NEWS
author wenzelm
Mon Jun 20 22:13:53 2005 +0200 (2005-06-20)
changeset 16481 fe61cdf5af51
parent 16456 451f1c46d4ca
child 16506 b2687ce38433
permissions -rw-r--r--
exclude pghead.pdf from doc;
     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 
   165 *** Locales ***
   166   
   167 * New commands for the interpretation of locale expressions in
   168 theories ('interpretation') and proof contexts ('interpret').  These
   169 take an instantiation of the locale parameters and compute proof
   170 obligations from the instantiated specification.  After the
   171 obligations have been discharged, the instantiated theorems of the
   172 locale are added to the theory or proof context.  Interpretation is
   173 smart in that already active interpretations do not occur in proof
   174 obligations, neither are instantiated theorems stored in duplicate.
   175 Use print_interps to inspect active interpretations of a particular
   176 locale.  For details, see the Isar Reference manual.
   177 
   178 INCOMPATIBILITY: former 'instantiate' has been withdrawn, use
   179 'interpret' instead.
   180 
   181 * Proper static binding of attribute syntax -- i.e. types / terms /
   182 facts mentioned as arguments are always those of the locale definition
   183 context, independently of the context of later invocations.  Moreover,
   184 locale operations (renaming and type / term instantiation) are applied
   185 to attribute arguments as expected.
   186 
   187 INCOMPATIBILITY of the ML interface: always pass Attrib.src instead of
   188 actual attributes; rare situations may require Attrib.attribute to
   189 embed those attributes into Attrib.src that lack concrete syntax.
   190 Attribute implementations need to cooperate properly with the static
   191 binding mechanism.  Basic parsers Args.XXX_typ/term/prop and
   192 Attrib.XXX_thm etc. already do the right thing without further
   193 intervention.  Only unusual applications -- such as "where" or "of"
   194 (cf. src/Pure/Isar/attrib.ML), which process arguments depending both
   195 on the context and the facts involved -- may have to assign parsed
   196 values to argument tokens explicitly.
   197 
   198 * New context element "constrains" adds type constraints to parameters --
   199 there is no logical significance.
   200 
   201 * Context expressions: renaming parameters permits syntax
   202 redeclaration as well.
   203 
   204 * Locale definition: 'includes' now disallowed.
   205 
   206 * Changed parameter management in theorem generation for long goal
   207 statements with 'includes'.  INCOMPATIBILITY: produces a different
   208 theorem statement in rare situations.
   209 
   210 * Attributes 'induct' and 'cases': type or set names may now be
   211 locally fixed variables as well.
   212 
   213 * Antiquotations now provide the option 'locale=NAME' to specify an
   214 alternative context used for evaluating and printing the subsequent
   215 argument, as in @{thm [locale=LC] fold_commute}, for example.
   216 
   217 
   218 *** Provers ***
   219 
   220 * Provers/hypsubst.ML: improved version of the subst method, for
   221 single-step rewriting: it now works in bound variable contexts. New is
   222 'subst (asm)', for rewriting an assumption.  INCOMPATIBILITY: may
   223 rewrite a different subterm than the original subst method, which is
   224 still available as 'simplesubst'.
   225 
   226 * Provers/quasi.ML: new transitivity reasoners for transitivity only
   227 and quasi orders.
   228 
   229 * Provers/trancl.ML: new transitivity reasoner for transitive and
   230 reflexive-transitive closure of relations.
   231 
   232 * Provers/blast.ML: new reference depth_limit to make blast's depth
   233 limit (previously hard-coded with a value of 20) user-definable.
   234 
   235 * Provers/simplifier.ML has been moved to Pure, where Simplifier.setup
   236 is peformed already.  Object-logics merely need to finish their
   237 initial simpset configuration as before.  INCOMPATIBILITY.
   238 
   239 
   240 *** HOL ***
   241 
   242 * Symbolic syntax of Hilbert Choice Operator is now as follows:
   243 
   244   syntax (epsilon)
   245     "_Eps" :: "[pttrn, bool] => 'a"    ("(3\<some>_./ _)" [0, 10] 10)
   246 
   247 The symbol \<some> is displayed as the alternative epsilon of LaTeX
   248 and x-symbol; use option '-m epsilon' to get it actually printed.
   249 Moreover, the mathematically important symbolic identifier \<epsilon>
   250 becomes available as variable, constant etc.  INCOMPATIBILITY,
   251 
   252 * "x > y" abbreviates "y < x" and "x >= y" abbreviates "y <= x".
   253 Similarly for all quantifiers: "ALL x > y" etc.  The x-symbol for >=
   254 is \<ge>.
   255 
   256 * "{x:A. P}" abbreviates "{x. x:A & P}", and similarly for "\<in>"
   257 instead of ":".
   258 
   259 * theory SetInterval: changed the syntax for open intervals:
   260 
   261   Old       New
   262   {..n(}    {..<n}
   263   {)n..}    {n<..}
   264   {m..n(}   {m..<n}
   265   {)m..n}   {m<..n}
   266   {)m..n(}  {m<..<n}
   267 
   268 The old syntax is still supported but will disappear in the next
   269 release.  For conversion use the following Emacs search and replace
   270 patterns (these are not perfect but work quite well):
   271 
   272   {)\([^\.]*\)\.\.  ->  {\1<\.\.}
   273   \.\.\([^(}]*\)(}  ->  \.\.<\1}
   274 
   275 * theory Finite_Set: changed the syntax for 'setsum', summation over
   276 finite sets: "setsum (%x. e) A", which used to be "\<Sum>x:A. e", is
   277 now either "SUM x:A. e" or "\<Sum>x \<in> A. e".
   278 
   279 Some new syntax forms are available:
   280 
   281   "\<Sum>x | P. e"      for     "setsum (%x. e) {x. P}"
   282   "\<Sum>x = a..b. e"   for     "setsum (%x. e) {a..b}"
   283   "\<Sum>x = a..<b. e"  for     "setsum (%x. e) {a..<b}"
   284   "\<Sum>x < k. e"      for     "setsum (%x. e) {..<k}"
   285 
   286 The latter form "\<Sum>x < k. e" used to be based on a separate
   287 function "Summation", which has been discontinued.
   288 
   289 * theory Finite_Set: in structured induction proofs, the insert case
   290 is now 'case (insert x F)' instead of the old counterintuitive 'case
   291 (insert F x)'.
   292 
   293 * The 'refute' command has been extended to support a much larger
   294 fragment of HOL, including axiomatic type classes, constdefs and
   295 typedefs, inductive datatypes and recursion.
   296 
   297 * Datatype induction via method 'induct' now preserves the name of the
   298 induction variable. For example, when proving P(xs::'a list) by
   299 induction on xs, the induction step is now P(xs) ==> P(a#xs) rather
   300 than P(list) ==> P(a#list) as previously.  Potential INCOMPATIBILITY
   301 in unstructured proof scripts.
   302 
   303 * Reworked implementation of records.  Improved scalability for
   304 records with many fields, avoiding performance problems for type
   305 inference. Records are no longer composed of nested field types, but
   306 of nested extension types. Therefore the record type only grows linear
   307 in the number of extensions and not in the number of fields.  The
   308 top-level (users) view on records is preserved.  Potential
   309 INCOMPATIBILITY only in strange cases, where the theory depends on the
   310 old record representation. The type generated for a record is called
   311 <record_name>_ext_type.
   312 
   313 Flag record_quick_and_dirty_sensitive can be enabled to skip the
   314 proofs triggered by a record definition or a simproc (if
   315 quick_and_dirty is enabled).  Definitions of large records can take
   316 quite long.
   317 
   318 New simproc record_upd_simproc for simplification of multiple record
   319 updates enabled by default.  Moreover, trivial updates are also
   320 removed: r(|x := x r|) = r.  INCOMPATIBILITY: old proofs break
   321 occasionally, since simplification is more powerful by default.
   322 
   323 * Simplifier: automatically reasons about transitivity chains
   324 involving "trancl" (r^+) and "rtrancl" (r^*) by setting up tactics
   325 provided by Provers/trancl.ML as additional solvers.  INCOMPATIBILITY:
   326 old proofs break occasionally as simplification may now solve more
   327 goals than previously.
   328 
   329 * Simplifier: converts x <= y into x = y if assumption y <= x is
   330 present.  Works for all partial orders (class "order"), in particular
   331 numbers and sets.  For linear orders (e.g. numbers) it treats ~ x < y
   332 just like y <= x.
   333 
   334 * Simplifier: new simproc for "let x = a in f x".  If a is a free or
   335 bound variable or a constant then the let is unfolded.  Otherwise
   336 first a is simplified to b, and then f b is simplified to g. If
   337 possible we abstract b from g arriving at "let x = b in h x",
   338 otherwise we unfold the let and arrive at g.  The simproc can be
   339 enabled/disabled by the reference use_let_simproc.  Potential
   340 INCOMPATIBILITY since simplification is more powerful by default.
   341 
   342 
   343 *** HOLCF ***
   344 
   345 * HOLCF: discontinued special version of 'constdefs' (which used to
   346 support continuous functions) in favor of the general Pure one with
   347 full type-inference.
   348 
   349 
   350 *** ZF ***
   351 
   352 * ZF/ex: theories Group and Ring provide examples in abstract algebra,
   353 including the First Isomorphism Theorem (on quotienting by the kernel
   354 of a homomorphism).
   355 
   356 * ZF/Simplifier: install second copy of type solver that actually
   357 makes use of TC rules declared to Isar proof contexts (or locales);
   358 the old version is still required for ML proof scripts.
   359 
   360 
   361 *** ML ***
   362 
   363 * Pure/library.ML no longer defines its own option datatype, but uses
   364 that of the SML basis, which has constructors NONE and SOME instead of
   365 None and Some, as well as exception Option.Option instead of OPTION.
   366 The functions the, if_none, is_some, is_none have been adapted
   367 accordingly, while Option.map replaces apsome.
   368 
   369 * The exception LIST has been given up in favour of the standard
   370 exceptions Empty and Subscript, as well as Library.UnequalLengths.
   371 Function like Library.hd and Library.tl are superceded by the standard
   372 hd and tl functions etc.
   373 
   374 A number of basic functions are now no longer exported to the ML
   375 toplevel, as they are variants of standard functions.  The following
   376 suggests how one can translate existing code:
   377 
   378     rev_append xs ys = List.revAppend (xs, ys)
   379     nth_elem (i, xs) = List.nth (xs, i)
   380     last_elem xs = List.last xs
   381     flat xss = List.concat xss
   382     seq fs = List.app fs
   383     partition P xs = List.partition P xs
   384     filter P xs = List.filter P xs
   385     mapfilter f xs = List.mapPartial f xs
   386 
   387 * Pure: output via the Isabelle channels of writeln/warning/error
   388 etc. is now passed through Output.output, with a hook for arbitrary
   389 transformations depending on the print_mode (cf. Output.add_mode --
   390 the first active mode that provides a output function wins).  Already
   391 formatted output may be embedded into further text via Output.raw; the
   392 result of Pretty.string_of/str_of and derived functions
   393 (string_of_term/cterm/thm etc.) is already marked raw to accommodate
   394 easy composition of diagnostic messages etc.  Programmers rarely need
   395 to care about Output.output or Output.raw at all, with some notable
   396 exceptions: Output.output is required when bypassing the standard
   397 channels (writeln etc.), or in token translations to produce properly
   398 formatted results; Output.raw is required when capturing already
   399 output material that will eventually be presented to the user a second
   400 time.  For the default print mode, both Output.output and Output.raw
   401 have no effect.
