NEWS
author wenzelm
Fri Jul 01 14:55:05 2005 +0200 (2005-07-01)
changeset 16662 0836569a8ffc
parent 16563 a92f96951355
child 16689 05b986733a59
permissions -rw-r--r--
* Isar profiling: new reference Toplevel.profiling (default 0);
     1 Isabelle NEWS -- history user-relevant changes
     2 ==============================================
     3 
     4 New in this Isabelle release
     5 ----------------------------
     6 
     7 *** General ***
     8 
     9 * Theory headers: the new header syntax for Isar theories is
    10 
    11   theory <name>
    12   imports <theory1> ... <theoryN>
    13   uses <file1> ... <fileM>
    14   begin
    15 
    16 where the 'uses' part is optional.  The previous syntax
    17 
    18   theory <name> = <theory1> + ... + <theoryN>:
    19 
    20 will disappear in the next release.  Note that there is no change in
    21 ancient non-Isar theories.
    22 
    23 * Theory loader: parent theories can now also be referred to via
    24 relative and absolute paths.
    25 
    26 * Improved version of thms_containing searches for a list of criteria
    27 instead of a list of constants. Known criteria are: intro, elim, dest,
    28 name:string, simp:term, and any term. Criteria can be preceded by '-'
    29 to select theorems that do not match. Intro, elim, dest select
    30 theorems that match the current goal, name:s selects theorems whose
    31 fully qualified name contain s, and simp:term selects all
    32 simplification rules whose lhs match term.  Any other term is
    33 interpreted as pattern and selects all theorems matching the
    34 pattern. Available in ProofGeneral under 'ProofGeneral -> Find
    35 Theorems' or C-c C-f.  Example:
    36 
    37   C-c C-f (100) "(_::nat) + _ + _" intro -name:"HOL."
    38 
    39 prints the last 100 theorems matching the pattern "(_::nat) + _ + _",
    40 matching the current goal as introduction rule and not having "HOL."
    41 in their name (i.e. not being defined in theory HOL).
    42 
    43 
    44 *** Document preparation ***
    45 
    46 * Commands 'display_drafts' and 'print_drafts' perform simple output
    47 of raw sources.  Only those symbols that do not require additional
    48 LaTeX packages (depending on comments in isabellesym.sty) are
    49 displayed properly, everything else is left verbatim.  isatool display
    50 and isatool print are used as front ends (these are subject to the
    51 DVI/PDF_VIEWER and PRINT_COMMAND settings, respectively).
    52 
    53 * There is now a flag to control hiding of proofs and some other
    54 commands (such as 'ML' or 'parse/print_translation') in document
    55 output.  Hiding is enabled by default, and can be disabled by the
    56 option '-H false' of isatool usedir or by resetting the reference
    57 variable IsarOutput.hide_commands in ML.  Additional commands to be
    58 hidden may be declared using IsarOutput.add_hidden_commands.
    59 
    60 * Several new antiquotation:
    61 
    62   @{term_type term} prints a term with its type annotated;
    63 
    64   @{typeof term} prints the type of a term;
    65 
    66   @{const const} is the same as @{term const}, but checks that the
    67   argument is a known logical constant;
    68 
    69   @{term_style style term} and @{thm_style style thm} print a term or
    70   theorem applying a "style" to it
    71 
    72 Predefined styles are 'lhs' and 'rhs' printing the lhs/rhs of
    73 definitions, equations, inequations etc., 'concl' printing only the
    74 conclusion of a meta-logical statement theorem, and 'prem1' .. 'prem9'
    75 to print the specified premise.  TermStyle.add_style provides an ML
    76 interface for introducing further styles.  See also the "LaTeX Sugar"
    77 document practical applications.
    78 
    79 
    80 *** Pure ***
    81 
    82 * Considerably improved version of 'constdefs' command.  Now performs
    83 automatic type-inference of declared constants; additional support for
    84 local structure declarations (cf. locales and HOL records), see also
    85 isar-ref manual.  Potential INCOMPATIBILITY: need to observe strictly
    86 sequential dependencies of definitions within a single 'constdefs'
    87 section; moreover, the declared name needs to be an identifier.  If
    88 all fails, consider to fall back on 'consts' and 'defs' separately.
    89 
    90 * Improved indexed syntax and implicit structures.  First of all,
    91 indexed syntax provides a notational device for subscripted
    92 application, using the new syntax \<^bsub>term\<^esub> for arbitrary
    93 expressions.  Secondly, in a local context with structure
    94 declarations, number indexes \<^sub>n or the empty index (default
    95 number 1) refer to a certain fixed variable implicitly; option
    96 show_structs controls printing of implicit structures.  Typical
    97 applications of these concepts involve record types and locales.
    98 
    99 * New command 'no_syntax' removes grammar declarations (and
   100 translations) resulting from the given syntax specification, which is
   101 interpreted in the same manner as for the 'syntax' command.
   102 
   103 * 'Advanced' translation functions (parse_translation etc.) may depend
   104 on the signature of the theory context being presently used for
   105 parsing/printing, see also isar-ref manual.
   106 
   107 * Improved internal renaming of symbolic identifiers -- attach primes
   108 instead of base 26 numbers.
   109 
   110 * New flag show_question_marks controls printing of leading question
   111 marks in schematic variable names.
   112 
   113 * In schematic variable names, *any* symbol following \<^isub> or
   114 \<^isup> is now treated as part of the base name.  For example, the
   115 following works without printing of awkward ".0" indexes:
   116 
   117   lemma "x\<^isub>1 = x\<^isub>2 ==> x\<^isub>2 = x\<^isub>1"
   118     by simp
   119 
   120 * Inner syntax includes (*(*nested*) comments*).
   121 
   122 * Pretty pinter now supports unbreakable blocks, specified in mixfix
   123 annotations as "(00...)".
   124 
   125 * Clear separation of logical types and nonterminals, where the latter
   126 may only occur in 'syntax' specifications or type abbreviations.
   127 Before that distinction was only partially implemented via type class
   128 "logic" vs. "{}".  Potential INCOMPATIBILITY in rare cases of improper
   129 use of 'types'/'consts' instead of 'nonterminals'/'syntax'.  Some very
   130 exotic syntax specifications may require further adaption
   131 (e.g. Cube/Base.thy).
   132 
   133 * Removed obsolete type class "logic", use the top sort {} instead.
   134 Note that non-logical types should be declared as 'nonterminals'
   135 rather than 'types'.  INCOMPATIBILITY for new object-logic
   136 specifications.
   137 
   138 * Simplifier: can now control the depth to which conditional rewriting
   139 is traced via the PG menu Isabelle -> Settings -> Trace Simp Depth
   140 Limit.
   141 
   142 * Simplifier: simplification procedures may now take the current
   143 simpset into account (cf. Simplifier.simproc(_i) / mk_simproc
   144 interface), which is very useful for calling the Simplifier
   145 recursively.  Minor INCOMPATIBILITY: the 'prems' argument of simprocs
   146 is gone -- use prems_of_ss on the simpset instead.  Moreover, the
   147 low-level mk_simproc no longer applies Logic.varify internally, to
   148 allow for use in a context of fixed variables.
   149 
   150 * thin_tac now works even if the assumption being deleted contains !!
   151 or ==>.  More generally, erule now works even if the major premise of
   152 the elimination rule contains !! or ==>.
   153 
   154 * Reorganized bootstrapping of the Pure theories; CPure is now derived
   155 from Pure, which contains all common declarations already.  Both
   156 theories are defined via plain Isabelle/Isar .thy files.
   157 INCOMPATIBILITY: elements of CPure (such as the CPure.intro /
   158 CPure.elim / CPure.dest attributes) now appear in the Pure name space;
   159 use isatool fixcpure to adapt your theory and ML sources.
   160 
   161 * New syntax 'name(i-j, i-, i, ...)' for referring to specific
   162 selections of theorems in named facts via index ranges.
   163 
   164 * More efficient treatment of intermediate checkpoints in interactive
   165 theory development.
   166 
   167 
   168 *** Locales ***
   169   
   170 * New commands for the interpretation of locale expressions in
   171 theories ('interpretation') and proof contexts ('interpret').  These
   172 take an instantiation of the locale parameters and compute proof
   173 obligations from the instantiated specification.  After the
   174 obligations have been discharged, the instantiated theorems of the
   175 locale are added to the theory or proof context.  Interpretation is
   176 smart in that already active interpretations do not occur in proof
   177 obligations, neither are instantiated theorems stored in duplicate.
   178 Use print_interps to inspect active interpretations of a particular
   179 locale.  For details, see the Isar Reference manual.
   180 
   181 INCOMPATIBILITY: former 'instantiate' has been withdrawn, use
   182 'interpret' instead.
   183 
   184 * Proper static binding of attribute syntax -- i.e. types / terms /
   185 facts mentioned as arguments are always those of the locale definition
   186 context, independently of the context of later invocations.  Moreover,
   187 locale operations (renaming and type / term instantiation) are applied
   188 to attribute arguments as expected.
   189 
   190 INCOMPATIBILITY of the ML interface: always pass Attrib.src instead of
   191 actual attributes; rare situations may require Attrib.attribute to
   192 embed those attributes into Attrib.src that lack concrete syntax.
   193 Attribute implementations need to cooperate properly with the static
   194 binding mechanism.  Basic parsers Args.XXX_typ/term/prop and
   195 Attrib.XXX_thm etc. already do the right thing without further
   196 intervention.  Only unusual applications -- such as "where" or "of"
   197 (cf. src/Pure/Isar/attrib.ML), which process arguments depending both
   198 on the context and the facts involved -- may have to assign parsed
   199 values to argument tokens explicitly.
   200 
   201 * New context element "constrains" adds type constraints to parameters --
   202 there is no logical significance.
   203 
   204 * Context expressions: renaming parameters permits syntax
   205 redeclaration as well.
   206 
   207 * Locale definition: 'includes' now disallowed.
   208 
   209 * Changed parameter management in theorem generation for long goal
   210 statements with 'includes'.  INCOMPATIBILITY: produces a different
   211 theorem statement in rare situations.
   212 
   213 * Attributes 'induct' and 'cases': type or set names may now be
   214 locally fixed variables as well.
   215 
   216 * Antiquotations now provide the option 'locale=NAME' to specify an
   217 alternative context used for evaluating and printing the subsequent
   218 argument, as in @{thm [locale=LC] fold_commute}, for example.
   219 
   220 
   221 *** Provers ***
   222 
   223 * Provers/hypsubst.ML: improved version of the subst method, for
   224 single-step rewriting: it now works in bound variable contexts. New is
   225 'subst (asm)', for rewriting an assumption.  INCOMPATIBILITY: may
   226 rewrite a different subterm than the original subst method, which is
   227 still available as 'simplesubst'.
   228 
   229 * Provers/quasi.ML: new transitivity reasoners for transitivity only
   230 and quasi orders.
   231 
   232 * Provers/trancl.ML: new transitivity reasoner for transitive and
   233 reflexive-transitive closure of relations.
   234 
   235 * Provers/blast.ML: new reference depth_limit to make blast's depth
   236 limit (previously hard-coded with a value of 20) user-definable.
   237 
   238 * Provers/simplifier.ML has been moved to Pure, where Simplifier.setup
   239 is peformed already.  Object-logics merely need to finish their
   240 initial simpset configuration as before.  INCOMPATIBILITY.
   241 
   242 
   243 *** HOL ***
   244 
   245 * Symbolic syntax of Hilbert Choice Operator is now as follows:
   246 
   247   syntax (epsilon)
   248     "_Eps" :: "[pttrn, bool] => 'a"    ("(3\<some>_./ _)" [0, 10] 10)
   249 
   250 The symbol \<some> is displayed as the alternative epsilon of LaTeX
   251 and x-symbol; use option '-m epsilon' to get it actually printed.
   252 Moreover, the mathematically important symbolic identifier \<epsilon>
   253 becomes available as variable, constant etc.  INCOMPATIBILITY,
   254 
   255 * "x > y" abbreviates "y < x" and "x >= y" abbreviates "y <= x".
   256 Similarly for all quantifiers: "ALL x > y" etc.  The x-symbol for >=
   257 is \<ge>.
   258 
   259 * "{x:A. P}" abbreviates "{x. x:A & P}", and similarly for "\<in>"
   260 instead of ":".
   261 
   262 * theory SetInterval: changed the syntax for open intervals:
   263 
   264   Old       New
   265   {..n(}    {..<n}
   266   {)n..}    {n<..}
   267   {m..n(}   {m..<n}
   268   {)m..n}   {m<..n}
   269   {)m..n(}  {m<..<n}
   270 
   271 The old syntax is still supported but will disappear in the next
   272 release.  For conversion use the following Emacs search and replace
   273 patterns (these are not perfect but work quite well):
   274 
   275   {)\([^\.]*\)\.\.  ->  {\1<\.\.}
   276   \.\.\([^(}]*\)(}  ->  \.\.<\1}
   277 
   278 * theory Finite_Set: changed the syntax for 'setsum', summation over
   279 finite sets: "setsum (%x. e) A", which used to be "\<Sum>x:A. e", is
   280 now either "SUM x:A. e" or "\<Sum>x \<in> A. e".
   281 
   282 Some new syntax forms are available:
   283 
   284   "\<Sum>x | P. e"      for     "setsum (%x. e) {x. P}"
   285   "\<Sum>x = a..b. e"   for     "setsum (%x. e) {a..b}"
   286   "\<Sum>x = a..<b. e"  for     "setsum (%x. e) {a..<b}"
   287   "\<Sum>x < k. e"      for     "setsum (%x. e) {..<k}"
   288 
   289 The latter form "\<Sum>x < k. e" used to be based on a separate
   290 function "Summation", which has been discontinued.
   291 
   292 * theory Finite_Set: in structured induction proofs, the insert case
   293 is now 'case (insert x F)' instead of the old counterintuitive 'case
   294 (insert F x)'.
   295 
   296 * The 'refute' command has been extended to support a much larger
   297 fragment of HOL, including axiomatic type classes, constdefs and
   298 typedefs, inductive datatypes and recursion.
   299 
   300 * Datatype induction via method 'induct' now preserves the name of the
   301 induction variable. For example, when proving P(xs::'a list) by
   302 induction on xs, the induction step is now P(xs) ==> P(a#xs) rather
   303 than P(list) ==> P(a#list) as previously.  Potential INCOMPATIBILITY
   304 in unstructured proof scripts.
   305 
   306 * Reworked implementation of records.  Improved scalability for
   307 records with many fields, avoiding performance problems for type
   308 inference. Records are no longer composed of nested field types, but
   309 of nested extension types. Therefore the record type only grows linear
   310 in the number of extensions and not in the number of fields.  The
   311 top-level (users) view on records is preserved.  Potential
   312 INCOMPATIBILITY only in strange cases, where the theory depends on the
   313 old record representation. The type generated for a record is called
   314 <record_name>_ext_type.
   315 
   316 Flag record_quick_and_dirty_sensitive can be enabled to skip the
   317 proofs triggered by a record definition or a simproc (if
   318 quick_and_dirty is enabled).  Definitions of large records can take
   319 quite long.
   320 
   321 New simproc record_upd_simproc for simplification of multiple record
   322 updates enabled by default.  Moreover, trivial updates are also
   323 removed: r(|x := x r|) = r.  INCOMPATIBILITY: old proofs break
   324 occasionally, since simplification is more powerful by default.
   325 
   326 * Simplifier: automatically reasons about transitivity chains
   327 involving "trancl" (r^+) and "rtrancl" (r^*) by setting up tactics
   328 provided by Provers/trancl.ML as additional solvers.  INCOMPATIBILITY:
   329 old proofs break occasionally as simplification may now solve more
   330 goals than previously.
   331 
   332 * Simplifier: converts x <= y into x = y if assumption y <= x is
   333 present.  Works for all partial orders (class "order"), in particular
   334 numbers and sets.  For linear orders (e.g. numbers) it treats ~ x < y
   335 just like y <= x.
   336 
   337 * Simplifier: new simproc for "let x = a in f x".  If a is a free or
   338 bound variable or a constant then the let is unfolded.  Otherwise
   339 first a is simplified to b, and then f b is simplified to g. If
   340 possible we abstract b from g arriving at "let x = b in h x",
   341 otherwise we unfold the let and arrive at g.  The simproc can be
   342 enabled/disabled by the reference use_let_simproc.  Potential
   343 INCOMPATIBILITY since simplification is more powerful by default.
   344 
   345 * Classical reasoning: the meson method now accepts theorems as arguments.
   346 
   347 
   348 *** HOLCF ***
   349 
   350 * HOLCF: discontinued special version of 'constdefs' (which used to
   351 support continuous functions) in favor of the general Pure one with
   352 full type-inference.
   353 
   354 
   355 *** ZF ***
   356 
   357 * ZF/ex: theories Group and Ring provide examples in abstract algebra,
   358 including the First Isomorphism Theorem (on quotienting by the kernel
   359 of a homomorphism).
   360 
   361 * ZF/Simplifier: install second copy of type solver that actually
   362 makes use of TC rules declared to Isar proof contexts (or locales);
   363 the old version is still required for ML proof scripts.
   364 
   365 
   366 *** ML ***
   367 
   368 * Pure/library.ML no longer defines its own option datatype, but uses
   369 that of the SML basis, which has constructors NONE and SOME instead of
   370 None and Some, as well as exception Option.Option instead of OPTION.
   371 The functions the, if_none, is_some, is_none have been adapted
   372 accordingly, while Option.map replaces apsome.
   373 
   374 * The exception LIST has been given up in favour of the standard
   375 exceptions Empty and Subscript, as well as Library.UnequalLengths.
   376 Function like Library.hd and Library.tl are superceded by the standard
   377 hd and tl functions etc.
