproc "record_upd_simproc" for simplification of multiple updates added
   671     (not enabled by default).
   672   - Simproc "record_ex_sel_eq_simproc" to simplify EX x. sel r = x resp.
   673     EX x. x = sel r to True (not enabled by default).
   674   - Tactic "record_split_simp_tac" to split and simplify records added.
   675 
   676 * 'specification' command added, allowing for definition by
   677   specification.  There is also an 'ax_specification' command that
   678   introduces the new constants axiomatically.
   679 
   680 * arith(_tac) is now able to generate counterexamples for reals as well.
   681 
   682 * HOL-Algebra: new locale "ring" for non-commutative rings.
   683 
   684 * HOL-ex: InductiveInvariant_examples illustrates advanced recursive function
   685   definitions, thanks to Sava Krsti\'{c} and John Matthews.
   686 
   687 * HOL-Matrix: a first theory for matrices in HOL with an application of
   688   matrix theory to linear programming.
   689 
   690 * Unions and Intersections:
   691   The latex output syntax of UN and INT has been changed
   692   from "\Union x \in A. B" to "\Union_{x \in A} B"
   693   i.e. the index formulae has become a subscript.
   694   Similarly for "\Union x. B", and for \Inter instead of \Union.
   695 
   696 * Unions and Intersections over Intervals:
   697   There is new short syntax "UN i<=n. A" for "UN i:{0..n}. A". There is
   698   also an x-symbol version with subscripts "\<Union>\<^bsub>i <= n\<^esub>. A"
   699   like in normal math, and corresponding versions for < and for intersection.
   700 
   701 * HOL/List: Ordering "lexico" is renamed "lenlex" and the standard
   702   lexicographic dictonary ordering has been added as "lexord".
   703 
   704 * ML: the legacy theory structures Int and List have been removed. They had
   705   conflicted with ML Basis Library structures having the same names.
   706 
   707 * 'refute' command added to search for (finite) countermodels.  Only works
   708   for a fragment of HOL.  The installation of an external SAT solver is
   709   highly recommended.  See "HOL/Refute.thy" for details.
   710 
   711 * 'quickcheck' command: Allows to find counterexamples by evaluating
   712   formulae under an assignment of free variables to random values.
   713   In contrast to 'refute', it can deal with inductive datatypes,
   714   but cannot handle quantifiers. See "HOL/ex/Quickcheck_Examples.thy"
   715   for examples.
   716 
   717 
   718 *** HOLCF ***
   719 
   720 * Streams now come with concatenation and are part of the HOLCF image
   721 
   722 
   723 
   724 New in Isabelle2003 (May 2003)
   725 ------------------------------
   726 
   727 *** General ***
   728 
   729 * Provers/simplifier:
   730 
   731   - Completely reimplemented method simp (ML: Asm_full_simp_tac):
   732     Assumptions are now subject to complete mutual simplification,
   733     not just from left to right. The simplifier now preserves
   734     the order of assumptions.
   735 
   736     Potential INCOMPATIBILITY:
   737 
   738     -- simp sometimes diverges where the old version did
   739        not, e.g. invoking simp on the goal
   740 
   741         [| P (f x); y = x; f x = f y |] ==> Q
   742 
   743        now gives rise to the infinite reduction sequence
   744 
   745         P(f x) --(f x = f y)--> P(f y) --(y = x)--> P(f x) --(f x = f y)--> ...
   746 
   747        Using "simp (asm_lr)" (ML: Asm_lr_simp_tac) instead often solves this
   748        kind of problem.
   749 
   750     -- Tactics combining classical reasoner and simplification (such as auto)
   751        are also affected by this change, because many of them rely on
   752        simp. They may sometimes diverge as well or yield a different numbers
   753        of subgoals. Try to use e.g. force, fastsimp, or safe instead of auto
   754        in case of problems. Sometimes subsequent calls to the classical
   755        reasoner will fail because a preceeding call to the simplifier too
   756        eagerly simplified the goal, e.g. deleted redundant premises.
   757 
   758   - The simplifier trace now shows the names of the applied rewrite rules
   759 
   760   - You can limit the number of recursive invocations of the simplifier
   761     during conditional rewriting (where the simplifie tries to solve the
   762     conditions before applying the rewrite rule):
   763     ML "simp_depth_limit := n"
   764     where n is an integer. Thus you can force termination where previously
   765     the simplifier would diverge.
   766 
   767   - Accepts free variables as head terms in congruence rules.  Useful in Isar.
   768 
   769   - No longer aborts on failed congruence proof.  Instead, the
   770     congruence is ignored.
   771 
   772 * Pure: New generic framework for extracting programs from constructive
   773   proofs. See HOL/Extraction.thy for an example instantiation, as well
   774   as HOL/Extraction for some case studies.
   775 
   776 * Pure: The main goal of the proof state is no longer shown by default, only
   777 the subgoals. This behaviour is controlled by a new flag.
   778    PG menu: Isabelle/Isar -> Settings -> Show Main Goal
   779 (ML: Proof.show_main_goal).
   780 
   781 * Pure: You can find all matching introduction rules for subgoal 1, i.e. all
   782 rules whose conclusion matches subgoal 1:
   783       PG menu: Isabelle/Isar -> Show me -> matching rules
   784 The rules are ordered by how closely they match the subgoal.
   785 In particular, rules that solve a subgoal outright are displayed first
   786 (or rather last, the way they are printed).
   787 (ML: ProofGeneral.print_intros())
   788 
   789 * Pure: New flag trace_unify_fail causes unification to print
   790 diagnostic information (PG: in trace buffer) when it fails. This is
   791 useful for figuring out why single step proofs like rule, erule or
   792 assumption failed.
   793 
   794 * Pure: Locale specifications now produce predicate definitions
   795 according to the body of text (covering assumptions modulo local
   796 definitions); predicate "loc_axioms" covers newly introduced text,
   797 while "loc" is cumulative wrt. all included locale expressions; the
   798 latter view is presented only on export into the global theory
   799 context; potential INCOMPATIBILITY, use "(open)" option to fall back
   800 on the old view without predicates;
   801 
   802 * Pure: predefined locales "var" and "struct" are useful for sharing
   803 parameters (as in CASL, for example); just specify something like
   804 ``var x + var y + struct M'' as import;
   805 
   806 * Pure: improved thms_containing: proper indexing of facts instead of
   807 raw theorems; check validity of results wrt. current name space;
   808 include local facts of proof configuration (also covers active
   809 locales), cover fixed variables in index; may use "_" in term
   810 specification; an optional limit for the number of printed facts may
   811 be given (the default is 40);
   812 
   813 * Pure: disallow duplicate fact bindings within new-style theory files
   814 (batch-mode only);
   815 
   816 * Provers: improved induct method: assumptions introduced by case
   817 "foo" are split into "foo.hyps" (from the rule) and "foo.prems" (from
   818 the goal statement); "foo" still refers to all facts collectively;
   819 
   820 * Provers: the function blast.overloaded has been removed: all constants
   821 are regarded as potentially overloaded, which improves robustness in exchange
   822 for slight decrease in efficiency;
   823 
   824 * Provers/linorder: New generic prover for transitivity reasoning over
   825 linear orders.  Note: this prover is not efficient!
   826 
   827 * Isar: preview of problems to finish 'show' now produce an error
   828 rather than just a warning (in interactive mode);
   829 
   830 
   831 *** HOL ***
   832 
   833 * arith(_tac)
   834 
   835  - Produces a counter example if it cannot prove a goal.
   836    Note that the counter example may be spurious if the goal is not a formula
   837    of quantifier-free linear arithmetic.
   838    In ProofGeneral the counter example appears in the trace buffer.
   839 
   840  - Knows about div k and mod k where k is a numeral of type nat or int.
   841 
   842  - Calls full Presburger arithmetic (by Amine Chaieb) if quantifier-free
   843    linear arithmetic fails. This takes account of quantifiers and divisibility.
   844    Presburger arithmetic can also be called explicitly via presburger(_tac).
   845 
   846 * simp's arithmetic capabilities have been enhanced a bit: it now
   847 takes ~= in premises into account (by performing a case split);
   848 
   849 * simp reduces "m*(n div m) + n mod m" to n, even if the two summands
   850 are distributed over a sum of terms;
   851 
   852 * New tactic "trans_tac" and method "trans" instantiate
   853 Provers/linorder.ML for axclasses "order" and "linorder" (predicates
   854 "<=", "<" and "=").
   855 
   856 * function INCOMPATIBILITIES: Pi-sets have been redefined and moved from main
   857 HOL to Library/FuncSet; constant "Fun.op o" is now called "Fun.comp";
   858 
   859 * 'typedef' command has new option "open" to suppress the set
   860 definition;
   861 
   862 * functions Min and Max on finite sets have been introduced (theory
   863 Finite_Set);
   864 
   865 * attribute [symmetric] now works for relations as well; it turns
   866 (x,y) : R^-1 into (y,x) : R, and vice versa;
   867 
   868 * induct over a !!-quantified statement (say !!x1..xn):
   869   each "case" automatically performs "fix x1 .. xn" with exactly those names.
   870 
   871 * Map: `empty' is no longer a constant but a syntactic abbreviation for
   872 %x. None. Warning: empty_def now refers to the previously hidden definition
   873 of the empty set.
   874 
   875 * Algebra: formalization of classical algebra.  Intended as base for
   876 any algebraic development in Isabelle.  Currently covers group theory
   877 (up to Sylow's theorem) and ring theory (Universal Property of
   878 Univariate Polynomials).  Contributions welcome;
   879 
   880 * GroupTheory: deleted, since its material has been moved to Algebra;
   881 
   882 * Complex: new directory of the complex numbers with numeric constants,
   883 nonstandard complex numbers, and some complex analysis, standard and
   884 nonstandard (Jacques Fleuriot);
   885 
   886 * HOL-Complex: new image for analysis, replacing HOL-Real and HOL-Hyperreal;
   887 
   888 * Hyperreal: introduced Gauge integration and hyperreal logarithms (Jacques
   889 Fleuriot);
   890 
   891 * Real/HahnBanach: updated and adapted to locales;
   892 
   893 * NumberTheory: added Gauss's law of quadratic reciprocity (by Avigad,
   894 Gray and Kramer);
   895 
   896 * UNITY: added the Meier-Sanders theory of progress sets;
   897 
   898 * MicroJava: bytecode verifier and lightweight bytecode verifier
   899 as abstract algorithms, instantiated to the JVM;
   900 
   901 * Bali: Java source language formalization. Type system, operational
   902 semantics, axiomatic semantics. Supported language features:
   903 classes, interfaces, objects,virtual methods, static methods,
   904 static/instance fields, arrays, access modifiers, definite
   905 assignment, exceptions.
   906 
   907 
   908 *** ZF ***
   909 
   910 * ZF/Constructible: consistency proof for AC (Gdel's constructible
   911 universe, etc.);
   912 
   913 * Main ZF: virtually all theories converted to new-style format;
   914 
   915 
   916 *** ML ***
   917 
   918 * Pure: Tactic.prove provides sane interface for internal proofs;
   919 omits the infamous "standard" operation, so this is more appropriate
   920 than prove_goalw_cterm in many situations (e.g. in simprocs);
   921 
   922 * Pure: improved error reporting of simprocs;
   923 
   924 * Provers: Simplifier.simproc(_i) provides sane interface for setting
   925 up simprocs;
   926 
   927 
   928 *** Document preparation ***
   929 
   930 * uses \par instead of \\ for line breaks in theory text. This may
   931 shift some page breaks in large documents. To get the old behaviour
   932 use \renewcommand{\isanewline}{\mbox{}\\\mbox{}} in root.tex.