   402 
   403 * Pure: print_tac now outputs the goal through the trace channel.
   404 
   405 * Isar debugging: new reference Toplevel.debug; default false.  Set to
   406 make printing of exceptions THM, TERM, TYPE and THEORY more verbose.
   407 
   408 * Pure: name spaces have been refined, with significant changes of the
   409 internal interfaces -- INCOMPATIBILITY.  Renamed cond_extern(_table)
   410 to extern(_table).  The plain name entry path is superceded by a
   411 general 'naming' context, which also includes the 'policy' to produce
   412 a fully qualified name and external accesses of a fully qualified
   413 name; NameSpace.extend is superceded by context dependent
   414 Sign.declare_name.  Several theory and proof context operations modify
   415 the naming context.  Especially note Theory.restore_naming and
   416 ProofContext.restore_naming to get back to a sane state; note that
   417 Theory.add_path is no longer sufficient to recover from
   418 Theory.absolute_path in particular.
   419 
   420 * Pure: new flags short_names (default false) and unique_names
   421 (default true) for controlling output of qualified names.  If
   422 short_names is set, names are printed unqualified.  If unique_names is
   423 reset, the name prefix is reduced to the minimum required to achieve
   424 the original result when interning again, even if there is an overlap
   425 with earlier declarations.
   426 
   427 * Pure/TheoryDataFun: change of the argument structure; 'prep_ext' is
   428 now 'extend', and 'merge' gets an additional Pretty.pp argument
   429 (useful for printing error messages).  INCOMPATIBILITY.
   430 
   431 * Pure: major reorganization of the theory context.  Type Sign.sg and
   432 Theory.theory are now identified, referring to the universal
   433 Context.theory (see Pure/context.ML).  Actual signature and theory
   434 content is managed as theory data.  The old code and interfaces were
   435 spread over many files and structures; the new arrangement introduces
   436 considerable INCOMPATIBILITY to gain more clarity:
   437 
   438   Context -- theory management operations (name, identity, inclusion,
   439     parents, ancestors, merge, etc.), plus generic theory data;
   440 
   441   Sign -- logical signature and syntax operations (declaring consts,
   442     types, etc.), plus certify/read for common entities;
   443 
   444   Theory -- logical theory operations (stating axioms, definitions,
   445     oracles), plus a copy of logical signature operations (consts,
   446     types, etc.); also a few basic management operations (Theory.copy,
   447     Theory.merge, etc.)
   448 
   449 The most basic sign_of operations (Theory.sign_of, Thm.sign_of_thm
   450 etc.) as well as the sign field in Thm.rep_thm etc. have been retained
   451 for convenience -- they merely return the theory.
   452 
   453 * Pure/sign/theory: discontinued named name spaces (i.e. classK,
   454 typeK, constK, axiomK, oracleK), but provide explicit operations for
   455 any of these kinds.  For example, Sign.intern typeK is now
   456 Sign.intern_type, Theory.hide_space Sign.typeK is now
   457 Theory.hide_types.  Also note that former
   458 Theory.hide_classes/types/consts are now
   459 Theory.hide_classes_i/types_i/consts_i, while the non '_i' versions
   460 internalize their arguments!  INCOMPATIBILITY.
   461 
   462 * Pure: cases produced by proof methods specify options, where NONE
   463 means to remove case bindings -- INCOMPATIBILITY in
   464 (RAW_)METHOD_CASES.
   465 
   466 * Pure: the following operations retrieve axioms or theorems from a
   467 theory node or theory hierarchy, respectively:
   468 
   469   Theory.axioms_of: theory -> (string * term) list
   470   Theory.all_axioms_of: theory -> (string * term) list
   471   PureThy.thms_of: theory -> (string * thm) list
   472   PureThy.all_thms_of: theory -> (string * thm) list
   473 
   474 * Provers: Simplifier and Classical Reasoner now support proof context
   475 dependent plug-ins (simprocs, solvers, wrappers etc.).  These extra
   476 components are stored in the theory and patched into the
   477 simpset/claset when used in an Isar proof context.  Context dependent
   478 components are maintained by the following theory operations:
   479 
   480   Simplifier.add_context_simprocs
   481   Simplifier.del_context_simprocs
   482   Simplifier.set_context_subgoaler
   483   Simplifier.reset_context_subgoaler
   484   Simplifier.add_context_looper
   485   Simplifier.del_context_looper
   486   Simplifier.add_context_unsafe_solver
   487   Simplifier.add_context_safe_solver
   488 
   489   Classical.add_context_safe_wrapper
   490   Classical.del_context_safe_wrapper
   491   Classical.add_context_unsafe_wrapper
   492   Classical.del_context_unsafe_wrapper
   493 
   494 IMPORTANT NOTE: proof tools (methods etc.) need to use
   495 local_simpset_of and local_claset_of to instead of the primitive
   496 Simplifier.get_local_simpset and Classical.get_local_claset,
   497 respectively, in order to see the context dependent fields!
   498 
   499 * File.sysify_path and File.quote_sysify path have been replaced by
   500 File.platform_path and File.shell_path (with appropriate hooks).  This
   501 provides a clean interface for unusual systems where the internal and
   502 external process view of file names are different.
   503 
   504 
   505 *** System ***
   506 
   507 * Allow symlinks to all proper Isabelle executables (Isabelle,
   508 isabelle, isatool etc.).
   509 
   510 * ISABELLE_DOC_FORMAT setting specifies preferred document format (for
   511 isatool doc, isatool mkdir, display_drafts etc.).
   512 
   513 * isatool usedir: option -f allows specification of the ML file to be
   514 used by Isabelle; default is ROOT.ML.
   515 
   516 * New isatool version outputs the version identifier of the Isabelle
   517 distribution being used.
   518 
   519 * HOL: new isatool dimacs2hol converts files in DIMACS CNF format
   520 (containing Boolean satisfiability problems) into Isabelle/HOL
   521 theories.
   522 
   523 
   524 
   525 New in Isabelle2004 (April 2004)
   526 --------------------------------
   527 
   528 *** General ***
   529 
   530 * Provers/order.ML:  new efficient reasoner for partial and linear orders.
   531   Replaces linorder.ML.
   532 
   533 * Pure: Greek letters (except small lambda, \<lambda>), as well as Gothic
   534   (\<aa>...\<zz>\<AA>...\<ZZ>), calligraphic (\<A>...\<Z>), and Euler
   535   (\<a>...\<z>), are now considered normal letters, and can therefore
   536   be used anywhere where an ASCII letter (a...zA...Z) has until
   537   now. COMPATIBILITY: This obviously changes the parsing of some
   538   terms, especially where a symbol has been used as a binder, say
   539   '\<Pi>x. ...', which is now a type error since \<Pi>x will be parsed
   540   as an identifier.  Fix it by inserting a space around former
   541   symbols.  Call 'isatool fixgreek' to try to fix parsing errors in
   542   existing theory and ML files.
   543 
   544 * Pure: Macintosh and Windows line-breaks are now allowed in theory files.
   545 
   546 * Pure: single letter sub/superscripts (\<^isub> and \<^isup>) are now
   547   allowed in identifiers. Similar to Greek letters \<^isub> is now considered
   548   a normal (but invisible) letter. For multiple letter subscripts repeat
   549   \<^isub> like this: x\<^isub>1\<^isub>2.
   550 
   551 * Pure: There are now sub-/superscripts that can span more than one
   552   character. Text between \<^bsub> and \<^esub> is set in subscript in
   553   ProofGeneral and LaTeX, text between \<^bsup> and \<^esup> in
   554   superscript. The new control characters are not identifier parts.
   555 
   556 * Pure: Control-symbols of the form \<^raw:...> will literally print the
   557   content of "..." to the latex file instead of \isacntrl... . The "..."
   558   may consist of any printable characters excluding the end bracket >.
   559 
   560 * Pure: Using new Isar command "finalconsts" (or the ML functions
   561   Theory.add_finals or Theory.add_finals_i) it is now possible to
   562   declare constants "final", which prevents their being given a definition
   563   later.  It is useful for constants whose behaviour is fixed axiomatically
   564   rather than definitionally, such as the meta-logic connectives.
   565 
   566 * Pure: 'instance' now handles general arities with general sorts
   567   (i.e. intersections of classes),
   568 
   569 * Presentation: generated HTML now uses a CSS style sheet to make layout
   570   (somewhat) independent of content. It is copied from lib/html/isabelle.css.
   571   It can be changed to alter the colors/layout of generated pages.
   572 
   573 
   574 *** Isar ***
   575 
   576 * Tactic emulation methods rule_tac, erule_tac, drule_tac, frule_tac,
   577   cut_tac, subgoal_tac and thin_tac:
   578   - Now understand static (Isar) contexts.  As a consequence, users of Isar
   579     locales are no longer forced to write Isar proof scripts.
   580     For details see Isar Reference Manual, paragraph 4.3.2: Further tactic
   581     emulations.
   582   - INCOMPATIBILITY: names of variables to be instantiated may no
   583     longer be enclosed in quotes.  Instead, precede variable name with `?'.
   584     This is consistent with the instantiation attribute "where".
   585 
   586 * Attributes "where" and "of":
   587   - Now take type variables of instantiated theorem into account when reading
   588     the instantiation string.  This fixes a bug that caused instantiated
   589     theorems to have too special types in some circumstances.
   590   - "where" permits explicit instantiations of type variables.
   591 
   592 * Calculation commands "moreover" and "also" no longer interfere with
   593   current facts ("this"), admitting arbitrary combinations with "then"
   594   and derived forms.
   595 
   596 * Locales:
   597   - Goal statements involving the context element "includes" no longer
   598     generate theorems with internal delta predicates (those ending on
   599     "_axioms") in the premise.
   600     Resolve particular premise with <locale>.intro to obtain old form.
   601   - Fixed bug in type inference ("unify_frozen") that prevented mix of target
   602     specification and "includes" elements in goal statement.
   603   - Rule sets <locale>.intro and <locale>.axioms no longer declared as
   604     [intro?] and [elim?] (respectively) by default.
   605   - Experimental command for instantiation of locales in proof contexts:
   606         instantiate <label>[<attrs>]: <loc>
   607     Instantiates locale <loc> and adds all its theorems to the current context
   608     taking into account their attributes.  Label and attrs are optional
   609     modifiers, like in theorem declarations.  If present, names of
   610     instantiated theorems are qualified with <label>, and the attributes
   611     <attrs> are applied after any attributes these theorems might have already.
   612       If the locale has assumptions, a chained fact of the form
   613     "<loc> t1 ... tn" is expected from which instantiations of the parameters
   614     are derived.  The command does not support old-style locales declared
   615     with "locale (open)".
   616       A few (very simple) examples can be found in FOL/ex/LocaleInst.thy.
   617 
   618 * HOL: Tactic emulation methods induct_tac and case_tac understand static
   619   (Isar) contexts.