   378 
   379 A number of basic functions are now no longer exported to the ML
   380 toplevel, as they are variants of standard functions.  The following
   381 suggests how one can translate existing code:
   382 
   383     rev_append xs ys = List.revAppend (xs, ys)
   384     nth_elem (i, xs) = List.nth (xs, i)
   385     last_elem xs = List.last xs
   386     flat xss = List.concat xss
   387     seq fs = List.app fs
   388     partition P xs = List.partition P xs
   389     filter P xs = List.filter P xs
   390     mapfilter f xs = List.mapPartial f xs
   391 
   392 * Pure: output via the Isabelle channels of writeln/warning/error
   393 etc. is now passed through Output.output, with a hook for arbitrary
   394 transformations depending on the print_mode (cf. Output.add_mode --
   395 the first active mode that provides a output function wins).  Already
   396 formatted output may be embedded into further text via Output.raw; the
   397 result of Pretty.string_of/str_of and derived functions
   398 (string_of_term/cterm/thm etc.) is already marked raw to accommodate
   399 easy composition of diagnostic messages etc.  Programmers rarely need
   400 to care about Output.output or Output.raw at all, with some notable
   401 exceptions: Output.output is required when bypassing the standard
   402 channels (writeln etc.), or in token translations to produce properly
   403 formatted results; Output.raw is required when capturing already
   404 output material that will eventually be presented to the user a second
   405 time.  For the default print mode, both Output.output and Output.raw
   406 have no effect.
   407 
   408 * Pure: print_tac now outputs the goal through the trace channel.
   409 
   410 * Isar debugging: new reference Toplevel.debug (default false).  Set
   411 to make printing of exceptions THM, TERM, TYPE and THEORY more
   412 verbose.
   413 
   414 * Isar profiling: new reference Toplevel.profiling (default 0).  For
   415 Poly/ML, set to 1 to profile time, 2 to profile space (which increases
   416 the runtime).
   417 
   418 * Pure: name spaces have been refined, with significant changes of the
   419 internal interfaces -- INCOMPATIBILITY.  Renamed cond_extern(_table)
   420 to extern(_table).  The plain name entry path is superceded by a
   421 general 'naming' context, which also includes the 'policy' to produce
   422 a fully qualified name and external accesses of a fully qualified
   423 name; NameSpace.extend is superceded by context dependent
   424 Sign.declare_name.  Several theory and proof context operations modify
   425 the naming context.  Especially note Theory.restore_naming and
   426 ProofContext.restore_naming to get back to a sane state; note that
   427 Theory.add_path is no longer sufficient to recover from
   428 Theory.absolute_path in particular.
   429 
   430 * Pure: new flags short_names (default false) and unique_names
   431 (default true) for controlling output of qualified names.  If
   432 short_names is set, names are printed unqualified.  If unique_names is
   433 reset, the name prefix is reduced to the minimum required to achieve
   434 the original result when interning again, even if there is an overlap
   435 with earlier declarations.
   436 
   437 * Pure/TheoryDataFun: change of the argument structure; 'prep_ext' is
   438 now 'extend', and 'merge' gets an additional Pretty.pp argument
   439 (useful for printing error messages).  INCOMPATIBILITY.
   440 
   441 * Pure: major reorganization of the theory context.  Type Sign.sg and
   442 Theory.theory are now identified, referring to the universal
   443 Context.theory (see Pure/context.ML).  Actual signature and theory
   444 content is managed as theory data.  The old code and interfaces were
   445 spread over many files and structures; the new arrangement introduces
   446 considerable INCOMPATIBILITY to gain more clarity:
   447 
   448   Context -- theory management operations (name, identity, inclusion,
   449     parents, ancestors, merge, etc.), plus generic theory data;
   450 
   451   Sign -- logical signature and syntax operations (declaring consts,
   452     types, etc.), plus certify/read for common entities;
   453 
   454   Theory -- logical theory operations (stating axioms, definitions,
   455     oracles), plus a copy of logical signature operations (consts,
   456     types, etc.); also a few basic management operations (Theory.copy,
   457     Theory.merge, etc.)
   458 
   459 The most basic sign_of operations (Theory.sign_of, Thm.sign_of_thm
   460 etc.) as well as the sign field in Thm.rep_thm etc. have been retained
   461 for convenience -- they merely return the theory.
   462 
   463 * Pure: the Isar proof context type is already defined early in Pure
   464 as Context.proof (note that ProofContext.context and Proof.context are
   465 aliases, where the latter is the preferred name).  This enables other
   466 Isabelle components to refer to that type even before Isar is present.
   467 
   468 * Pure/sign/theory: discontinued named name spaces (i.e. classK,
   469 typeK, constK, axiomK, oracleK), but provide explicit operations for
   470 any of these kinds.  For example, Sign.intern typeK is now
   471 Sign.intern_type, Theory.hide_space Sign.typeK is now
   472 Theory.hide_types.  Also note that former
   473 Theory.hide_classes/types/consts are now
   474 Theory.hide_classes_i/types_i/consts_i, while the non '_i' versions
   475 internalize their arguments!  INCOMPATIBILITY.
   476 
   477 * Pure: get_thm interface (of PureThy and ProofContext) expects
   478 datatype thmref (with constructors Name and NameSelection) instead of
   479 plain string -- INCOMPATIBILITY;
   480 
   481 * Pure: cases produced by proof methods specify options, where NONE
   482 means to remove case bindings -- INCOMPATIBILITY in
   483 (RAW_)METHOD_CASES.
   484 
   485 * Pure: the following operations retrieve axioms or theorems from a
   486 theory node or theory hierarchy, respectively:
   487 
   488   Theory.axioms_of: theory -> (string * term) list
   489   Theory.all_axioms_of: theory -> (string * term) list
   490   PureThy.thms_of: theory -> (string * thm) list
   491   PureThy.all_thms_of: theory -> (string * thm) list
   492 
   493 * Provers: Simplifier and Classical Reasoner now support proof context
   494 dependent plug-ins (simprocs, solvers, wrappers etc.).  These extra
   495 components are stored in the theory and patched into the
   496 simpset/claset when used in an Isar proof context.  Context dependent
   497 components are maintained by the following theory operations:
   498 
   499   Simplifier.add_context_simprocs
   500   Simplifier.del_context_simprocs
   501   Simplifier.set_context_subgoaler
   502   Simplifier.reset_context_subgoaler
   503   Simplifier.add_context_looper
   504   Simplifier.del_context_looper
   505   Simplifier.add_context_unsafe_solver
   506   Simplifier.add_context_safe_solver
   507 
   508   Classical.add_context_safe_wrapper
   509   Classical.del_context_safe_wrapper
   510   Classical.add_context_unsafe_wrapper
   511   Classical.del_context_unsafe_wrapper
   512 
   513 IMPORTANT NOTE: proof tools (methods etc.) need to use
   514 local_simpset_of and local_claset_of to instead of the primitive
   515 Simplifier.get_local_simpset and Classical.get_local_claset,
   516 respectively, in order to see the context dependent fields!
   517 
   518 * File.sysify_path and File.quote_sysify path have been replaced by
   519 File.platform_path and File.shell_path (with appropriate hooks).  This
   520 provides a clean interface for unusual systems where the internal and
   521 external process view of file names are different.
   522 
   523 
   524 *** System ***
   525 
   526 * Allow symlinks to all proper Isabelle executables (Isabelle,
   527 isabelle, isatool etc.).
   528 
   529 * ISABELLE_DOC_FORMAT setting specifies preferred document format (for
   530 isatool doc, isatool mkdir, display_drafts etc.).
   531 
   532 * isatool usedir: option -f allows specification of the ML file to be
   533 used by Isabelle; default is ROOT.ML.
   534 
   535 * New isatool version outputs the version identifier of the Isabelle
   536 distribution being used.
   537 
   538 * HOL: new isatool dimacs2hol converts files in DIMACS CNF format
   539 (containing Boolean satisfiability problems) into Isabelle/HOL
   540 theories.
   541 
   542 
   543 
   544 New in Isabelle2004 (April 2004)
   545 --------------------------------
   546 
   547 *** General ***
   548 
   549 * Provers/order.ML:  new efficient reasoner for partial and linear orders.
   550   Replaces linorder.ML.
   551 
   552 * Pure: Greek letters (except small lambda, \<lambda>), as well as Gothic
   553   (\<aa>...\<zz>\<AA>...\<ZZ>), calligraphic (\<A>...\<Z>), and Euler
   554   (\<a>...\<z>), are now considered normal letters, and can therefore
   555   be used anywhere where an ASCII letter (a...zA...Z) has until
   556   now. COMPATIBILITY: This obviously changes the parsing of some
   557   terms, especially where a symbol has been used as a binder, say
   558   '\<Pi>x. ...', which is now a type error since \<Pi>x will be parsed
   559   as an identifier.  Fix it by inserting a space around former
   560   symbols.  Call 'isatool fixgreek' to try to fix parsing errors in
   561   existing theory and ML files.
   562 
   563 * Pure: Macintosh and Windows line-breaks are now allowed in theory files.
   564 
   565 * Pure: single letter sub/superscripts (\<^isub> and \<^isup>) are now
   566   allowed in identifiers. Similar to Greek letters \<^isub> is now considered
   567   a normal (but invisible) letter. For multiple letter subscripts repeat
   568   \<^isub> like this: x\<^isub>1\<^isub>2.
   569 
   570 * Pure: There are now sub-/superscripts that can span more than one
   571   character. Text between \<^bsub> and \<^esub> is set in subscript in
   572   ProofGeneral and LaTeX, text between \<^bsup> and \<^esup> in
   573   superscript. The new control characters are not identifier parts.
   574 
   575 * Pure: Control-symbols of the form \<^raw:...> will literally print the
   576   content of "..." to the latex file instead of \isacntrl... . The "..."
   577   may consist of any printable characters excluding the end bracket >.
   578 
   579 * Pure: Using new Isar command "finalconsts" (or the ML functions
   580   Theory.add_finals or Theory.add_finals_i) it is now possible to
   581   declare constants "final", which prevents their being given a definition
   582   later.  It is useful for constants whose behaviour is fixed axiomatically
   583   rather than definitionally, such as the meta-logic connectives.
   584 
   585 * Pure: 'instance' now handles general arities with general sorts
   586   (i.e. intersections of classes),
   587 
   588 * Presentation: generated HTML now uses a CSS style sheet to make layout
   589   (somewhat) independent of content. It is copied from lib/html/isabelle.css.
   590   It can be changed to alter the colors/layout of generated pages.
   591 
   592 
   593 *** Isar ***
   594 
   595 * Tactic emulation methods rule_tac, erule_tac, drule_tac, frule_tac,
   596   cut_tac, subgoal_tac and thin_tac:
   597   - Now understand static (Isar) contexts.  As a consequence, users of Isar
   598     locales are no longer forced to write Isar proof scripts.
   599     For details see Isar Reference Manual, paragraph 4.3.2: Further tactic
   600     emulations.
   601   - INCOMPATIBILITY: names of variables to be instantiated may no
   602     longer be enclosed in quotes.  Instead, precede variable name with `?'.
   603     This is consistent with the instantiation attribute "where".
   604 
   605 * Attributes "where" and "of":
   606   - Now take type variables of instantiated theorem into account when reading
   607     the instantiation string.  This fixes a bug that caused instantiated
   608     theorems to have too special types in some circumstances.
   609   - "where" permits explicit instantiations of type variables.
   610 
   611 * Calculation commands "moreover" and "also" no longer interfere with
   612   current facts ("this"), admitting arbitrary combinations with "then"
   613   and derived forms.
   614 
   615 * Locales:
   616   - Goal statements involving the context element "includes" no longer
   617     generate theorems with internal delta predicates (those ending on
   618     "_axioms") in the premise.
   619     Resolve particular premise with <locale>.intro to obtain old form.
   620   - Fixed bug in type inference ("unify_frozen") that prevented mix of target
   621     specification and "includes" elements in goal statement.
   622   - Rule sets <locale>.intro and <locale>.axioms no longer declared as
   623     [intro?] and [elim?] (respectively) by default.
   624   - Experimental command for instantiation of locales in proof contexts:
   625         instantiate <label>[<attrs>]: <loc>
   626     Instantiates locale <loc> and adds all its theorems to the current context
   627     taking into account their attributes.  Label and attrs are optional
   628     modifiers, like in theorem declarations.  If present, names of
   629     instantiated theorems are qualified with <label>, and the attributes
   630     <attrs> are applied after any attributes these theorems might have already.
   631       If the locale has assumptions, a chained fact of the form
   632     "<loc> t1 ... tn" is expected from which instantiations of the parameters
   633     are derived.  The command does not support old-style locales declared
   634     with "locale (open)".
   635       A few (very simple) examples can be found in FOL/ex/LocaleInst.thy.
   636 
   637 * HOL: Tactic emulation methods induct_tac and case_tac understand static
   638   (Isar) contexts.
   639 
   640 
   641 *** HOL ***
   642 
   643 * Proof import: new image HOL4 contains the imported library from
   644   the HOL4 system with about 2500 theorems. It is imported by
   645   replaying proof terms produced by HOL4 in Isabelle. The HOL4 image
   646   can be used like any other Isabelle image.  See
   647   HOL/Import/HOL/README for more information.
   648 
   649 * Simplifier:
   650   - Much improved handling of linear and partial orders.
   651     Reasoners for linear and partial orders are set up for type classes
   652     "linorder" and "order" respectively, and are added to the default simpset
   653     as solvers.  This means that the simplifier can build transitivity chains
   654     to solve goals from the assumptions.
   655   - INCOMPATIBILITY: old proofs break occasionally.  Typically, applications
   656     of blast or auto after simplification become unnecessary because the goal
   657     is solved by simplification already.
   658 
   659 * Numerics: new theory Ring_and_Field contains over 250 basic numerical laws,
   660     all proved in axiomatic type classes for semirings, rings and fields.
   661 
   662 * Numerics:
   663   - Numeric types (nat, int, and in HOL-Complex rat, real, complex, etc.) are
   664     now formalized using the Ring_and_Field theory mentioned above.
   665   - INCOMPATIBILITY: simplification and arithmetic behaves somewhat differently
   666     than before, because now they are set up once in a generic manner.
   667   - INCOMPATIBILITY: many type-specific arithmetic laws have gone.
   668     Look for the general versions in Ring_and_Field (and Power if they concern
   669     exponentiation).
   670 
   671 * Type "rat" of the rational numbers is now available in HOL-Complex.
   672 
   673 * Records:
   674   - Record types are now by default printed with their type abbreviation
   675     instead of the list of all field types. This can be configured via
   676     the reference "print_record_type_abbr".
   677   - Simproc "record_upd_simproc" for simplification of multiple updates added
   678     (not enabled by default).
   679   - Simproc "record_ex_sel_eq_simproc" to simplify EX x. sel r = x resp.
   680     EX x. x = sel r to True (not enabled by default).
   681   - Tactic "record_split_simp_tac" to split and simplify records added.
   682 
   683 * 'specification' command added, allowing for definition by
   684   specification.  There is also an 'ax_specification' command that
   685   introduces the new constants axiomatically.
   686 
   687 * arith(_tac) is now able to generate counterexamples for reals as well.
   688 
   689 * HOL-Algebra: new locale "ring" for non-commutative rings.
   690 
   691 * HOL-ex: InductiveInvariant_examples illustrates advanced recursive function
   692   definitions, thanks to Sava Krsti\'{c} and John Matthews.
   693 
   694 * HOL-Matrix: a first theory for matrices in HOL with an application of
   695   matrix theory to linear programming.
   696 
   697 * Unions and Intersections:
   698   The latex output syntax of UN and INT has been changed
   699   from "\Union x \in A. B" to "\Union_{x \in A} B"
   700   i.e. the index formulae has become a subscript.
   701   Similarly for "\Union x. B", and for \Inter instead of \Union.
   702 
   703 * Unions and Intersections over Intervals:
   704   There is new short syntax "UN i<=n. A" for "UN i:{0..n}. A". There is
   705   also an x-symbol version with subscripts "\<Union>\<^bsub>i <= n\<^esub>. A"
   706   like in normal math, and corresponding versions for < and for intersection.
   707 
   708 * HOL/List: Ordering "lexico" is renamed "lenlex" and the standard
   709   lexicographic dictonary ordering has been added as "lexord".
   710 
   711 * ML: the legacy theory structures Int and List have been removed. They had
   712   conflicted with ML Basis Library structures having the same names.
   713 
   714 * 'refute' command added to search for (finite) countermodels.  Only works
   715   for a fragment of HOL.  The installation of an external SAT solver is
   716   highly recommended.  See "HOL/Refute.thy" for details.
   717 
   718 * 'quickcheck' command: Allows to find counterexamples by evaluating
   719   formulae under an assignment of free variables to random values.
   720   In contrast to 'refute', it can deal with inductive datatypes,
   721   but cannot handle quantifiers. See "HOL/ex/Quickcheck_Examples.thy"
   722   for examples.
   723 
   724 
   725 *** HOLCF ***
   726 
   727 * Streams now come with concatenation and are part of the HOLCF image
   728 
   729 
   730 
   731 New in Isabelle2003 (May 2003)
   732 ------------------------------
   733 
   734 *** General ***
   735 
   736 * Provers/simplifier:
   737 
   738   - Completely reimplemented method simp (ML: Asm_full_simp_tac):
   739     Assumptions are now subject to complete mutual simplification,
   740     not just from left to right. The simplifier now preserves
   741     the order of assumptions.
   742 
   743     Potential INCOMPATIBILITY:
   744 
   745     -- simp sometimes diverges where the old version did
   746        not, e.g. invoking simp on the goal
   747 
   748         [| P (f x); y = x; f x = f y |] ==> Q
   749 
   750        now gives rise to the infinite reduction sequence
   751 
   752         P(f x) --(f x = f y)--> P(f y) --(y = x)--> P(f x) --(f x = f y)--> ...
   753 
   754        Using "simp (asm_lr)" (ML: Asm_lr_simp_tac) instead often solves this
   755        kind of problem.
   756 
   757     -- Tactics combining classical reasoner and simplification (such as auto)
   758        are also affected by this change, because many of them rely on
   759        simp. They may sometimes diverge as well or yield a different numbers
   760        of subgoals. Try to use e.g. force, fastsimp, or safe instead of auto
   761        in case of problems. Sometimes subsequent calls to the classical
   762        reasoner will fail because a preceeding call to the simplifier too
   763        eagerly simplified the goal, e.g. deleted redundant premises.
   764 
   765   - The simplifier trace now shows the names of the applied rewrite rules
   766 
   767   - You can limit the number of recursive invocations of the simplifier
   768     during conditional rewriting (where the simplifie tries to solve the
   769     conditions before applying the rewrite rule):
   770     ML "simp_depth_limit := n"
   771     where n is an integer. Thus you can force termination where previously
   772     the simplifier would diverge.