   933 
   934 * minimized dependencies of isabelle.sty and isabellesym.sty on
   935 other packages
   936 
   937 * \<euro> now needs package babel/greek instead of marvosym (which
   938 broke \Rightarrow)
   939 
   940 * normal size for \<zero>...\<nine> (uses \mathbf instead of
   941 textcomp package)
   942 
   943 
   944 
   945 New in Isabelle2002 (March 2002)
   946 --------------------------------
   947 
   948 *** Document preparation ***
   949 
   950 * greatly simplified document preparation setup, including more
   951 graceful interpretation of isatool usedir -i/-d/-D options, and more
   952 instructive isatool mkdir; users should basically be able to get
   953 started with "isatool mkdir HOL Test && isatool make"; alternatively,
   954 users may run a separate document processing stage manually like this:
   955 "isatool usedir -D output HOL Test && isatool document Test/output";
   956 
   957 * theory dependency graph may now be incorporated into documents;
   958 isatool usedir -g true will produce session_graph.eps/.pdf for use
   959 with \includegraphics of LaTeX;
   960 
   961 * proper spacing of consecutive markup elements, especially text
   962 blocks after section headings;
   963 
   964 * support bold style (for single symbols only), input syntax is like
   965 this: "\<^bold>\<alpha>" or "\<^bold>A";
   966 
   967 * \<bullet> is now output as bold \cdot by default, which looks much
   968 better in printed text;
   969 
   970 * added default LaTeX bindings for \<tturnstile> and \<TTurnstile>;
   971 note that these symbols are currently unavailable in Proof General /
   972 X-Symbol; new symbols \<zero>, \<one>, ..., \<nine>, and \<euro>;
   973 
   974 * isatool latex no longer depends on changed TEXINPUTS, instead
   975 isatool document copies the Isabelle style files to the target
   976 location;
   977 
   978 
   979 *** Isar ***
   980 
   981 * Pure/Provers: improved proof by cases and induction;
   982   - 'case' command admits impromptu naming of parameters (such as
   983     "case (Suc n)");
   984   - 'induct' method divinates rule instantiation from the inductive
   985     claim; no longer requires excessive ?P bindings for proper
   986     instantiation of cases;
   987   - 'induct' method properly enumerates all possibilities of set/type
   988     rules; as a consequence facts may be also passed through *type*
   989     rules without further ado;
   990   - 'induct' method now derives symbolic cases from the *rulified*
   991     rule (before it used to rulify cases stemming from the internal
   992     atomized version); this means that the context of a non-atomic
   993     statement becomes is included in the hypothesis, avoiding the
   994     slightly cumbersome show "PROP ?case" form;
   995   - 'induct' may now use elim-style induction rules without chaining
   996     facts, using ``missing'' premises from the goal state; this allows
   997     rules stemming from inductive sets to be applied in unstructured
   998     scripts, while still benefitting from proper handling of non-atomic
   999     statements; NB: major inductive premises need to be put first, all
  1000     the rest of the goal is passed through the induction;
  1001   - 'induct' proper support for mutual induction involving non-atomic
  1002     rule statements (uses the new concept of simultaneous goals, see
  1003     below);
  1004   - append all possible rule selections, but only use the first
  1005     success (no backtracking);
  1006   - removed obsolete "(simplified)" and "(stripped)" options of methods;
  1007   - undeclared rule case names default to numbers 1, 2, 3, ...;
  1008   - added 'print_induct_rules' (covered by help item in recent Proof
  1009     General versions);
  1010   - moved induct/cases attributes to Pure, methods to Provers;
  1011   - generic method setup instantiated for FOL and HOL;
  1012 
  1013 * Pure: support multiple simultaneous goal statements, for example
  1014 "have a: A and b: B" (same for 'theorem' etc.); being a pure
  1015 meta-level mechanism, this acts as if several individual goals had
  1016 been stated separately; in particular common proof methods need to be
  1017 repeated in order to cover all claims; note that a single elimination
  1018 step is *not* sufficient to establish the two conjunctions, so this
  1019 fails:
  1020 
  1021   assume "A & B" then have A and B ..   (*".." fails*)
  1022 
  1023 better use "obtain" in situations as above; alternative refer to
  1024 multi-step methods like 'auto', 'simp_all', 'blast+' etc.;
  1025 
  1026 * Pure: proper integration with ``locales''; unlike the original
  1027 version by Florian Kammller, Isar locales package high-level proof
  1028 contexts rather than raw logical ones (e.g. we admit to include
  1029 attributes everywhere); operations on locales include merge and
  1030 rename; support for implicit arguments (``structures''); simultaneous
  1031 type-inference over imports and text; see also HOL/ex/Locales.thy for
  1032 some examples;
  1033 
  1034 * Pure: the following commands have been ``localized'', supporting a
  1035 target locale specification "(in name)": 'lemma', 'theorem',
  1036 'corollary', 'lemmas', 'theorems', 'declare'; the results will be
  1037 stored both within the locale and at the theory level (exported and
  1038 qualified by the locale name);
  1039 
  1040 * Pure: theory goals may now be specified in ``long'' form, with
  1041 ad-hoc contexts consisting of arbitrary locale elements. for example
  1042 ``lemma foo: fixes x assumes "A x" shows "B x"'' (local syntax and
  1043 definitions may be given, too); the result is a meta-level rule with
  1044 the context elements being discharged in the obvious way;
  1045 
  1046 * Pure: new proof command 'using' allows to augment currently used
  1047 facts after a goal statement ('using' is syntactically analogous to
  1048 'apply', but acts on the goal's facts only); this allows chained facts
  1049 to be separated into parts given before and after a claim, as in
  1050 ``from a and b have C using d and e <proof>'';
  1051 
  1052 * Pure: renamed "antecedent" case to "rule_context";
  1053 
  1054 * Pure: new 'judgment' command records explicit information about the
  1055 object-logic embedding (used by several tools internally); no longer
  1056 use hard-wired "Trueprop";
  1057 
  1058 * Pure: added 'corollary' command;
  1059 
  1060 * Pure: fixed 'token_translation' command;
  1061 
  1062 * Pure: removed obsolete 'exported' attribute;
  1063 
  1064 * Pure: dummy pattern "_" in is/let is now automatically lifted over
  1065 bound variables: "ALL x. P x --> Q x" (is "ALL x. _ --> ?C x")
  1066 supersedes more cumbersome ... (is "ALL x. _ x --> ?C x");
  1067 
  1068 * Pure: method 'atomize' presents local goal premises as object-level
  1069 statements (atomic meta-level propositions); setup controlled via
  1070 rewrite rules declarations of 'atomize' attribute; example
  1071 application: 'induct' method with proper rule statements in improper
  1072 proof *scripts*;
  1073 
  1074 * Pure: emulation of instantiation tactics (rule_tac, cut_tac, etc.)
  1075 now consider the syntactic context of assumptions, giving a better
  1076 chance to get type-inference of the arguments right (this is
  1077 especially important for locales);
  1078 
  1079 * Pure: "sorry" no longer requires quick_and_dirty in interactive
  1080 mode;
  1081 
  1082 * Pure/obtain: the formal conclusion "thesis", being marked as
  1083 ``internal'', may no longer be reference directly in the text;
  1084 potential INCOMPATIBILITY, may need to use "?thesis" in rare
  1085 situations;
  1086 
  1087 * Pure: generic 'sym' attribute which declares a rule both as pure
  1088 'elim?' and for the 'symmetric' operation;
  1089 
  1090 * Pure: marginal comments ``--'' may now occur just anywhere in the
  1091 text; the fixed correlation with particular command syntax has been
  1092 discontinued;
  1093 
  1094 * Pure: new method 'rules' is particularly well-suited for proof
  1095 search in intuitionistic logic; a bit slower than 'blast' or 'fast',
  1096 but often produces more compact proof terms with less detours;
  1097 
  1098 * Pure/Provers/classical: simplified integration with pure rule
  1099 attributes and methods; the classical "intro?/elim?/dest?"
  1100 declarations coincide with the pure ones; the "rule" method no longer
  1101 includes classically swapped intros; "intro" and "elim" methods no
  1102 longer pick rules from the context; also got rid of ML declarations
  1103 AddXIs/AddXEs/AddXDs; all of this has some potential for
  1104 INCOMPATIBILITY;
  1105 
  1106 * Provers/classical: attribute 'swapped' produces classical inversions
  1107 of introduction rules;
  1108 
  1109 * Provers/simplifier: 'simplified' attribute may refer to explicit
  1110 rules instead of full simplifier context; 'iff' attribute handles
  1111 conditional rules;
  1112 
  1113 * HOL: 'typedef' now allows alternative names for Rep/Abs morphisms;
  1114 
  1115 * HOL: 'recdef' now fails on unfinished automated proofs, use
  1116 "(permissive)" option to recover old behavior;
  1117 
  1118 * HOL: 'inductive' no longer features separate (collective) attributes
  1119 for 'intros' (was found too confusing);
  1120 
  1121 * HOL: properly declared induction rules less_induct and
  1122 wf_induct_rule;
  1123 
  1124 
  1125 *** HOL ***
  1126 
  1127 * HOL: moved over to sane numeral syntax; the new policy is as
  1128 follows:
  1129 
  1130   - 0 and 1 are polymorphic constants, which are defined on any
  1131   numeric type (nat, int, real etc.);
  1132 
  1133   - 2, 3, 4, ... and -1, -2, -3, ... are polymorphic numerals, based
  1134   binary representation internally;
  1135 
  1136   - type nat has special constructor Suc, and generally prefers Suc 0
  1137   over 1::nat and Suc (Suc 0) over 2::nat;
  1138 
  1139 This change may cause significant problems of INCOMPATIBILITY; here
  1140 are some hints on converting existing sources:
  1141 
  1142   - due to the new "num" token, "-0" and "-1" etc. are now atomic
  1143   entities, so expressions involving "-" (unary or binary minus) need
  1144   to be spaced properly;
  1145 
  1146   - existing occurrences of "1" may need to be constraint "1::nat" or
  1147   even replaced by Suc 0; similar for old "2";
  1148 
  1149   - replace "#nnn" by "nnn", and "#-nnn" by "-nnn";
  1150 
  1151   - remove all special provisions on numerals in proofs;
  1152 
  1153 * HOL: simp rules nat_number expand numerals on nat to Suc/0
  1154 representation (depends on bin_arith_simps in the default context);
  1155 
  1156 * HOL: symbolic syntax for x^2 (numeral 2);
  1157 
  1158 * HOL: the class of all HOL types is now called "type" rather than
  1159 "term"; INCOMPATIBILITY, need to adapt references to this type class
  1160 in axclass/classes, instance/arities, and (usually rare) occurrences
  1161 in typings (of consts etc.); internally the class is called
  1162 "HOL.type", ML programs should refer to HOLogic.typeS;
  1163 
  1164 * HOL/record package improvements:
  1165   - new derived operations "fields" to build a partial record section,
  1166     "extend" to promote a fixed record to a record scheme, and
  1167     "truncate" for the reverse; cf. theorems "xxx.defs", which are *not*
  1168     declared as simp by default;
  1169   - shared operations ("more", "fields", etc.) now need to be always
  1170     qualified) --- potential INCOMPATIBILITY;
  1171   - removed "make_scheme" operations (use "make" with "extend") --
  1172     INCOMPATIBILITY;
  1173   - removed "more" class (simply use "term") -- INCOMPATIBILITY;
  1174   - provides cases/induct rules for use with corresponding Isar
  1175     methods (for concrete records, record schemes, concrete more
  1176     parts, and schematic more parts -- in that order);
  1177   - internal definitions directly based on a light-weight abstract
  1178     theory of product types over typedef rather than datatype;
  1179 
  1180 * HOL: generic code generator for generating executable ML code from
  1181 specifications; specific support for HOL constructs such as inductive
  1182 datatypes and sets, as well as recursive functions; can be invoked
  1183 via 'generate_code' theory section;
  1184 
  1185 * HOL: canonical cases/induct rules for n-tuples (n = 3..7);
  1186 
  1187 * HOL: consolidated and renamed several theories.  In particular:
  1188         Ord.thy has been absorbed into HOL.thy
  1189         String.thy has been absorbed into List.thy
  1190 
  1191 * HOL: concrete setsum syntax "\<Sum>i:A. b" == "setsum (%i. b) A"
  1192 (beware of argument permutation!);
  1193 
  1194 * HOL: linorder_less_split superseded by linorder_cases;
  1195 
  1196 * HOL/List: "nodups" renamed to "distinct";
  1197 
  1198 * HOL: added "The" definite description operator; move Hilbert's "Eps"
  1199 to peripheral theory "Hilbert_Choice"; some INCOMPATIBILITIES:
  1200   - Ex_def has changed, now need to use some_eq_ex
  1201 
  1202 * HOL: made split_all_tac safe; EXISTING PROOFS MAY FAIL OR LOOP, so
  1203 in this (rare) case use:
  1204 
  1205   delSWrapper "split_all_tac"
  1206   addSbefore ("unsafe_split_all_tac", unsafe_split_all_tac)
  1207 
  1208 * HOL: added safe wrapper "split_conv_tac" to claset; EXISTING PROOFS
  1209 MAY FAIL;
  1210 
  1211 * HOL: introduced f^n = f o ... o f; warning: due to the limits of
  1212 Isabelle's type classes, ^ on functions and relations has too general
  1213 a domain, namely ('a * 'b) set and 'a => 'b; this means that it may be
  1214 necessary to attach explicit type constraints;
  1215 
  1216 * HOL/Relation: the prefix name of the infix "O" has been changed from
  1217 "comp" to "rel_comp"; INCOMPATIBILITY: a few theorems have been
  1218 renamed accordingly (eg "compI" -> "rel_compI").