   620 
   621 
   622 *** HOL ***
   623 
   624 * Proof import: new image HOL4 contains the imported library from
   625   the HOL4 system with about 2500 theorems. It is imported by
   626   replaying proof terms produced by HOL4 in Isabelle. The HOL4 image
   627   can be used like any other Isabelle image.  See
   628   HOL/Import/HOL/README for more information.
   629 
   630 * Simplifier:
   631   - Much improved handling of linear and partial orders.
   632     Reasoners for linear and partial orders are set up for type classes
   633     "linorder" and "order" respectively, and are added to the default simpset
   634     as solvers.  This means that the simplifier can build transitivity chains
   635     to solve goals from the assumptions.
   636   - INCOMPATIBILITY: old proofs break occasionally.  Typically, applications
   637     of blast or auto after simplification become unnecessary because the goal
   638     is solved by simplification already.
   639 
   640 * Numerics: new theory Ring_and_Field contains over 250 basic numerical laws,
   641     all proved in axiomatic type classes for semirings, rings and fields.
   642 
   643 * Numerics:
   644   - Numeric types (nat, int, and in HOL-Complex rat, real, complex, etc.) are
   645     now formalized using the Ring_and_Field theory mentioned above.
   646   - INCOMPATIBILITY: simplification and arithmetic behaves somewhat differently
   647     than before, because now they are set up once in a generic manner.
   648   - INCOMPATIBILITY: many type-specific arithmetic laws have gone.
   649     Look for the general versions in Ring_and_Field (and Power if they concern
   650     exponentiation).
   651 
   652 * Type "rat" of the rational numbers is now available in HOL-Complex.
   653 
   654 * Records:
   655   - Record types are now by default printed with their type abbreviation
   656     instead of the list of all field types. This can be configured via
   657     the reference "print_record_type_abbr".
   658   - Simproc "record_upd_simproc" for simplification of multiple updates added
   659     (not enabled by default).
   660   - Simproc "record_ex_sel_eq_simproc" to simplify EX x. sel r = x resp.
   661     EX x. x = sel r to True (not enabled by default).
   662   - Tactic "record_split_simp_tac" to split and simplify records added.
   663 
   664 * 'specification' command added, allowing for definition by
   665   specification.  There is also an 'ax_specification' command that
   666   introduces the new constants axiomatically.
   667 
   668 * arith(_tac) is now able to generate counterexamples for reals as well.
   669 
   670 * HOL-Algebra: new locale "ring" for non-commutative rings.
   671 
   672 * HOL-ex: InductiveInvariant_examples illustrates advanced recursive function
   673   definitions, thanks to Sava Krsti\'{c} and John Matthews.
   674 
   675 * HOL-Matrix: a first theory for matrices in HOL with an application of
   676   matrix theory to linear programming.
   677 
   678 * Unions and Intersections:
   679   The latex output syntax of UN and INT has been changed
   680   from "\Union x \in A. B" to "\Union_{x \in A} B"
   681   i.e. the index formulae has become a subscript.
   682   Similarly for "\Union x. B", and for \Inter instead of \Union.
   683 
   684 * Unions and Intersections over Intervals:
   685   There is new short syntax "UN i<=n. A" for "UN i:{0..n}. A". There is
   686   also an x-symbol version with subscripts "\<Union>\<^bsub>i <= n\<^esub>. A"
   687   like in normal math, and corresponding versions for < and for intersection.
   688 
   689 * HOL/List: Ordering "lexico" is renamed "lenlex" and the standard
   690   lexicographic dictonary ordering has been added as "lexord".
   691 
   692 * ML: the legacy theory structures Int and List have been removed. They had
   693   conflicted with ML Basis Library structures having the same names.
   694 
   695 * 'refute' command added to search for (finite) countermodels.  Only works
   696   for a fragment of HOL.  The installation of an external SAT solver is
   697   highly recommended.  See "HOL/Refute.thy" for details.
   698 
   699 * 'quickcheck' command: Allows to find counterexamples by evaluating
   700   formulae under an assignment of free variables to random values.
   701   In contrast to 'refute', it can deal with inductive datatypes,
   702   but cannot handle quantifiers. See "HOL/ex/Quickcheck_Examples.thy"
   703   for examples.
   704 
   705 
   706 *** HOLCF ***
   707 
   708 * Streams now come with concatenation and are part of the HOLCF image
   709 
   710 
   711 
   712 New in Isabelle2003 (May 2003)
   713 ------------------------------
   714 
   715 *** General ***
   716 
   717 * Provers/simplifier:
   718 
   719   - Completely reimplemented method simp (ML: Asm_full_simp_tac):
   720     Assumptions are now subject to complete mutual simplification,
   721     not just from left to right. The simplifier now preserves
   722     the order of assumptions.
   723 
   724     Potential INCOMPATIBILITY:
   725 
   726     -- simp sometimes diverges where the old version did
   727        not, e.g. invoking simp on the goal
   728 
   729         [| P (f x); y = x; f x = f y |] ==> Q
   730 
   731        now gives rise to the infinite reduction sequence
   732 
   733         P(f x) --(f x = f y)--> P(f y) --(y = x)--> P(f x) --(f x = f y)--> ...
   734 
   735        Using "simp (asm_lr)" (ML: Asm_lr_simp_tac) instead often solves this
   736        kind of problem.
   737 
   738     -- Tactics combining classical reasoner and simplification (such as auto)
   739        are also affected by this change, because many of them rely on
   740        simp. They may sometimes diverge as well or yield a different numbers
   741        of subgoals. Try to use e.g. force, fastsimp, or safe instead of auto
   742        in case of problems. Sometimes subsequent calls to the classical
   743        reasoner will fail because a preceeding call to the simplifier too
   744        eagerly simplified the goal, e.g. deleted redundant premises.
   745 
   746   - The simplifier trace now shows the names of the applied rewrite rules
   747 
   748   - You can limit the number of recursive invocations of the simplifier
   749     during conditional rewriting (where the simplifie tries to solve the
   750     conditions before applying the rewrite rule):
   751     ML "simp_depth_limit := n"
   752     where n is an integer. Thus you can force termination where previously
   753     the simplifier would diverge.
   754 
   755   - Accepts free variables as head terms in congruence rules.  Useful in Isar.
   756 
   757   - No longer aborts on failed congruence proof.  Instead, the
   758     congruence is ignored.
   759 
   760 * Pure: New generic framework for extracting programs from constructive
   761   proofs. See HOL/Extraction.thy for an example instantiation, as well
   762   as HOL/Extraction for some case studies.
   763 
   764 * Pure: The main goal of the proof state is no longer shown by default, only
   765 the subgoals. This behaviour is controlled by a new flag.
   766    PG menu: Isabelle/Isar -> Settings -> Show Main Goal
   767 (ML: Proof.show_main_goal).
   768 
   769 * Pure: You can find all matching introduction rules for subgoal 1, i.e. all
   770 rules whose conclusion matches subgoal 1:
   771       PG menu: Isabelle/Isar -> Show me -> matching rules
   772 The rules are ordered by how closely they match the subgoal.
   773 In particular, rules that solve a subgoal outright are displayed first
   774 (or rather last, the way they are printed).
   775 (ML: ProofGeneral.print_intros())
   776 
   777 * Pure: New flag trace_unify_fail causes unification to print
   778 diagnostic information (PG: in trace buffer) when it fails. This is
   779 useful for figuring out why single step proofs like rule, erule or
   780 assumption failed.
   781 
   782 * Pure: Locale specifications now produce predicate definitions
   783 according to the body of text (covering assumptions modulo local
   784 definitions); predicate "loc_axioms" covers newly introduced text,
   785 while "loc" is cumulative wrt. all included locale expressions; the
   786 latter view is presented only on export into the global theory
   787 context; potential INCOMPATIBILITY, use "(open)" option to fall back
   788 on the old view without predicates;
   789 
   790 * Pure: predefined locales "var" and "struct" are useful for sharing
   791 parameters (as in CASL, for example); just specify something like
   792 ``var x + var y + struct M'' as import;
   793 
   794 * Pure: improved thms_containing: proper indexing of facts instead of
   795 raw theorems; check validity of results wrt. current name space;
   796 include local facts of proof configuration (also covers active
   797 locales), cover fixed variables in index; may use "_" in term
   798 specification; an optional limit for the number of printed facts may
   799 be given (the default is 40);
   800 
   801 * Pure: disallow duplicate fact bindings within new-style theory files
   802 (batch-mode only);
   803 
   804 * Provers: improved induct method: assumptions introduced by case
   805 "foo" are split into "foo.hyps" (from the rule) and "foo.prems" (from
   806 the goal statement); "foo" still refers to all facts collectively;
   807 
   808 * Provers: the function blast.overloaded has been removed: all constants
   809 are regarded as potentially overloaded, which improves robustness in exchange
   810 for slight decrease in efficiency;
   811 
   812 * Provers/linorder: New generic prover for transitivity reasoning over
   813 linear orders.  Note: this prover is not efficient!
   814 
   815 * Isar: preview of problems to finish 'show' now produce an error
   816 rather than just a warning (in interactive mode);
   817 
   818 
   819 *** HOL ***
   820 
   821 * arith(_tac)
   822 
   823  - Produces a counter example if it cannot prove a goal.
   824    Note that the counter example may be spurious if the goal is not a formula
   825    of quantifier-free linear arithmetic.
   826    In ProofGeneral the counter example appears in the trace buffer.
   827 
   828  - Knows about div k and mod k where k is a numeral of type nat or int.
   829 
   830  - Calls full Presburger arithmetic (by Amine Chaieb) if quantifier-free
   831    linear arithmetic fails. This takes account of quantifiers and divisibility.
   832    Presburger arithmetic can also be called explicitly via presburger(_tac).
   833 
   834 * simp's arithmetic capabilities have been enhanced a bit: it now
   835 takes ~= in premises into account (by performing a case split);
   836 
   837 * simp reduces "m*(n div m) + n mod m" to n, even if the two summands
   838 are distributed over a sum of terms;
   839 
   840 * New tactic "trans_tac" and method "trans" instantiate
   841 Provers/linorder.ML for axclasses "order" and "linorder" (predicates
   842 "<=", "<" and "=").
   843 
   844 * function INCOMPATIBILITIES: Pi-sets have been redefined and moved from main
   845 HOL to Library/FuncSet; constant "Fun.op o" is now called "Fun.comp";
   846 
   847 * 'typedef' command has new option "open" to suppress the set
   848 definition;
   849 
   850 * functions Min and Max on finite sets have been introduced (theory
   851 Finite_Set);
   852 
   853 * attribute [symmetric] now works for relations as well; it turns
   854 (x,y) : R^-1 into (y,x) : R, and vice versa;
   855 
   856 * induct over a !!-quantified statement (say !!x1..xn):
   857   each "case" automatically performs "fix x1 .. xn" with exactly those names.
   858 
   859 * Map: `empty' is no longer a constant but a syntactic abbreviation for
   860 %x. None. Warning: empty_def now refers to the previously hidden definition
   861 of the empty set.