   773 
   774   - Accepts free variables as head terms in congruence rules.  Useful in Isar.
   775 
   776   - No longer aborts on failed congruence proof.  Instead, the
   777     congruence is ignored.
   778 
   779 * Pure: New generic framework for extracting programs from constructive
   780   proofs. See HOL/Extraction.thy for an example instantiation, as well
   781   as HOL/Extraction for some case studies.
   782 
   783 * Pure: The main goal of the proof state is no longer shown by default, only
   784 the subgoals. This behaviour is controlled by a new flag.
   785    PG menu: Isabelle/Isar -> Settings -> Show Main Goal
   786 (ML: Proof.show_main_goal).
   787 
   788 * Pure: You can find all matching introduction rules for subgoal 1, i.e. all
   789 rules whose conclusion matches subgoal 1:
   790       PG menu: Isabelle/Isar -> Show me -> matching rules
   791 The rules are ordered by how closely they match the subgoal.
   792 In particular, rules that solve a subgoal outright are displayed first
   793 (or rather last, the way they are printed).
   794 (ML: ProofGeneral.print_intros())
   795 
   796 * Pure: New flag trace_unify_fail causes unification to print
   797 diagnostic information (PG: in trace buffer) when it fails. This is
   798 useful for figuring out why single step proofs like rule, erule or
   799 assumption failed.
   800 
   801 * Pure: Locale specifications now produce predicate definitions
   802 according to the body of text (covering assumptions modulo local
   803 definitions); predicate "loc_axioms" covers newly introduced text,
   804 while "loc" is cumulative wrt. all included locale expressions; the
   805 latter view is presented only on export into the global theory
   806 context; potential INCOMPATIBILITY, use "(open)" option to fall back
   807 on the old view without predicates;
   808 
   809 * Pure: predefined locales "var" and "struct" are useful for sharing
   810 parameters (as in CASL, for example); just specify something like
   811 ``var x + var y + struct M'' as import;
   812 
   813 * Pure: improved thms_containing: proper indexing of facts instead of
   814 raw theorems; check validity of results wrt. current name space;
   815 include local facts of proof configuration (also covers active
   816 locales), cover fixed variables in index; may use "_" in term
   817 specification; an optional limit for the number of printed facts may
   818 be given (the default is 40);
   819 
   820 * Pure: disallow duplicate fact bindings within new-style theory files
   821 (batch-mode only);
   822 
   823 * Provers: improved induct method: assumptions introduced by case
   824 "foo" are split into "foo.hyps" (from the rule) and "foo.prems" (from
   825 the goal statement); "foo" still refers to all facts collectively;
   826 
   827 * Provers: the function blast.overloaded has been removed: all constants
   828 are regarded as potentially overloaded, which improves robustness in exchange
   829 for slight decrease in efficiency;
   830 
   831 * Provers/linorder: New generic prover for transitivity reasoning over
   832 linear orders.  Note: this prover is not efficient!
   833 
   834 * Isar: preview of problems to finish 'show' now produce an error
   835 rather than just a warning (in interactive mode);
   836 
   837 
   838 *** HOL ***
   839 
   840 * arith(_tac)
   841 
   842  - Produces a counter example if it cannot prove a goal.
   843    Note that the counter example may be spurious if the goal is not a formula
   844    of quantifier-free linear arithmetic.
   845    In ProofGeneral the counter example appears in the trace buffer.
   846 
   847  - Knows about div k and mod k where k is a numeral of type nat or int.
   848 
   849  - Calls full Presburger arithmetic (by Amine Chaieb) if quantifier-free
   850    linear arithmetic fails. This takes account of quantifiers and divisibility.
   851    Presburger arithmetic can also be called explicitly via presburger(_tac).
   852 
   853 * simp's arithmetic capabilities have been enhanced a bit: it now
   854 takes ~= in premises into account (by performing a case split);
   855 
   856 * simp reduces "m*(n div m) + n mod m" to n, even if the two summands
   857 are distributed over a sum of terms;
   858 
   859 * New tactic "trans_tac" and method "trans" instantiate
   860 Provers/linorder.ML for axclasses "order" and "linorder" (predicates
   861 "<=", "<" and "=").
   862 
   863 * function INCOMPATIBILITIES: Pi-sets have been redefined and moved from main
   864 HOL to Library/FuncSet; constant "Fun.op o" is now called "Fun.comp";
   865 
   866 * 'typedef' command has new option "open" to suppress the set
   867 definition;
   868 
   869 * functions Min and Max on finite sets have been introduced (theory
   870 Finite_Set);
   871 
   872 * attribute [symmetric] now works for relations as well; it turns
   873 (x,y) : R^-1 into (y,x) : R, and vice versa;
   874 
   875 * induct over a !!-quantified statement (say !!x1..xn):
   876   each "case" automatically performs "fix x1 .. xn" with exactly those names.
   877 
   878 * Map: `empty' is no longer a constant but a syntactic abbreviation for
   879 %x. None. Warning: empty_def now refers to the previously hidden definition
   880 of the empty set.
   881 
   882 * Algebra: formalization of classical algebra.  Intended as base for
   883 any algebraic development in Isabelle.  Currently covers group theory
   884 (up to Sylow's theorem) and ring theory (Universal Property of
   885 Univariate Polynomials).  Contributions welcome;
   886 
   887 * GroupTheory: deleted, since its material has been moved to Algebra;
   888 
   889 * Complex: new directory of the complex numbers with numeric constants,
   890 nonstandard complex numbers, and some complex analysis, standard and
   891 nonstandard (Jacques Fleuriot);
   892 
   893 * HOL-Complex: new image for analysis, replacing HOL-Real and HOL-Hyperreal;
   894 
   895 * Hyperreal: introduced Gauge integration and hyperreal logarithms (Jacques
   896 Fleuriot);
   897 
   898 * Real/HahnBanach: updated and adapted to locales;
   899 
   900 * NumberTheory: added Gauss's law of quadratic reciprocity (by Avigad,
   901 Gray and Kramer);
   902 
   903 * UNITY: added the Meier-Sanders theory of progress sets;
   904 
   905 * MicroJava: bytecode verifier and lightweight bytecode verifier
   906 as abstract algorithms, instantiated to the JVM;
   907 
   908 * Bali: Java source language formalization. Type system, operational
   909 semantics, axiomatic semantics. Supported language features:
   910 classes, interfaces, objects,virtual methods, static methods,
   911 static/instance fields, arrays, access modifiers, definite
   912 assignment, exceptions.
   913 
   914 
   915 *** ZF ***
   916 
   917 * ZF/Constructible: consistency proof for AC (Gdel's constructible
   918 universe, etc.);
   919 
   920 * Main ZF: virtually all theories converted to new-style format;
   921 
   922 
   923 *** ML ***
   924 
   925 * Pure: Tactic.prove provides sane interface for internal proofs;
   926 omits the infamous "standard" operation, so this is more appropriate
   927 than prove_goalw_cterm in many situations (e.g. in simprocs);
   928 
   929 * Pure: improved error reporting of simprocs;
   930 
   931 * Provers: Simplifier.simproc(_i) provides sane interface for setting
   932 up simprocs;
   933 
   934 
   935 *** Document preparation ***
   936 
   937 * uses \par instead of \\ for line breaks in theory text. This may
   938 shift some page breaks in large documents. To get the old behaviour
   939 use \renewcommand{\isanewline}{\mbox{}\\\mbox{}} in root.tex.
   940 
   941 * minimized dependencies of isabelle.sty and isabellesym.sty on
   942 other packages
   943 
   944 * \<euro> now needs package babel/greek instead of marvosym (which
   945 broke \Rightarrow)
   946 
   947 * normal size for \<zero>...\<nine> (uses \mathbf instead of
   948 textcomp package)
   949 
   950 
   951 
   952 New in Isabelle2002 (March 2002)
   953 --------------------------------
   954 
   955 *** Document preparation ***
   956 
   957 * greatly simplified document preparation setup, including more
   958 graceful interpretation of isatool usedir -i/-d/-D options, and more
   959 instructive isatool mkdir; users should basically be able to get
   960 started with "isatool mkdir HOL Test && isatool make"; alternatively,
   961 users may run a separate document processing stage manually like this:
   962 "isatool usedir -D output HOL Test && isatool document Test/output";
   963 
   964 * theory dependency graph may now be incorporated into documents;
   965 isatool usedir -g true will produce session_graph.eps/.pdf for use
   966 with \includegraphics of LaTeX;
   967 
   968 * proper spacing of consecutive markup elements, especially text
   969 blocks after section headings;
   970 
   971 * support bold style (for single symbols only), input syntax is like
   972 this: "\<^bold>\<alpha>" or "\<^bold>A";
   973 
   974 * \<bullet> is now output as bold \cdot by default, which looks much
   975 better in printed text;
   976 
   977 * added default LaTeX bindings for \<tturnstile> and \<TTurnstile>;
   978 note that these symbols are currently unavailable in Proof General /
   979 X-Symbol; new symbols \<zero>, \<one>, ..., \<nine>, and \<euro>;
   980 
   981 * isatool latex no longer depends on changed TEXINPUTS, instead
   982 isatool document copies the Isabelle style files to the target
   983 location;
   984 
   985 
   986 *** Isar ***
   987 
   988 * Pure/Provers: improved proof by cases and induction;
   989   - 'case' command admits impromptu naming of parameters (such as
   990     "case (Suc n)");
   991   - 'induct' method divinates rule instantiation from the inductive
   992     claim; no longer requires excessive ?P bindings for proper
   993     instantiation of cases;
   994   - 'induct' method properly enumerates all possibilities of set/type
   995     rules; as a consequence facts may be also passed through *type*
   996     rules without further ado;
   997   - 'induct' method now derives symbolic cases from the *rulified*
   998     rule (before it used to rulify cases stemming from the internal
   999     atomized version); this means that the context of a non-atomic
  1000     statement becomes is included in the hypothesis, avoiding the
  1001     slightly cumbersome show "PROP ?case" form;
  1002   - 'induct' may now use elim-style induction rules without chaining
  1003     facts, using ``missing'' premises from the goal state; this allows
  1004     rules stemming from inductive sets to be applied in unstructured
  1005     scripts, while still benefitting from proper handling of non-atomic
  1006     statements; NB: major inductive premises need to be put first, all
  1007     the rest of the goal is passed through the induction;
  1008   - 'induct' proper support for mutual induction involving non-atomic
  1009     rule statements (uses the new concept of simultaneous goals, see
  1010     below);
  1011   - append all possible rule selections, but only use the first
  1012     success (no backtracking);
  1013   - removed obsolete "(simplified)" and "(stripped)" options of methods;
  1014   - undeclared rule case names default to numbers 1, 2, 3, ...;
  1015   - added 'print_induct_rules' (covered by help item in recent Proof
  1016     General versions);
  1017   - moved induct/cases attributes to Pure, methods to Provers;
  1018   - generic method setup instantiated for FOL and HOL;
  1019 
  1020 * Pure: support multiple simultaneous goal statements, for example
  1021 "have a: A and b: B" (same for 'theorem' etc.); being a pure
  1022 meta-level mechanism, this acts as if several individual goals had
  1023 been stated separately; in particular common proof methods need to be
  1024 repeated in order to cover all claims; note that a single elimination
  1025 step is *not* sufficient to establish the two conjunctions, so this
  1026 fails:
  1027 
  1028   assume "A & B" then have A and B ..   (*".." fails*)
  1029 
  1030 better use "obtain" in situations as above; alternative refer to
  1031 multi-step methods like 'auto', 'simp_all', 'blast+' etc.;
  1032 
  1033 * Pure: proper integration with ``locales''; unlike the original
  1034 version by Florian Kammller, Isar locales package high-level proof
  1035 contexts rather than raw logical ones (e.g. we admit to include
  1036 attributes everywhere); operations on locales include merge and
  1037 rename; support for implicit arguments (``structures''); simultaneous
  1038 type-inference over imports and text; see also HOL/ex/Locales.thy for
  1039 some examples;
  1040 
  1041 * Pure: the following commands have been ``localized'', supporting a
  1042 target locale specification "(in name)": 'lemma', 'theorem',
  1043 'corollary', 'lemmas', 'theorems', 'declare'; the results will be
  1044 stored both within the locale and at the theory level (exported and
  1045 qualified by the locale name);
  1046 
  1047 * Pure: theory goals may now be specified in ``long'' form, with
  1048 ad-hoc contexts consisting of arbitrary locale elements. for example
  1049 ``lemma foo: fixes x assumes "A x" shows "B x"'' (local syntax and
  1050 definitions may be given, too); the result is a meta-level rule with
  1051 the context elements being discharged in the obvious way;
  1052 
  1053 * Pure: new proof command 'using' allows to augment currently used
  1054 facts after a goal statement ('using' is syntactically analogous to
  1055 'apply', but acts on the goal's facts only); this allows chained facts
  1056 to be separated into parts given before and after a claim, as in
  1057 ``from a and b have C using d and e <proof>'';
  1058 
  1059 * Pure: renamed "antecedent" case to "rule_context";
  1060 
  1061 * Pure: new 'judgment' command records explicit information about the
  1062 object-logic embedding (used by several tools internally); no longer
  1063 use hard-wired "Trueprop";
  1064 
  1065 * Pure: added 'corollary' command;
  1066 
  1067 * Pure: fixed 'token_translation' command;
  1068 
  1069 * Pure: removed obsolete 'exported' attribute;
  1070 
  1071 * Pure: dummy pattern "_" in is/let is now automatically lifted over
  1072 bound variables: "ALL x. P x --> Q x" (is "ALL x. _ --> ?C x")
  1073 supersedes more cumbersome ... (is "ALL x. _ x --> ?C x");
  1074 
  1075 * Pure: method 'atomize' presents local goal premises as object-level
  1076 statements (atomic meta-level propositions); setup controlled via
  1077 rewrite rules declarations of 'atomize' attribute; example
  1078 application: 'induct' method with proper rule statements in improper
  1079 proof *scripts*;
  1080 
  1081 * Pure: emulation of instantiation tactics (rule_tac, cut_tac, etc.)
  1082 now consider the syntactic context of assumptions, giving a better
  1083 chance to get type-inference of the arguments right (this is
  1084 especially important for locales);
  1085 
  1086 * Pure: "sorry" no longer requires quick_and_dirty in interactive
  1087 mode;
  1088 
  1089 * Pure/obtain: the formal conclusion "thesis", being marked as
  1090 ``internal'', may no longer be reference directly in the text;
  1091 potential INCOMPATIBILITY, may need to use "?thesis" in rare
  1092 situations;
  1093 
  1094 * Pure: generic 'sym' attribute which declares a rule both as pure
  1095 'elim?' and for the 'symmetric' operation;
  1096 
  1097 * Pure: marginal comments ``--'' may now occur just anywhere in the
  1098 text; the fixed correlation with particular command syntax has been
  1099 discontinued;
  1100 
  1101 * Pure: new method 'rules' is particularly well-suited for proof
  1102 search in intuitionistic logic; a bit slower than 'blast' or 'fast',
  1103 but often produces more compact proof terms with less detours;
  1104 
  1105 * Pure/Provers/classical: simplified integration with pure rule
  1106 attributes and methods; the classical "intro?/elim?/dest?"