  1219 
  1220 * HOL: syntax translations now work properly with numerals and records
  1221 expressions;
  1222 
  1223 * HOL: bounded abstraction now uses syntax "%" / "\<lambda>" instead
  1224 of "lam" -- INCOMPATIBILITY;
  1225 
  1226 * HOL: got rid of some global declarations (potential INCOMPATIBILITY
  1227 for ML tools): const "()" renamed "Product_Type.Unity", type "unit"
  1228 renamed "Product_Type.unit";
  1229 
  1230 * HOL: renamed rtrancl_into_rtrancl2 to converse_rtrancl_into_rtrancl
  1231 
  1232 * HOL: removed obsolete theorem "optionE" (use "option.exhaust", or
  1233 the "cases" method);
  1234 
  1235 * HOL/GroupTheory: group theory examples including Sylow's theorem (by
  1236 Florian Kammller);
  1237 
  1238 * HOL/IMP: updated and converted to new-style theory format; several
  1239 parts turned into readable document, with proper Isar proof texts and
  1240 some explanations (by Gerwin Klein);
  1241 
  1242 * HOL-Real: added Complex_Numbers (by Gertrud Bauer);
  1243 
  1244 * HOL-Hyperreal is now a logic image;
  1245 
  1246 
  1247 *** HOLCF ***
  1248 
  1249 * Isar: consts/constdefs supports mixfix syntax for continuous
  1250 operations;
  1251 
  1252 * Isar: domain package adapted to new-style theory format, e.g. see
  1253 HOLCF/ex/Dnat.thy;
  1254 
  1255 * theory Lift: proper use of rep_datatype lift instead of ML hacks --
  1256 potential INCOMPATIBILITY; now use plain induct_tac instead of former
  1257 lift.induct_tac, always use UU instead of Undef;
  1258 
  1259 * HOLCF/IMP: updated and converted to new-style theory;
  1260 
  1261 
  1262 *** ZF ***
  1263 
  1264 * Isar: proper integration of logic-specific tools and packages,
  1265 including theory commands '(co)inductive', '(co)datatype',
  1266 'rep_datatype', 'inductive_cases', as well as methods 'ind_cases',
  1267 'induct_tac', 'case_tac', and 'typecheck' (with attribute 'TC');
  1268 
  1269 * theory Main no longer includes AC; for the Axiom of Choice, base
  1270 your theory on Main_ZFC;
  1271 
  1272 * the integer library now covers quotients and remainders, with many
  1273 laws relating division to addition, multiplication, etc.;
  1274 
  1275 * ZF/UNITY: Chandy and Misra's UNITY is now available in ZF, giving a
  1276 typeless version of the formalism;
  1277 
  1278 * ZF/AC, Coind, IMP, Resid: updated and converted to new-style theory
  1279 format;
  1280 
  1281 * ZF/Induct: new directory for examples of inductive definitions,
  1282 including theory Multiset for multiset orderings; converted to
  1283 new-style theory format;
  1284 
  1285 * ZF: many new theorems about lists, ordinals, etc.;
  1286 
  1287 
  1288 *** General ***
  1289 
  1290 * Pure/kernel: meta-level proof terms (by Stefan Berghofer); reference
  1291 variable proof controls level of detail: 0 = no proofs (only oracle
  1292 dependencies), 1 = lemma dependencies, 2 = compact proof terms; see
  1293 also ref manual for further ML interfaces;
  1294 
  1295 * Pure/axclass: removed obsolete ML interface
  1296 goal_subclass/goal_arity;
  1297 
  1298 * Pure/syntax: new token syntax "num" for plain numerals (without "#"
  1299 of "xnum"); potential INCOMPATIBILITY, since -0, -1 etc. are now
  1300 separate tokens, so expressions involving minus need to be spaced
  1301 properly;
  1302 
  1303 * Pure/syntax: support non-oriented infixes, using keyword "infix"
  1304 rather than "infixl" or "infixr";
  1305 
  1306 * Pure/syntax: concrete syntax for dummy type variables admits genuine
  1307 sort constraint specifications in type inference; e.g. "x::_::foo"
  1308 ensures that the type of "x" is of sort "foo" (but not necessarily a
  1309 type variable);
  1310 
  1311 * Pure/syntax: print modes "type_brackets" and "no_type_brackets"
  1312 control output of nested => (types); the default behavior is
  1313 "type_brackets";
  1314 
  1315 * Pure/syntax: builtin parse translation for "_constify" turns valued
  1316 tokens into AST constants;
  1317 
  1318 * Pure/syntax: prefer later declarations of translations and print
  1319 translation functions; potential INCOMPATIBILITY: need to reverse
  1320 multiple declarations for same syntax element constant;
  1321 
  1322 * Pure/show_hyps reset by default (in accordance to existing Isar
  1323 practice);
  1324 
  1325 * Provers/classical: renamed addaltern to addafter, addSaltern to
  1326 addSafter;
  1327 
  1328 * Provers/clasimp: ``iff'' declarations now handle conditional rules
  1329 as well;
  1330 
  1331 * system: tested support for MacOS X; should be able to get Isabelle +
  1332 Proof General to work in a plain Terminal after installing Poly/ML
  1333 (e.g. from the Isabelle distribution area) and GNU bash alone
  1334 (e.g. from http://www.apple.com); full X11, XEmacs and X-Symbol
  1335 support requires further installations, e.g. from
  1336 http://fink.sourceforge.net/);
  1337 
  1338 * system: support Poly/ML 4.1.1 (able to manage larger heaps);
  1339 
  1340 * system: reduced base memory usage by Poly/ML (approx. 20 MB instead
  1341 of 40 MB), cf. ML_OPTIONS;
  1342 
  1343 * system: Proof General keywords specification is now part of the
  1344 Isabelle distribution (see etc/isar-keywords.el);
  1345 
  1346 * system: support for persistent Proof General sessions (refrain from
  1347 outdating all loaded theories on startup); user may create writable
  1348 logic images like this: ``isabelle -q HOL Test'';
  1349 
  1350 * system: smart selection of Isabelle process versus Isabelle
  1351 interface, accommodates case-insensitive file systems (e.g. HFS+); may
  1352 run both "isabelle" and "Isabelle" even if file names are badly
  1353 damaged (executable inspects the case of the first letter of its own
  1354 name); added separate "isabelle-process" and "isabelle-interface";
  1355 
  1356 * system: refrain from any attempt at filtering input streams; no
  1357 longer support ``8bit'' encoding of old isabelle font, instead proper
  1358 iso-latin characters may now be used; the related isatools
  1359 "symbolinput" and "nonascii" have disappeared as well;
  1360 
  1361 * system: removed old "xterm" interface (the print modes "xterm" and
  1362 "xterm_color" are still available for direct use in a suitable
  1363 terminal);
  1364 
  1365 
  1366 
  1367 New in Isabelle99-2 (February 2001)
  1368 -----------------------------------
  1369 
  1370 *** Overview of INCOMPATIBILITIES ***
  1371 
  1372 * HOL: please note that theories in the Library and elsewhere often use the
  1373 new-style (Isar) format; to refer to their theorems in an ML script you must
  1374 bind them to ML identifers by e.g.      val thm_name = thm "thm_name";
  1375 
  1376 * HOL: inductive package no longer splits induction rule aggressively,
  1377 but only as far as specified by the introductions given; the old
  1378 format may be recovered via ML function complete_split_rule or attribute
  1379 'split_rule (complete)';
  1380 
  1381 * HOL: induct renamed to lfp_induct, lfp_Tarski to lfp_unfold,
  1382 gfp_Tarski to gfp_unfold;
  1383 
  1384 * HOL: contrapos, contrapos2 renamed to contrapos_nn, contrapos_pp;
  1385 
  1386 * HOL: infix "dvd" now has priority 50 rather than 70 (because it is a
  1387 relation); infix "^^" has been renamed "``"; infix "``" has been
  1388 renamed "`"; "univalent" has been renamed "single_valued";
  1389 
  1390 * HOL/Real: "rinv" and "hrinv" replaced by overloaded "inverse"
  1391 operation;
  1392 
  1393 * HOLCF: infix "`" has been renamed "$"; the symbol syntax is \<cdot>;
  1394 
  1395 * Isar: 'obtain' no longer declares "that" fact as simp/intro;
  1396 
  1397 * Isar/HOL: method 'induct' now handles non-atomic goals; as a
  1398 consequence, it is no longer monotonic wrt. the local goal context
  1399 (which is now passed through the inductive cases);
  1400 
  1401 * Document preparation: renamed standard symbols \<ll> to \<lless> and
  1402 \<gg> to \<ggreater>;
  1403 
  1404 
  1405 *** Document preparation ***
  1406 
  1407 * \isabellestyle{NAME} selects version of Isabelle output (currently
  1408 available: are "it" for near math-mode best-style output, "sl" for
  1409 slanted text style, and "tt" for plain type-writer; if no
  1410 \isabellestyle command is given, output is according to slanted
  1411 type-writer);
  1412 
  1413 * support sub/super scripts (for single symbols only), input syntax is
  1414 like this: "A\<^sup>*" or "A\<^sup>\<star>";
  1415 
  1416 * some more standard symbols; see Appendix A of the system manual for
  1417 the complete list of symbols defined in isabellesym.sty;
  1418 
  1419 * improved isabelle style files; more abstract symbol implementation
  1420 (should now use \isamath{...} and \isatext{...} in custom symbol
  1421 definitions);
  1422 
  1423 * antiquotation @{goals} and @{subgoals} for output of *dynamic* goals
  1424 state; Note that presentation of goal states does not conform to
  1425 actual human-readable proof documents.  Please do not include goal
  1426 states into document output unless you really know what you are doing!
  1427 
  1428 * proper indentation of antiquoted output with proportional LaTeX
  1429 fonts;
  1430 
  1431 * no_document ML operator temporarily disables LaTeX document
  1432 generation;
  1433 
  1434 * isatool unsymbolize tunes sources for plain ASCII communication;
  1435 
  1436 
  1437 *** Isar ***
  1438 
  1439 * Pure: Isar now suffers initial goal statements to contain unbound
  1440 schematic variables (this does not conform to actual readable proof
  1441 documents, due to unpredictable outcome and non-compositional proof
  1442 checking); users who know what they are doing may use schematic goals
  1443 for Prolog-style synthesis of proven results;
  1444 
  1445 * Pure: assumption method (an implicit finishing) now handles actual
  1446 rules as well;
  1447 
  1448 * Pure: improved 'obtain' --- moved to Pure, insert "that" into
  1449 initial goal, declare "that" only as Pure intro (only for single
  1450 steps); the "that" rule assumption may now be involved in implicit
  1451 finishing, thus ".." becomes a feasible for trivial obtains;
  1452 
  1453 * Pure: default proof step now includes 'intro_classes'; thus trivial
  1454 instance proofs may be performed by "..";
  1455 
  1456 * Pure: ?thesis / ?this / "..." now work for pure meta-level
  1457 statements as well;
  1458 
  1459 * Pure: more robust selection of calculational rules;
  1460 
  1461 * Pure: the builtin notion of 'finished' goal now includes the ==-refl
  1462 rule (as well as the assumption rule);
  1463 
  1464 * Pure: 'thm_deps' command visualizes dependencies of theorems and
  1465 lemmas, using the graph browser tool;
  1466 
  1467 * Pure: predict failure of "show" in interactive mode;
  1468 
  1469 * Pure: 'thms_containing' now takes actual terms as arguments;
  1470 
  1471 * HOL: improved method 'induct' --- now handles non-atomic goals
  1472 (potential INCOMPATIBILITY); tuned error handling;
  1473 
  1474 * HOL: cases and induct rules now provide explicit hints about the
  1475 number of facts to be consumed (0 for "type" and 1 for "set" rules);
  1476 any remaining facts are inserted into the goal verbatim;
  1477 
  1478 * HOL: local contexts (aka cases) may now contain term bindings as
  1479 well; the 'cases' and 'induct' methods new provide a ?case binding for
  1480 the result to be shown in each case;
  1481 
  1482 * HOL: added 'recdef_tc' command;
  1483 
  1484 * isatool convert assists in eliminating legacy ML scripts;
  1485 
  1486 
  1487 *** HOL ***
  1488 
  1489 * HOL/Library: a collection of generic theories to be used together
  1490 with main HOL; the theory loader path already includes this directory
  1491 by default; the following existing theories have been moved here:
  1492 HOL/Induct/Multiset, HOL/Induct/Acc (as Accessible_Part), HOL/While
  1493 (as While_Combinator), HOL/Lex/Prefix (as List_Prefix);
  1494 
  1495 * HOL/Unix: "Some aspects of Unix file-system security", a typical
  1496 modelling and verification task performed in Isabelle/HOL +
  1497 Isabelle/Isar + Isabelle document preparation (by Markus Wenzel).
  1498 
  1499 * HOL/Algebra: special summation operator SUM no longer exists, it has
  1500 been replaced by setsum; infix 'assoc' now has priority 50 (like
  1501 'dvd'); axiom 'one_not_zero' has been moved from axclass 'ring' to
  1502 'domain', this makes the theory consistent with mathematical
  1503 literature;
  1504 
  1505 * HOL basics: added overloaded operations "inverse" and "divide"
  1506 (infix "/"), syntax for generic "abs" operation, generic summation
  1507 operator \<Sum>;
  1508 
  1509 * HOL/typedef: simplified package, provide more useful rules (see also
  1510 HOL/subset.thy);
  1511 
  1512 * HOL/datatype: induction rule for arbitrarily branching datatypes is
  1513 now expressed as a proper nested rule (old-style tactic scripts may
  1514 require atomize_strip_tac to cope with non-atomic premises);
  1515 
  1516 * HOL: renamed theory "Prod" to "Product_Type", renamed "split" rule
  1517 to "split_conv" (old name still available for compatibility);
  1518 
  1519 * HOL: improved concrete syntax for strings (e.g. allows translation
  1520 rules with string literals);
  1521 
  1522 * HOL-Real-Hyperreal: this extends HOL-Real with the hyperreals
  1523  and Fleuriot's mechanization of analysis, including the transcendental
  1524  functions for the reals;
  1525 
  1526 * HOL/Real, HOL/Hyperreal: improved arithmetic simplification;
  1527 
  1528 
  1529 *** CTT ***
  1530 
  1531 * CTT: x-symbol support for Pi, Sigma, -->, : (membership); note that
  1532 "lam" is displayed as TWO lambda-symbols
  1533 
  1534 * CTT: theory Main now available, containing everything (that is, Bool
  1535 and Arith);
  1536 
  1537 
  1538 *** General ***
  1539 
  1540 * Pure: the Simplifier has been implemented properly as a derived rule
  1541 outside of the actual kernel (at last!); the overall performance
  1542 penalty in practical applications is about 50%, while reliability of
  1543 the Isabelle inference kernel has been greatly improved;
  1544 
  1545 * print modes "brackets" and "no_brackets" control output of nested =>
  1546 (types) and ==> (props); the default behaviour is "brackets";
  1547 
  1548 * Provers: fast_tac (and friends) now handle actual object-logic rules
  1549 as assumptions as well;
  1550 
  1551 * system: support Poly/ML 4.0;
  1552 