   862 
   863 * Algebra: formalization of classical algebra.  Intended as base for
   864 any algebraic development in Isabelle.  Currently covers group theory
   865 (up to Sylow's theorem) and ring theory (Universal Property of
   866 Univariate Polynomials).  Contributions welcome;
   867 
   868 * GroupTheory: deleted, since its material has been moved to Algebra;
   869 
   870 * Complex: new directory of the complex numbers with numeric constants,
   871 nonstandard complex numbers, and some complex analysis, standard and
   872 nonstandard (Jacques Fleuriot);
   873 
   874 * HOL-Complex: new image for analysis, replacing HOL-Real and HOL-Hyperreal;
   875 
   876 * Hyperreal: introduced Gauge integration and hyperreal logarithms (Jacques
   877 Fleuriot);
   878 
   879 * Real/HahnBanach: updated and adapted to locales;
   880 
   881 * NumberTheory: added Gauss's law of quadratic reciprocity (by Avigad,
   882 Gray and Kramer);
   883 
   884 * UNITY: added the Meier-Sanders theory of progress sets;
   885 
   886 * MicroJava: bytecode verifier and lightweight bytecode verifier
   887 as abstract algorithms, instantiated to the JVM;
   888 
   889 * Bali: Java source language formalization. Type system, operational
   890 semantics, axiomatic semantics. Supported language features:
   891 classes, interfaces, objects,virtual methods, static methods,
   892 static/instance fields, arrays, access modifiers, definite
   893 assignment, exceptions.
   894 
   895 
   896 *** ZF ***
   897 
   898 * ZF/Constructible: consistency proof for AC (Gdel's constructible
   899 universe, etc.);
   900 
   901 * Main ZF: virtually all theories converted to new-style format;
   902 
   903 
   904 *** ML ***
   905 
   906 * Pure: Tactic.prove provides sane interface for internal proofs;
   907 omits the infamous "standard" operation, so this is more appropriate
   908 than prove_goalw_cterm in many situations (e.g. in simprocs);
   909 
   910 * Pure: improved error reporting of simprocs;
   911 
   912 * Provers: Simplifier.simproc(_i) provides sane interface for setting
   913 up simprocs;
   914 
   915 
   916 *** Document preparation ***
   917 
   918 * uses \par instead of \\ for line breaks in theory text. This may
   919 shift some page breaks in large documents. To get the old behaviour
   920 use \renewcommand{\isanewline}{\mbox{}\\\mbox{}} in root.tex.
   921 
   922 * minimized dependencies of isabelle.sty and isabellesym.sty on
   923 other packages
   924 
   925 * \<euro> now needs package babel/greek instead of marvosym (which
   926 broke \Rightarrow)
   927 
   928 * normal size for \<zero>...\<nine> (uses \mathbf instead of
   929 textcomp package)
   930 
   931 
   932 
   933 New in Isabelle2002 (March 2002)
   934 --------------------------------
   935 
   936 *** Document preparation ***
   937 
   938 * greatly simplified document preparation setup, including more
   939 graceful interpretation of isatool usedir -i/-d/-D options, and more
   940 instructive isatool mkdir; users should basically be able to get
   941 started with "isatool mkdir HOL Test && isatool make"; alternatively,
   942 users may run a separate document processing stage manually like this:
   943 "isatool usedir -D output HOL Test && isatool document Test/output";
   944 
   945 * theory dependency graph may now be incorporated into documents;
   946 isatool usedir -g true will produce session_graph.eps/.pdf for use
   947 with \includegraphics of LaTeX;
   948 
   949 * proper spacing of consecutive markup elements, especially text
   950 blocks after section headings;
   951 
   952 * support bold style (for single symbols only), input syntax is like
   953 this: "\<^bold>\<alpha>" or "\<^bold>A";
   954 
   955 * \<bullet> is now output as bold \cdot by default, which looks much
   956 better in printed text;
   957 
   958 * added default LaTeX bindings for \<tturnstile> and \<TTurnstile>;
   959 note that these symbols are currently unavailable in Proof General /
   960 X-Symbol; new symbols \<zero>, \<one>, ..., \<nine>, and \<euro>;
   961 
   962 * isatool latex no longer depends on changed TEXINPUTS, instead
   963 isatool document copies the Isabelle style files to the target
   964 location;
   965 
   966 
   967 *** Isar ***
   968 
   969 * Pure/Provers: improved proof by cases and induction;
   970   - 'case' command admits impromptu naming of parameters (such as
   971     "case (Suc n)");
   972   - 'induct' method divinates rule instantiation from the inductive
   973     claim; no longer requires excessive ?P bindings for proper
   974     instantiation of cases;
   975   - 'induct' method properly enumerates all possibilities of set/type
   976     rules; as a consequence facts may be also passed through *type*
   977     rules without further ado;
   978   - 'induct' method now derives symbolic cases from the *rulified*
   979     rule (before it used to rulify cases stemming from the internal
   980     atomized version); this means that the context of a non-atomic
   981     statement becomes is included in the hypothesis, avoiding the
   982     slightly cumbersome show "PROP ?case" form;
   983   - 'induct' may now use elim-style induction rules without chaining
   984     facts, using ``missing'' premises from the goal state; this allows
   985     rules stemming from inductive sets to be applied in unstructured
   986     scripts, while still benefitting from proper handling of non-atomic
   987     statements; NB: major inductive premises need to be put first, all
   988     the rest of the goal is passed through the induction;
   989   - 'induct' proper support for mutual induction involving non-atomic
   990     rule statements (uses the new concept of simultaneous goals, see
   991     below);
   992   - append all possible rule selections, but only use the first
   993     success (no backtracking);
   994   - removed obsolete "(simplified)" and "(stripped)" options of methods;
   995   - undeclared rule case names default to numbers 1, 2, 3, ...;
   996   - added 'print_induct_rules' (covered by help item in recent Proof
   997     General versions);
   998   - moved induct/cases attributes to Pure, methods to Provers;
   999   - generic method setup instantiated for FOL and HOL;
  1000 
  1001 * Pure: support multiple simultaneous goal statements, for example
  1002 "have a: A and b: B" (same for 'theorem' etc.); being a pure
  1003 meta-level mechanism, this acts as if several individual goals had
  1004 been stated separately; in particular common proof methods need to be
  1005 repeated in order to cover all claims; note that a single elimination
  1006 step is *not* sufficient to establish the two conjunctions, so this
  1007 fails:
  1008 
  1009   assume "A & B" then have A and B ..   (*".." fails*)
  1010 
  1011 better use "obtain" in situations as above; alternative refer to
  1012 multi-step methods like 'auto', 'simp_all', 'blast+' etc.;
  1013 
  1014 * Pure: proper integration with ``locales''; unlike the original
  1015 version by Florian Kammller, Isar locales package high-level proof
  1016 contexts rather than raw logical ones (e.g. we admit to include
  1017 attributes everywhere); operations on locales include merge and
  1018 rename; support for implicit arguments (``structures''); simultaneous
  1019 type-inference over imports and text; see also HOL/ex/Locales.thy for
  1020 some examples;
  1021 
  1022 * Pure: the following commands have been ``localized'', supporting a
  1023 target locale specification "(in name)": 'lemma', 'theorem',
  1024 'corollary', 'lemmas', 'theorems', 'declare'; the results will be
  1025 stored both within the locale and at the theory level (exported and
  1026 qualified by the locale name);
  1027 
  1028 * Pure: theory goals may now be specified in ``long'' form, with
  1029 ad-hoc contexts consisting of arbitrary locale elements. for example
  1030 ``lemma foo: fixes x assumes "A x" shows "B x"'' (local syntax and
  1031 definitions may be given, too); the result is a meta-level rule with
  1032 the context elements being discharged in the obvious way;
  1033 
  1034 * Pure: new proof command 'using' allows to augment currently used
  1035 facts after a goal statement ('using' is syntactically analogous to
  1036 'apply', but acts on the goal's facts only); this allows chained facts
  1037 to be separated into parts given before and after a claim, as in
  1038 ``from a and b have C using d and e <proof>'';
  1039 
  1040 * Pure: renamed "antecedent" case to "rule_context";
  1041 
  1042 * Pure: new 'judgment' command records explicit information about the
  1043 object-logic embedding (used by several tools internally); no longer
  1044 use hard-wired "Trueprop";
  1045 
  1046 * Pure: added 'corollary' command;
  1047 
  1048 * Pure: fixed 'token_translation' command;
  1049 
  1050 * Pure: removed obsolete 'exported' attribute;
  1051 
  1052 * Pure: dummy pattern "_" in is/let is now automatically lifted over
  1053 bound variables: "ALL x. P x --> Q x" (is "ALL x. _ --> ?C x")
  1054 supersedes more cumbersome ... (is "ALL x. _ x --> ?C x");
  1055 
  1056 * Pure: method 'atomize' presents local goal premises as object-level
  1057 statements (atomic meta-level propositions); setup controlled via
  1058 rewrite rules declarations of 'atomize' attribute; example
  1059 application: 'induct' method with proper rule statements in improper
  1060 proof *scripts*;
  1061 
  1062 * Pure: emulation of instantiation tactics (rule_tac, cut_tac, etc.)
  1063 now consider the syntactic context of assumptions, giving a better
  1064 chance to get type-inference of the arguments right (this is
  1065 especially important for locales);
  1066 
  1067 * Pure: "sorry" no longer requires quick_and_dirty in interactive
  1068 mode;
  1069 
  1070 * Pure/obtain: the formal conclusion "thesis", being marked as
  1071 ``internal'', may no longer be reference directly in the text;
  1072 potential INCOMPATIBILITY, may need to use "?thesis" in rare
  1073 situations;
  1074 
  1075 * Pure: generic 'sym' attribute which declares a rule both as pure
  1076 'elim?' and for the 'symmetric' operation;
  1077 
  1078 * Pure: marginal comments ``--'' may now occur just anywhere in the
  1079 text; the fixed correlation with particular command syntax has been
  1080 discontinued;
  1081 
  1082 * Pure: new method 'rules' is particularly well-suited for proof
  1083 search in intuitionistic logic; a bit slower than 'blast' or 'fast',
  1084 but often produces more compact proof terms with less detours;
  1085 
  1086 * Pure/Provers/classical: simplified integration with pure rule
  1087 attributes and methods; the classical "intro?/elim?/dest?"