  1107 declarations coincide with the pure ones; the "rule" method no longer
  1108 includes classically swapped intros; "intro" and "elim" methods no
  1109 longer pick rules from the context; also got rid of ML declarations
  1110 AddXIs/AddXEs/AddXDs; all of this has some potential for
  1111 INCOMPATIBILITY;
  1112 
  1113 * Provers/classical: attribute 'swapped' produces classical inversions
  1114 of introduction rules;
  1115 
  1116 * Provers/simplifier: 'simplified' attribute may refer to explicit
  1117 rules instead of full simplifier context; 'iff' attribute handles
  1118 conditional rules;
  1119 
  1120 * HOL: 'typedef' now allows alternative names for Rep/Abs morphisms;
  1121 
  1122 * HOL: 'recdef' now fails on unfinished automated proofs, use
  1123 "(permissive)" option to recover old behavior;
  1124 
  1125 * HOL: 'inductive' no longer features separate (collective) attributes
  1126 for 'intros' (was found too confusing);
  1127 
  1128 * HOL: properly declared induction rules less_induct and
  1129 wf_induct_rule;
  1130 
  1131 
  1132 *** HOL ***
  1133 
  1134 * HOL: moved over to sane numeral syntax; the new policy is as
  1135 follows:
  1136 
  1137   - 0 and 1 are polymorphic constants, which are defined on any
  1138   numeric type (nat, int, real etc.);
  1139 
  1140   - 2, 3, 4, ... and -1, -2, -3, ... are polymorphic numerals, based
  1141   binary representation internally;
  1142 
  1143   - type nat has special constructor Suc, and generally prefers Suc 0
  1144   over 1::nat and Suc (Suc 0) over 2::nat;
  1145 
  1146 This change may cause significant problems of INCOMPATIBILITY; here
  1147 are some hints on converting existing sources:
  1148 
  1149   - due to the new "num" token, "-0" and "-1" etc. are now atomic
  1150   entities, so expressions involving "-" (unary or binary minus) need
  1151   to be spaced properly;
  1152 
  1153   - existing occurrences of "1" may need to be constraint "1::nat" or
  1154   even replaced by Suc 0; similar for old "2";
  1155 
  1156   - replace "#nnn" by "nnn", and "#-nnn" by "-nnn";
  1157 
  1158   - remove all special provisions on numerals in proofs;
  1159 
  1160 * HOL: simp rules nat_number expand numerals on nat to Suc/0
  1161 representation (depends on bin_arith_simps in the default context);
  1162 
  1163 * HOL: symbolic syntax for x^2 (numeral 2);
  1164 
  1165 * HOL: the class of all HOL types is now called "type" rather than
  1166 "term"; INCOMPATIBILITY, need to adapt references to this type class
  1167 in axclass/classes, instance/arities, and (usually rare) occurrences
  1168 in typings (of consts etc.); internally the class is called
  1169 "HOL.type", ML programs should refer to HOLogic.typeS;
  1170 
  1171 * HOL/record package improvements:
  1172   - new derived operations "fields" to build a partial record section,
  1173     "extend" to promote a fixed record to a record scheme, and
  1174     "truncate" for the reverse; cf. theorems "xxx.defs", which are *not*
  1175     declared as simp by default;
  1176   - shared operations ("more", "fields", etc.) now need to be always
  1177     qualified) --- potential INCOMPATIBILITY;
  1178   - removed "make_scheme" operations (use "make" with "extend") --
  1179     INCOMPATIBILITY;
  1180   - removed "more" class (simply use "term") -- INCOMPATIBILITY;
  1181   - provides cases/induct rules for use with corresponding Isar
  1182     methods (for concrete records, record schemes, concrete more
  1183     parts, and schematic more parts -- in that order);
  1184   - internal definitions directly based on a light-weight abstract
  1185     theory of product types over typedef rather than datatype;
  1186 
  1187 * HOL: generic code generator for generating executable ML code from
  1188 specifications; specific support for HOL constructs such as inductive
  1189 datatypes and sets, as well as recursive functions; can be invoked
  1190 via 'generate_code' theory section;
  1191 
  1192 * HOL: canonical cases/induct rules for n-tuples (n = 3..7);
  1193 
  1194 * HOL: consolidated and renamed several theories.  In particular:
  1195         Ord.thy has been absorbed into HOL.thy
  1196         String.thy has been absorbed into List.thy
  1197 
  1198 * HOL: concrete setsum syntax "\<Sum>i:A. b" == "setsum (%i. b) A"
  1199 (beware of argument permutation!);
  1200 
  1201 * HOL: linorder_less_split superseded by linorder_cases;
  1202 
  1203 * HOL/List: "nodups" renamed to "distinct";
  1204 
  1205 * HOL: added "The" definite description operator; move Hilbert's "Eps"
  1206 to peripheral theory "Hilbert_Choice"; some INCOMPATIBILITIES:
  1207   - Ex_def has changed, now need to use some_eq_ex
  1208 
  1209 * HOL: made split_all_tac safe; EXISTING PROOFS MAY FAIL OR LOOP, so
  1210 in this (rare) case use:
  1211 
  1212   delSWrapper "split_all_tac"
  1213   addSbefore ("unsafe_split_all_tac", unsafe_split_all_tac)
  1214 
  1215 * HOL: added safe wrapper "split_conv_tac" to claset; EXISTING PROOFS
  1216 MAY FAIL;
  1217 
  1218 * HOL: introduced f^n = f o ... o f; warning: due to the limits of
  1219 Isabelle's type classes, ^ on functions and relations has too general
  1220 a domain, namely ('a * 'b) set and 'a => 'b; this means that it may be
  1221 necessary to attach explicit type constraints;
  1222 
  1223 * HOL/Relation: the prefix name of the infix "O" has been changed from
  1224 "comp" to "rel_comp"; INCOMPATIBILITY: a few theorems have been
  1225 renamed accordingly (eg "compI" -> "rel_compI").
  1226 
  1227 * HOL: syntax translations now work properly with numerals and records
  1228 expressions;
  1229 
  1230 * HOL: bounded abstraction now uses syntax "%" / "\<lambda>" instead
  1231 of "lam" -- INCOMPATIBILITY;
  1232 
  1233 * HOL: got rid of some global declarations (potential INCOMPATIBILITY
  1234 for ML tools): const "()" renamed "Product_Type.Unity", type "unit"
  1235 renamed "Product_Type.unit";
  1236 
  1237 * HOL: renamed rtrancl_into_rtrancl2 to converse_rtrancl_into_rtrancl
  1238 
  1239 * HOL: removed obsolete theorem "optionE" (use "option.exhaust", or
  1240 the "cases" method);
  1241 
  1242 * HOL/GroupTheory: group theory examples including Sylow's theorem (by
  1243 Florian Kammller);
  1244 
  1245 * HOL/IMP: updated and converted to new-style theory format; several
  1246 parts turned into readable document, with proper Isar proof texts and
  1247 some explanations (by Gerwin Klein);
  1248 
  1249 * HOL-Real: added Complex_Numbers (by Gertrud Bauer);
  1250 
  1251 * HOL-Hyperreal is now a logic image;
  1252 
  1253 
  1254 *** HOLCF ***
  1255 
  1256 * Isar: consts/constdefs supports mixfix syntax for continuous
  1257 operations;
  1258 
  1259 * Isar: domain package adapted to new-style theory format, e.g. see
  1260 HOLCF/ex/Dnat.thy;
  1261 
  1262 * theory Lift: proper use of rep_datatype lift instead of ML hacks --
  1263 potential INCOMPATIBILITY; now use plain induct_tac instead of former
  1264 lift.induct_tac, always use UU instead of Undef;
  1265 
  1266 * HOLCF/IMP: updated and converted to new-style theory;
  1267 
  1268 
  1269 *** ZF ***
  1270 
  1271 * Isar: proper integration of logic-specific tools and packages,
  1272 including theory commands '(co)inductive', '(co)datatype',
  1273 'rep_datatype', 'inductive_cases', as well as methods 'ind_cases',
  1274 'induct_tac', 'case_tac', and 'typecheck' (with attribute 'TC');
  1275 
  1276 * theory Main no longer includes AC; for the Axiom of Choice, base
  1277 your theory on Main_ZFC;
  1278 
  1279 * the integer library now covers quotients and remainders, with many
  1280 laws relating division to addition, multiplication, etc.;
  1281 
  1282 * ZF/UNITY: Chandy and Misra's UNITY is now available in ZF, giving a
  1283 typeless version of the formalism;
  1284 
  1285 * ZF/AC, Coind, IMP, Resid: updated and converted to new-style theory
  1286 format;
  1287 
  1288 * ZF/Induct: new directory for examples of inductive definitions,
  1289 including theory Multiset for multiset orderings; converted to
  1290 new-style theory format;
  1291 
  1292 * ZF: many new theorems about lists, ordinals, etc.;
  1293 
  1294 
  1295 *** General ***
  1296 
  1297 * Pure/kernel: meta-level proof terms (by Stefan Berghofer); reference
  1298 variable proof controls level of detail: 0 = no proofs (only oracle
  1299 dependencies), 1 = lemma dependencies, 2 = compact proof terms; see
  1300 also ref manual for further ML interfaces;
  1301 
  1302 * Pure/axclass: removed obsolete ML interface
  1303 goal_subclass/goal_arity;
  1304 
  1305 * Pure/syntax: new token syntax "num" for plain numerals (without "#"
  1306 of "xnum"); potential INCOMPATIBILITY, since -0, -1 etc. are now
  1307 separate tokens, so expressions involving minus need to be spaced
  1308 properly;
  1309 
  1310 * Pure/syntax: support non-oriented infixes, using keyword "infix"
  1311 rather than "infixl" or "infixr";
  1312 
  1313 * Pure/syntax: concrete syntax for dummy type variables admits genuine
  1314 sort constraint specifications in type inference; e.g. "x::_::foo"
  1315 ensures that the type of "x" is of sort "foo" (but not necessarily a
  1316 type variable);
  1317 
  1318 * Pure/syntax: print modes "type_brackets" and "no_type_brackets"
  1319 control output of nested => (types); the default behavior is
  1320 "type_brackets";
  1321 
  1322 * Pure/syntax: builtin parse translation for "_constify" turns valued
  1323 tokens into AST constants;
  1324 
  1325 * Pure/syntax: prefer later declarations of translations and print
  1326 translation functions; potential INCOMPATIBILITY: need to reverse
  1327 multiple declarations for same syntax element constant;
  1328 
  1329 * Pure/show_hyps reset by default (in accordance to existing Isar
  1330 practice);
  1331 
  1332 * Provers/classical: renamed addaltern to addafter, addSaltern to
  1333 addSafter;
  1334 
  1335 * Provers/clasimp: ``iff'' declarations now handle conditional rules
  1336 as well;
  1337 
  1338 * system: tested support for MacOS X; should be able to get Isabelle +
  1339 Proof General to work in a plain Terminal after installing Poly/ML
  1340 (e.g. from the Isabelle distribution area) and GNU bash alone
  1341 (e.g. from http://www.apple.com); full X11, XEmacs and X-Symbol
  1342 support requires further installations, e.g. from
  1343 http://fink.sourceforge.net/);
  1344 
  1345 * system: support Poly/ML 4.1.1 (able to manage larger heaps);
  1346 
  1347 * system: reduced base memory usage by Poly/ML (approx. 20 MB instead
  1348 of 40 MB), cf. ML_OPTIONS;
  1349 
  1350 * system: Proof General keywords specification is now part of the
  1351 Isabelle distribution (see etc/isar-keywords.el);
  1352 
  1353 * system: support for persistent Proof General sessions (refrain from
  1354 outdating all loaded theories on startup); user may create writable
  1355 logic images like this: ``isabelle -q HOL Test'';
  1356 
  1357 * system: smart selection of Isabelle process versus Isabelle
  1358 interface, accommodates case-insensitive file systems (e.g. HFS+); may
  1359 run both "isabelle" and "Isabelle" even if file names are badly
  1360 damaged (executable inspects the case of the first letter of its own
  1361 name); added separate "isabelle-process" and "isabelle-interface";
  1362 
  1363 * system: refrain from any attempt at filtering input streams; no
  1364 longer support ``8bit'' encoding of old isabelle font, instead proper
  1365 iso-latin characters may now be used; the related isatools
  1366 "symbolinput" and "nonascii" have disappeared as well;
  1367 
  1368 * system: removed old "xterm" interface (the print modes "xterm" and
  1369 "xterm_color" are still available for direct use in a suitable
  1370 terminal);
  1371 
  1372 
  1373 
  1374 New in Isabelle99-2 (February 2001)
  1375 -----------------------------------
  1376 
  1377 *** Overview of INCOMPATIBILITIES ***
  1378 
  1379 * HOL: please note that theories in the Library and elsewhere often use the
  1380 new-style (Isar) format; to refer to their theorems in an ML script you must
  1381 bind them to ML identifers by e.g.      val thm_name = thm "thm_name";
  1382 
  1383 * HOL: inductive package no longer splits induction rule aggressively,
  1384 but only as far as specified by the introductions given; the old
  1385 format may be recovered via ML function complete_split_rule or attribute
  1386 'split_rule (complete)';
  1387 
  1388 * HOL: induct renamed to lfp_induct, lfp_Tarski to lfp_unfold,
  1389 gfp_Tarski to gfp_unfold;
  1390 
  1391 * HOL: contrapos, contrapos2 renamed to contrapos_nn, contrapos_pp;
  1392 
  1393 * HOL: infix "dvd" now has priority 50 rather than 70 (because it is a
  1394 relation); infix "^^" has been renamed "``"; infix "``" has been
  1395 renamed "`"; "univalent" has been renamed "single_valued";
  1396 
  1397 * HOL/Real: "rinv" and "hrinv" replaced by overloaded "inverse"
  1398 operation;
  1399 
  1400 * HOLCF: infix "`" has been renamed "$"; the symbol syntax is \<cdot>;
  1401 
  1402 * Isar: 'obtain' no longer declares "that" fact as simp/intro;
  1403 
  1404 * Isar/HOL: method 'induct' now handles non-atomic goals; as a
  1405 consequence, it is no longer monotonic wrt. the local goal context
  1406 (which is now passed through the inductive cases);
  1407 
  1408 * Document preparation: renamed standard symbols \<ll> to \<lless> and
  1409 \<gg> to \<ggreater>;
  1410 
  1411 
  1412 *** Document preparation ***
  1413 
  1414 * \isabellestyle{NAME} selects version of Isabelle output (currently
  1415 available: are "it" for near math-mode best-style output, "sl" for
  1416 slanted text style, and "tt" for plain type-writer; if no
  1417 \isabellestyle command is given, output is according to slanted
  1418 type-writer);
  1419 
  1420 * support sub/super scripts (for single symbols only), input syntax is
  1421 like this: "A\<^sup>*" or "A\<^sup>\<star>";
  1422 
  1423 * some more standard symbols; see Appendix A of the system manual for
  1424 the complete list of symbols defined in isabellesym.sty;
  1425 
  1426 * improved isabelle style files; more abstract symbol implementation
  1427 (should now use \isamath{...} and \isatext{...} in custom symbol
  1428 definitions);
  1429 
  1430 * antiquotation @{goals} and @{subgoals} for output of *dynamic* goals
  1431 state; Note that presentation of goal states does not conform to
  1432 actual human-readable proof documents.  Please do not include goal
  1433 states into document output unless you really know what you are doing!
  1434 
  1435 * proper indentation of antiquoted output with proportional LaTeX
  1436 fonts;
  1437 
  1438 * no_document ML operator temporarily disables LaTeX document
  1439 generation;
  1440 
  1441 * isatool unsymbolize tunes sources for plain ASCII communication;
  1442 
  1443 
  1444 *** Isar ***
  1445 
  1446 * Pure: Isar now suffers initial goal statements to contain unbound
  1447 schematic variables (this does not conform to actual readable proof
  1448 documents, due to unpredictable outcome and non-compositional proof
  1449 checking); users who know what they are doing may use schematic goals
  1450 for Prolog-style synthesis of proven results;
  1451 
  1452 * Pure: assumption method (an implicit finishing) now handles actual
  1453 rules as well;
  1454 
  1455 * Pure: improved 'obtain' --- moved to Pure, insert "that" into
  1456 initial goal, declare "that" only as Pure intro (only for single
  1457 steps); the "that" rule assumption may now be involved in implicit
  1458 finishing, thus ".." becomes a feasible for trivial obtains;
  1459 
  1460 * Pure: default proof step now includes 'intro_classes'; thus trivial
  1461 instance proofs may be performed by "..";
  1462 
  1463 * Pure: ?thesis / ?this / "..." now work for pure meta-level
  1464 statements as well;
  1465 
  1466 * Pure: more robust selection of calculational rules;
  1467 
  1468 * Pure: the builtin notion of 'finished' goal now includes the ==-refl
  1469 rule (as well as the assumption rule);
  1470 
  1471 * Pure: 'thm_deps' command visualizes dependencies of theorems and
  1472 lemmas, using the graph browser tool;
  1473 
  1474 * Pure: predict failure of "show" in interactive mode;
  1475 
  1476 * Pure: 'thms_containing' now takes actual terms as arguments;
  1477 
  1478 * HOL: improved method 'induct' --- now handles non-atomic goals
  1479 (potential INCOMPATIBILITY); tuned error handling;
  1480 
  1481 * HOL: cases and induct rules now provide explicit hints about the
  1482 number of facts to be consumed (0 for "type" and 1 for "set" rules);
  1483 any remaining facts are inserted into the goal verbatim;
  1484 
  1485 * HOL: local contexts (aka cases) may now contain term bindings as
  1486 well; the 'cases' and 'induct' methods new provide a ?case binding for
  1487 the result to be shown in each case;
  1488 
  1489 * HOL: added 'recdef_tc' command;
  1490 
  1491 * isatool convert assists in eliminating legacy ML scripts;
  1492 
  1493 
  1494 *** HOL ***
  1495 
  1496 * HOL/Library: a collection of generic theories to be used together
  1497 with main HOL; the theory loader path already includes this directory
  1498 by default; the following existing theories have been moved here:
  1499 HOL/Induct/Multiset, HOL/Induct/Acc (as Accessible_Part), HOL/While
  1500 (as While_Combinator), HOL/Lex/Prefix (as List_Prefix);