  1553 * system: isatool install handles KDE version 1 or 2;
  1554 
  1555 
  1556 
  1557 New in Isabelle99-1 (October 2000)
  1558 ----------------------------------
  1559 
  1560 *** Overview of INCOMPATIBILITIES ***
  1561 
  1562 * HOL: simplification of natural numbers is much changed; to partly
  1563 recover the old behaviour (e.g. to prevent n+n rewriting to #2*n)
  1564 issue the following ML commands:
  1565 
  1566   Delsimprocs Nat_Numeral_Simprocs.cancel_numerals;
  1567   Delsimprocs [Nat_Numeral_Simprocs.combine_numerals];
  1568 
  1569 * HOL: simplification no longer dives into case-expressions; this is
  1570 controlled by "t.weak_case_cong" for each datatype t;
  1571 
  1572 * HOL: nat_less_induct renamed to less_induct;
  1573 
  1574 * HOL: systematic renaming of the SOME (Eps) rules, may use isatool
  1575 fixsome to patch .thy and .ML sources automatically;
  1576 
  1577   select_equality  -> some_equality
  1578   select_eq_Ex     -> some_eq_ex
  1579   selectI2EX       -> someI2_ex
  1580   selectI2         -> someI2
  1581   selectI          -> someI
  1582   select1_equality -> some1_equality
  1583   Eps_sym_eq       -> some_sym_eq_trivial
  1584   Eps_eq           -> some_eq_trivial
  1585 
  1586 * HOL: exhaust_tac on datatypes superceded by new generic case_tac;
  1587 
  1588 * HOL: removed obsolete theorem binding expand_if (refer to split_if
  1589 instead);
  1590 
  1591 * HOL: the recursion equations generated by 'recdef' are now called
  1592 f.simps instead of f.rules;
  1593 
  1594 * HOL: qed_spec_mp now also handles bounded ALL as well;
  1595 
  1596 * HOL: 0 is now overloaded, so the type constraint ":: nat" may
  1597 sometimes be needed;
  1598 
  1599 * HOL: the constant for "f``x" is now "image" rather than "op ``";
  1600 
  1601 * HOL: the constant for "f-``x" is now "vimage" rather than "op -``";
  1602 
  1603 * HOL: the disjoint sum is now "<+>" instead of "Plus"; the cartesian
  1604 product is now "<*>" instead of "Times"; the lexicographic product is
  1605 now "<*lex*>" instead of "**";
  1606 
  1607 * HOL: theory Sexp is now in HOL/Induct examples (it used to be part
  1608 of main HOL, but was unused); better use HOL's datatype package;
  1609 
  1610 * HOL: removed "symbols" syntax for constant "override" of theory Map;
  1611 the old syntax may be recovered as follows:
  1612 
  1613   syntax (symbols)
  1614     override  :: "('a ~=> 'b) => ('a ~=> 'b) => ('a ~=> 'b)"
  1615       (infixl "\\<oplus>" 100)
  1616 
  1617 * HOL/Real: "rabs" replaced by overloaded "abs" function;
  1618 
  1619 * HOL/ML: even fewer consts are declared as global (see theories Ord,
  1620 Lfp, Gfp, WF); this only affects ML packages that refer to const names
  1621 internally;
  1622 
  1623 * HOL and ZF: syntax for quotienting wrt an equivalence relation
  1624 changed from A/r to A//r;
  1625 
  1626 * ZF: new treatment of arithmetic (nat & int) may break some old
  1627 proofs;
  1628 
  1629 * Isar: renamed some attributes (RS -> THEN, simplify -> simplified,
  1630 rulify -> rule_format, elimify -> elim_format, ...);
  1631 
  1632 * Isar/Provers: intro/elim/dest attributes changed; renamed
  1633 intro/intro!/intro!! flags to intro!/intro/intro? (in most cases, one
  1634 should have to change intro!! to intro? only); replaced "delrule" by
  1635 "rule del";
  1636 
  1637 * Isar/HOL: renamed "intrs" to "intros" in inductive definitions;
  1638 
  1639 * Provers: strengthened force_tac by using new first_best_tac;
  1640 
  1641 * LaTeX document preparation: several changes of isabelle.sty (see
  1642 lib/texinputs);
  1643 
  1644 
  1645 *** Document preparation ***
  1646 
  1647 * formal comments (text blocks etc.) in new-style theories may now
  1648 contain antiquotations of thm/prop/term/typ/text to be presented
  1649 according to latex print mode; concrete syntax is like this:
  1650 @{term[show_types] "f(x) = a + x"};
  1651 
  1652 * isatool mkdir provides easy setup of Isabelle session directories,
  1653 including proper document sources;
  1654 
  1655 * generated LaTeX sources are now deleted after successful run
  1656 (isatool document -c); may retain a copy somewhere else via -D option
  1657 of isatool usedir;
  1658 
  1659 * isatool usedir -D now lets isatool latex -o sty update the Isabelle
  1660 style files, achieving self-contained LaTeX sources and simplifying
  1661 LaTeX debugging;
  1662 
  1663 * old-style theories now produce (crude) LaTeX output as well;
  1664 
  1665 * browser info session directories are now self-contained (may be put
  1666 on WWW server seperately); improved graphs of nested sessions; removed
  1667 graph for 'all sessions';
  1668 
  1669 * several improvements in isabelle style files; \isabellestyle{it}
  1670 produces fake math mode output; \isamarkupheader is now \section by
  1671 default; see lib/texinputs/isabelle.sty etc.;
  1672 
  1673 
  1674 *** Isar ***
  1675 
  1676 * Isar/Pure: local results and corresponding term bindings are now
  1677 subject to Hindley-Milner polymorphism (similar to ML); this
  1678 accommodates incremental type-inference very nicely;
  1679 
  1680 * Isar/Pure: new derived language element 'obtain' supports
  1681 generalized existence reasoning;
  1682 
  1683 * Isar/Pure: new calculational elements 'moreover' and 'ultimately'
  1684 support accumulation of results, without applying any rules yet;
  1685 useful to collect intermediate results without explicit name
  1686 references, and for use with transitivity rules with more than 2
  1687 premises;
  1688 
  1689 * Isar/Pure: scalable support for case-analysis type proofs: new
  1690 'case' language element refers to local contexts symbolically, as
  1691 produced by certain proof methods; internally, case names are attached
  1692 to theorems as "tags";
  1693 
  1694 * Isar/Pure: theory command 'hide' removes declarations from
  1695 class/type/const name spaces;
  1696 
  1697 * Isar/Pure: theory command 'defs' supports option "(overloaded)" to
  1698 indicate potential overloading;
  1699 
  1700 * Isar/Pure: changed syntax of local blocks from {{ }} to { };
  1701 
  1702 * Isar/Pure: syntax of sorts made 'inner', i.e. have to write
  1703 "{a,b,c}" instead of {a,b,c};
  1704 
  1705 * Isar/Pure now provides its own version of intro/elim/dest
  1706 attributes; useful for building new logics, but beware of confusion
  1707 with the version in Provers/classical;
  1708 
  1709 * Isar/Pure: the local context of (non-atomic) goals is provided via
  1710 case name 'antecedent';
  1711 
  1712 * Isar/Pure: removed obsolete 'transfer' attribute (transfer of thms
  1713 to the current context is now done automatically);
  1714 
  1715 * Isar/Pure: theory command 'method_setup' provides a simple interface
  1716 for definining proof methods in ML;
  1717 
  1718 * Isar/Provers: intro/elim/dest attributes changed; renamed
  1719 intro/intro!/intro!! flags to intro!/intro/intro? (INCOMPATIBILITY, in
  1720 most cases, one should have to change intro!! to intro? only);
  1721 replaced "delrule" by "rule del";
  1722 
  1723 * Isar/Provers: new 'hypsubst' method, plain 'subst' method and
  1724 'symmetric' attribute (the latter supercedes [RS sym]);
  1725 
  1726 * Isar/Provers: splitter support (via 'split' attribute and 'simp'
  1727 method modifier); 'simp' method: 'only:' modifier removes loopers as
  1728 well (including splits);
  1729 
  1730 * Isar/Provers: Simplifier and Classical methods now support all kind
  1731 of modifiers used in the past, including 'cong', 'iff', etc.
  1732 
  1733 * Isar/Provers: added 'fastsimp' and 'clarsimp' methods (combination
  1734 of Simplifier and Classical reasoner);
  1735 
  1736 * Isar/HOL: new proof method 'cases' and improved version of 'induct'
  1737 now support named cases; major packages (inductive, datatype, primrec,
  1738 recdef) support case names and properly name parameters;
  1739 
  1740 * Isar/HOL: new transitivity rules for substitution in inequalities --
  1741 monotonicity conditions are extracted to be proven at end of
  1742 calculations;
  1743 
  1744 * Isar/HOL: removed 'case_split' thm binding, should use 'cases' proof
  1745 method anyway;
  1746 
  1747 * Isar/HOL: removed old expand_if = split_if; theorems if_splits =
  1748 split_if split_if_asm; datatype package provides theorems foo.splits =
  1749 foo.split foo.split_asm for each datatype;
  1750 
  1751 * Isar/HOL: tuned inductive package, rename "intrs" to "intros"
  1752 (potential INCOMPATIBILITY), emulation of mk_cases feature for proof
  1753 scripts: new 'inductive_cases' command and 'ind_cases' method; (Note:
  1754 use "(cases (simplified))" method in proper proof texts);
  1755 
  1756 * Isar/HOL: added global 'arith_split' attribute for 'arith' method;
  1757 
  1758 * Isar: names of theorems etc. may be natural numbers as well;
  1759 
  1760 * Isar: 'pr' command: optional arguments for goals_limit and
  1761 ProofContext.prems_limit; no longer prints theory contexts, but only
  1762 proof states;
  1763 
  1764 * Isar: diagnostic commands 'pr', 'thm', 'prop', 'term', 'typ' admit
  1765 additional print modes to be specified; e.g. "pr(latex)" will print
  1766 proof state according to the Isabelle LaTeX style;
  1767 
  1768 * Isar: improved support for emulating tactic scripts, including proof
  1769 methods 'rule_tac' etc., 'cut_tac', 'thin_tac', 'subgoal_tac',
  1770 'rename_tac', 'rotate_tac', 'tactic', and 'case_tac' / 'induct_tac'
  1771 (for HOL datatypes);
  1772 
  1773 * Isar: simplified (more robust) goal selection of proof methods: 1st
  1774 goal, all goals, or explicit goal specifier (tactic emulation); thus
  1775 'proof method scripts' have to be in depth-first order;
  1776 
  1777 * Isar: tuned 'let' syntax: replaced 'as' keyword by 'and';
  1778 
  1779 * Isar: removed 'help' command, which hasn't been too helpful anyway;
  1780 should instead use individual commands for printing items
  1781 (print_commands, print_methods etc.);
  1782 
  1783 * Isar: added 'nothing' --- the empty list of theorems;
  1784 
  1785 
  1786 *** HOL ***
  1787 
  1788 * HOL/MicroJava: formalization of a fragment of Java, together with a
  1789 corresponding virtual machine and a specification of its bytecode
  1790 verifier and a lightweight bytecode verifier, including proofs of
  1791 type-safety; by Gerwin Klein, Tobias Nipkow, David von Oheimb, and
  1792 Cornelia Pusch (see also the homepage of project Bali at
  1793 http://isabelle.in.tum.de/Bali/);
  1794 
  1795 * HOL/Algebra: new theory of rings and univariate polynomials, by
  1796 Clemens Ballarin;
  1797 
  1798 * HOL/NumberTheory: fundamental Theorem of Arithmetic, Chinese
  1799 Remainder Theorem, Fermat/Euler Theorem, Wilson's Theorem, by Thomas M
  1800 Rasmussen;
  1801 
  1802 * HOL/Lattice: fundamental concepts of lattice theory and order
  1803 structures, including duals, properties of bounds versus algebraic
  1804 laws, lattice operations versus set-theoretic ones, the Knaster-Tarski
  1805 Theorem for complete lattices etc.; may also serve as a demonstration
  1806 for abstract algebraic reasoning using axiomatic type classes, and
  1807 mathematics-style proof in Isabelle/Isar; by Markus Wenzel;
  1808 
  1809 * HOL/Prolog: a (bare-bones) implementation of Lambda-Prolog, by David
  1810 von Oheimb;
  1811 
  1812 * HOL/IMPP: extension of IMP with local variables and mutually
  1813 recursive procedures, by David von Oheimb;
  1814 
  1815 * HOL/Lambda: converted into new-style theory and document;
  1816 
  1817 * HOL/ex/Multiquote: example of multiple nested quotations and
  1818 anti-quotations -- basically a generalized version of de-Bruijn
  1819 representation; very useful in avoiding lifting of operations;
  1820 
  1821 * HOL/record: added general record equality rule to simpset; fixed
  1822 select-update simplification procedure to handle extended records as
  1823 well; admit "r" as field name;
  1824 
  1825 * HOL: 0 is now overloaded over the new sort "zero", allowing its use with
  1826 other numeric types and also as the identity of groups, rings, etc.;
  1827 
  1828 * HOL: new axclass plus_ac0 for addition with the AC-laws and 0 as identity.
  1829 Types nat and int belong to this axclass;
  1830 
  1831 * HOL: greatly improved simplification involving numerals of type nat, int, real:
  1832    (i + #8 + j) = Suc k simplifies to  #7 + (i + j) = k
  1833    i*j + k + j*#3*i     simplifies to  #4*(i*j) + k
  1834   two terms #m*u and #n*u are replaced by #(m+n)*u
  1835     (where #m, #n and u can implicitly be 1; this is simproc combine_numerals)
  1836   and the term/formula #m*u+x ~~ #n*u+y simplifies simplifies to #(m-n)+x ~~ y
  1837     or x ~~ #(n-m)+y, where ~~ is one of = < <= or - (simproc cancel_numerals);
  1838 
  1839 * HOL: meson_tac is available (previously in ex/meson.ML); it is a
  1840 powerful prover for predicate logic but knows nothing of clasets; see
  1841 ex/mesontest.ML and ex/mesontest2.ML for example applications;
  1842 
  1843 * HOL: new version of "case_tac" subsumes both boolean case split and
  1844 "exhaust_tac" on datatypes; INCOMPATIBILITY: exhaust_tac no longer
  1845 exists, may define val exhaust_tac = case_tac for ad-hoc portability;
  1846 
  1847 * HOL: simplification no longer dives into case-expressions: only the
  1848 selector expression is simplified, but not the remaining arms; to
  1849 enable full simplification of case-expressions for datatype t, you may
  1850 remove t.weak_case_cong from the simpset, either globally (Delcongs
  1851 [thm"t.weak_case_cong"];) or locally (delcongs [...]).
  1852 
  1853 * HOL/recdef: the recursion equations generated by 'recdef' for
  1854 function 'f' are now called f.simps instead of f.rules; if all
  1855 termination conditions are proved automatically, these simplification
  1856 rules are added to the simpset, as in primrec; rules may be named
  1857 individually as well, resulting in a separate list of theorems for
  1858 each equation;
  1859 
  1860 * HOL/While is a new theory that provides a while-combinator. It
  1861 permits the definition of tail-recursive functions without the
  1862 provision of a termination measure. The latter is necessary once the
  1863 invariant proof rule for while is applied.
  1864 
  1865 * HOL: new (overloaded) notation for the set of elements below/above
  1866 some element: {..u}, {..u(}, {l..}, {)l..}. See theory SetInterval.