  1088 declarations coincide with the pure ones; the "rule" method no longer
  1089 includes classically swapped intros; "intro" and "elim" methods no
  1090 longer pick rules from the context; also got rid of ML declarations
  1091 AddXIs/AddXEs/AddXDs; all of this has some potential for
  1092 INCOMPATIBILITY;
  1093 
  1094 * Provers/classical: attribute 'swapped' produces classical inversions
  1095 of introduction rules;
  1096 
  1097 * Provers/simplifier: 'simplified' attribute may refer to explicit
  1098 rules instead of full simplifier context; 'iff' attribute handles
  1099 conditional rules;
  1100 
  1101 * HOL: 'typedef' now allows alternative names for Rep/Abs morphisms;
  1102 
  1103 * HOL: 'recdef' now fails on unfinished automated proofs, use
  1104 "(permissive)" option to recover old behavior;
  1105 
  1106 * HOL: 'inductive' no longer features separate (collective) attributes
  1107 for 'intros' (was found too confusing);
  1108 
  1109 * HOL: properly declared induction rules less_induct and
  1110 wf_induct_rule;
  1111 
  1112 
  1113 *** HOL ***
  1114 
  1115 * HOL: moved over to sane numeral syntax; the new policy is as
  1116 follows:
  1117 
  1118   - 0 and 1 are polymorphic constants, which are defined on any
  1119   numeric type (nat, int, real etc.);
  1120 
  1121   - 2, 3, 4, ... and -1, -2, -3, ... are polymorphic numerals, based
  1122   binary representation internally;
  1123 
  1124   - type nat has special constructor Suc, and generally prefers Suc 0
  1125   over 1::nat and Suc (Suc 0) over 2::nat;
  1126 
  1127 This change may cause significant problems of INCOMPATIBILITY; here
  1128 are some hints on converting existing sources:
  1129 
  1130   - due to the new "num" token, "-0" and "-1" etc. are now atomic
  1131   entities, so expressions involving "-" (unary or binary minus) need
  1132   to be spaced properly;
  1133 
  1134   - existing occurrences of "1" may need to be constraint "1::nat" or
  1135   even replaced by Suc 0; similar for old "2";
  1136 
  1137   - replace "#nnn" by "nnn", and "#-nnn" by "-nnn";
  1138 
  1139   - remove all special provisions on numerals in proofs;
  1140 
  1141 * HOL: simp rules nat_number expand numerals on nat to Suc/0
  1142 representation (depends on bin_arith_simps in the default context);
  1143 
  1144 * HOL: symbolic syntax for x^2 (numeral 2);
  1145 
  1146 * HOL: the class of all HOL types is now called "type" rather than
  1147 "term"; INCOMPATIBILITY, need to adapt references to this type class
  1148 in axclass/classes, instance/arities, and (usually rare) occurrences
  1149 in typings (of consts etc.); internally the class is called
  1150 "HOL.type", ML programs should refer to HOLogic.typeS;
  1151 
  1152 * HOL/record package improvements:
  1153   - new derived operations "fields" to build a partial record section,
  1154     "extend" to promote a fixed record to a record scheme, and
  1155     "truncate" for the reverse; cf. theorems "xxx.defs", which are *not*
  1156     declared as simp by default;
  1157   - shared operations ("more", "fields", etc.) now need to be always
  1158     qualified) --- potential INCOMPATIBILITY;
  1159   - removed "make_scheme" operations (use "make" with "extend") --
  1160     INCOMPATIBILITY;
  1161   - removed "more" class (simply use "term") -- INCOMPATIBILITY;
  1162   - provides cases/induct rules for use with corresponding Isar
  1163     methods (for concrete records, record schemes, concrete more
  1164     parts, and schematic more parts -- in that order);
  1165   - internal definitions directly based on a light-weight abstract
  1166     theory of product types over typedef rather than datatype;
  1167 
  1168 * HOL: generic code generator for generating executable ML code from
  1169 specifications; specific support for HOL constructs such as inductive
  1170 datatypes and sets, as well as recursive functions; can be invoked
  1171 via 'generate_code' theory section;
  1172 
  1173 * HOL: canonical cases/induct rules for n-tuples (n = 3..7);
  1174 
  1175 * HOL: consolidated and renamed several theories.  In particular:
  1176         Ord.thy has been absorbed into HOL.thy
  1177         String.thy has been absorbed into List.thy
  1178 
  1179 * HOL: concrete setsum syntax "\<Sum>i:A. b" == "setsum (%i. b) A"
  1180 (beware of argument permutation!);
  1181 
  1182 * HOL: linorder_less_split superseded by linorder_cases;
  1183 
  1184 * HOL/List: "nodups" renamed to "distinct";
  1185 
  1186 * HOL: added "The" definite description operator; move Hilbert's "Eps"
  1187 to peripheral theory "Hilbert_Choice"; some INCOMPATIBILITIES:
  1188   - Ex_def has changed, now need to use some_eq_ex
  1189 
  1190 * HOL: made split_all_tac safe; EXISTING PROOFS MAY FAIL OR LOOP, so
  1191 in this (rare) case use:
  1192 
  1193   delSWrapper "split_all_tac"
  1194   addSbefore ("unsafe_split_all_tac", unsafe_split_all_tac)
  1195 
  1196 * HOL: added safe wrapper "split_conv_tac" to claset; EXISTING PROOFS
  1197 MAY FAIL;
  1198 
  1199 * HOL: introduced f^n = f o ... o f; warning: due to the limits of
  1200 Isabelle's type classes, ^ on functions and relations has too general
  1201 a domain, namely ('a * 'b) set and 'a => 'b; this means that it may be
  1202 necessary to attach explicit type constraints;
  1203 
  1204 * HOL/Relation: the prefix name of the infix "O" has been changed from
  1205 "comp" to "rel_comp"; INCOMPATIBILITY: a few theorems have been
  1206 renamed accordingly (eg "compI" -> "rel_compI").
  1207 
  1208 * HOL: syntax translations now work properly with numerals and records
  1209 expressions;
  1210 
  1211 * HOL: bounded abstraction now uses syntax "%" / "\<lambda>" instead
  1212 of "lam" -- INCOMPATIBILITY;
  1213 
  1214 * HOL: got rid of some global declarations (potential INCOMPATIBILITY
  1215 for ML tools): const "()" renamed "Product_Type.Unity", type "unit"
  1216 renamed "Product_Type.unit";
  1217 
  1218 * HOL: renamed rtrancl_into_rtrancl2 to converse_rtrancl_into_rtrancl
  1219 
  1220 * HOL: removed obsolete theorem "optionE" (use "option.exhaust", or
  1221 the "cases" method);
  1222 
  1223 * HOL/GroupTheory: group theory examples including Sylow's theorem (by
  1224 Florian Kammller);
  1225 
  1226 * HOL/IMP: updated and converted to new-style theory format; several
  1227 parts turned into readable document, with proper Isar proof texts and
  1228 some explanations (by Gerwin Klein);
  1229 
  1230 * HOL-Real: added Complex_Numbers (by Gertrud Bauer);
  1231 
  1232 * HOL-Hyperreal is now a logic image;
  1233 
  1234 
  1235 *** HOLCF ***
  1236 
  1237 * Isar: consts/constdefs supports mixfix syntax for continuous
  1238 operations;
  1239 
  1240 * Isar: domain package adapted to new-style theory format, e.g. see
  1241 HOLCF/ex/Dnat.thy;
  1242 
  1243 * theory Lift: proper use of rep_datatype lift instead of ML hacks --
  1244 potential INCOMPATIBILITY; now use plain induct_tac instead of former
  1245 lift.induct_tac, always use UU instead of Undef;
  1246 
  1247 * HOLCF/IMP: updated and converted to new-style theory;
  1248 
  1249 
  1250 *** ZF ***
  1251 
  1252 * Isar: proper integration of logic-specific tools and packages,
  1253 including theory commands '(co)inductive', '(co)datatype',
  1254 'rep_datatype', 'inductive_cases', as well as methods 'ind_cases',
  1255 'induct_tac', 'case_tac', and 'typecheck' (with attribute 'TC');
  1256 
  1257 * theory Main no longer includes AC; for the Axiom of Choice, base
  1258 your theory on Main_ZFC;
  1259 
  1260 * the integer library now covers quotients and remainders, with many
  1261 laws relating division to addition, multiplication, etc.;
  1262 
  1263 * ZF/UNITY: Chandy and Misra's UNITY is now available in ZF, giving a
  1264 typeless version of the formalism;
  1265 
  1266 * ZF/AC, Coind, IMP, Resid: updated and converted to new-style theory
  1267 format;
  1268 
  1269 * ZF/Induct: new directory for examples of inductive definitions,
  1270 including theory Multiset for multiset orderings; converted to
  1271 new-style theory format;
  1272 
  1273 * ZF: many new theorems about lists, ordinals, etc.;
  1274 
  1275 
  1276 *** General ***
  1277 
  1278 * Pure/kernel: meta-level proof terms (by Stefan Berghofer); reference
  1279 variable proof controls level of detail: 0 = no proofs (only oracle
  1280 dependencies), 1 = lemma dependencies, 2 = compact proof terms; see
  1281 also ref manual for further ML interfaces;
  1282 
  1283 * Pure/axclass: removed obsolete ML interface
  1284 goal_subclass/goal_arity;
  1285 
  1286 * Pure/syntax: new token syntax "num" for plain numerals (without "#"
  1287 of "xnum"); potential INCOMPATIBILITY, since -0, -1 etc. are now
  1288 separate tokens, so expressions involving minus need to be spaced
  1289 properly;
  1290 
  1291 * Pure/syntax: support non-oriented infixes, using keyword "infix"
  1292 rather than "infixl" or "infixr";
  1293 
  1294 * Pure/syntax: concrete syntax for dummy type variables admits genuine
  1295 sort constraint specifications in type inference; e.g. "x::_::foo"
  1296 ensures that the type of "x" is of sort "foo" (but not necessarily a
  1297 type variable);
  1298 
  1299 * Pure/syntax: print modes "type_brackets" and "no_type_brackets"
  1300 control output of nested => (types); the default behavior is
  1301 "type_brackets";
  1302 
  1303 * Pure/syntax: builtin parse translation for "_constify" turns valued
  1304 tokens into AST constants;
  1305 
  1306 * Pure/syntax: prefer later declarations of translations and print
  1307 translation functions; potential INCOMPATIBILITY: need to reverse
  1308 multiple declarations for same syntax element constant;
  1309 
  1310 * Pure/show_hyps reset by default (in accordance to existing Isar
  1311 practice);
  1312 
  1313 * Provers/classical: renamed addaltern to addafter, addSaltern to
  1314 addSafter;
  1315 
  1316 * Provers/clasimp: ``iff'' declarations now handle conditional rules
  1317 as well;
  1318 
  1319 * system: tested support for MacOS X; should be able to get Isabelle +
  1320 Proof General to work in a plain Terminal after installing Poly/ML
  1321 (e.g. from the Isabelle distribution area) and GNU bash alone
  1322 (e.g. from http://www.apple.com); full X11, XEmacs and X-Symbol
  1323 support requires further installations, e.g. from
  1324 http://fink.sourceforge.net/);
  1325 
  1326 * system: support Poly/ML 4.1.1 (able to manage larger heaps);
  1327 
  1328 * system: reduced base memory usage by Poly/ML (approx. 20 MB instead
  1329 of 40 MB), cf. ML_OPTIONS;
  1330 
  1331 * system: Proof General keywords specification is now part of the
  1332 Isabelle distribution (see etc/isar-keywords.el);
  1333 
  1334 * system: support for persistent Proof General sessions (refrain from
  1335 outdating all loaded theories on startup); user may create writable
  1336 logic images like this: ``isabelle -q HOL Test'';
  1337 
  1338 * system: smart selection of Isabelle process versus Isabelle
  1339 interface, accommodates case-insensitive file systems (e.g. HFS+); may
  1340 run both "isabelle" and "Isabelle" even if file names are badly
  1341 damaged (executable inspects the case of the first letter of its own
  1342 name); added separate "isabelle-process" and "isabelle-interface";
  1343 
  1344 * system: refrain from any attempt at filtering input streams; no
  1345 longer support ``8bit'' encoding of old isabelle font, instead proper
  1346 iso-latin characters may now be used; the related isatools
  1347 "symbolinput" and "nonascii" have disappeared as well;
  1348 
  1349 * system: removed old "xterm" interface (the print modes "xterm" and
  1350 "xterm_color" are still available for direct use in a suitable
  1351 terminal);
  1352 
  1353 
  1354 
  1355 New in Isabelle99-2 (February 2001)
  1356 -----------------------------------
  1357 
  1358 *** Overview of INCOMPATIBILITIES ***
  1359 
  1360 * HOL: please note that theories in the Library and elsewhere often use the
  1361 new-style (Isar) format; to refer to their theorems in an ML script you must
  1362 bind them to ML identifers by e.g.      val thm_name = thm "thm_name";
  1363 
  1364 * HOL: inductive package no longer splits induction rule aggressively,
  1365 but only as far as specified by the introductions given; the old
  1366 format may be recovered via ML function complete_split_rule or attribute
  1367 'split_rule (complete)';
  1368 
  1369 * HOL: induct renamed to lfp_induct, lfp_Tarski to lfp_unfold,
  1370 gfp_Tarski to gfp_unfold;
  1371 
  1372 * HOL: contrapos, contrapos2 renamed to contrapos_nn, contrapos_pp;
  1373 
  1374 * HOL: infix "dvd" now has priority 50 rather than 70 (because it is a
  1375 relation); infix "^^" has been renamed "``"; infix "``" has been
  1376 renamed "`"; "univalent" has been renamed "single_valued";
  1377 
  1378 * HOL/Real: "rinv" and "hrinv" replaced by overloaded "inverse"
  1379 operation;
  1380 
  1381 * HOLCF: infix "`" has been renamed "$"; the symbol syntax is \<cdot>;
  1382 
  1383 * Isar: 'obtain' no longer declares "that" fact as simp/intro;
  1384 
  1385 * Isar/HOL: method 'induct' now handles non-atomic goals; as a
  1386 consequence, it is no longer monotonic wrt. the local goal context
  1387 (which is now passed through the inductive cases);
  1388 
  1389 * Document preparation: renamed standard symbols \<ll> to \<lless> and
  1390 \<gg> to \<ggreater>;
  1391 
  1392 
  1393 *** Document preparation ***
  1394 
  1395 * \isabellestyle{NAME} selects version of Isabelle output (currently
  1396 available: are "it" for near math-mode best-style output, "sl" for
  1397 slanted text style, and "tt" for plain type-writer; if no
  1398 \isabellestyle command is given, output is according to slanted
  1399 type-writer);
  1400 
  1401 * support sub/super scripts (for single symbols only), input syntax is
  1402 like this: "A\<^sup>*" or "A\<^sup>\<star>";
  1403 
  1404 * some more standard symbols; see Appendix A of the system manual for
  1405 the complete list of symbols defined in isabellesym.sty;
  1406 
  1407 * improved isabelle style files; more abstract symbol implementation
  1408 (should now use \isamath{...} and \isatext{...} in custom symbol
  1409 definitions);
  1410 
  1411 * antiquotation @{goals} and @{subgoals} for output of *dynamic* goals
  1412 state; Note that presentation of goal states does not conform to
  1413 actual human-readable proof documents.  Please do not include goal
  1414 states into document output unless you really know what you are doing!