  1501 
  1502 * HOL/Unix: "Some aspects of Unix file-system security", a typical
  1503 modelling and verification task performed in Isabelle/HOL +
  1504 Isabelle/Isar + Isabelle document preparation (by Markus Wenzel).
  1505 
  1506 * HOL/Algebra: special summation operator SUM no longer exists, it has
  1507 been replaced by setsum; infix 'assoc' now has priority 50 (like
  1508 'dvd'); axiom 'one_not_zero' has been moved from axclass 'ring' to
  1509 'domain', this makes the theory consistent with mathematical
  1510 literature;
  1511 
  1512 * HOL basics: added overloaded operations "inverse" and "divide"
  1513 (infix "/"), syntax for generic "abs" operation, generic summation
  1514 operator \<Sum>;
  1515 
  1516 * HOL/typedef: simplified package, provide more useful rules (see also
  1517 HOL/subset.thy);
  1518 
  1519 * HOL/datatype: induction rule for arbitrarily branching datatypes is
  1520 now expressed as a proper nested rule (old-style tactic scripts may
  1521 require atomize_strip_tac to cope with non-atomic premises);
  1522 
  1523 * HOL: renamed theory "Prod" to "Product_Type", renamed "split" rule
  1524 to "split_conv" (old name still available for compatibility);
  1525 
  1526 * HOL: improved concrete syntax for strings (e.g. allows translation
  1527 rules with string literals);
  1528 
  1529 * HOL-Real-Hyperreal: this extends HOL-Real with the hyperreals
  1530  and Fleuriot's mechanization of analysis, including the transcendental
  1531  functions for the reals;
  1532 
  1533 * HOL/Real, HOL/Hyperreal: improved arithmetic simplification;
  1534 
  1535 
  1536 *** CTT ***
  1537 
  1538 * CTT: x-symbol support for Pi, Sigma, -->, : (membership); note that
  1539 "lam" is displayed as TWO lambda-symbols
  1540 
  1541 * CTT: theory Main now available, containing everything (that is, Bool
  1542 and Arith);
  1543 
  1544 
  1545 *** General ***
  1546 
  1547 * Pure: the Simplifier has been implemented properly as a derived rule
  1548 outside of the actual kernel (at last!); the overall performance
  1549 penalty in practical applications is about 50%, while reliability of
  1550 the Isabelle inference kernel has been greatly improved;
  1551 
  1552 * print modes "brackets" and "no_brackets" control output of nested =>
  1553 (types) and ==> (props); the default behaviour is "brackets";
  1554 
  1555 * Provers: fast_tac (and friends) now handle actual object-logic rules
  1556 as assumptions as well;
  1557 
  1558 * system: support Poly/ML 4.0;
  1559 
  1560 * system: isatool install handles KDE version 1 or 2;
  1561 
  1562 
  1563 
  1564 New in Isabelle99-1 (October 2000)
  1565 ----------------------------------
  1566 
  1567 *** Overview of INCOMPATIBILITIES ***
  1568 
  1569 * HOL: simplification of natural numbers is much changed; to partly
  1570 recover the old behaviour (e.g. to prevent n+n rewriting to #2*n)
  1571 issue the following ML commands:
  1572 
  1573   Delsimprocs Nat_Numeral_Simprocs.cancel_numerals;
  1574   Delsimprocs [Nat_Numeral_Simprocs.combine_numerals];
  1575 
  1576 * HOL: simplification no longer dives into case-expressions; this is
  1577 controlled by "t.weak_case_cong" for each datatype t;
  1578 
  1579 * HOL: nat_less_induct renamed to less_induct;
  1580 
  1581 * HOL: systematic renaming of the SOME (Eps) rules, may use isatool
  1582 fixsome to patch .thy and .ML sources automatically;
  1583 
  1584   select_equality  -> some_equality
  1585   select_eq_Ex     -> some_eq_ex
  1586   selectI2EX       -> someI2_ex
  1587   selectI2         -> someI2
  1588   selectI          -> someI
  1589   select1_equality -> some1_equality
  1590   Eps_sym_eq       -> some_sym_eq_trivial
  1591   Eps_eq           -> some_eq_trivial
  1592 
  1593 * HOL: exhaust_tac on datatypes superceded by new generic case_tac;
  1594 
  1595 * HOL: removed obsolete theorem binding expand_if (refer to split_if
  1596 instead);
  1597 
  1598 * HOL: the recursion equations generated by 'recdef' are now called
  1599 f.simps instead of f.rules;
  1600 
  1601 * HOL: qed_spec_mp now also handles bounded ALL as well;
  1602 
  1603 * HOL: 0 is now overloaded, so the type constraint ":: nat" may
  1604 sometimes be needed;
  1605 
  1606 * HOL: the constant for "f``x" is now "image" rather than "op ``";
  1607 
  1608 * HOL: the constant for "f-``x" is now "vimage" rather than "op -``";
  1609 
  1610 * HOL: the disjoint sum is now "<+>" instead of "Plus"; the cartesian
  1611 product is now "<*>" instead of "Times"; the lexicographic product is
  1612 now "<*lex*>" instead of "**";
  1613 
  1614 * HOL: theory Sexp is now in HOL/Induct examples (it used to be part
  1615 of main HOL, but was unused); better use HOL's datatype package;
  1616 
  1617 * HOL: removed "symbols" syntax for constant "override" of theory Map;
  1618 the old syntax may be recovered as follows:
  1619 
  1620   syntax (symbols)
  1621     override  :: "('a ~=> 'b) => ('a ~=> 'b) => ('a ~=> 'b)"
  1622       (infixl "\\<oplus>" 100)
  1623 
  1624 * HOL/Real: "rabs" replaced by overloaded "abs" function;
  1625 
  1626 * HOL/ML: even fewer consts are declared as global (see theories Ord,
  1627 Lfp, Gfp, WF); this only affects ML packages that refer to const names
  1628 internally;
  1629 
  1630 * HOL and ZF: syntax for quotienting wrt an equivalence relation
  1631 changed from A/r to A//r;
  1632 
  1633 * ZF: new treatment of arithmetic (nat & int) may break some old
  1634 proofs;
  1635 
  1636 * Isar: renamed some attributes (RS -> THEN, simplify -> simplified,
  1637 rulify -> rule_format, elimify -> elim_format, ...);
  1638 
  1639 * Isar/Provers: intro/elim/dest attributes changed; renamed
  1640 intro/intro!/intro!! flags to intro!/intro/intro? (in most cases, one
  1641 should have to change intro!! to intro? only); replaced "delrule" by
  1642 "rule del";
  1643 
  1644 * Isar/HOL: renamed "intrs" to "intros" in inductive definitions;
  1645 
  1646 * Provers: strengthened force_tac by using new first_best_tac;
  1647 
  1648 * LaTeX document preparation: several changes of isabelle.sty (see
  1649 lib/texinputs);
  1650 
  1651 
  1652 *** Document preparation ***
  1653 
  1654 * formal comments (text blocks etc.) in new-style theories may now
  1655 contain antiquotations of thm/prop/term/typ/text to be presented
  1656 according to latex print mode; concrete syntax is like this:
  1657 @{term[show_types] "f(x) = a + x"};
  1658 
  1659 * isatool mkdir provides easy setup of Isabelle session directories,
  1660 including proper document sources;
  1661 
  1662 * generated LaTeX sources are now deleted after successful run
  1663 (isatool document -c); may retain a copy somewhere else via -D option
  1664 of isatool usedir;
  1665 
  1666 * isatool usedir -D now lets isatool latex -o sty update the Isabelle
  1667 style files, achieving self-contained LaTeX sources and simplifying
  1668 LaTeX debugging;
  1669 
  1670 * old-style theories now produce (crude) LaTeX output as well;
  1671 
  1672 * browser info session directories are now self-contained (may be put
  1673 on WWW server seperately); improved graphs of nested sessions; removed
  1674 graph for 'all sessions';
  1675 
  1676 * several improvements in isabelle style files; \isabellestyle{it}
  1677 produces fake math mode output; \isamarkupheader is now \section by
  1678 default; see lib/texinputs/isabelle.sty etc.;
  1679 
  1680 
  1681 *** Isar ***
  1682 
  1683 * Isar/Pure: local results and corresponding term bindings are now
  1684 subject to Hindley-Milner polymorphism (similar to ML); this
  1685 accommodates incremental type-inference very nicely;
  1686 
  1687 * Isar/Pure: new derived language element 'obtain' supports
  1688 generalized existence reasoning;
  1689 
  1690 * Isar/Pure: new calculational elements 'moreover' and 'ultimately'
  1691 support accumulation of results, without applying any rules yet;
  1692 useful to collect intermediate results without explicit name
  1693 references, and for use with transitivity rules with more than 2
  1694 premises;
  1695 
  1696 * Isar/Pure: scalable support for case-analysis type proofs: new
  1697 'case' language element refers to local contexts symbolically, as
  1698 produced by certain proof methods; internally, case names are attached
  1699 to theorems as "tags";
  1700 
  1701 * Isar/Pure: theory command 'hide' removes declarations from
  1702 class/type/const name spaces;
  1703 
  1704 * Isar/Pure: theory command 'defs' supports option "(overloaded)" to
  1705 indicate potential overloading;
  1706 
  1707 * Isar/Pure: changed syntax of local blocks from {{ }} to { };
  1708 
  1709 * Isar/Pure: syntax of sorts made 'inner', i.e. have to write
  1710 "{a,b,c}" instead of {a,b,c};
  1711 
  1712 * Isar/Pure now provides its own version of intro/elim/dest
  1713 attributes; useful for building new logics, but beware of confusion
  1714 with the version in Provers/classical;
  1715 
  1716 * Isar/Pure: the local context of (non-atomic) goals is provided via
  1717 case name 'antecedent';
  1718 
  1719 * Isar/Pure: removed obsolete 'transfer' attribute (transfer of thms
  1720 to the current context is now done automatically);
  1721 
  1722 * Isar/Pure: theory command 'method_setup' provides a simple interface
  1723 for definining proof methods in ML;
  1724 
  1725 * Isar/Provers: intro/elim/dest attributes changed; renamed
  1726 intro/intro!/intro!! flags to intro!/intro/intro? (INCOMPATIBILITY, in
  1727 most cases, one should have to change intro!! to intro? only);
  1728 replaced "delrule" by "rule del";
  1729 
  1730 * Isar/Provers: new 'hypsubst' method, plain 'subst' method and
  1731 'symmetric' attribute (the latter supercedes [RS sym]);
  1732 
  1733 * Isar/Provers: splitter support (via 'split' attribute and 'simp'
  1734 method modifier); 'simp' method: 'only:' modifier removes loopers as
  1735 well (including splits);
  1736 
  1737 * Isar/Provers: Simplifier and Classical methods now support all kind
  1738 of modifiers used in the past, including 'cong', 'iff', etc.
  1739 
  1740 * Isar/Provers: added 'fastsimp' and 'clarsimp' methods (combination
  1741 of Simplifier and Classical reasoner);
  1742 
  1743 * Isar/HOL: new proof method 'cases' and improved version of 'induct'
  1744 now support named cases; major packages (inductive, datatype, primrec,
  1745 recdef) support case names and properly name parameters;
  1746 
  1747 * Isar/HOL: new transitivity rules for substitution in inequalities --
  1748 monotonicity conditions are extracted to be proven at end of
  1749 calculations;
  1750 
  1751 * Isar/HOL: removed 'case_split' thm binding, should use 'cases' proof
  1752 method anyway;
  1753 
  1754 * Isar/HOL: removed old expand_if = split_if; theorems if_splits =
  1755 split_if split_if_asm; datatype package provides theorems foo.splits =
  1756 foo.split foo.split_asm for each datatype;
  1757 
  1758 * Isar/HOL: tuned inductive package, rename "intrs" to "intros"
  1759 (potential INCOMPATIBILITY), emulation of mk_cases feature for proof
  1760 scripts: new 'inductive_cases' command and 'ind_cases' method; (Note:
  1761 use "(cases (simplified))" method in proper proof texts);
  1762 
  1763 * Isar/HOL: added global 'arith_split' attribute for 'arith' method;
  1764 
  1765 * Isar: names of theorems etc. may be natural numbers as well;
  1766 
  1767 * Isar: 'pr' command: optional arguments for goals_limit and
  1768 ProofContext.prems_limit; no longer prints theory contexts, but only
  1769 proof states;
  1770 
  1771 * Isar: diagnostic commands 'pr', 'thm', 'prop', 'term', 'typ' admit
  1772 additional print modes to be specified; e.g. "pr(latex)" will print
  1773 proof state according to the Isabelle LaTeX style;
  1774 
  1775 * Isar: improved support for emulating tactic scripts, including proof
  1776 methods 'rule_tac' etc., 'cut_tac', 'thin_tac', 'subgoal_tac',
  1777 'rename_tac', 'rotate_tac', 'tactic', and 'case_tac' / 'induct_tac'
  1778 (for HOL datatypes);
  1779 
  1780 * Isar: simplified (more robust) goal selection of proof methods: 1st
  1781 goal, all goals, or explicit goal specifier (tactic emulation); thus
  1782 'proof method scripts' have to be in depth-first order;
  1783 
  1784 * Isar: tuned 'let' syntax: replaced 'as' keyword by 'and';
  1785 
  1786 * Isar: removed 'help' command, which hasn't been too helpful anyway;
  1787 should instead use individual commands for printing items
  1788 (print_commands, print_methods etc.);
  1789 
  1790 * Isar: added 'nothing' --- the empty list of theorems;
  1791 
  1792 
  1793 *** HOL ***
  1794 
  1795 * HOL/MicroJava: formalization of a fragment of Java, together with a
  1796 corresponding virtual machine and a specification of its bytecode
  1797 verifier and a lightweight bytecode verifier, including proofs of
  1798 type-safety; by Gerwin Klein, Tobias Nipkow, David von Oheimb, and
  1799 Cornelia Pusch (see also the homepage of project Bali at
  1800 http://isabelle.in.tum.de/Bali/);
  1801 
  1802 * HOL/Algebra: new theory of rings and univariate polynomials, by
  1803 Clemens Ballarin;
  1804 
  1805 * HOL/NumberTheory: fundamental Theorem of Arithmetic, Chinese
  1806 Remainder Theorem, Fermat/Euler Theorem, Wilson's Theorem, by Thomas M
  1807 Rasmussen;
  1808 
  1809 * HOL/Lattice: fundamental concepts of lattice theory and order
  1810 structures, including duals, properties of bounds versus algebraic
  1811 laws, lattice operations versus set-theoretic ones, the Knaster-Tarski
  1812 Theorem for complete lattices etc.; may also serve as a demonstration
  1813 for abstract algebraic reasoning using axiomatic type classes, and
  1814 mathematics-style proof in Isabelle/Isar; by Markus Wenzel;
  1815 
  1816 * HOL/Prolog: a (bare-bones) implementation of Lambda-Prolog, by David
  1817 von Oheimb;
  1818 
  1819 * HOL/IMPP: extension of IMP with local variables and mutually
  1820 recursive procedures, by David von Oheimb;
  1821 
  1822 * HOL/Lambda: converted into new-style theory and document;
  1823 
  1824 * HOL/ex/Multiquote: example of multiple nested quotations and
  1825 anti-quotations -- basically a generalized version of de-Bruijn
  1826 representation; very useful in avoiding lifting of operations;
  1827 
  1828 * HOL/record: added general record equality rule to simpset; fixed
  1829 select-update simplification procedure to handle extended records as
  1830 well; admit "r" as field name;
  1831 
  1832 * HOL: 0 is now overloaded over the new sort "zero", allowing its use with
  1833 other numeric types and also as the identity of groups, rings, etc.;
  1834 
  1835 * HOL: new axclass plus_ac0 for addition with the AC-laws and 0 as identity.
  1836 Types nat and int belong to this axclass;
  1837 
  1838 * HOL: greatly improved simplification involving numerals of type nat, int, real:
  1839    (i + #8 + j) = Suc k simplifies to  #7 + (i + j) = k
  1840    i*j + k + j*#3*i     simplifies to  #4*(i*j) + k
  1841   two terms #m*u and #n*u are replaced by #(m+n)*u
  1842     (where #m, #n and u can implicitly be 1; this is simproc combine_numerals)
  1843   and the term/formula #m*u+x ~~ #n*u+y simplifies simplifies to #(m-n)+x ~~ y
  1844     or x ~~ #(n-m)+y, where ~~ is one of = < <= or - (simproc cancel_numerals);
  1845 
  1846 * HOL: meson_tac is available (previously in ex/meson.ML); it is a
  1847 powerful prover for predicate logic but knows nothing of clasets; see
  1848 ex/mesontest.ML and ex/mesontest2.ML for example applications;
  1849 
  1850 * HOL: new version of "case_tac" subsumes both boolean case split and
  1851 "exhaust_tac" on datatypes; INCOMPATIBILITY: exhaust_tac no longer
  1852 exists, may define val exhaust_tac = case_tac for ad-hoc portability;
  1853 
  1854 * HOL: simplification no longer dives into case-expressions: only the
  1855 selector expression is simplified, but not the remaining arms; to
  1856 enable full simplification of case-expressions for datatype t, you may
  1857 remove t.weak_case_cong from the simpset, either globally (Delcongs
  1858 [thm"t.weak_case_cong"];) or locally (delcongs [...]).
  1859 
  1860 * HOL/recdef: the recursion equations generated by 'recdef' for
  1861 function 'f' are now called f.simps instead of f.rules; if all
  1862 termination conditions are proved automatically, these simplification
  1863 rules are added to the simpset, as in primrec; rules may be named
  1864 individually as well, resulting in a separate list of theorems for
  1865 each equation;
  1866 
  1867 * HOL/While is a new theory that provides a while-combinator. It
  1868 permits the definition of tail-recursive functions without the
  1869 provision of a termination measure. The latter is necessary once the
  1870 invariant proof rule for while is applied.
  1871 
  1872 * HOL: new (overloaded) notation for the set of elements below/above
  1873 some element: {..u}, {..u(}, {l..}, {)l..}. See theory SetInterval.
  1874 
  1875 * HOL: theorems impI, allI, ballI bound as "strip";
  1876 
  1877 * HOL: new tactic induct_thm_tac: thm -> string -> int -> tactic
  1878 induct_tac th "x1 ... xn" expects th to have a conclusion of the form
  1879 P v1 ... vn and abbreviates res_inst_tac [("v1","x1"),...,("vn","xn")] th;
  1880 
  1881 * HOL/Real: "rabs" replaced by overloaded "abs" function;
  1882 
  1883 * HOL: theory Sexp now in HOL/Induct examples (it used to be part of
  1884 main HOL, but was unused);
  1885 
  1886 * HOL: fewer consts declared as global (e.g. have to refer to
  1887 "Lfp.lfp" instead of "lfp" internally; affects ML packages only);
  1888 
  1889 * HOL: tuned AST representation of nested pairs, avoiding bogus output
  1890 in case of overlap with user translations (e.g. judgements over
  1891 tuples); (note that the underlying logical represenation is still
  1892 bogus);
  1893 
  1894 
  1895 *** ZF ***
  1896 
  1897 * ZF: simplification automatically cancels common terms in arithmetic
  1898 expressions over nat and int;
  1899 
  1900 * ZF: new treatment of nat to minimize type-checking: all operators
  1901 coerce their operands to a natural number using the function natify,
  1902 making the algebraic laws unconditional;
  1903 
  1904 * ZF: as above, for int: operators coerce their operands to an integer
  1905 using the function intify;
  1906 
  1907 * ZF: the integer library now contains many of the usual laws for the
  1908 orderings, including $<=, and monotonicity laws for $+ and $*;
  1909 
  1910 * ZF: new example ZF/ex/NatSum to demonstrate integer arithmetic
  1911 simplification;
  1912 
  1913 * FOL and ZF: AddIffs now available, giving theorems of the form P<->Q
  1914 to the simplifier and classical reasoner simultaneously;
  1915 
  1916 
  1917 *** General ***
  1918 
  1919 * Provers: blast_tac now handles actual object-logic rules as
  1920 assumptions; note that auto_tac uses blast_tac internally as well;
  1921 
  1922 * Provers: new functions rulify/rulify_no_asm: thm -> thm for turning
  1923 outer -->/All/Ball into ==>/!!; qed_spec_mp now uses rulify_no_asm;
  1924 
  1925 * Provers: delrules now handles destruct rules as well (no longer need
  1926 explicit make_elim);
  1927 
  1928 * Provers: Blast_tac now warns of and ignores "weak elimination rules" e.g.