  1867 
  1868 * HOL: theorems impI, allI, ballI bound as "strip";
  1869 
  1870 * HOL: new tactic induct_thm_tac: thm -> string -> int -> tactic
  1871 induct_tac th "x1 ... xn" expects th to have a conclusion of the form
  1872 P v1 ... vn and abbreviates res_inst_tac [("v1","x1"),...,("vn","xn")] th;
  1873 
  1874 * HOL/Real: "rabs" replaced by overloaded "abs" function;
  1875 
  1876 * HOL: theory Sexp now in HOL/Induct examples (it used to be part of
  1877 main HOL, but was unused);
  1878 
  1879 * HOL: fewer consts declared as global (e.g. have to refer to
  1880 "Lfp.lfp" instead of "lfp" internally; affects ML packages only);
  1881 
  1882 * HOL: tuned AST representation of nested pairs, avoiding bogus output
  1883 in case of overlap with user translations (e.g. judgements over
  1884 tuples); (note that the underlying logical represenation is still
  1885 bogus);
  1886 
  1887 
  1888 *** ZF ***
  1889 
  1890 * ZF: simplification automatically cancels common terms in arithmetic
  1891 expressions over nat and int;
  1892 
  1893 * ZF: new treatment of nat to minimize type-checking: all operators
  1894 coerce their operands to a natural number using the function natify,
  1895 making the algebraic laws unconditional;
  1896 
  1897 * ZF: as above, for int: operators coerce their operands to an integer
  1898 using the function intify;
  1899 
  1900 * ZF: the integer library now contains many of the usual laws for the
  1901 orderings, including $<=, and monotonicity laws for $+ and $*;
  1902 
  1903 * ZF: new example ZF/ex/NatSum to demonstrate integer arithmetic
  1904 simplification;
  1905 
  1906 * FOL and ZF: AddIffs now available, giving theorems of the form P<->Q
  1907 to the simplifier and classical reasoner simultaneously;
  1908 
  1909 
  1910 *** General ***
  1911 
  1912 * Provers: blast_tac now handles actual object-logic rules as
  1913 assumptions; note that auto_tac uses blast_tac internally as well;
  1914 
  1915 * Provers: new functions rulify/rulify_no_asm: thm -> thm for turning
  1916 outer -->/All/Ball into ==>/!!; qed_spec_mp now uses rulify_no_asm;
  1917 
  1918 * Provers: delrules now handles destruct rules as well (no longer need
  1919 explicit make_elim);
  1920 
  1921 * Provers: Blast_tac now warns of and ignores "weak elimination rules" e.g.
  1922   [| inj ?f;          ?f ?x = ?f ?y; ?x = ?y ==> ?W |] ==> ?W
  1923 use instead the strong form,
  1924   [| inj ?f; ~ ?W ==> ?f ?x = ?f ?y; ?x = ?y ==> ?W |] ==> ?W
  1925 in HOL, FOL and ZF the function cla_make_elim will create such rules
  1926 from destruct-rules;
  1927 
  1928 * Provers: Simplifier.easy_setup provides a fast path to basic
  1929 Simplifier setup for new object-logics;
  1930 
  1931 * Pure: AST translation rules no longer require constant head on LHS;
  1932 
  1933 * Pure: improved name spaces: ambiguous output is qualified; support
  1934 for hiding of names;
  1935 
  1936 * system: smart setup of canonical ML_HOME, ISABELLE_INTERFACE, and
  1937 XSYMBOL_HOME; no longer need to do manual configuration in most
  1938 situations;
  1939 
  1940 * system: compression of ML heaps images may now be controlled via -c
  1941 option of isabelle and isatool usedir (currently only observed by
  1942 Poly/ML);
  1943 
  1944 * system: isatool installfonts may handle X-Symbol fonts as well (very
  1945 useful for remote X11);
  1946 
  1947 * system: provide TAGS file for Isabelle sources;
  1948 
  1949 * ML: infix 'OF' is a version of 'MRS' with more appropriate argument
  1950 order;
  1951 
  1952 * ML: renamed flags Syntax.trace_norm_ast to Syntax.trace_ast; global
  1953 timing flag supersedes proof_timing and Toplevel.trace;
  1954 
  1955 * ML: new combinators |>> and |>>> for incremental transformations
  1956 with secondary results (e.g. certain theory extensions):
  1957 
  1958 * ML: PureThy.add_defs gets additional argument to indicate potential
  1959 overloading (usually false);
  1960 
  1961 * ML: PureThy.add_thms/add_axioms/add_defs now return theorems as
  1962 results;
  1963 
  1964 
  1965 
  1966 New in Isabelle99 (October 1999)
  1967 --------------------------------
  1968 
  1969 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  1970 
  1971 * HOL: The THEN and ELSE parts of conditional expressions (if P then x else y)
  1972 are no longer simplified.  (This allows the simplifier to unfold recursive
  1973 functional programs.)  To restore the old behaviour, declare
  1974 
  1975     Delcongs [if_weak_cong];
  1976 
  1977 * HOL: Removed the obsolete syntax "Compl A"; use -A for set
  1978 complement;
  1979 
  1980 * HOL: the predicate "inj" is now defined by translation to "inj_on";
  1981 
  1982 * HOL/datatype: mutual_induct_tac no longer exists --
  1983   use induct_tac "x_1 ... x_n" instead of mutual_induct_tac ["x_1", ..., "x_n"]
  1984 
  1985 * HOL/typedef: fixed type inference for representing set; type
  1986 arguments now have to occur explicitly on the rhs as type constraints;
  1987 
  1988 * ZF: The con_defs part of an inductive definition may no longer refer
  1989 to constants declared in the same theory;
  1990 
  1991 * HOL, ZF: the function mk_cases, generated by the inductive
  1992 definition package, has lost an argument.  To simplify its result, it
  1993 uses the default simpset instead of a supplied list of theorems.
  1994 
  1995 * HOL/List: the constructors of type list are now Nil and Cons;
  1996 
  1997 * Simplifier: the type of the infix ML functions
  1998         setSSolver addSSolver setSolver addSolver
  1999 is now  simpset * solver -> simpset  where `solver' is a new abstract type
  2000 for packaging solvers. A solver is created via
  2001         mk_solver: string -> (thm list -> int -> tactic) -> solver
  2002 where the string argument is only a comment.
  2003 
  2004 
  2005 *** Proof tools ***
  2006 
  2007 * Provers/Arith/fast_lin_arith.ML contains a functor for creating a
  2008 decision procedure for linear arithmetic. Currently it is used for
  2009 types `nat', `int', and `real' in HOL (see below); it can, should and
  2010 will be instantiated for other types and logics as well.
  2011 
  2012 * The simplifier now accepts rewrite rules with flexible heads, eg
  2013      hom ?f ==> ?f(?x+?y) = ?f ?x + ?f ?y
  2014   They are applied like any rule with a non-pattern lhs, i.e. by first-order
  2015   matching.
  2016 
  2017 
  2018 *** General ***
  2019 
  2020 * New Isabelle/Isar subsystem provides an alternative to traditional
  2021 tactical theorem proving; together with the ProofGeneral/isar user
  2022 interface it offers an interactive environment for developing human
  2023 readable proof documents (Isar == Intelligible semi-automated
  2024 reasoning); for further information see isatool doc isar-ref,
  2025 src/HOL/Isar_examples and http://isabelle.in.tum.de/Isar/
  2026 
  2027 * improved and simplified presentation of theories: better HTML markup
  2028 (including colors), graph views in several sizes; isatool usedir now
  2029 provides a proper interface for user theories (via -P option); actual
  2030 document preparation based on (PDF)LaTeX is available as well (for
  2031 new-style theories only); see isatool doc system for more information;
  2032 
  2033 * native support for Proof General, both for classic Isabelle and
  2034 Isabelle/Isar;
  2035 
  2036 * ML function thm_deps visualizes dependencies of theorems and lemmas,
  2037 using the graph browser tool;
  2038 
  2039 * Isabelle manuals now also available as PDF;
  2040 
  2041 * theory loader rewritten from scratch (may not be fully
  2042 bug-compatible); old loadpath variable has been replaced by show_path,
  2043 add_path, del_path, reset_path functions; new operations such as
  2044 update_thy, touch_thy, remove_thy, use/update_thy_only (see also
  2045 isatool doc ref);
  2046 
  2047 * improved isatool install: option -k creates KDE application icon,
  2048 option -p DIR installs standalone binaries;
  2049 
  2050 * added ML_PLATFORM setting (useful for cross-platform installations);
  2051 more robust handling of platform specific ML images for SML/NJ;
  2052 
  2053 * the settings environment is now statically scoped, i.e. it is never
  2054 created again in sub-processes invoked from isabelle, isatool, or
  2055 Isabelle;
  2056 
  2057 * path element specification '~~' refers to '$ISABELLE_HOME';
  2058 
  2059 * in locales, the "assumes" and "defines" parts may be omitted if
  2060 empty;
  2061 
  2062 * new print_mode "xsymbols" for extended symbol support (e.g. genuine
  2063 long arrows);
  2064 
  2065 * new print_mode "HTML";
  2066 
  2067 * new flag show_tags controls display of tags of theorems (which are
  2068 basically just comments that may be attached by some tools);
  2069 
  2070 * Isamode 2.6 requires patch to accomodate change of Isabelle font
  2071 mode and goal output format:
  2072 
  2073 diff -r Isamode-2.6/elisp/isa-load.el Isamode/elisp/isa-load.el
  2074 244c244
  2075 <       (list (isa-getenv "ISABELLE") "-msymbols" logic-name)
  2076 ---
  2077 >       (list (isa-getenv "ISABELLE") "-misabelle_font" "-msymbols" logic-name)
  2078 diff -r Isabelle-2.6/elisp/isa-proofstate.el Isamode/elisp/isa-proofstate.el
  2079 181c181
  2080 < (defconst proofstate-proofstart-regexp "^Level [0-9]+$"
  2081 ---
  2082 > (defconst proofstate-proofstart-regexp "^Level [0-9]+"
  2083 
  2084 * function bind_thms stores lists of theorems (cf. bind_thm);
  2085 
  2086 * new shorthand tactics ftac, eatac, datac, fatac;
  2087 
  2088 * qed (and friends) now accept "" as result name; in that case the
  2089 theorem is not stored, but proper checks and presentation of the
  2090 result still apply;
  2091 
  2092 * theorem database now also indexes constants "Trueprop", "all",
  2093 "==>", "=="; thus thms_containing, findI etc. may retrieve more rules;
  2094 
  2095 
  2096 *** HOL ***
  2097 
  2098 ** HOL arithmetic **
  2099 
  2100 * There are now decision procedures for linear arithmetic over nat and
  2101 int:
  2102 
  2103 1. arith_tac copes with arbitrary formulae involving `=', `<', `<=',
  2104 `+', `-', `Suc', `min', `max' and numerical constants; other subterms
  2105 are treated as atomic; subformulae not involving type `nat' or `int'
  2106 are ignored; quantified subformulae are ignored unless they are
  2107 positive universal or negative existential. The tactic has to be
  2108 invoked by hand and can be a little bit slow. In particular, the
  2109 running time is exponential in the number of occurrences of `min' and
  2110 `max', and `-' on `nat'.
  2111 
  2112 2. fast_arith_tac is a cut-down version of arith_tac: it only takes
  2113 (negated) (in)equalities among the premises and the conclusion into
  2114 account (i.e. no compound formulae) and does not know about `min' and
  2115 `max', and `-' on `nat'. It is fast and is used automatically by the
  2116 simplifier.
  2117 
  2118 NB: At the moment, these decision procedures do not cope with mixed
  2119 nat/int formulae where the two parts interact, such as `m < n ==>
  2120 int(m) < int(n)'.
  2121 
  2122 * HOL/Numeral provides a generic theory of numerals (encoded
  2123 efficiently as bit strings); setup for types nat/int/real is in place;
  2124 INCOMPATIBILITY: since numeral syntax is now polymorphic, rather than
  2125 int, existing theories and proof scripts may require a few additional
  2126 type constraints;
  2127 
  2128 * integer division and remainder can now be performed on constant
  2129 arguments;
  2130 
  2131 * many properties of integer multiplication, division and remainder
  2132 are now available;
  2133 
  2134 * An interface to the Stanford Validity Checker (SVC) is available through the
  2135 tactic svc_tac.  Propositional tautologies and theorems of linear arithmetic
  2136 are proved automatically.  SVC must be installed separately, and its results
  2137 must be TAKEN ON TRUST (Isabelle does not check the proofs, but tags any
  2138 invocation of the underlying oracle).  For SVC see
  2139   http://verify.stanford.edu/SVC
  2140 
  2141 * IsaMakefile: the HOL-Real target now builds an actual image;
  2142 
  2143 
  2144 ** HOL misc **
  2145 
  2146 * HOL/Real/HahnBanach: the Hahn-Banach theorem for real vector spaces
  2147 (in Isabelle/Isar) -- by Gertrud Bauer;
  2148 
  2149 * HOL/BCV: generic model of bytecode verification, i.e. data-flow
  2150 analysis for assembly languages with subtypes;
  2151 
  2152 * HOL/TLA (Lamport's Temporal Logic of Actions): major reorganization
  2153 -- avoids syntactic ambiguities and treats state, transition, and
  2154 temporal levels more uniformly; introduces INCOMPATIBILITIES due to
  2155 changed syntax and (many) tactics;
  2156 
  2157 * HOL/inductive: Now also handles more general introduction rules such
  2158   as "ALL y. (y, x) : r --> y : acc r ==> x : acc r"; monotonicity
  2159   theorems are now maintained within the theory (maintained via the
  2160   "mono" attribute);
  2161 
  2162 * HOL/datatype: Now also handles arbitrarily branching datatypes
  2163   (using function types) such as
  2164 
  2165   datatype 'a tree = Atom 'a | Branch "nat => 'a tree"
  2166 
  2167 * HOL/record: record_simproc (part of the default simpset) takes care
  2168 of selectors applied to updated records; record_split_tac is no longer
  2169 part of the default claset; update_defs may now be removed from the
  2170 simpset in many cases; COMPATIBILITY: old behavior achieved by
  2171 
  2172   claset_ref () := claset() addSWrapper record_split_wrapper;
  2173   Delsimprocs [record_simproc]
  2174 
  2175 * HOL/typedef: fixed type inference for representing set; type
  2176 arguments now have to occur explicitly on the rhs as type constraints;
  2177 
  2178 * HOL/recdef (TFL): 'congs' syntax now expects comma separated list of theorem
  2179 names rather than an ML expression;
  2180 
  2181 * HOL/defer_recdef (TFL): like recdef but the well-founded relation can be
  2182 supplied later.  Program schemes can be defined, such as
  2183     "While B C s = (if B s then While B C (C s) else s)"
  2184 where the well-founded relation can be chosen after B and C have been given.