  1415 
  1416 * proper indentation of antiquoted output with proportional LaTeX
  1417 fonts;
  1418 
  1419 * no_document ML operator temporarily disables LaTeX document
  1420 generation;
  1421 
  1422 * isatool unsymbolize tunes sources for plain ASCII communication;
  1423 
  1424 
  1425 *** Isar ***
  1426 
  1427 * Pure: Isar now suffers initial goal statements to contain unbound
  1428 schematic variables (this does not conform to actual readable proof
  1429 documents, due to unpredictable outcome and non-compositional proof
  1430 checking); users who know what they are doing may use schematic goals
  1431 for Prolog-style synthesis of proven results;
  1432 
  1433 * Pure: assumption method (an implicit finishing) now handles actual
  1434 rules as well;
  1435 
  1436 * Pure: improved 'obtain' --- moved to Pure, insert "that" into
  1437 initial goal, declare "that" only as Pure intro (only for single
  1438 steps); the "that" rule assumption may now be involved in implicit
  1439 finishing, thus ".." becomes a feasible for trivial obtains;
  1440 
  1441 * Pure: default proof step now includes 'intro_classes'; thus trivial
  1442 instance proofs may be performed by "..";
  1443 
  1444 * Pure: ?thesis / ?this / "..." now work for pure meta-level
  1445 statements as well;
  1446 
  1447 * Pure: more robust selection of calculational rules;
  1448 
  1449 * Pure: the builtin notion of 'finished' goal now includes the ==-refl
  1450 rule (as well as the assumption rule);
  1451 
  1452 * Pure: 'thm_deps' command visualizes dependencies of theorems and
  1453 lemmas, using the graph browser tool;
  1454 
  1455 * Pure: predict failure of "show" in interactive mode;
  1456 
  1457 * Pure: 'thms_containing' now takes actual terms as arguments;
  1458 
  1459 * HOL: improved method 'induct' --- now handles non-atomic goals
  1460 (potential INCOMPATIBILITY); tuned error handling;
  1461 
  1462 * HOL: cases and induct rules now provide explicit hints about the
  1463 number of facts to be consumed (0 for "type" and 1 for "set" rules);
  1464 any remaining facts are inserted into the goal verbatim;
  1465 
  1466 * HOL: local contexts (aka cases) may now contain term bindings as
  1467 well; the 'cases' and 'induct' methods new provide a ?case binding for
  1468 the result to be shown in each case;
  1469 
  1470 * HOL: added 'recdef_tc' command;
  1471 
  1472 * isatool convert assists in eliminating legacy ML scripts;
  1473 
  1474 
  1475 *** HOL ***
  1476 
  1477 * HOL/Library: a collection of generic theories to be used together
  1478 with main HOL; the theory loader path already includes this directory
  1479 by default; the following existing theories have been moved here:
  1480 HOL/Induct/Multiset, HOL/Induct/Acc (as Accessible_Part), HOL/While
  1481 (as While_Combinator), HOL/Lex/Prefix (as List_Prefix);
  1482 
  1483 * HOL/Unix: "Some aspects of Unix file-system security", a typical
  1484 modelling and verification task performed in Isabelle/HOL +
  1485 Isabelle/Isar + Isabelle document preparation (by Markus Wenzel).
  1486 
  1487 * HOL/Algebra: special summation operator SUM no longer exists, it has
  1488 been replaced by setsum; infix 'assoc' now has priority 50 (like
  1489 'dvd'); axiom 'one_not_zero' has been moved from axclass 'ring' to
  1490 'domain', this makes the theory consistent with mathematical
  1491 literature;
  1492 
  1493 * HOL basics: added overloaded operations "inverse" and "divide"
  1494 (infix "/"), syntax for generic "abs" operation, generic summation
  1495 operator \<Sum>;
  1496 
  1497 * HOL/typedef: simplified package, provide more useful rules (see also
  1498 HOL/subset.thy);
  1499 
  1500 * HOL/datatype: induction rule for arbitrarily branching datatypes is
  1501 now expressed as a proper nested rule (old-style tactic scripts may
  1502 require atomize_strip_tac to cope with non-atomic premises);
  1503 
  1504 * HOL: renamed theory "Prod" to "Product_Type", renamed "split" rule
  1505 to "split_conv" (old name still available for compatibility);
  1506 
  1507 * HOL: improved concrete syntax for strings (e.g. allows translation
  1508 rules with string literals);
  1509 
  1510 * HOL-Real-Hyperreal: this extends HOL-Real with the hyperreals
  1511  and Fleuriot's mechanization of analysis, including the transcendental
  1512  functions for the reals;
  1513 
  1514 * HOL/Real, HOL/Hyperreal: improved arithmetic simplification;
  1515 
  1516 
  1517 *** CTT ***
  1518 
  1519 * CTT: x-symbol support for Pi, Sigma, -->, : (membership); note that
  1520 "lam" is displayed as TWO lambda-symbols
  1521 
  1522 * CTT: theory Main now available, containing everything (that is, Bool
  1523 and Arith);
  1524 
  1525 
  1526 *** General ***
  1527 
  1528 * Pure: the Simplifier has been implemented properly as a derived rule
  1529 outside of the actual kernel (at last!); the overall performance
  1530 penalty in practical applications is about 50%, while reliability of
  1531 the Isabelle inference kernel has been greatly improved;
  1532 
  1533 * print modes "brackets" and "no_brackets" control output of nested =>
  1534 (types) and ==> (props); the default behaviour is "brackets";
  1535 
  1536 * Provers: fast_tac (and friends) now handle actual object-logic rules
  1537 as assumptions as well;
  1538 
  1539 * system: support Poly/ML 4.0;
  1540 
  1541 * system: isatool install handles KDE version 1 or 2;
  1542 
  1543 
  1544 
  1545 New in Isabelle99-1 (October 2000)
  1546 ----------------------------------
  1547 
  1548 *** Overview of INCOMPATIBILITIES ***
  1549 
  1550 * HOL: simplification of natural numbers is much changed; to partly
  1551 recover the old behaviour (e.g. to prevent n+n rewriting to #2*n)
  1552 issue the following ML commands:
  1553 
  1554   Delsimprocs Nat_Numeral_Simprocs.cancel_numerals;
  1555   Delsimprocs [Nat_Numeral_Simprocs.combine_numerals];
  1556 
  1557 * HOL: simplification no longer dives into case-expressions; this is
  1558 controlled by "t.weak_case_cong" for each datatype t;
  1559 
  1560 * HOL: nat_less_induct renamed to less_induct;
  1561 
  1562 * HOL: systematic renaming of the SOME (Eps) rules, may use isatool
  1563 fixsome to patch .thy and .ML sources automatically;
  1564 
  1565   select_equality  -> some_equality
  1566   select_eq_Ex     -> some_eq_ex
  1567   selectI2EX       -> someI2_ex
  1568   selectI2         -> someI2
  1569   selectI          -> someI
  1570   select1_equality -> some1_equality
  1571   Eps_sym_eq       -> some_sym_eq_trivial
  1572   Eps_eq           -> some_eq_trivial
  1573 
  1574 * HOL: exhaust_tac on datatypes superceded by new generic case_tac;
  1575 
  1576 * HOL: removed obsolete theorem binding expand_if (refer to split_if
  1577 instead);
  1578 
  1579 * HOL: the recursion equations generated by 'recdef' are now called
  1580 f.simps instead of f.rules;
  1581 
  1582 * HOL: qed_spec_mp now also handles bounded ALL as well;
  1583 
  1584 * HOL: 0 is now overloaded, so the type constraint ":: nat" may
  1585 sometimes be needed;
  1586 
  1587 * HOL: the constant for "f``x" is now "image" rather than "op ``";
  1588 
  1589 * HOL: the constant for "f-``x" is now "vimage" rather than "op -``";
  1590 
  1591 * HOL: the disjoint sum is now "<+>" instead of "Plus"; the cartesian
  1592 product is now "<*>" instead of "Times"; the lexicographic product is
  1593 now "<*lex*>" instead of "**";
  1594 
  1595 * HOL: theory Sexp is now in HOL/Induct examples (it used to be part
  1596 of main HOL, but was unused); better use HOL's datatype package;
  1597 
  1598 * HOL: removed "symbols" syntax for constant "override" of theory Map;
  1599 the old syntax may be recovered as follows:
  1600 
  1601   syntax (symbols)
  1602     override  :: "('a ~=> 'b) => ('a ~=> 'b) => ('a ~=> 'b)"
  1603       (infixl "\\<oplus>" 100)
  1604 
  1605 * HOL/Real: "rabs" replaced by overloaded "abs" function;
  1606 
  1607 * HOL/ML: even fewer consts are declared as global (see theories Ord,
  1608 Lfp, Gfp, WF); this only affects ML packages that refer to const names
  1609 internally;
  1610 
  1611 * HOL and ZF: syntax for quotienting wrt an equivalence relation
  1612 changed from A/r to A//r;
  1613 
  1614 * ZF: new treatment of arithmetic (nat & int) may break some old
  1615 proofs;
  1616 
  1617 * Isar: renamed some attributes (RS -> THEN, simplify -> simplified,
  1618 rulify -> rule_format, elimify -> elim_format, ...);
  1619 
  1620 * Isar/Provers: intro/elim/dest attributes changed; renamed
  1621 intro/intro!/intro!! flags to intro!/intro/intro? (in most cases, one
  1622 should have to change intro!! to intro? only); replaced "delrule" by
  1623 "rule del";
  1624 
  1625 * Isar/HOL: renamed "intrs" to "intros" in inductive definitions;
  1626 
  1627 * Provers: strengthened force_tac by using new first_best_tac;
  1628 
  1629 * LaTeX document preparation: several changes of isabelle.sty (see
  1630 lib/texinputs);
  1631 
  1632 
  1633 *** Document preparation ***
  1634 
  1635 * formal comments (text blocks etc.) in new-style theories may now
  1636 contain antiquotations of thm/prop/term/typ/text to be presented
  1637 according to latex print mode; concrete syntax is like this:
  1638 @{term[show_types] "f(x) = a + x"};
  1639 
  1640 * isatool mkdir provides easy setup of Isabelle session directories,
  1641 including proper document sources;
  1642 
  1643 * generated LaTeX sources are now deleted after successful run