  1929   [| inj ?f;          ?f ?x = ?f ?y; ?x = ?y ==> ?W |] ==> ?W
  1930 use instead the strong form,
  1931   [| inj ?f; ~ ?W ==> ?f ?x = ?f ?y; ?x = ?y ==> ?W |] ==> ?W
  1932 in HOL, FOL and ZF the function cla_make_elim will create such rules
  1933 from destruct-rules;
  1934 
  1935 * Provers: Simplifier.easy_setup provides a fast path to basic
  1936 Simplifier setup for new object-logics;
  1937 
  1938 * Pure: AST translation rules no longer require constant head on LHS;
  1939 
  1940 * Pure: improved name spaces: ambiguous output is qualified; support
  1941 for hiding of names;
  1942 
  1943 * system: smart setup of canonical ML_HOME, ISABELLE_INTERFACE, and
  1944 XSYMBOL_HOME; no longer need to do manual configuration in most
  1945 situations;
  1946 
  1947 * system: compression of ML heaps images may now be controlled via -c
  1948 option of isabelle and isatool usedir (currently only observed by
  1949 Poly/ML);
  1950 
  1951 * system: isatool installfonts may handle X-Symbol fonts as well (very
  1952 useful for remote X11);
  1953 
  1954 * system: provide TAGS file for Isabelle sources;
  1955 
  1956 * ML: infix 'OF' is a version of 'MRS' with more appropriate argument
  1957 order;
  1958 
  1959 * ML: renamed flags Syntax.trace_norm_ast to Syntax.trace_ast; global
  1960 timing flag supersedes proof_timing and Toplevel.trace;
  1961 
  1962 * ML: new combinators |>> and |>>> for incremental transformations
  1963 with secondary results (e.g. certain theory extensions):
  1964 
  1965 * ML: PureThy.add_defs gets additional argument to indicate potential
  1966 overloading (usually false);
  1967 
  1968 * ML: PureThy.add_thms/add_axioms/add_defs now return theorems as
  1969 results;
  1970 
  1971 
  1972 
  1973 New in Isabelle99 (October 1999)
  1974 --------------------------------
  1975 
  1976 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  1977 
  1978 * HOL: The THEN and ELSE parts of conditional expressions (if P then x else y)
  1979 are no longer simplified.  (This allows the simplifier to unfold recursive
  1980 functional programs.)  To restore the old behaviour, declare
  1981 
  1982     Delcongs [if_weak_cong];
  1983 
  1984 * HOL: Removed the obsolete syntax "Compl A"; use -A for set
  1985 complement;
  1986 
  1987 * HOL: the predicate "inj" is now defined by translation to "inj_on";
  1988 
  1989 * HOL/datatype: mutual_induct_tac no longer exists --
  1990   use induct_tac "x_1 ... x_n" instead of mutual_induct_tac ["x_1", ..., "x_n"]
  1991 
  1992 * HOL/typedef: fixed type inference for representing set; type
  1993 arguments now have to occur explicitly on the rhs as type constraints;
  1994 
  1995 * ZF: The con_defs part of an inductive definition may no longer refer
  1996 to constants declared in the same theory;
  1997 
  1998 * HOL, ZF: the function mk_cases, generated by the inductive
  1999 definition package, has lost an argument.  To simplify its result, it
  2000 uses the default simpset instead of a supplied list of theorems.
  2001 
  2002 * HOL/List: the constructors of type list are now Nil and Cons;
  2003 
  2004 * Simplifier: the type of the infix ML functions
  2005         setSSolver addSSolver setSolver addSolver
  2006 is now  simpset * solver -> simpset  where `solver' is a new abstract type
  2007 for packaging solvers. A solver is created via
  2008         mk_solver: string -> (thm list -> int -> tactic) -> solver
  2009 where the string argument is only a comment.
  2010 
  2011 
  2012 *** Proof tools ***
  2013 
  2014 * Provers/Arith/fast_lin_arith.ML contains a functor for creating a
  2015 decision procedure for linear arithmetic. Currently it is used for
  2016 types `nat', `int', and `real' in HOL (see below); it can, should and
  2017 will be instantiated for other types and logics as well.
  2018 
  2019 * The simplifier now accepts rewrite rules with flexible heads, eg
  2020      hom ?f ==> ?f(?x+?y) = ?f ?x + ?f ?y
  2021   They are applied like any rule with a non-pattern lhs, i.e. by first-order
  2022   matching.
  2023 
  2024 
  2025 *** General ***
  2026 
  2027 * New Isabelle/Isar subsystem provides an alternative to traditional
  2028 tactical theorem proving; together with the ProofGeneral/isar user
  2029 interface it offers an interactive environment for developing human
  2030 readable proof documents (Isar == Intelligible semi-automated
  2031 reasoning); for further information see isatool doc isar-ref,
  2032 src/HOL/Isar_examples and http://isabelle.in.tum.de/Isar/
  2033 
  2034 * improved and simplified presentation of theories: better HTML markup
  2035 (including colors), graph views in several sizes; isatool usedir now
  2036 provides a proper interface for user theories (via -P option); actual
  2037 document preparation based on (PDF)LaTeX is available as well (for
  2038 new-style theories only); see isatool doc system for more information;
  2039 
  2040 * native support for Proof General, both for classic Isabelle and
  2041 Isabelle/Isar;
  2042 
  2043 * ML function thm_deps visualizes dependencies of theorems and lemmas,
  2044 using the graph browser tool;
  2045 
  2046 * Isabelle manuals now also available as PDF;
  2047 
  2048 * theory loader rewritten from scratch (may not be fully
  2049 bug-compatible); old loadpath variable has been replaced by show_path,
  2050 add_path, del_path, reset_path functions; new operations such as
  2051 update_thy, touch_thy, remove_thy, use/update_thy_only (see also
  2052 isatool doc ref);
  2053 
  2054 * improved isatool install: option -k creates KDE application icon,
  2055 option -p DIR installs standalone binaries;
  2056 
  2057 * added ML_PLATFORM setting (useful for cross-platform installations);
  2058 more robust handling of platform specific ML images for SML/NJ;
  2059 
  2060 * the settings environment is now statically scoped, i.e. it is never
  2061 created again in sub-processes invoked from isabelle, isatool, or
  2062 Isabelle;
  2063 
  2064 * path element specification '~~' refers to '$ISABELLE_HOME';
  2065 
  2066 * in locales, the "assumes" and "defines" parts may be omitted if
  2067 empty;
  2068 
  2069 * new print_mode "xsymbols" for extended symbol support (e.g. genuine
  2070 long arrows);
  2071 
  2072 * new print_mode "HTML";
  2073 
  2074 * new flag show_tags controls display of tags of theorems (which are
  2075 basically just comments that may be attached by some tools);
  2076 
  2077 * Isamode 2.6 requires patch to accomodate change of Isabelle font
  2078 mode and goal output format:
  2079 
  2080 diff -r Isamode-2.6/elisp/isa-load.el Isamode/elisp/isa-load.el
  2081 244c244
  2082 <       (list (isa-getenv "ISABELLE") "-msymbols" logic-name)
  2083 ---
  2084 >       (list (isa-getenv "ISABELLE") "-misabelle_font" "-msymbols" logic-name)
  2085 diff -r Isabelle-2.6/elisp/isa-proofstate.el Isamode/elisp/isa-proofstate.el
  2086 181c181
  2087 < (defconst proofstate-proofstart-regexp "^Level [0-9]+$"
  2088 ---
  2089 > (defconst proofstate-proofstart-regexp "^Level [0-9]+"
  2090 
  2091 * function bind_thms stores lists of theorems (cf. bind_thm);
  2092 
  2093 * new shorthand tactics ftac, eatac, datac, fatac;
  2094 
  2095 * qed (and friends) now accept "" as result name; in that case the
  2096 theorem is not stored, but proper checks and presentation of the
  2097 result still apply;
  2098 
  2099 * theorem database now also indexes constants "Trueprop", "all",
  2100 "==>", "=="; thus thms_containing, findI etc. may retrieve more rules;
  2101 
  2102 
  2103 *** HOL ***
  2104 
  2105 ** HOL arithmetic **
  2106 
  2107 * There are now decision procedures for linear arithmetic over nat and
  2108 int:
  2109 
  2110 1. arith_tac copes with arbitrary formulae involving `=', `<', `<=',
  2111 `+', `-', `Suc', `min', `max' and numerical constants; other subterms
  2112 are treated as atomic; subformulae not involving type `nat' or `int'
  2113 are ignored; quantified subformulae are ignored unless they are
  2114 positive universal or negative existential. The tactic has to be
  2115 invoked by hand and can be a little bit slow. In particular, the
  2116 running time is exponential in the number of occurrences of `min' and
  2117 `max', and `-' on `nat'.
  2118 
  2119 2. fast_arith_tac is a cut-down version of arith_tac: it only takes
  2120 (negated) (in)equalities among the premises and the conclusion into
  2121 account (i.e. no compound formulae) and does not know about `min' and
  2122 `max', and `-' on `nat'. It is fast and is used automatically by the
  2123 simplifier.
  2124 
  2125 NB: At the moment, these decision procedures do not cope with mixed
  2126 nat/int formulae where the two parts interact, such as `m < n ==>
  2127 int(m) < int(n)'.
  2128 
  2129 * HOL/Numeral provides a generic theory of numerals (encoded
  2130 efficiently as bit strings); setup for types nat/int/real is in place;
  2131 INCOMPATIBILITY: since numeral syntax is now polymorphic, rather than
  2132 int, existing theories and proof scripts may require a few additional
  2133 type constraints;
  2134 
  2135 * integer division and remainder can now be performed on constant
  2136 arguments;
  2137 
  2138 * many properties of integer multiplication, division and remainder
  2139 are now available;
  2140 
  2141 * An interface to the Stanford Validity Checker (SVC) is available through the
  2142 tactic svc_tac.  Propositional tautologies and theorems of linear arithmetic
  2143 are proved automatically.  SVC must be installed separately, and its results
  2144 must be TAKEN ON TRUST (Isabelle does not check the proofs, but tags any
  2145 invocation of the underlying oracle).  For SVC see
  2146   http://verify.stanford.edu/SVC
  2147 
  2148 * IsaMakefile: the HOL-Real target now builds an actual image;
  2149 
  2150 
  2151 ** HOL misc **
  2152 
  2153 * HOL/Real/HahnBanach: the Hahn-Banach theorem for real vector spaces
  2154 (in Isabelle/Isar) -- by Gertrud Bauer;
  2155 
  2156 * HOL/BCV: generic model of bytecode verification, i.e. data-flow
  2157 analysis for assembly languages with subtypes;
  2158 
  2159 * HOL/TLA (Lamport's Temporal Logic of Actions): major reorganization
  2160 -- avoids syntactic ambiguities and treats state, transition, and
  2161 temporal levels more uniformly; introduces INCOMPATIBILITIES due to
  2162 changed syntax and (many) tactics;
  2163 
  2164 * HOL/inductive: Now also handles more general introduction rules such
  2165   as "ALL y. (y, x) : r --> y : acc r ==> x : acc r"; monotonicity
  2166   theorems are now maintained within the theory (maintained via the
  2167   "mono" attribute);
  2168 
  2169 * HOL/datatype: Now also handles arbitrarily branching datatypes
  2170   (using function types) such as
  2171 
  2172   datatype 'a tree = Atom 'a | Branch "nat => 'a tree"
  2173 
  2174 * HOL/record: record_simproc (part of the default simpset) takes care
  2175 of selectors applied to updated records; record_split_tac is no longer
  2176 part of the default claset; update_defs may now be removed from the
  2177 simpset in many cases; COMPATIBILITY: old behavior achieved by
  2178 
  2179   claset_ref () := claset() addSWrapper record_split_wrapper;
  2180   Delsimprocs [record_simproc]
  2181 
  2182 * HOL/typedef: fixed type inference for representing set; type
  2183 arguments now have to occur explicitly on the rhs as type constraints;
  2184 
  2185 * HOL/recdef (TFL): 'congs' syntax now expects comma separated list of theorem
  2186 names rather than an ML expression;
  2187 
  2188 * HOL/defer_recdef (TFL): like recdef but the well-founded relation can be
  2189 supplied later.  Program schemes can be defined, such as
  2190     "While B C s = (if B s then While B C (C s) else s)"
  2191 where the well-founded relation can be chosen after B and C have been given.
  2192 
  2193 * HOL/List: the constructors of type list are now Nil and Cons;
  2194 INCOMPATIBILITY: while [] and infix # syntax is still there, of
  2195 course, ML tools referring to List.list.op # etc. have to be adapted;
  2196 
  2197 * HOL_quantifiers flag superseded by "HOL" print mode, which is
  2198 disabled by default; run isabelle with option -m HOL to get back to
  2199 the original Gordon/HOL-style output;
  2200 
  2201 * HOL/Ord.thy: new bounded quantifier syntax (input only): ALL x<y. P,
  2202 ALL x<=y. P, EX x<y. P, EX x<=y. P;
  2203 
  2204 * HOL basic syntax simplified (more orthogonal): all variants of
  2205 All/Ex now support plain / symbolic / HOL notation; plain syntax for
  2206 Eps operator is provided as well: "SOME x. P[x]";
  2207 
  2208 * HOL/Sum.thy: sum_case has been moved to HOL/Datatype;
  2209 
  2210 * HOL/Univ.thy: infix syntax <*>, <+>, <**>, <+> eliminated and made
  2211 thus available for user theories;
  2212 
  2213 * HOLCF/IOA/Sequents: renamed 'Cons' to 'Consq' to avoid clash with
  2214 HOL/List; hardly an INCOMPATIBILITY since '>>' syntax is used all the
  2215 time;
  2216 
  2217 * HOL: new tactic smp_tac: int -> int -> tactic, which applies spec
  2218 several times and then mp;
  2219 
  2220 
  2221 *** LK ***
  2222 
  2223 * the notation <<...>> is now available as a notation for sequences of
  2224 formulas;
  2225 
  2226 * the simplifier is now installed
  2227 
  2228 * the axiom system has been generalized (thanks to Soren Heilmann)
  2229 
  2230 * the classical reasoner now has a default rule database
  2231 
  2232 
  2233 *** ZF ***
  2234 
  2235 * new primrec section allows primitive recursive functions to be given
  2236 directly (as in HOL) over datatypes and the natural numbers;
  2237 
  2238 * new tactics induct_tac and exhaust_tac for induction (or case
  2239 analysis) over datatypes and the natural numbers;
  2240 
  2241 * the datatype declaration of type T now defines the recursor T_rec;
  2242 
  2243 * simplification automatically does freeness reasoning for datatype
  2244 constructors;
  2245 
  2246 * automatic type-inference, with AddTCs command to insert new
  2247 type-checking rules;
  2248 
  2249 * datatype introduction rules are now added as Safe Introduction rules
  2250 to the claset;
  2251 
  2252 * the syntax "if P then x else y" is now available in addition to
  2253 if(P,x,y);
  2254 
  2255 
  2256 *** Internal programming interfaces ***
  2257 
  2258 * tuned simplifier trace output; new flag debug_simp;
  2259 
  2260 * structures Vartab / Termtab (instances of TableFun) offer efficient
  2261 tables indexed by indexname_ord / term_ord (compatible with aconv);
  2262 
  2263 * AxClass.axclass_tac lost the theory argument;
  2264 
  2265 * tuned current_goals_markers semantics: begin / end goal avoids
  2266 printing empty lines;
  2267 
  2268 * removed prs and prs_fn hook, which was broken because it did not
  2269 include \n in its semantics, forcing writeln to add one
  2270 uncoditionally; replaced prs_fn by writeln_fn; consider std_output:
  2271 string -> unit if you really want to output text without newline;
  2272 
  2273 * Symbol.output subject to print mode; INCOMPATIBILITY: defaults to
  2274 plain output, interface builders may have to enable 'isabelle_font'
  2275 mode to get Isabelle font glyphs as before;
  2276 
  2277 * refined token_translation interface; INCOMPATIBILITY: output length
  2278 now of type real instead of int;
  2279 
  2280 * theory loader actions may be traced via new ThyInfo.add_hook
  2281 interface (see src/Pure/Thy/thy_info.ML); example application: keep
  2282 your own database of information attached to *whole* theories -- as
  2283 opposed to intra-theory data slots offered via TheoryDataFun;
  2284 
  2285 * proper handling of dangling sort hypotheses (at last!);
  2286 Thm.strip_shyps and Drule.strip_shyps_warning take care of removing
  2287 extra sort hypotheses that can be witnessed from the type signature;
  2288 the force_strip_shyps flag is gone, any remaining shyps are simply
  2289 left in the theorem (with a warning issued by strip_shyps_warning);
  2290 
  2291 
  2292 
  2293 New in Isabelle98-1 (October 1998)
  2294 ----------------------------------
  2295 
  2296 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  2297 
  2298 * several changes of automated proof tools;
  2299 
  2300 * HOL: major changes to the inductive and datatype packages, including
  2301 some minor incompatibilities of theory syntax;
  2302 
  2303 * HOL: renamed r^-1 to 'converse' from 'inverse'; 'inj_onto' is now
  2304 called `inj_on';
  2305 
  2306 * HOL: removed duplicate thms in Arith:
  2307   less_imp_add_less  should be replaced by  trans_less_add1
  2308   le_imp_add_le      should be replaced by  trans_le_add1
  2309 
  2310 * HOL: unary minus is now overloaded (new type constraints may be
  2311 required);
  2312 
  2313 * HOL and ZF: unary minus for integers is now #- instead of #~.  In
  2314 ZF, expressions such as n#-1 must be changed to n#- 1, since #-1 is
  2315 now taken as an integer constant.
  2316 
  2317 * Pure: ML function 'theory_of' renamed to 'theory';
  2318 
  2319 
  2320 *** Proof tools ***
  2321 
  2322 * Simplifier:
  2323   1. Asm_full_simp_tac is now more aggressive.
  2324      1. It will sometimes reorient premises if that increases their power to
  2325         simplify.
  2326      2. It does no longer proceed strictly from left to right but may also
  2327         rotate premises to achieve further simplification.
  2328      For compatibility reasons there is now Asm_lr_simp_tac which is like the
  2329      old Asm_full_simp_tac in that it does not rotate premises.
  2330   2. The simplifier now knows a little bit about nat-arithmetic.
  2331 
  2332 * Classical reasoner: wrapper mechanism for the classical reasoner now
  2333 allows for selected deletion of wrappers, by introduction of names for
  2334 wrapper functionals.  This implies that addbefore, addSbefore,
  2335 addaltern, and addSaltern now take a pair (name, tactic) as argument,
  2336 and that adding two tactics with the same name overwrites the first
  2337 one (emitting a warning).