  2185 
  2186 * HOL/List: the constructors of type list are now Nil and Cons;
  2187 INCOMPATIBILITY: while [] and infix # syntax is still there, of
  2188 course, ML tools referring to List.list.op # etc. have to be adapted;
  2189 
  2190 * HOL_quantifiers flag superseded by "HOL" print mode, which is
  2191 disabled by default; run isabelle with option -m HOL to get back to
  2192 the original Gordon/HOL-style output;
  2193 
  2194 * HOL/Ord.thy: new bounded quantifier syntax (input only): ALL x<y. P,
  2195 ALL x<=y. P, EX x<y. P, EX x<=y. P;
  2196 
  2197 * HOL basic syntax simplified (more orthogonal): all variants of
  2198 All/Ex now support plain / symbolic / HOL notation; plain syntax for
  2199 Eps operator is provided as well: "SOME x. P[x]";
  2200 
  2201 * HOL/Sum.thy: sum_case has been moved to HOL/Datatype;
  2202 
  2203 * HOL/Univ.thy: infix syntax <*>, <+>, <**>, <+> eliminated and made
  2204 thus available for user theories;
  2205 
  2206 * HOLCF/IOA/Sequents: renamed 'Cons' to 'Consq' to avoid clash with
  2207 HOL/List; hardly an INCOMPATIBILITY since '>>' syntax is used all the
  2208 time;
  2209 
  2210 * HOL: new tactic smp_tac: int -> int -> tactic, which applies spec
  2211 several times and then mp;
  2212 
  2213 
  2214 *** LK ***
  2215 
  2216 * the notation <<...>> is now available as a notation for sequences of
  2217 formulas;
  2218 
  2219 * the simplifier is now installed
  2220 
  2221 * the axiom system has been generalized (thanks to Soren Heilmann)
  2222 
  2223 * the classical reasoner now has a default rule database
  2224 
  2225 
  2226 *** ZF ***
  2227 
  2228 * new primrec section allows primitive recursive functions to be given
  2229 directly (as in HOL) over datatypes and the natural numbers;
  2230 
  2231 * new tactics induct_tac and exhaust_tac for induction (or case
  2232 analysis) over datatypes and the natural numbers;
  2233 
  2234 * the datatype declaration of type T now defines the recursor T_rec;
  2235 
  2236 * simplification automatically does freeness reasoning for datatype
  2237 constructors;
  2238 
  2239 * automatic type-inference, with AddTCs command to insert new
  2240 type-checking rules;
  2241 
  2242 * datatype introduction rules are now added as Safe Introduction rules
  2243 to the claset;
  2244 
  2245 * the syntax "if P then x else y" is now available in addition to
  2246 if(P,x,y);
  2247 
  2248 
  2249 *** Internal programming interfaces ***
  2250 
  2251 * tuned simplifier trace output; new flag debug_simp;
  2252 
  2253 * structures Vartab / Termtab (instances of TableFun) offer efficient
  2254 tables indexed by indexname_ord / term_ord (compatible with aconv);
  2255 
  2256 * AxClass.axclass_tac lost the theory argument;
  2257 
  2258 * tuned current_goals_markers semantics: begin / end goal avoids
  2259 printing empty lines;
  2260 
  2261 * removed prs and prs_fn hook, which was broken because it did not
  2262 include \n in its semantics, forcing writeln to add one
  2263 uncoditionally; replaced prs_fn by writeln_fn; consider std_output:
  2264 string -> unit if you really want to output text without newline;
  2265 
  2266 * Symbol.output subject to print mode; INCOMPATIBILITY: defaults to
  2267 plain output, interface builders may have to enable 'isabelle_font'
  2268 mode to get Isabelle font glyphs as before;
  2269 
  2270 * refined token_translation interface; INCOMPATIBILITY: output length
  2271 now of type real instead of int;
  2272 
  2273 * theory loader actions may be traced via new ThyInfo.add_hook
  2274 interface (see src/Pure/Thy/thy_info.ML); example application: keep
  2275 your own database of information attached to *whole* theories -- as
  2276 opposed to intra-theory data slots offered via TheoryDataFun;
  2277 
  2278 * proper handling of dangling sort hypotheses (at last!);
  2279 Thm.strip_shyps and Drule.strip_shyps_warning take care of removing
  2280 extra sort hypotheses that can be witnessed from the type signature;
  2281 the force_strip_shyps flag is gone, any remaining shyps are simply
  2282 left in the theorem (with a warning issued by strip_shyps_warning);
  2283 
  2284 
  2285 
  2286 New in Isabelle98-1 (October 1998)
  2287 ----------------------------------
  2288 
  2289 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  2290 
  2291 * several changes of automated proof tools;
  2292 
  2293 * HOL: major changes to the inductive and datatype packages, including
  2294 some minor incompatibilities of theory syntax;
  2295 
  2296 * HOL: renamed r^-1 to 'converse' from 'inverse'; 'inj_onto' is now
  2297 called `inj_on';
  2298 
  2299 * HOL: removed duplicate thms in Arith:
  2300   less_imp_add_less  should be replaced by  trans_less_add1
  2301   le_imp_add_le      should be replaced by  trans_le_add1
  2302 
  2303 * HOL: unary minus is now overloaded (new type constraints may be
  2304 required);
  2305 
  2306 * HOL and ZF: unary minus for integers is now #- instead of #~.  In
  2307 ZF, expressions such as n#-1 must be changed to n#- 1, since #-1 is
  2308 now taken as an integer constant.
  2309 
  2310 * Pure: ML function 'theory_of' renamed to 'theory';
  2311 
  2312 
  2313 *** Proof tools ***
  2314 
  2315 * Simplifier:
  2316   1. Asm_full_simp_tac is now more aggressive.
  2317      1. It will sometimes reorient premises if that increases their power to
  2318         simplify.
  2319      2. It does no longer proceed strictly from left to right but may also
  2320         rotate premises to achieve further simplification.
  2321      For compatibility reasons there is now Asm_lr_simp_tac which is like the
  2322      old Asm_full_simp_tac in that it does not rotate premises.
  2323   2. The simplifier now knows a little bit about nat-arithmetic.
  2324 
  2325 * Classical reasoner: wrapper mechanism for the classical reasoner now
  2326 allows for selected deletion of wrappers, by introduction of names for
  2327 wrapper functionals.  This implies that addbefore, addSbefore,
  2328 addaltern, and addSaltern now take a pair (name, tactic) as argument,
  2329 and that adding two tactics with the same name overwrites the first
  2330 one (emitting a warning).
  2331   type wrapper = (int -> tactic) -> (int -> tactic)
  2332   setWrapper, setSWrapper, compWrapper and compSWrapper are replaced by
  2333   addWrapper, addSWrapper: claset * (string * wrapper) -> claset
  2334   delWrapper, delSWrapper: claset *  string            -> claset
  2335   getWrapper is renamed to appWrappers, getSWrapper to appSWrappers;
  2336 
  2337 * Classical reasoner: addbefore/addSbefore now have APPEND/ORELSE
  2338 semantics; addbefore now affects only the unsafe part of step_tac
  2339 etc.; this affects addss/auto_tac/force_tac, so EXISTING PROOFS MAY
  2340 FAIL, but proofs should be fixable easily, e.g. by replacing Auto_tac
  2341 by Force_tac;
  2342 
  2343 * Classical reasoner: setwrapper to setWrapper and compwrapper to
  2344 compWrapper; added safe wrapper (and access functions for it);
  2345 
  2346 * HOL/split_all_tac is now much faster and fails if there is nothing
  2347 to split.  Some EXISTING PROOFS MAY REQUIRE ADAPTION because the order
  2348 and the names of the automatically generated variables have changed.
  2349 split_all_tac has moved within claset() from unsafe wrappers to safe
  2350 wrappers, which means that !!-bound variables are split much more
  2351 aggressively, and safe_tac and clarify_tac now split such variables.
  2352 If this splitting is not appropriate, use delSWrapper "split_all_tac".
  2353 Note: the same holds for record_split_tac, which does the job of
  2354 split_all_tac for record fields.
  2355 
  2356 * HOL/Simplifier: Rewrite rules for case distinctions can now be added
  2357 permanently to the default simpset using Addsplits just like
  2358 Addsimps. They can be removed via Delsplits just like
  2359 Delsimps. Lower-case versions are also available.
  2360 
  2361 * HOL/Simplifier: The rule split_if is now part of the default
  2362 simpset. This means that the simplifier will eliminate all occurrences
  2363 of if-then-else in the conclusion of a goal. To prevent this, you can
  2364 either remove split_if completely from the default simpset by
  2365 `Delsplits [split_if]' or remove it in a specific call of the
  2366 simplifier using `... delsplits [split_if]'.  You can also add/delete
  2367 other case splitting rules to/from the default simpset: every datatype
  2368 generates suitable rules `split_t_case' and `split_t_case_asm' (where
  2369 t is the name of the datatype).
  2370 
  2371 * Classical reasoner / Simplifier combination: new force_tac (and
  2372 derivatives Force_tac, force) combines rewriting and classical
  2373 reasoning (and whatever other tools) similarly to auto_tac, but is
  2374 aimed to solve the given subgoal completely.
  2375 
  2376 
  2377 *** General ***
  2378 
  2379 * new top-level commands `Goal' and `Goalw' that improve upon `goal'
  2380 and `goalw': the theory is no longer needed as an explicit argument -
  2381 the current theory context is used; assumptions are no longer returned
  2382 at the ML-level unless one of them starts with ==> or !!; it is
  2383 recommended to convert to these new commands using isatool fixgoal
  2384 (backup your sources first!);
  2385 
  2386 * new top-level commands 'thm' and 'thms' for retrieving theorems from
  2387 the current theory context, and 'theory' to lookup stored theories;
  2388 
  2389 * new theory section 'locale' for declaring constants, assumptions and
  2390 definitions that have local scope;
  2391 
  2392 * new theory section 'nonterminals' for purely syntactic types;
  2393 
  2394 * new theory section 'setup' for generic ML setup functions
  2395 (e.g. package initialization);
  2396 
  2397 * the distribution now includes Isabelle icons: see
  2398 lib/logo/isabelle-{small,tiny}.xpm;
  2399 
  2400 * isatool install - install binaries with absolute references to
  2401 ISABELLE_HOME/bin;
  2402 
  2403 * isatool logo -- create instances of the Isabelle logo (as EPS);
  2404 
  2405 * print mode 'emacs' reserved for Isamode;
  2406 
  2407 * support multiple print (ast) translations per constant name;
  2408 
  2409 * theorems involving oracles are now printed with a suffixed [!];
  2410 
  2411 
  2412 *** HOL ***
  2413 
  2414 * there is now a tutorial on Isabelle/HOL (do 'isatool doc tutorial');
  2415 
  2416 * HOL/inductive package reorganized and improved: now supports mutual
  2417 definitions such as
  2418 
  2419   inductive EVEN ODD
  2420     intrs
  2421       null "0 : EVEN"
  2422       oddI "n : EVEN ==> Suc n : ODD"
  2423       evenI "n : ODD ==> Suc n : EVEN"
  2424 
  2425 new theorem list "elims" contains an elimination rule for each of the
  2426 recursive sets; inductive definitions now handle disjunctive premises
  2427 correctly (also ZF);
  2428 
  2429 INCOMPATIBILITIES: requires Inductive as an ancestor; component
  2430 "mutual_induct" no longer exists - the induction rule is always
  2431 contained in "induct";
  2432 
  2433 
  2434 * HOL/datatype package re-implemented and greatly improved: now
  2435 supports mutually recursive datatypes such as
  2436 
  2437   datatype
  2438     'a aexp = IF_THEN_ELSE ('a bexp) ('a aexp) ('a aexp)
  2439             | SUM ('a aexp) ('a aexp)
  2440             | DIFF ('a aexp) ('a aexp)
  2441             | NUM 'a
  2442   and
  2443     'a bexp = LESS ('a aexp) ('a aexp)
  2444             | AND ('a bexp) ('a bexp)
  2445             | OR ('a bexp) ('a bexp)
  2446 
  2447 as well as indirectly recursive datatypes such as
  2448 
  2449   datatype
  2450     ('a, 'b) term = Var 'a
  2451                   | App 'b ((('a, 'b) term) list)
  2452 
  2453 The new tactic  mutual_induct_tac [<var_1>, ..., <var_n>] i  performs
  2454 induction on mutually / indirectly recursive datatypes.
  2455 
  2456 Primrec equations are now stored in theory and can be accessed via
  2457 <function_name>.simps.
  2458 
  2459 INCOMPATIBILITIES:
  2460 
  2461   - Theories using datatypes must now have theory Datatype as an
  2462     ancestor.
  2463   - The specific <typename>.induct_tac no longer exists - use the
  2464     generic induct_tac instead.
  2465   - natE has been renamed to nat.exhaust - use exhaust_tac
  2466     instead of res_inst_tac ... natE. Note that the variable
  2467     names in nat.exhaust differ from the names in natE, this
  2468     may cause some "fragile" proofs to fail.
  2469   - The theorems split_<typename>_case and split_<typename>_case_asm
  2470     have been renamed to <typename>.split and <typename>.split_asm.
  2471   - Since default sorts of type variables are now handled correctly,
  2472     some datatype definitions may have to be annotated with explicit
  2473     sort constraints.
  2474   - Primrec definitions no longer require function name and type
  2475     of recursive argument.
  2476 
  2477 Consider using isatool fixdatatype to adapt your theories and proof
  2478 scripts to the new package (backup your sources first!).
  2479 
  2480 
  2481 * HOL/record package: considerably improved implementation; now
  2482 includes concrete syntax for record types, terms, updates; theorems
  2483 for surjective pairing and splitting !!-bound record variables; proof
  2484 support is as follows:
  2485 
  2486   1) standard conversions (selectors or updates applied to record
  2487 constructor terms) are part of the standard simpset;
  2488 
  2489   2) inject equations of the form ((x, y) = (x', y')) == x=x' & y=y' are
  2490 made part of standard simpset and claset via addIffs;
  2491 
  2492   3) a tactic for record field splitting (record_split_tac) is part of
  2493 the standard claset (addSWrapper);
  2494 
  2495 To get a better idea about these rules you may retrieve them via
  2496 something like 'thms "foo.simps"' or 'thms "foo.iffs"', where "foo" is
  2497 the name of your record type.