  1644 (isatool document -c); may retain a copy somewhere else via -D option
  1645 of isatool usedir;
  1646 
  1647 * isatool usedir -D now lets isatool latex -o sty update the Isabelle
  1648 style files, achieving self-contained LaTeX sources and simplifying
  1649 LaTeX debugging;
  1650 
  1651 * old-style theories now produce (crude) LaTeX output as well;
  1652 
  1653 * browser info session directories are now self-contained (may be put
  1654 on WWW server seperately); improved graphs of nested sessions; removed
  1655 graph for 'all sessions';
  1656 
  1657 * several improvements in isabelle style files; \isabellestyle{it}
  1658 produces fake math mode output; \isamarkupheader is now \section by
  1659 default; see lib/texinputs/isabelle.sty etc.;
  1660 
  1661 
  1662 *** Isar ***
  1663 
  1664 * Isar/Pure: local results and corresponding term bindings are now
  1665 subject to Hindley-Milner polymorphism (similar to ML); this
  1666 accommodates incremental type-inference very nicely;
  1667 
  1668 * Isar/Pure: new derived language element 'obtain' supports
  1669 generalized existence reasoning;
  1670 
  1671 * Isar/Pure: new calculational elements 'moreover' and 'ultimately'
  1672 support accumulation of results, without applying any rules yet;
  1673 useful to collect intermediate results without explicit name
  1674 references, and for use with transitivity rules with more than 2
  1675 premises;
  1676 
  1677 * Isar/Pure: scalable support for case-analysis type proofs: new
  1678 'case' language element refers to local contexts symbolically, as
  1679 produced by certain proof methods; internally, case names are attached
  1680 to theorems as "tags";
  1681 
  1682 * Isar/Pure: theory command 'hide' removes declarations from
  1683 class/type/const name spaces;
  1684 
  1685 * Isar/Pure: theory command 'defs' supports option "(overloaded)" to
  1686 indicate potential overloading;
  1687 
  1688 * Isar/Pure: changed syntax of local blocks from {{ }} to { };
  1689 
  1690 * Isar/Pure: syntax of sorts made 'inner', i.e. have to write
  1691 "{a,b,c}" instead of {a,b,c};
  1692 
  1693 * Isar/Pure now provides its own version of intro/elim/dest
  1694 attributes; useful for building new logics, but beware of confusion
  1695 with the version in Provers/classical;
  1696 
  1697 * Isar/Pure: the local context of (non-atomic) goals is provided via
  1698 case name 'antecedent';
  1699 
  1700 * Isar/Pure: removed obsolete 'transfer' attribute (transfer of thms
  1701 to the current context is now done automatically);
  1702 
  1703 * Isar/Pure: theory command 'method_setup' provides a simple interface
  1704 for definining proof methods in ML;
  1705 
  1706 * Isar/Provers: intro/elim/dest attributes changed; renamed
  1707 intro/intro!/intro!! flags to intro!/intro/intro? (INCOMPATIBILITY, in
  1708 most cases, one should have to change intro!! to intro? only);
  1709 replaced "delrule" by "rule del";
  1710 
  1711 * Isar/Provers: new 'hypsubst' method, plain 'subst' method and
  1712 'symmetric' attribute (the latter supercedes [RS sym]);
  1713 
  1714 * Isar/Provers: splitter support (via 'split' attribute and 'simp'
  1715 method modifier); 'simp' method: 'only:' modifier removes loopers as
  1716 well (including splits);
  1717 
  1718 * Isar/Provers: Simplifier and Classical methods now support all kind
  1719 of modifiers used in the past, including 'cong', 'iff', etc.
  1720 
  1721 * Isar/Provers: added 'fastsimp' and 'clarsimp' methods (combination
  1722 of Simplifier and Classical reasoner);
  1723 
  1724 * Isar/HOL: new proof method 'cases' and improved version of 'induct'
  1725 now support named cases; major packages (inductive, datatype, primrec,
  1726 recdef) support case names and properly name parameters;
  1727 
  1728 * Isar/HOL: new transitivity rules for substitution in inequalities --
  1729 monotonicity conditions are extracted to be proven at end of
  1730 calculations;
  1731 
  1732 * Isar/HOL: removed 'case_split' thm binding, should use 'cases' proof
  1733 method anyway;
  1734 
  1735 * Isar/HOL: removed old expand_if = split_if; theorems if_splits =
  1736 split_if split_if_asm; datatype package provides theorems foo.splits =
  1737 foo.split foo.split_asm for each datatype;
  1738 
  1739 * Isar/HOL: tuned inductive package, rename "intrs" to "intros"
  1740 (potential INCOMPATIBILITY), emulation of mk_cases feature for proof
  1741 scripts: new 'inductive_cases' command and 'ind_cases' method; (Note:
  1742 use "(cases (simplified))" method in proper proof texts);
  1743 
  1744 * Isar/HOL: added global 'arith_split' attribute for 'arith' method;
  1745 
  1746 * Isar: names of theorems etc. may be natural numbers as well;
  1747 
  1748 * Isar: 'pr' command: optional arguments for goals_limit and
  1749 ProofContext.prems_limit; no longer prints theory contexts, but only
  1750 proof states;
  1751 
  1752 * Isar: diagnostic commands 'pr', 'thm', 'prop', 'term', 'typ' admit
  1753 additional print modes to be specified; e.g. "pr(latex)" will print
  1754 proof state according to the Isabelle LaTeX style;
  1755 
  1756 * Isar: improved support for emulating tactic scripts, including proof
  1757 methods 'rule_tac' etc., 'cut_tac', 'thin_tac', 'subgoal_tac',
  1758 'rename_tac', 'rotate_tac', 'tactic', and 'case_tac' / 'induct_tac'
  1759 (for HOL datatypes);
  1760 
  1761 * Isar: simplified (more robust) goal selection of proof methods: 1st
  1762 goal, all goals, or explicit goal specifier (tactic emulation); thus
  1763 'proof method scripts' have to be in depth-first order;
  1764 
  1765 * Isar: tuned 'let' syntax: replaced 'as' keyword by 'and';
  1766 
  1767 * Isar: removed 'help' command, which hasn't been too helpful anyway;
  1768 should instead use individual commands for printing items
  1769 (print_commands, print_methods etc.);
  1770 
  1771 * Isar: added 'nothing' --- the empty list of theorems;
  1772 
  1773 
  1774 *** HOL ***
  1775 
  1776 * HOL/MicroJava: formalization of a fragment of Java, together with a
  1777 corresponding virtual machine and a specification of its bytecode
  1778 verifier and a lightweight bytecode verifier, including proofs of
  1779 type-safety; by Gerwin Klein, Tobias Nipkow, David von Oheimb, and
  1780 Cornelia Pusch (see also the homepage of project Bali at
  1781 http://isabelle.in.tum.de/Bali/);
  1782 
  1783 * HOL/Algebra: new theory of rings and univariate polynomials, by
  1784 Clemens Ballarin;
  1785 
  1786 * HOL/NumberTheory: fundamental Theorem of Arithmetic, Chinese
  1787 Remainder Theorem, Fermat/Euler Theorem, Wilson's Theorem, by Thomas M
  1788 Rasmussen;
  1789 
  1790 * HOL/Lattice: fundamental concepts of lattice theory and order
  1791 structures, including duals, properties of bounds versus algebraic
  1792 laws, lattice operations versus set-theoretic ones, the Knaster-Tarski
  1793 Theorem for complete lattices etc.; may also serve as a demonstration
  1794 for abstract algebraic reasoning using axiomatic type classes, and
  1795 mathematics-style proof in Isabelle/Isar; by Markus Wenzel;
  1796 
  1797 * HOL/Prolog: a (bare-bones) implementation of Lambda-Prolog, by David
  1798 von Oheimb;
  1799 
  1800 * HOL/IMPP: extension of IMP with local variables and mutually
  1801 recursive procedures, by David von Oheimb;
  1802 
  1803 * HOL/Lambda: converted into new-style theory and document;
  1804 
  1805 * HOL/ex/Multiquote: example of multiple nested quotations and
  1806 anti-quotations -- basically a generalized version of de-Bruijn
  1807 representation; very useful in avoiding lifting of operations;
  1808 
  1809 * HOL/record: added general record equality rule to simpset; fixed
  1810 select-update simplification procedure to handle extended records as
  1811 well; admit "r" as field name;
  1812 
  1813 * HOL: 0 is now overloaded over the new sort "zero", allowing its use with
  1814 other numeric types and also as the identity of groups, rings, etc.;
  1815 
  1816 * HOL: new axclass plus_ac0 for addition with the AC-laws and 0 as identity.
  1817 Types nat and int belong to this axclass;
  1818 
  1819 * HOL: greatly improved simplification involving numerals of type nat, int, real:
  1820    (i + #8 + j) = Suc k simplifies to  #7 + (i + j) = k
  1821    i*j + k + j*#3*i     simplifies to  #4*(i*j) + k
  1822   two terms #m*u and #n*u are replaced by #(m+n)*u
  1823     (where #m, #n and u can implicitly be 1; this is simproc combine_numerals)
  1824   and the term/formula #m*u+x ~~ #n*u+y simplifies simplifies to #(m-n)+x ~~ y
  1825     or x ~~ #(n-m)+y, where ~~ is one of = < <= or - (simproc cancel_numerals);
  1826 
  1827 * HOL: meson_tac is available (previously in ex/meson.ML); it is a
  1828 powerful prover for predicate logic but knows nothing of clasets; see
  1829 ex/mesontest.ML and ex/mesontest2.ML for example applications;
  1830 
  1831 * HOL: new version of "case_tac" subsumes both boolean case split and
  1832 "exhaust_tac" on datatypes; INCOMPATIBILITY: exhaust_tac no longer
  1833 exists, may define val exhaust_tac = case_tac for ad-hoc portability;
  1834 
  1835 * HOL: simplification no longer dives into case-expressions: only the
  1836 selector expression is simplified, but not the remaining arms; to
  1837 enable full simplification of case-expressions for datatype t, you may
  1838 remove t.weak_case_cong from the simpset, either globally (Delcongs
  1839 [thm"t.weak_case_cong"];) or locally (delcongs [...]).