  2338   type wrapper = (int -> tactic) -> (int -> tactic)
  2339   setWrapper, setSWrapper, compWrapper and compSWrapper are replaced by
  2340   addWrapper, addSWrapper: claset * (string * wrapper) -> claset
  2341   delWrapper, delSWrapper: claset *  string            -> claset
  2342   getWrapper is renamed to appWrappers, getSWrapper to appSWrappers;
  2343 
  2344 * Classical reasoner: addbefore/addSbefore now have APPEND/ORELSE
  2345 semantics; addbefore now affects only the unsafe part of step_tac
  2346 etc.; this affects addss/auto_tac/force_tac, so EXISTING PROOFS MAY
  2347 FAIL, but proofs should be fixable easily, e.g. by replacing Auto_tac
  2348 by Force_tac;
  2349 
  2350 * Classical reasoner: setwrapper to setWrapper and compwrapper to
  2351 compWrapper; added safe wrapper (and access functions for it);
  2352 
  2353 * HOL/split_all_tac is now much faster and fails if there is nothing
  2354 to split.  Some EXISTING PROOFS MAY REQUIRE ADAPTION because the order
  2355 and the names of the automatically generated variables have changed.
  2356 split_all_tac has moved within claset() from unsafe wrappers to safe
  2357 wrappers, which means that !!-bound variables are split much more
  2358 aggressively, and safe_tac and clarify_tac now split such variables.
  2359 If this splitting is not appropriate, use delSWrapper "split_all_tac".
  2360 Note: the same holds for record_split_tac, which does the job of
  2361 split_all_tac for record fields.
  2362 
  2363 * HOL/Simplifier: Rewrite rules for case distinctions can now be added
  2364 permanently to the default simpset using Addsplits just like
  2365 Addsimps. They can be removed via Delsplits just like
  2366 Delsimps. Lower-case versions are also available.
  2367 
  2368 * HOL/Simplifier: The rule split_if is now part of the default
  2369 simpset. This means that the simplifier will eliminate all occurrences
  2370 of if-then-else in the conclusion of a goal. To prevent this, you can
  2371 either remove split_if completely from the default simpset by
  2372 `Delsplits [split_if]' or remove it in a specific call of the
  2373 simplifier using `... delsplits [split_if]'.  You can also add/delete
  2374 other case splitting rules to/from the default simpset: every datatype
  2375 generates suitable rules `split_t_case' and `split_t_case_asm' (where
  2376 t is the name of the datatype).
  2377 
  2378 * Classical reasoner / Simplifier combination: new force_tac (and
  2379 derivatives Force_tac, force) combines rewriting and classical
  2380 reasoning (and whatever other tools) similarly to auto_tac, but is
  2381 aimed to solve the given subgoal completely.
  2382 
  2383 
  2384 *** General ***
  2385 
  2386 * new top-level commands `Goal' and `Goalw' that improve upon `goal'
  2387 and `goalw': the theory is no longer needed as an explicit argument -
  2388 the current theory context is used; assumptions are no longer returned
  2389 at the ML-level unless one of them starts with ==> or !!; it is
  2390 recommended to convert to these new commands using isatool fixgoal
  2391 (backup your sources first!);
  2392 
  2393 * new top-level commands 'thm' and 'thms' for retrieving theorems from
  2394 the current theory context, and 'theory' to lookup stored theories;
  2395 
  2396 * new theory section 'locale' for declaring constants, assumptions and
  2397 definitions that have local scope;
  2398 
  2399 * new theory section 'nonterminals' for purely syntactic types;
  2400 
  2401 * new theory section 'setup' for generic ML setup functions
  2402 (e.g. package initialization);
  2403 
  2404 * the distribution now includes Isabelle icons: see
  2405 lib/logo/isabelle-{small,tiny}.xpm;
  2406 
  2407 * isatool install - install binaries with absolute references to
  2408 ISABELLE_HOME/bin;
  2409 
  2410 * isatool logo -- create instances of the Isabelle logo (as EPS);
  2411 
  2412 * print mode 'emacs' reserved for Isamode;
  2413 
  2414 * support multiple print (ast) translations per constant name;
  2415 
  2416 * theorems involving oracles are now printed with a suffixed [!];
  2417 
  2418 
  2419 *** HOL ***
  2420 
  2421 * there is now a tutorial on Isabelle/HOL (do 'isatool doc tutorial');
  2422 
  2423 * HOL/inductive package reorganized and improved: now supports mutual
  2424 definitions such as
  2425 
  2426   inductive EVEN ODD
  2427     intrs
  2428       null "0 : EVEN"
  2429       oddI "n : EVEN ==> Suc n : ODD"
  2430       evenI "n : ODD ==> Suc n : EVEN"
  2431 
  2432 new theorem list "elims" contains an elimination rule for each of the
  2433 recursive sets; inductive definitions now handle disjunctive premises
  2434 correctly (also ZF);
  2435 
  2436 INCOMPATIBILITIES: requires Inductive as an ancestor; component
  2437 "mutual_induct" no longer exists - the induction rule is always
  2438 contained in "induct";
  2439 
  2440 
  2441 * HOL/datatype package re-implemented and greatly improved: now
  2442 supports mutually recursive datatypes such as
  2443 
  2444   datatype
  2445     'a aexp = IF_THEN_ELSE ('a bexp) ('a aexp) ('a aexp)
  2446             | SUM ('a aexp) ('a aexp)
  2447             | DIFF ('a aexp) ('a aexp)
  2448             | NUM 'a
  2449   and
  2450     'a bexp = LESS ('a aexp) ('a aexp)
  2451             | AND ('a bexp) ('a bexp)
  2452             | OR ('a bexp) ('a bexp)
  2453 
  2454 as well as indirectly recursive datatypes such as
  2455 
  2456   datatype
  2457     ('a, 'b) term = Var 'a
  2458                   | App 'b ((('a, 'b) term) list)
  2459 
  2460 The new tactic  mutual_induct_tac [<var_1>, ..., <var_n>] i  performs
  2461 induction on mutually / indirectly recursive datatypes.
  2462 
  2463 Primrec equations are now stored in theory and can be accessed via
  2464 <function_name>.simps.
  2465 
  2466 INCOMPATIBILITIES:
  2467 
  2468   - Theories using datatypes must now have theory Datatype as an
  2469     ancestor.
  2470   - The specific <typename>.induct_tac no longer exists - use the
  2471     generic induct_tac instead.
  2472   - natE has been renamed to nat.exhaust - use exhaust_tac
  2473     instead of res_inst_tac ... natE. Note that the variable
  2474     names in nat.exhaust differ from the names in natE, this
  2475     may cause some "fragile" proofs to fail.
  2476   - The theorems split_<typename>_case and split_<typename>_case_asm
  2477     have been renamed to <typename>.split and <typename>.split_asm.
  2478   - Since default sorts of type variables are now handled correctly,
  2479     some datatype definitions may have to be annotated with explicit
  2480     sort constraints.
  2481   - Primrec definitions no longer require function name and type
  2482     of recursive argument.
  2483 
  2484 Consider using isatool fixdatatype to adapt your theories and proof
  2485 scripts to the new package (backup your sources first!).
  2486 
  2487 
  2488 * HOL/record package: considerably improved implementation; now
  2489 includes concrete syntax for record types, terms, updates; theorems
  2490 for surjective pairing and splitting !!-bound record variables; proof
  2491 support is as follows:
  2492 
  2493   1) standard conversions (selectors or updates applied to record
  2494 constructor terms) are part of the standard simpset;
  2495 
  2496   2) inject equations of the form ((x, y) = (x', y')) == x=x' & y=y' are
  2497 made part of standard simpset and claset via addIffs;
  2498 
  2499   3) a tactic for record field splitting (record_split_tac) is part of
  2500 the standard claset (addSWrapper);
  2501 
  2502 To get a better idea about these rules you may retrieve them via
  2503 something like 'thms "foo.simps"' or 'thms "foo.iffs"', where "foo" is
  2504 the name of your record type.
  2505 
  2506 The split tactic 3) conceptually simplifies by the following rule:
  2507 
  2508   "(!!x. PROP ?P x) == (!!a b. PROP ?P (a, b))"
  2509 
  2510 Thus any record variable that is bound by meta-all will automatically
  2511 blow up into some record constructor term, consequently the
  2512 simplifications of 1), 2) apply.  Thus force_tac, auto_tac etc. shall
  2513 solve record problems automatically.
  2514 
  2515 
  2516 * reorganized the main HOL image: HOL/Integ and String loaded by
  2517 default; theory Main includes everything;
  2518 
  2519 * automatic simplification of integer sums and comparisons, using cancellation;
  2520 
  2521 * added option_map_eq_Some and not_Some_eq to the default simpset and claset;
  2522 
  2523 * added disj_not1 = "(~P | Q) = (P --> Q)" to the default simpset;
  2524 
  2525 * many new identities for unions, intersections, set difference, etc.;
  2526 
  2527 * expand_if, expand_split, expand_sum_case and expand_nat_case are now
  2528 called split_if, split_split, split_sum_case and split_nat_case (to go
  2529 with add/delsplits);
  2530 
  2531 * HOL/Prod introduces simplification procedure unit_eq_proc rewriting
  2532 (?x::unit) = (); this is made part of the default simpset, which COULD
  2533 MAKE EXISTING PROOFS FAIL under rare circumstances (consider
  2534 'Delsimprocs [unit_eq_proc];' as last resort); also note that
  2535 unit_abs_eta_conv is added in order to counter the effect of
  2536 unit_eq_proc on (%u::unit. f u), replacing it by f rather than by
  2537 %u.f();
  2538 
  2539 * HOL/Fun INCOMPATIBILITY: `inj_onto' is now called `inj_on' (which
  2540 makes more sense);
  2541 
  2542 * HOL/Set INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
  2543   It and 'sym RS equals0D' are now in the default  claset, giving automatic
  2544   disjointness reasoning but breaking a few old proofs.
  2545 
  2546 * HOL/Relation INCOMPATIBILITY: renamed the relational operator r^-1
  2547 to 'converse' from 'inverse' (for compatibility with ZF and some
  2548 literature);
  2549 
  2550 * HOL/recdef can now declare non-recursive functions, with {} supplied as
  2551 the well-founded relation;
  2552 
  2553 * HOL/Set INCOMPATIBILITY: the complement of set A is now written -A instead of
  2554     Compl A.  The "Compl" syntax remains available as input syntax for this
  2555     release ONLY.
  2556 
  2557 * HOL/Update: new theory of function updates:
  2558     f(a:=b) == %x. if x=a then b else f x
  2559 may also be iterated as in f(a:=b,c:=d,...);
  2560 
  2561 * HOL/Vimage: new theory for inverse image of a function, syntax f-``B;
  2562 
  2563 * HOL/List:
  2564   - new function list_update written xs[i:=v] that updates the i-th
  2565     list position. May also be iterated as in xs[i:=a,j:=b,...].
  2566   - new function `upt' written [i..j(] which generates the list
  2567     [i,i+1,...,j-1], i.e. the upper bound is excluded. To include the upper
  2568     bound write [i..j], which is a shorthand for [i..j+1(].
  2569   - new lexicographic orderings and corresponding wellfoundedness theorems.
  2570 
  2571 * HOL/Arith:
  2572   - removed 'pred' (predecessor) function;
  2573   - generalized some theorems about n-1;
  2574   - many new laws about "div" and "mod";
  2575   - new laws about greatest common divisors (see theory ex/Primes);
  2576 
  2577 * HOL/Relation: renamed the relational operator r^-1 "converse"
  2578 instead of "inverse";
  2579 
  2580 * HOL/Induct/Multiset: a theory of multisets, including the wellfoundedness
  2581   of the multiset ordering;
  2582 
  2583 * directory HOL/Real: a construction of the reals using Dedekind cuts
  2584   (not included by default);
  2585 
  2586 * directory HOL/UNITY: Chandy and Misra's UNITY formalism;
  2587 
  2588 * directory HOL/Hoare: a new version of Hoare logic which permits many-sorted
  2589   programs, i.e. different program variables may have different types.
  2590 
  2591 * calling (stac rew i) now fails if "rew" has no effect on the goal
  2592   [previously, this check worked only if the rewrite rule was unconditional]
  2593   Now rew can involve either definitions or equalities (either == or =).
  2594 
  2595 
  2596 *** ZF ***
  2597 
  2598 * theory Main includes everything; INCOMPATIBILITY: theory ZF.thy contains
  2599   only the theorems proved on ZF.ML;
  2600 
  2601 * ZF INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
  2602   It and 'sym RS equals0D' are now in the default  claset, giving automatic
  2603   disjointness reasoning but breaking a few old proofs.
  2604 
  2605 * ZF/Update: new theory of function updates
  2606     with default rewrite rule  f(x:=y) ` z = if(z=x, y, f`z)
  2607   may also be iterated as in f(a:=b,c:=d,...);
  2608 
  2609 * in  let x=t in u(x), neither t nor u(x) has to be an FOL term.
  2610 
  2611 * calling (stac rew i) now fails if "rew" has no effect on the goal
  2612   [previously, this check worked only if the rewrite rule was unconditional]
  2613   Now rew can involve either definitions or equalities (either == or =).
  2614 
  2615 * case_tac provided for compatibility with HOL
  2616     (like the old excluded_middle_tac, but with subgoals swapped)
  2617 
  2618 
  2619 *** Internal programming interfaces ***
  2620 
  2621 * Pure: several new basic modules made available for general use, see
  2622 also src/Pure/README;
  2623 
  2624 * improved the theory data mechanism to support encapsulation (data
  2625 kind name replaced by private Object.kind, acting as authorization
  2626 key); new type-safe user interface via functor TheoryDataFun; generic
  2627 print_data function becomes basically useless;
  2628 
  2629 * removed global_names compatibility flag -- all theory declarations
  2630 are qualified by default;
  2631 
  2632 * module Pure/Syntax now offers quote / antiquote translation
  2633 functions (useful for Hoare logic etc. with implicit dependencies);
  2634 see HOL/ex/Antiquote for an example use;
  2635 
  2636 * Simplifier now offers conversions (asm_)(full_)rewrite: simpset ->
  2637 cterm -> thm;
  2638 
  2639 * new tactical CHANGED_GOAL for checking that a tactic modifies a
  2640 subgoal;
  2641 
  2642 * Display.print_goals function moved to Locale.print_goals;
  2643 
  2644 * standard print function for goals supports current_goals_markers
  2645 variable for marking begin of proof, end of proof, start of goal; the
  2646 default is ("", "", ""); setting current_goals_markers := ("<proof>",
  2647 "</proof>", "<goal>") causes SGML like tagged proof state printing,
  2648 for example;
  2649 
  2650 
  2651 
  2652 New in Isabelle98 (January 1998)
  2653 --------------------------------
  2654 
  2655 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  2656 
  2657 * changed lexical syntax of terms / types: dots made part of long
  2658 identifiers, e.g. "%x.x" no longer possible, should be "%x. x";
  2659 
  2660 * simpset (and claset) reference variable replaced by functions
  2661 simpset / simpset_ref;
  2662 
  2663 * no longer supports theory aliases (via merge) and non-trivial
  2664 implicit merge of thms' signatures;
  2665 
  2666 * most internal names of constants changed due to qualified names;
  2667 
  2668 * changed Pure/Sequence interface (see Pure/seq.ML);
  2669 
  2670 
  2671 *** General Changes ***
  2672 
  2673 * hierachically structured name spaces (for consts, types, axms, thms
  2674 etc.); new lexical class 'longid' (e.g. Foo.bar.x) may render much of
  2675 old input syntactically incorrect (e.g. "%x.x"); COMPATIBILITY:
  2676 isatool fixdots ensures space after dots (e.g. "%x. x"); set
  2677 long_names for fully qualified output names; NOTE: ML programs
  2678 (special tactics, packages etc.) referring to internal names may have
  2679 to be adapted to cope with fully qualified names; in case of severe
  2680 backward campatibility problems try setting 'global_names' at compile
  2681 time to have enrything declared within a flat name space; one may also
  2682 fine tune name declarations in theories via the 'global' and 'local'
  2683 section;
  2684 
  2685 * reimplemented the implicit simpset and claset using the new anytype
  2686 data filed in signatures; references simpset:simpset ref etc. are
  2687 replaced by functions simpset:unit->simpset and
  2688 simpset_ref:unit->simpset ref; COMPATIBILITY: use isatool fixclasimp
  2689 to patch your ML files accordingly;
  2690 
  2691 * HTML output now includes theory graph data for display with Java
  2692 applet or isatool browser; data generated automatically via isatool
  2693 usedir (see -i option, ISABELLE_USEDIR_OPTIONS);
  2694 
  2695 * defs may now be conditional; improved rewrite_goals_tac to handle
  2696 conditional equations;
  2697 
  2698 * defs now admits additional type arguments, using TYPE('a) syntax;
  2699 
  2700 * theory aliases via merge (e.g. M=A+B+C) no longer supported, always
  2701 creates a new theory node; implicit merge of thms' signatures is
  2702 restricted to 'trivial' ones; COMPATIBILITY: one may have to use
  2703 transfer:theory->thm->thm in (rare) cases;
  2704 
  2705 * improved handling of draft signatures / theories; draft thms (and
  2706 ctyps, cterms) are automatically promoted to real ones;
  2707 
  2708 * slightly changed interfaces for oracles: admit many per theory, named
  2709 (e.g. oracle foo = mlfun), additional name argument for invoke_oracle;
  2710 
  2711 * print_goals: optional output of const types (set show_consts and
  2712 show_types);
  2713 
  2714 * improved output of warnings (###) and errors (***);
  2715 
  2716 * subgoal_tac displays a warning if the new subgoal has type variables;
  2717 
  2718 * removed old README and Makefiles;
  2719 
  2720 * replaced print_goals_ref hook by print_current_goals_fn and result_error_fn;
  2721 
  2722 * removed obsolete init_pps and init_database;
  2723 
  2724 * deleted the obsolete tactical STATE, which was declared by
  2725     fun STATE tacfun st = tacfun st st;
  2726 
  2727 * cd and use now support path variables, e.g. $ISABELLE_HOME, or ~
  2728 (which abbreviates $HOME);
  2729 
  2730 * changed Pure/Sequence interface (see Pure/seq.ML); COMPATIBILITY:
  2731 use isatool fixseq to adapt your ML programs (this works for fully
  2732 qualified references to the Sequence structure only!);
  2733 
  2734 * use_thy no longer requires writable current directory; it always
  2735 reloads .ML *and* .thy file, if either one is out of date;
  2736 
  2737 
  2738 *** Classical Reasoner ***
  2739 
  2740 * Clarify_tac, clarify_tac, clarify_step_tac, Clarify_step_tac: new
  2741 tactics that use classical reasoning to simplify a subgoal without
  2742 splitting it into several subgoals;
  2743 
  2744 * Safe_tac: like safe_tac but uses the default claset;
  2745 
  2746 
  2747 *** Simplifier ***
  2748 
  2749 * added simplification meta rules:
  2750     (asm_)(full_)simplify: simpset -> thm -> thm;
  2751 
  2752 * simplifier.ML no longer part of Pure -- has to be loaded by object
  2753 logics (again);
  2754 
  2755 * added prems argument to simplification procedures;
  2756 
  2757 * HOL, FOL, ZF: added infix function `addsplits':
  2758   instead of `<simpset> setloop (split_tac <thms>)'
  2759   you can simply write `<simpset> addsplits <thms>'
  2760 
  2761 
  2762 *** Syntax ***
  2763 
  2764 * TYPE('a) syntax for type reflection terms;
  2765 
  2766 * no longer handles consts with name "" -- declare as 'syntax' instead;
  2767 
  2768 * pretty printer: changed order of mixfix annotation preference (again!);
  2769 
  2770 * Pure: fixed idt/idts vs. pttrn/pttrns syntactic categories;
  2771 
  2772 
  2773 *** HOL ***
  2774 
  2775 * HOL: there is a new splitter `split_asm_tac' that can be used e.g.