  2498 
  2499 The split tactic 3) conceptually simplifies by the following rule:
  2500 
  2501   "(!!x. PROP ?P x) == (!!a b. PROP ?P (a, b))"
  2502 
  2503 Thus any record variable that is bound by meta-all will automatically
  2504 blow up into some record constructor term, consequently the
  2505 simplifications of 1), 2) apply.  Thus force_tac, auto_tac etc. shall
  2506 solve record problems automatically.
  2507 
  2508 
  2509 * reorganized the main HOL image: HOL/Integ and String loaded by
  2510 default; theory Main includes everything;
  2511 
  2512 * automatic simplification of integer sums and comparisons, using cancellation;
  2513 
  2514 * added option_map_eq_Some and not_Some_eq to the default simpset and claset;
  2515 
  2516 * added disj_not1 = "(~P | Q) = (P --> Q)" to the default simpset;
  2517 
  2518 * many new identities for unions, intersections, set difference, etc.;
  2519 
  2520 * expand_if, expand_split, expand_sum_case and expand_nat_case are now
  2521 called split_if, split_split, split_sum_case and split_nat_case (to go
  2522 with add/delsplits);
  2523 
  2524 * HOL/Prod introduces simplification procedure unit_eq_proc rewriting
  2525 (?x::unit) = (); this is made part of the default simpset, which COULD
  2526 MAKE EXISTING PROOFS FAIL under rare circumstances (consider
  2527 'Delsimprocs [unit_eq_proc];' as last resort); also note that
  2528 unit_abs_eta_conv is added in order to counter the effect of
  2529 unit_eq_proc on (%u::unit. f u), replacing it by f rather than by
  2530 %u.f();
  2531 
  2532 * HOL/Fun INCOMPATIBILITY: `inj_onto' is now called `inj_on' (which
  2533 makes more sense);
  2534 
  2535 * HOL/Set INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
  2536   It and 'sym RS equals0D' are now in the default  claset, giving automatic
  2537   disjointness reasoning but breaking a few old proofs.
  2538 
  2539 * HOL/Relation INCOMPATIBILITY: renamed the relational operator r^-1
  2540 to 'converse' from 'inverse' (for compatibility with ZF and some
  2541 literature);
  2542 
  2543 * HOL/recdef can now declare non-recursive functions, with {} supplied as
  2544 the well-founded relation;
  2545 
  2546 * HOL/Set INCOMPATIBILITY: the complement of set A is now written -A instead of
  2547     Compl A.  The "Compl" syntax remains available as input syntax for this
  2548     release ONLY.
  2549 
  2550 * HOL/Update: new theory of function updates:
  2551     f(a:=b) == %x. if x=a then b else f x
  2552 may also be iterated as in f(a:=b,c:=d,...);
  2553 
  2554 * HOL/Vimage: new theory for inverse image of a function, syntax f-``B;
  2555 
  2556 * HOL/List:
  2557   - new function list_update written xs[i:=v] that updates the i-th
  2558     list position. May also be iterated as in xs[i:=a,j:=b,...].
  2559   - new function `upt' written [i..j(] which generates the list
  2560     [i,i+1,...,j-1], i.e. the upper bound is excluded. To include the upper
  2561     bound write [i..j], which is a shorthand for [i..j+1(].
  2562   - new lexicographic orderings and corresponding wellfoundedness theorems.
  2563 
  2564 * HOL/Arith:
  2565   - removed 'pred' (predecessor) function;
  2566   - generalized some theorems about n-1;
  2567   - many new laws about "div" and "mod";
  2568   - new laws about greatest common divisors (see theory ex/Primes);
  2569 
  2570 * HOL/Relation: renamed the relational operator r^-1 "converse"
  2571 instead of "inverse";
  2572 
  2573 * HOL/Induct/Multiset: a theory of multisets, including the wellfoundedness
  2574   of the multiset ordering;
  2575 
  2576 * directory HOL/Real: a construction of the reals using Dedekind cuts
  2577   (not included by default);
  2578 
  2579 * directory HOL/UNITY: Chandy and Misra's UNITY formalism;
  2580 
  2581 * directory HOL/Hoare: a new version of Hoare logic which permits many-sorted
  2582   programs, i.e. different program variables may have different types.
  2583 
  2584 * calling (stac rew i) now fails if "rew" has no effect on the goal
  2585   [previously, this check worked only if the rewrite rule was unconditional]
  2586   Now rew can involve either definitions or equalities (either == or =).
  2587 
  2588 
  2589 *** ZF ***
  2590 
  2591 * theory Main includes everything; INCOMPATIBILITY: theory ZF.thy contains
  2592   only the theorems proved on ZF.ML;
  2593 
  2594 * ZF INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
  2595   It and 'sym RS equals0D' are now in the default  claset, giving automatic
  2596   disjointness reasoning but breaking a few old proofs.
  2597 
  2598 * ZF/Update: new theory of function updates
  2599     with default rewrite rule  f(x:=y) ` z = if(z=x, y, f`z)
  2600   may also be iterated as in f(a:=b,c:=d,...);
  2601 
  2602 * in  let x=t in u(x), neither t nor u(x) has to be an FOL term.
  2603 
  2604 * calling (stac rew i) now fails if "rew" has no effect on the goal
  2605   [previously, this check worked only if the rewrite rule was unconditional]
  2606   Now rew can involve either definitions or equalities (either == or =).
  2607 
  2608 * case_tac provided for compatibility with HOL
  2609     (like the old excluded_middle_tac, but with subgoals swapped)
  2610 
  2611 
  2612 *** Internal programming interfaces ***
  2613 
  2614 * Pure: several new basic modules made available for general use, see
  2615 also src/Pure/README;
  2616 
  2617 * improved the theory data mechanism to support encapsulation (data
  2618 kind name replaced by private Object.kind, acting as authorization
  2619 key); new type-safe user interface via functor TheoryDataFun; generic
  2620 print_data function becomes basically useless;
  2621 
  2622 * removed global_names compatibility flag -- all theory declarations
  2623 are qualified by default;
  2624 
  2625 * module Pure/Syntax now offers quote / antiquote translation
  2626 functions (useful for Hoare logic etc. with implicit dependencies);
  2627 see HOL/ex/Antiquote for an example use;
  2628 
  2629 * Simplifier now offers conversions (asm_)(full_)rewrite: simpset ->
  2630 cterm -> thm;
  2631 
  2632 * new tactical CHANGED_GOAL for checking that a tactic modifies a
  2633 subgoal;
  2634 
  2635 * Display.print_goals function moved to Locale.print_goals;
  2636 
  2637 * standard print function for goals supports current_goals_markers
  2638 variable for marking begin of proof, end of proof, start of goal; the
  2639 default is ("", "", ""); setting current_goals_markers := ("<proof>",
  2640 "</proof>", "<goal>") causes SGML like tagged proof state printing,
  2641 for example;
  2642 
  2643 
  2644 
  2645 New in Isabelle98 (January 1998)
  2646 --------------------------------
  2647 
  2648 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  2649 
  2650 * changed lexical syntax of terms / types: dots made part of long
  2651 identifiers, e.g. "%x.x" no longer possible, should be "%x. x";
  2652 
  2653 * simpset (and claset) reference variable replaced by functions
  2654 simpset / simpset_ref;
  2655 
  2656 * no longer supports theory aliases (via merge) and non-trivial
  2657 implicit merge of thms' signatures;
  2658 
  2659 * most internal names of constants changed due to qualified names;
  2660 
  2661 * changed Pure/Sequence interface (see Pure/seq.ML);
  2662 
  2663 
  2664 *** General Changes ***
  2665 
  2666 * hierachically structured name spaces (for consts, types, axms, thms
  2667 etc.); new lexical class 'longid' (e.g. Foo.bar.x) may render much of
  2668 old input syntactically incorrect (e.g. "%x.x"); COMPATIBILITY:
  2669 isatool fixdots ensures space after dots (e.g. "%x. x"); set
  2670 long_names for fully qualified output names; NOTE: ML programs
  2671 (special tactics, packages etc.) referring to internal names may have
  2672 to be adapted to cope with fully qualified names; in case of severe
  2673 backward campatibility problems try setting 'global_names' at compile
  2674 time to have enrything declared within a flat name space; one may also
  2675 fine tune name declarations in theories via the 'global' and 'local'
  2676 section;
  2677 
  2678 * reimplemented the implicit simpset and claset using the new anytype
  2679 data filed in signatures; references simpset:simpset ref etc. are
  2680 replaced by functions simpset:unit->simpset and
  2681 simpset_ref:unit->simpset ref; COMPATIBILITY: use isatool fixclasimp
  2682 to patch your ML files accordingly;
  2683 
  2684 * HTML output now includes theory graph data for display with Java
  2685 applet or isatool browser; data generated automatically via isatool
  2686 usedir (see -i option, ISABELLE_USEDIR_OPTIONS);
  2687 
  2688 * defs may now be conditional; improved rewrite_goals_tac to handle
  2689 conditional equations;
  2690 
  2691 * defs now admits additional type arguments, using TYPE('a) syntax;
  2692 
  2693 * theory aliases via merge (e.g. M=A+B+C) no longer supported, always
  2694 creates a new theory node; implicit merge of thms' signatures is
  2695 restricted to 'trivial' ones; COMPATIBILITY: one may have to use
  2696 transfer:theory->thm->thm in (rare) cases;
  2697 
  2698 * improved handling of draft signatures / theories; draft thms (and
  2699 ctyps, cterms) are automatically promoted to real ones;
  2700 
  2701 * slightly changed interfaces for oracles: admit many per theory, named
  2702 (e.g. oracle foo = mlfun), additional name argument for invoke_oracle;
  2703 
  2704 * print_goals: optional output of const types (set show_consts and
  2705 show_types);
  2706 
  2707 * improved output of warnings (###) and errors (***);
  2708 
  2709 * subgoal_tac displays a warning if the new subgoal has type variables;
  2710 
  2711 * removed old README and Makefiles;
  2712 
  2713 * replaced print_goals_ref hook by print_current_goals_fn and result_error_fn;
  2714 
  2715 * removed obsolete init_pps and init_database;
  2716 
  2717 * deleted the obsolete tactical STATE, which was declared by
  2718     fun STATE tacfun st = tacfun st st;
  2719 
  2720 * cd and use now support path variables, e.g. $ISABELLE_HOME, or ~
  2721 (which abbreviates $HOME);
  2722 
  2723 * changed Pure/Sequence interface (see Pure/seq.ML); COMPATIBILITY:
  2724 use isatool fixseq to adapt your ML programs (this works for fully
  2725 qualified references to the Sequence structure only!);
  2726 
  2727 * use_thy no longer requires writable current directory; it always
  2728 reloads .ML *and* .thy file, if either one is out of date;
  2729 
  2730 
  2731 *** Classical Reasoner ***
  2732 
  2733 * Clarify_tac, clarify_tac, clarify_step_tac, Clarify_step_tac: new
  2734 tactics that use classical reasoning to simplify a subgoal without
  2735 splitting it into several subgoals;
  2736 
  2737 * Safe_tac: like safe_tac but uses the default claset;
  2738 
  2739 
  2740 *** Simplifier ***
  2741 
  2742 * added simplification meta rules:
  2743     (asm_)(full_)simplify: simpset -> thm -> thm;
  2744 
  2745 * simplifier.ML no longer part of Pure -- has to be loaded by object
  2746 logics (again);
  2747 
  2748 * added prems argument to simplification procedures;
  2749 
  2750 * HOL, FOL, ZF: added infix function `addsplits':
  2751   instead of `<simpset> setloop (split_tac <thms>)'
  2752   you can simply write `<simpset> addsplits <thms>'
  2753 
  2754 
  2755 *** Syntax ***
  2756 
  2757 * TYPE('a) syntax for type reflection terms;
  2758 
  2759 * no longer handles consts with name "" -- declare as 'syntax' instead;
  2760 
  2761 * pretty printer: changed order of mixfix annotation preference (again!);
  2762 
  2763 * Pure: fixed idt/idts vs. pttrn/pttrns syntactic categories;
  2764 
  2765 
  2766 *** HOL ***
  2767 
  2768 * HOL: there is a new splitter `split_asm_tac' that can be used e.g.
  2769   with `addloop' of the simplifier to faciliate case splitting in premises.
  2770 
  2771 * HOL/TLA: Stephan Merz's formalization of Lamport's Temporal Logic of Actions;
  2772 
  2773 * HOL/Auth: new protocol proofs including some for the Internet
  2774   protocol TLS;
  2775 
  2776 * HOL/Map: new theory of `maps' a la VDM;
  2777 
  2778 * HOL/simplifier: simplification procedures nat_cancel_sums for
  2779 cancelling out common nat summands from =, <, <= (in)equalities, or
  2780 differences; simplification procedures nat_cancel_factor for
  2781 cancelling common factor from =, <, <= (in)equalities over natural
  2782 sums; nat_cancel contains both kinds of procedures, it is installed by
  2783 default in Arith.thy -- this COULD MAKE EXISTING PROOFS FAIL;
  2784 
  2785 * HOL/simplifier: terms of the form
  2786   `? x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x)'  (or t=x)
  2787   are rewritten to
  2788   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t)',
  2789   and those of the form
  2790   `! x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x) --> R(x)'  (or t=x)
  2791   are rewritten to
  2792   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t) --> R(t)',
  2793 
  2794 * HOL/datatype
  2795   Each datatype `t' now comes with a theorem `split_t_case' of the form
  2796 
  2797   P(t_case f1 ... fn x) =
  2798      ( (!y1 ... ym1. x = C1 y1 ... ym1 --> P(f1 y1 ... ym1)) &
  2799         ...
  2800        (!y1 ... ymn. x = Cn y1 ... ymn --> P(f1 y1 ... ymn))
  2801      )
  2802 
  2803   and a theorem `split_t_case_asm' of the form
  2804 
  2805   P(t_case f1 ... fn x) =
  2806     ~( (? y1 ... ym1. x = C1 y1 ... ym1 & ~P(f1 y1 ... ym1)) |
  2807         ...
  2808        (? y1 ... ymn. x = Cn y1 ... ymn & ~P(f1 y1 ... ymn))
  2809      )
  2810   which can be added to a simpset via `addsplits'. The existing theorems
  2811   expand_list_case and expand_option_case have been renamed to
  2812   split_list_case and split_option_case.
  2813 
  2814 * HOL/Arithmetic:
  2815   - `pred n' is automatically converted to `n-1'.
  2816     Users are strongly encouraged not to use `pred' any longer,
  2817     because it will disappear altogether at some point.
  2818   - Users are strongly encouraged to write "0 < n" rather than
  2819     "n ~= 0". Theorems and proof tools have been modified towards this
  2820     `standard'.
  2821 
  2822 * HOL/Lists:
  2823   the function "set_of_list" has been renamed "set" (and its theorems too);
  2824   the function "nth" now takes its arguments in the reverse order and
  2825   has acquired the infix notation "!" as in "xs!n".
  2826 
  2827 * HOL/Set: UNIV is now a constant and is no longer translated to Compl{};
  2828 
  2829 * HOL/Set: The operator (UN x.B x) now abbreviates (UN x:UNIV. B x) and its
  2830   specialist theorems (like UN1_I) are gone.  Similarly for (INT x.B x);
  2831 
  2832 * HOL/record: extensible records with schematic structural subtyping
  2833 (single inheritance); EXPERIMENTAL version demonstrating the encoding,
  2834 still lacks various theorems and concrete record syntax;
  2835 
  2836 
  2837 *** HOLCF ***
  2838 
  2839 * removed "axioms" and "generated by" sections;
  2840 
  2841 * replaced "ops" section by extended "consts" section, which is capable of
  2842   handling the continuous function space "->" directly;
  2843 
  2844 * domain package:
  2845   . proves theorems immediately and stores them in the theory,
  2846   . creates hierachical name space,
  2847   . now uses normal mixfix annotations (instead of cinfix...),
  2848   . minor changes to some names and values (for consistency),
  2849   . e.g. cases -> casedist, dists_eq -> dist_eqs, [take_lemma] -> take_lemmas,
  2850   . separator between mutual domain defs: changed "," to "and",
  2851   . improved handling of sort constraints;  now they have to
  2852     appear on the left-hand side of the equations only;
  2853 
  2854 * fixed LAM <x,y,zs>.b syntax;
  2855 
  2856 * added extended adm_tac to simplifier in HOLCF -- can now discharge
  2857 adm (%x. P (t x)), where P is chainfinite and t continuous;
  2858 
  2859 
  2860 *** FOL and ZF ***
  2861 
  2862 * FOL: there is a new splitter `split_asm_tac' that can be used e.g.
  2863   with `addloop' of the simplifier to faciliate case splitting in premises.
  2864 
  2865 * qed_spec_mp, qed_goal_spec_mp, qed_goalw_spec_mp are available, as
  2866 in HOL, they strip ALL and --> from proved theorems;
  2867 
  2868 
  2869 
  2870 New in Isabelle94-8 (May 1997)
  2871 ------------------------------
  2872 
  2873 *** General Changes ***
  2874 
  2875 * new utilities to build / run / maintain Isabelle etc. (in parts
  2876 still somewhat experimental); old Makefiles etc. still functional;
  2877 
  2878 * new 'Isabelle System Manual';
  2879 
  2880 * INSTALL text, together with ./configure and ./build scripts;
  2881 
  2882 * reimplemented type inference for greater efficiency, better error
  2883 messages and clean internal interface;
  2884 
  2885 * prlim command for dealing with lots of subgoals (an easier way of
  2886 setting goals_limit);
  2887 
  2888 
  2889 *** Syntax ***
  2890 
  2891 * supports alternative (named) syntax tables (parser and pretty
  2892 printer); internal interface is provided by add_modesyntax(_i);
  2893 
  2894 * Pure, FOL, ZF, HOL, HOLCF now support symbolic input and output; to
  2895 be used in conjunction with the Isabelle symbol font; uses the
  2896 "symbols" syntax table;
  2897 
  2898 * added token_translation interface (may translate name tokens in
  2899 arbitrary ways, dependent on their type (free, bound, tfree, ...) and
  2900 the current print_mode); IMPORTANT: user print translation functions
  2901 are responsible for marking newly introduced bounds
  2902 (Syntax.mark_boundT);
  2903 
  2904 * token translations for modes "xterm" and "xterm_color" that display
  2905 names in bold, underline etc. or colors (which requires a color
  2906 version of xterm);
  2907 
  2908 * infixes may now be declared with names independent of their syntax;
  2909 
  2910 * added typed_print_translation (like print_translation, but may
  2911 access type of constant);
  2912 
  2913 
  2914 *** Classical Reasoner ***
  2915 
  2916 Blast_tac: a new tactic!  It is often more powerful than fast_tac, but has
  2917 some limitations.  Blast_tac...
  2918   + ignores addss, addbefore, addafter; this restriction is intrinsic
  2919   + ignores elimination rules that don't have the correct format
  2920         (the conclusion MUST be a formula variable)
  2921   + ignores types, which can make HOL proofs fail
  2922   + rules must not require higher-order unification, e.g. apply_type in ZF
  2923     [message "Function Var's argument not a bound variable" relates to this]
  2924   + its proof strategy is more general but can actually be slower
  2925 
  2926 * substitution with equality assumptions no longer permutes other
  2927 assumptions;
  2928 
  2929 * minor changes in semantics of addafter (now called addaltern); renamed
  2930 setwrapper to setWrapper and compwrapper to compWrapper; added safe wrapper
  2931 (and access functions for it);
  2932 
  2933 * improved combination of classical reasoner and simplifier:
  2934   + functions for handling clasimpsets
  2935   + improvement of addss: now the simplifier is called _after_ the
  2936     safe steps.
  2937   + safe variant of addss called addSss: uses safe simplifications
  2938     _during_ the safe steps. It is more complete as it allows multiple
  2939     instantiations of unknowns (e.g. with slow_tac).
  2940 
  2941 *** Simplifier ***
  2942 
  2943 * added interface for simplification procedures (functions that
  2944 produce *proven* rewrite rules on the fly, depending on current
  2945 redex);
  2946 
  2947 * ordering on terms as parameter (used for ordered rewriting);
  2948 
  2949 * new functions delcongs, deleqcongs, and Delcongs. richer rep_ss;
  2950 
  2951 * the solver is now split into a safe and an unsafe part.
  2952 This should be invisible for the normal user, except that the
  2953 functions setsolver and addsolver have been renamed to setSolver and
  2954 addSolver; added safe_asm_full_simp_tac;
  2955 
  2956 
  2957 *** HOL ***
  2958 
  2959 * a generic induction tactic `induct_tac' which works for all datatypes and
  2960 also for type `nat';
  2961 
  2962 * a generic case distinction tactic `exhaust_tac' which works for all
  2963 datatypes and also for type `nat';
  2964 
  2965 * each datatype comes with a function `size';
  2966 
  2967 * patterns in case expressions allow tuple patterns as arguments to
  2968 constructors, for example `case x of [] => ... | (x,y,z)#ps => ...';
  2969 
  2970 * primrec now also works with type nat;
  2971 
  2972 * recdef: a new declaration form, allows general recursive functions to be
  2973 defined in theory files.  See HOL/ex/Fib, HOL/ex/Primes, HOL/Subst/Unify.
  2974 
  2975 * the constant for negation has been renamed from "not" to "Not" to
  2976 harmonize with FOL, ZF, LK, etc.;
  2977 
  2978 * HOL/ex/LFilter theory of a corecursive "filter" functional for
  2979 infinite lists;
  2980 
  2981 * HOL/Modelcheck demonstrates invocation of model checker oracle;
  2982 
  2983 * HOL/ex/Ring.thy declares cring_simp, which solves equational
  2984 problems in commutative rings, using axiomatic type classes for + and *;
  2985 
  2986 * more examples in HOL/MiniML and HOL/Auth;
  2987 
  2988 * more default rewrite rules for quantifiers, union/intersection;
  2989 
  2990 * a new constant `arbitrary == @x.False';
  2991 
  2992 * HOLCF/IOA replaces old HOL/IOA;
  2993 
  2994 * HOLCF changes: derived all rules and arities
  2995   + axiomatic type classes instead of classes
  2996   + typedef instead of faking type definitions
  2997   + eliminated the internal constants less_fun, less_cfun, UU_fun, UU_cfun etc.
  2998   + new axclasses cpo, chfin, flat with flat < chfin < pcpo < cpo < po
  2999   + eliminated the types void, one, tr
  3000   + use unit lift and bool lift (with translations) instead of one and tr
  3001   + eliminated blift from Lift3.thy (use Def instead of blift)
  3002   all eliminated rules are derived as theorems --> no visible changes ;
  3003 
  3004 
  3005 *** ZF ***
  3006 
  3007 * ZF now has Fast_tac, Simp_tac and Auto_tac.  Union_iff is a now a default
  3008 rewrite rule; this may affect some proofs.  eq_cs is gone but can be put back
  3009 as ZF_cs addSIs [equalityI];
  3010 
  3011 
  3012 
  3013 New in Isabelle94-7 (November 96)
  3014 ---------------------------------
  3015 
  3016 * allowing negative levels (as offsets) in prlev and choplev;
  3017 
  3018 * super-linear speedup for large simplifications;
  3019 
  3020 * FOL, ZF and HOL now use miniscoping: rewriting pushes
  3021 quantifications in as far as possible (COULD MAKE EXISTING PROOFS
  3022 FAIL); can suppress it using the command Delsimps (ex_simps @
  3023 all_simps); De Morgan laws are also now included, by default;
  3024 
  3025 * improved printing of ==>  :  ~:
  3026 
  3027 * new object-logic "Sequents" adds linear logic, while replacing LK
  3028 and Modal (thanks to Sara Kalvala);
  3029 
  3030 * HOL/Auth: correctness proofs for authentication protocols;
  3031 
  3032 * HOL: new auto_tac combines rewriting and classical reasoning (many
  3033 examples on HOL/Auth);
  3034 
  3035 * HOL: new command AddIffs for declaring theorems of the form P=Q to
  3036 the rewriter and classical reasoner simultaneously;
  3037 
  3038 * function uresult no longer returns theorems in "standard" format;
  3039 regain previous version by: val uresult = standard o uresult;
  3040 
  3041 
  3042 
  3043 New in Isabelle94-6
  3044 -------------------
  3045 
  3046 * oracles -- these establish an interface between Isabelle and trusted
  3047 external reasoners, which may deliver results as theorems;
  3048 
  3049 * proof objects (in particular record all uses of oracles);
  3050 
  3051 * Simp_tac, Fast_tac, etc. that refer to implicit simpset / claset;
  3052 
  3053 * "constdefs" section in theory files;
  3054 
  3055 * "primrec" section (HOL) no longer requires names;
  3056 
  3057 * internal type "tactic" now simply "thm -> thm Sequence.seq";
  3058 
  3059 
  3060 
  3061 New in Isabelle94-5
  3062 -------------------
  3063 
  3064 * reduced space requirements;
  3065 
  3066 * automatic HTML generation from theories;
  3067 
  3068 * theory files no longer require "..." (quotes) around most types;
  3069 
  3070 * new examples, including two proofs of the Church-Rosser theorem;
  3071 
  3072 * non-curried (1994) version of HOL is no longer distributed;
  3073 
  3074 
  3075 
  3076 New in Isabelle94-4
  3077 -------------------
  3078 
  3079 * greatly reduced space requirements;
  3080 
  3081 * theory files (.thy) no longer require \...\ escapes at line breaks;
  3082 
  3083 * searchable theorem database (see the section "Retrieving theorems" on
  3084 page 8 of the Reference Manual);
  3085 
  3086 * new examples, including Grabczewski's monumental case study of the
  3087 Axiom of Choice;
  3088 
  3089 * The previous version of HOL renamed to Old_HOL;
  3090 
  3091 * The new version of HOL (previously called CHOL) uses a curried syntax
  3092 for functions.  Application looks like f a b instead of f(a,b);
  3093 
  3094 * Mutually recursive inductive definitions finally work in HOL;
  3095 
  3096 * In ZF, pattern-matching on tuples is now available in all abstractions and
  3097 translates to the operator "split";
  3098 
  3099 
  3100 
  3101 New in Isabelle94-3
  3102 -------------------
  3103 
  3104 * new infix operator, addss, allowing the classical reasoner to
  3105 perform simplification at each step of its search.  Example:
  3106         fast_tac (cs addss ss)
  3107 
  3108 * a new logic, CHOL, the same as HOL, but with a curried syntax
  3109 for functions.  Application looks like f a b instead of f(a,b).  Also pairs
  3110 look like (a,b) instead of <a,b>;
  3111 
  3112 * PLEASE NOTE: CHOL will eventually replace HOL!
  3113 
  3114 * In CHOL, pattern-matching on tuples is now available in all abstractions.
  3115 It translates to the operator "split".  A new theory of integers is available;
  3116 
  3117 * In ZF, integer numerals now denote two's-complement binary integers.
  3118 Arithmetic operations can be performed by rewriting.  See ZF/ex/Bin.ML;
  3119 
  3120 * Many new examples: I/O automata, Church-Rosser theorem, equivalents
  3121 of the Axiom of Choice;
  3122 
  3123 
  3124 
  3125 New in Isabelle94-2
  3126 -------------------
  3127 
  3128 * Significantly faster resolution;
  3129 
  3130 * the different sections in a .thy file can now be mixed and repeated
  3131 freely;
  3132 
  3133 * Database of theorems for FOL, HOL and ZF.  New
  3134 commands including qed, qed_goal and bind_thm store theorems in the database.
  3135 
  3136 * Simple database queries: return a named theorem (get_thm) or all theorems of
  3137 a given theory (thms_of), or find out what theory a theorem was proved in
  3138 (theory_of_thm);
  3139 
  3140 * Bugs fixed in the inductive definition and datatype packages;
  3141 
  3142 * The classical reasoner provides deepen_tac and depth_tac, making FOL_dup_cs
  3143 and HOL_dup_cs obsolete;
  3144 
  3145 * Syntactic ambiguities caused by the new treatment of syntax in Isabelle94-1
  3146 have been removed;
  3147 
  3148 * Simpler definition of function space in ZF;
  3149 
  3150 * new results about cardinal and ordinal arithmetic in ZF;
  3151 
  3152 * 'subtype' facility in HOL for introducing new types as subsets of existing
  3153 types;
  3154 
  3155 
  3156 $Id$