  2776   with `addloop' of the simplifier to faciliate case splitting in premises.
  2777 
  2778 * HOL/TLA: Stephan Merz's formalization of Lamport's Temporal Logic of Actions;
  2779 
  2780 * HOL/Auth: new protocol proofs including some for the Internet
  2781   protocol TLS;
  2782 
  2783 * HOL/Map: new theory of `maps' a la VDM;
  2784 
  2785 * HOL/simplifier: simplification procedures nat_cancel_sums for
  2786 cancelling out common nat summands from =, <, <= (in)equalities, or
  2787 differences; simplification procedures nat_cancel_factor for
  2788 cancelling common factor from =, <, <= (in)equalities over natural
  2789 sums; nat_cancel contains both kinds of procedures, it is installed by
  2790 default in Arith.thy -- this COULD MAKE EXISTING PROOFS FAIL;
  2791 
  2792 * HOL/simplifier: terms of the form
  2793   `? x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x)'  (or t=x)
  2794   are rewritten to
  2795   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t)',
  2796   and those of the form
  2797   `! x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x) --> R(x)'  (or t=x)
  2798   are rewritten to
  2799   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t) --> R(t)',
  2800 
  2801 * HOL/datatype
  2802   Each datatype `t' now comes with a theorem `split_t_case' of the form
  2803 
  2804   P(t_case f1 ... fn x) =
  2805      ( (!y1 ... ym1. x = C1 y1 ... ym1 --> P(f1 y1 ... ym1)) &
  2806         ...
  2807        (!y1 ... ymn. x = Cn y1 ... ymn --> P(f1 y1 ... ymn))
  2808      )
  2809 
  2810   and a theorem `split_t_case_asm' of the form
  2811 
  2812   P(t_case f1 ... fn x) =
  2813     ~( (? y1 ... ym1. x = C1 y1 ... ym1 & ~P(f1 y1 ... ym1)) |
  2814         ...
  2815        (? y1 ... ymn. x = Cn y1 ... ymn & ~P(f1 y1 ... ymn))
  2816      )
  2817   which can be added to a simpset via `addsplits'. The existing theorems
  2818   expand_list_case and expand_option_case have been renamed to
  2819   split_list_case and split_option_case.
  2820 
  2821 * HOL/Arithmetic:
  2822   - `pred n' is automatically converted to `n-1'.
  2823     Users are strongly encouraged not to use `pred' any longer,
  2824     because it will disappear altogether at some point.
  2825   - Users are strongly encouraged to write "0 < n" rather than
  2826     "n ~= 0". Theorems and proof tools have been modified towards this
  2827     `standard'.
  2828 
  2829 * HOL/Lists:
  2830   the function "set_of_list" has been renamed "set" (and its theorems too);
  2831   the function "nth" now takes its arguments in the reverse order and
  2832   has acquired the infix notation "!" as in "xs!n".
  2833 
  2834 * HOL/Set: UNIV is now a constant and is no longer translated to Compl{};
  2835 
  2836 * HOL/Set: The operator (UN x.B x) now abbreviates (UN x:UNIV. B x) and its
  2837   specialist theorems (like UN1_I) are gone.  Similarly for (INT x.B x);
  2838 
  2839 * HOL/record: extensible records with schematic structural subtyping
  2840 (single inheritance); EXPERIMENTAL version demonstrating the encoding,
  2841 still lacks various theorems and concrete record syntax;
  2842 
  2843 
  2844 *** HOLCF ***
  2845 
  2846 * removed "axioms" and "generated by" sections;
  2847 
  2848 * replaced "ops" section by extended "consts" section, which is capable of
  2849   handling the continuous function space "->" directly;
  2850 
  2851 * domain package:
  2852   . proves theorems immediately and stores them in the theory,
  2853   . creates hierachical name space,
  2854   . now uses normal mixfix annotations (instead of cinfix...),
  2855   . minor changes to some names and values (for consistency),
  2856   . e.g. cases -> casedist, dists_eq -> dist_eqs, [take_lemma] -> take_lemmas,
  2857   . separator between mutual domain defs: changed "," to "and",
  2858   . improved handling of sort constraints;  now they have to
  2859     appear on the left-hand side of the equations only;
  2860 
  2861 * fixed LAM <x,y,zs>.b syntax;
  2862 
  2863 * added extended adm_tac to simplifier in HOLCF -- can now discharge
  2864 adm (%x. P (t x)), where P is chainfinite and t continuous;
  2865 
  2866 
  2867 *** FOL and ZF ***
  2868 
  2869 * FOL: there is a new splitter `split_asm_tac' that can be used e.g.
  2870   with `addloop' of the simplifier to faciliate case splitting in premises.
  2871 
  2872 * qed_spec_mp, qed_goal_spec_mp, qed_goalw_spec_mp are available, as
  2873 in HOL, they strip ALL and --> from proved theorems;
  2874 
  2875 
  2876 
  2877 New in Isabelle94-8 (May 1997)
  2878 ------------------------------
  2879 
  2880 *** General Changes ***
  2881 
  2882 * new utilities to build / run / maintain Isabelle etc. (in parts
  2883 still somewhat experimental); old Makefiles etc. still functional;
  2884 
  2885 * new 'Isabelle System Manual';
  2886 
  2887 * INSTALL text, together with ./configure and ./build scripts;
  2888 
  2889 * reimplemented type inference for greater efficiency, better error
  2890 messages and clean internal interface;
  2891 
  2892 * prlim command for dealing with lots of subgoals (an easier way of
  2893 setting goals_limit);
  2894 
  2895 
  2896 *** Syntax ***
  2897 
  2898 * supports alternative (named) syntax tables (parser and pretty
  2899 printer); internal interface is provided by add_modesyntax(_i);
  2900 
  2901 * Pure, FOL, ZF, HOL, HOLCF now support symbolic input and output; to
  2902 be used in conjunction with the Isabelle symbol font; uses the
  2903 "symbols" syntax table;
  2904 
  2905 * added token_translation interface (may translate name tokens in
  2906 arbitrary ways, dependent on their type (free, bound, tfree, ...) and
  2907 the current print_mode); IMPORTANT: user print translation functions
  2908 are responsible for marking newly introduced bounds
  2909 (Syntax.mark_boundT);
  2910 
  2911 * token translations for modes "xterm" and "xterm_color" that display
  2912 names in bold, underline etc. or colors (which requires a color
  2913 version of xterm);
  2914 
  2915 * infixes may now be declared with names independent of their syntax;
  2916 
  2917 * added typed_print_translation (like print_translation, but may
  2918 access type of constant);
  2919 
  2920 
  2921 *** Classical Reasoner ***
  2922 
  2923 Blast_tac: a new tactic!  It is often more powerful than fast_tac, but has
  2924 some limitations.  Blast_tac...
  2925   + ignores addss, addbefore, addafter; this restriction is intrinsic
  2926   + ignores elimination rules that don't have the correct format
  2927         (the conclusion MUST be a formula variable)
  2928   + ignores types, which can make HOL proofs fail
  2929   + rules must not require higher-order unification, e.g. apply_type in ZF
  2930     [message "Function Var's argument not a bound variable" relates to this]
  2931   + its proof strategy is more general but can actually be slower
  2932 
  2933 * substitution with equality assumptions no longer permutes other
  2934 assumptions;
  2935 
  2936 * minor changes in semantics of addafter (now called addaltern); renamed
  2937 setwrapper to setWrapper and compwrapper to compWrapper; added safe wrapper
  2938 (and access functions for it);
  2939 
  2940 * improved combination of classical reasoner and simplifier:
  2941   + functions for handling clasimpsets
  2942   + improvement of addss: now the simplifier is called _after_ the
  2943     safe steps.
  2944   + safe variant of addss called addSss: uses safe simplifications
  2945     _during_ the safe steps. It is more complete as it allows multiple
  2946     instantiations of unknowns (e.g. with slow_tac).
  2947 
  2948 *** Simplifier ***
  2949 
  2950 * added interface for simplification procedures (functions that
  2951 produce *proven* rewrite rules on the fly, depending on current
  2952 redex);
  2953 
  2954 * ordering on terms as parameter (used for ordered rewriting);
  2955 
  2956 * new functions delcongs, deleqcongs, and Delcongs. richer rep_ss;
  2957 
  2958 * the solver is now split into a safe and an unsafe part.
  2959 This should be invisible for the normal user, except that the
  2960 functions setsolver and addsolver have been renamed to setSolver and
  2961 addSolver; added safe_asm_full_simp_tac;
  2962 
  2963 
  2964 *** HOL ***
  2965 
  2966 * a generic induction tactic `induct_tac' which works for all datatypes and
  2967 also for type `nat';
  2968 
  2969 * a generic case distinction tactic `exhaust_tac' which works for all
  2970 datatypes and also for type `nat';
  2971 
  2972 * each datatype comes with a function `size';
  2973 
  2974 * patterns in case expressions allow tuple patterns as arguments to
  2975 constructors, for example `case x of [] => ... | (x,y,z)#ps => ...';
  2976 
  2977 * primrec now also works with type nat;
  2978 
  2979 * recdef: a new declaration form, allows general recursive functions to be
  2980 defined in theory files.  See HOL/ex/Fib, HOL/ex/Primes, HOL/Subst/Unify.
  2981 
  2982 * the constant for negation has been renamed from "not" to "Not" to
  2983 harmonize with FOL, ZF, LK, etc.;
  2984 
  2985 * HOL/ex/LFilter theory of a corecursive "filter" functional for
  2986 infinite lists;
  2987 
  2988 * HOL/Modelcheck demonstrates invocation of model checker oracle;
  2989 
  2990 * HOL/ex/Ring.thy declares cring_simp, which solves equational
  2991 problems in commutative rings, using axiomatic type classes for + and *;
  2992 
  2993 * more examples in HOL/MiniML and HOL/Auth;
  2994 
  2995 * more default rewrite rules for quantifiers, union/intersection;
  2996 
  2997 * a new constant `arbitrary == @x.False';
  2998 
  2999 * HOLCF/IOA replaces old HOL/IOA;
  3000 
  3001 * HOLCF changes: derived all rules and arities
  3002   + axiomatic type classes instead of classes
  3003   + typedef instead of faking type definitions
  3004   + eliminated the internal constants less_fun, less_cfun, UU_fun, UU_cfun etc.
  3005   + new axclasses cpo, chfin, flat with flat < chfin < pcpo < cpo < po
  3006   + eliminated the types void, one, tr
  3007   + use unit lift and bool lift (with translations) instead of one and tr
  3008   + eliminated blift from Lift3.thy (use Def instead of blift)
  3009   all eliminated rules are derived as theorems --> no visible changes ;
  3010 
  3011 
  3012 *** ZF ***
  3013 
  3014 * ZF now has Fast_tac, Simp_tac and Auto_tac.  Union_iff is a now a default
  3015 rewrite rule; this may affect some proofs.  eq_cs is gone but can be put back
  3016 as ZF_cs addSIs [equalityI];
  3017 
  3018 
  3019 
  3020 New in Isabelle94-7 (November 96)
  3021 ---------------------------------
  3022 
  3023 * allowing negative levels (as offsets) in prlev and choplev;
  3024 
  3025 * super-linear speedup for large simplifications;
  3026 
  3027 * FOL, ZF and HOL now use miniscoping: rewriting pushes
  3028 quantifications in as far as possible (COULD MAKE EXISTING PROOFS
  3029 FAIL); can suppress it using the command Delsimps (ex_simps @
  3030 all_simps); De Morgan laws are also now included, by default;
  3031 
  3032 * improved printing of ==>  :  ~:
  3033 
  3034 * new object-logic "Sequents" adds linear logic, while replacing LK
  3035 and Modal (thanks to Sara Kalvala);
  3036 
  3037 * HOL/Auth: correctness proofs for authentication protocols;
  3038 
  3039 * HOL: new auto_tac combines rewriting and classical reasoning (many
  3040 examples on HOL/Auth);
  3041 
  3042 * HOL: new command AddIffs for declaring theorems of the form P=Q to
  3043 the rewriter and classical reasoner simultaneously;
  3044 
  3045 * function uresult no longer returns theorems in "standard" format;
  3046 regain previous version by: val uresult = standard o uresult;
  3047 
  3048 
  3049 
  3050 New in Isabelle94-6
  3051 -------------------
  3052 
  3053 * oracles -- these establish an interface between Isabelle and trusted
  3054 external reasoners, which may deliver results as theorems;
  3055 
  3056 * proof objects (in particular record all uses of oracles);
  3057 
  3058 * Simp_tac, Fast_tac, etc. that refer to implicit simpset / claset;
  3059 
  3060 * "constdefs" section in theory files;
  3061 
  3062 * "primrec" section (HOL) no longer requires names;
  3063 
  3064 * internal type "tactic" now simply "thm -> thm Sequence.seq";
  3065 
  3066 
  3067 
  3068 New in Isabelle94-5
  3069 -------------------
  3070 
  3071 * reduced space requirements;
  3072 
  3073 * automatic HTML generation from theories;
  3074 
  3075 * theory files no longer require "..." (quotes) around most types;
  3076 
  3077 * new examples, including two proofs of the Church-Rosser theorem;
  3078 
  3079 * non-curried (1994) version of HOL is no longer distributed;
  3080 
  3081 
  3082 
  3083 New in Isabelle94-4
  3084 -------------------
  3085 
  3086 * greatly reduced space requirements;
  3087 
  3088 * theory files (.thy) no longer require \...\ escapes at line breaks;
  3089 
  3090 * searchable theorem database (see the section "Retrieving theorems" on
  3091 page 8 of the Reference Manual);
  3092 
  3093 * new examples, including Grabczewski's monumental case study of the
  3094 Axiom of Choice;
  3095 
  3096 * The previous version of HOL renamed to Old_HOL;
  3097 
  3098 * The new version of HOL (previously called CHOL) uses a curried syntax
  3099 for functions.  Application looks like f a b instead of f(a,b);
  3100 
  3101 * Mutually recursive inductive definitions finally work in HOL;
  3102 
  3103 * In ZF, pattern-matching on tuples is now available in all abstractions and
  3104 translates to the operator "split";
  3105 
  3106 
  3107 
  3108 New in Isabelle94-3
  3109 -------------------
  3110 
  3111 * new infix operator, addss, allowing the classical reasoner to
  3112 perform simplification at each step of its search.  Example:
  3113         fast_tac (cs addss ss)
  3114 
  3115 * a new logic, CHOL, the same as HOL, but with a curried syntax
  3116 for functions.  Application looks like f a b instead of f(a,b).  Also pairs
  3117 look like (a,b) instead of <a,b>;
  3118 
  3119 * PLEASE NOTE: CHOL will eventually replace HOL!
  3120 
  3121 * In CHOL, pattern-matching on tuples is now available in all abstractions.
  3122 It translates to the operator "split".  A new theory of integers is available;
  3123 
  3124 * In ZF, integer numerals now denote two's-complement binary integers.
  3125 Arithmetic operations can be performed by rewriting.  See ZF/ex/Bin.ML;
  3126 
  3127 * Many new examples: I/O automata, Church-Rosser theorem, equivalents
  3128 of the Axiom of Choice;
  3129 
  3130 
  3131 
  3132 New in Isabelle94-2
  3133 -------------------
  3134 
  3135 * Significantly faster resolution;
  3136 
  3137 * the different sections in a .thy file can now be mixed and repeated
  3138 freely;
  3139 
  3140 * Database of theorems for FOL, HOL and ZF.  New
  3141 commands including qed, qed_goal and bind_thm store theorems in the database.
  3142 
  3143 * Simple database queries: return a named theorem (get_thm) or all theorems of
  3144 a given theory (thms_of), or find out what theory a theorem was proved in
  3145 (theory_of_thm);
  3146 
  3147 * Bugs fixed in the inductive definition and datatype packages;
  3148 
  3149 * The classical reasoner provides deepen_tac and depth_tac, making FOL_dup_cs
  3150 and HOL_dup_cs obsolete;
  3151 
  3152 * Syntactic ambiguities caused by the new treatment of syntax in Isabelle94-1
  3153 have been removed;
  3154 
  3155 * Simpler definition of function space in ZF;
  3156 
  3157 * new results about cardinal and ordinal arithmetic in ZF;
  3158 
  3159 * 'subtype' facility in HOL for introducing new types as subsets of existing
  3160 types;
  3161 
  3162 
  3163 $Id$