  1840 
  1841 * HOL/recdef: the recursion equations generated by 'recdef' for
  1842 function 'f' are now called f.simps instead of f.rules; if all
  1843 termination conditions are proved automatically, these simplification
  1844 rules are added to the simpset, as in primrec; rules may be named
  1845 individually as well, resulting in a separate list of theorems for
  1846 each equation;
  1847 
  1848 * HOL/While is a new theory that provides a while-combinator. It
  1849 permits the definition of tail-recursive functions without the
  1850 provision of a termination measure. The latter is necessary once the
  1851 invariant proof rule for while is applied.
  1852 
  1853 * HOL: new (overloaded) notation for the set of elements below/above
  1854 some element: {..u}, {..u(}, {l..}, {)l..}. See theory SetInterval.
  1855 
  1856 * HOL: theorems impI, allI, ballI bound as "strip";
  1857 
  1858 * HOL: new tactic induct_thm_tac: thm -> string -> int -> tactic
  1859 induct_tac th "x1 ... xn" expects th to have a conclusion of the form
  1860 P v1 ... vn and abbreviates res_inst_tac [("v1","x1"),...,("vn","xn")] th;
  1861 
  1862 * HOL/Real: "rabs" replaced by overloaded "abs" function;
  1863 
  1864 * HOL: theory Sexp now in HOL/Induct examples (it used to be part of
  1865 main HOL, but was unused);
  1866 
  1867 * HOL: fewer consts declared as global (e.g. have to refer to
  1868 "Lfp.lfp" instead of "lfp" internally; affects ML packages only);
  1869 
  1870 * HOL: tuned AST representation of nested pairs, avoiding bogus output
  1871 in case of overlap with user translations (e.g. judgements over
  1872 tuples); (note that the underlying logical represenation is still
  1873 bogus);
  1874 
  1875 
  1876 *** ZF ***
  1877 
  1878 * ZF: simplification automatically cancels common terms in arithmetic
  1879 expressions over nat and int;
  1880 
  1881 * ZF: new treatment of nat to minimize type-checking: all operators
  1882 coerce their operands to a natural number using the function natify,
  1883 making the algebraic laws unconditional;
  1884 
  1885 * ZF: as above, for int: operators coerce their operands to an integer
  1886 using the function intify;
  1887 
  1888 * ZF: the integer library now contains many of the usual laws for the
  1889 orderings, including $<=, and monotonicity laws for $+ and $*;
  1890 
  1891 * ZF: new example ZF/ex/NatSum to demonstrate integer arithmetic
  1892 simplification;
  1893 
  1894 * FOL and ZF: AddIffs now available, giving theorems of the form P<->Q
  1895 to the simplifier and classical reasoner simultaneously;
  1896 
  1897 
  1898 *** General ***
  1899 
  1900 * Provers: blast_tac now handles actual object-logic rules as
  1901 assumptions; note that auto_tac uses blast_tac internally as well;
  1902 
  1903 * Provers: new functions rulify/rulify_no_asm: thm -> thm for turning
  1904 outer -->/All/Ball into ==>/!!; qed_spec_mp now uses rulify_no_asm;
  1905 
  1906 * Provers: delrules now handles destruct rules as well (no longer need
  1907 explicit make_elim);
  1908 
  1909 * Provers: Blast_tac now warns of and ignores "weak elimination rules" e.g.
  1910   [| inj ?f;          ?f ?x = ?f ?y; ?x = ?y ==> ?W |] ==> ?W
  1911 use instead the strong form,
  1912   [| inj ?f; ~ ?W ==> ?f ?x = ?f ?y; ?x = ?y ==> ?W |] ==> ?W
  1913 in HOL, FOL and ZF the function cla_make_elim will create such rules
  1914 from destruct-rules;
  1915 
  1916 * Provers: Simplifier.easy_setup provides a fast path to basic
  1917 Simplifier setup for new object-logics;
  1918 
  1919 * Pure: AST translation rules no longer require constant head on LHS;
  1920 
  1921 * Pure: improved name spaces: ambiguous output is qualified; support
  1922 for hiding of names;
  1923 
  1924 * system: smart setup of canonical ML_HOME, ISABELLE_INTERFACE, and
  1925 XSYMBOL_HOME; no longer need to do manual configuration in most
  1926 situations;
  1927 
  1928 * system: compression of ML heaps images may now be controlled via -c
  1929 option of isabelle and isatool usedir (currently only observed by
  1930 Poly/ML);
  1931 
  1932 * system: isatool installfonts may handle X-Symbol fonts as well (very
  1933 useful for remote X11);
  1934 
  1935 * system: provide TAGS file for Isabelle sources;
  1936 
  1937 * ML: infix 'OF' is a version of 'MRS' with more appropriate argument
  1938 order;
  1939 
  1940 * ML: renamed flags Syntax.trace_norm_ast to Syntax.trace_ast; global
  1941 timing flag supersedes proof_timing and Toplevel.trace;
  1942 
  1943 * ML: new combinators |>> and |>>> for incremental transformations
  1944 with secondary results (e.g. certain theory extensions):
  1945 
  1946 * ML: PureThy.add_defs gets additional argument to indicate potential
  1947 overloading (usually false);
  1948 
  1949 * ML: PureThy.add_thms/add_axioms/add_defs now return theorems as
  1950 results;
  1951 
  1952 
  1953 
  1954 New in Isabelle99 (October 1999)
  1955 --------------------------------
  1956 
  1957 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  1958 
  1959 * HOL: The THEN and ELSE parts of conditional expressions (if P then x else y)
  1960 are no longer simplified.  (This allows the simplifier to unfold recursive
  1961 functional programs.)  To restore the old behaviour, declare
  1962 
  1963     Delcongs [if_weak_cong];
  1964 
  1965 * HOL: Removed the obsolete syntax "Compl A"; use -A for set
  1966 complement;
  1967 
  1968 * HOL: the predicate "inj" is now defined by translation to "inj_on";
  1969 
  1970 * HOL/datatype: mutual_induct_tac no longer exists --
  1971   use induct_tac "x_1 ... x_n" instead of mutual_induct_tac ["x_1", ..., "x_n"]
  1972 
  1973 * HOL/typedef: fixed type inference for representing set; type
  1974 arguments now have to occur explicitly on the rhs as type constraints;
  1975 
  1976 * ZF: The con_defs part of an inductive definition may no longer refer
  1977 to constants declared in the same theory;
  1978 
  1979 * HOL, ZF: the function mk_cases, generated by the inductive
  1980 definition package, has lost an argument.  To simplify its result, it
  1981 uses the default simpset instead of a supplied list of theorems.
  1982 
  1983 * HOL/List: the constructors of type list are now Nil and Cons;
  1984 
  1985 * Simplifier: the type of the infix ML functions
  1986         setSSolver addSSolver setSolver addSolver
  1987 is now  simpset * solver -> simpset  where `solver' is a new abstract type
  1988 for packaging solvers. A solver is created via
  1989         mk_solver: string -> (thm list -> int -> tactic) -> solver
  1990 where the string argument is only a comment.
  1991 
  1992 
  1993 *** Proof tools ***
  1994 
  1995 * Provers/Arith/fast_lin_arith.ML contains a functor for creating a
  1996 decision procedure for linear arithmetic. Currently it is used for
  1997 types `nat', `int', and `real' in HOL (see below); it can, should and
  1998 will be instantiated for other types and logics as well.
  1999 
  2000 * The simplifier now accepts rewrite rules with flexible heads, eg
  2001      hom ?f ==> ?f(?x+?y) = ?f ?x + ?f ?y
  2002   They are applied like any rule with a non-pattern lhs, i.e. by first-order
  2003   matching.
  2004 
  2005 
  2006 *** General ***
  2007 
  2008 * New Isabelle/Isar subsystem provides an alternative to traditional
  2009 tactical theorem proving; together with the ProofGeneral/isar user
  2010 interface it offers an interactive environment for developing human
  2011 readable proof documents (Isar == Intelligible semi-automated
  2012 reasoning); for further information see isatool doc isar-ref,
  2013 src/HOL/Isar_examples and http://isabelle.in.tum.de/Isar/
  2014 
  2015 * improved and simplified presentation of theories: better HTML markup
  2016 (including colors), graph views in several sizes; isatool usedir now
  2017 provides a proper interface for user theories (via -P option); actual
  2018 document preparation based on (PDF)LaTeX is available as well (for
  2019 new-style theories only); see isatool doc system for more information;
  2020 
  2021 * native support for Proof General, both for classic Isabelle and
  2022 Isabelle/Isar;
  2023 
  2024 * ML function thm_deps visualizes dependencies of theorems and lemmas,
  2025 using the graph browser tool;
  2026 
  2027 * Isabelle manuals now also available as PDF;
  2028 
  2029 * theory loader rewritten from scratch (may not be fully
  2030 bug-compatible); old loadpath variable has been replaced by show_path,
  2031 add_path, del_path, reset_path functions; new operations such as
  2032 update_thy, touch_thy, remove_thy, use/update_thy_only (see also
  2033 isatool doc ref);
  2034 
  2035 * improved isatool install: option -k creates KDE application icon,
  2036 option -p DIR installs standalone binaries;
  2037 
  2038 * added ML_PLATFORM setting (useful for cross-platform installations);
  2039 more robust handling of platform specific ML images for SML/NJ;
  2040 
  2041 * the settings environment is now statically scoped, i.e. it is never
  2042 created again in sub-processes invoked from isabelle, isatool, or
  2043 Isabelle;
  2044 
  2045 * path element specification '~~' refers to '$ISABELLE_HOME';
  2046 
  2047 * in locales, the "assumes" and "defines" parts may be omitted if
  2048 empty;
  2049 
  2050 * new print_mode "xsymbols" for extended symbol support (e.g. genuine
  2051 long arrows);
  2052 
  2053 * new print_mode "HTML";
  2054 
  2055 * new flag show_tags controls display of tags of theorems (which are
  2056 basically just comments that may be attached by some tools);
  2057 
  2058 * Isamode 2.6 requires patch to accomodate change of Isabelle font
  2059 mode and goal output format:
  2060 
  2061 diff -r Isamode-2.6/elisp/isa-load.el Isamode/elisp/isa-load.el
  2062 244c244
  2063 <       (list (isa-getenv "ISABELLE") "-msymbols" logic-name)
  2064 ---
  2065 >       (list (isa-getenv "ISABELLE") "-misabelle_font" "-msymbols" logic-name)
  2066 diff -r Isabelle-2.6/elisp/isa-proofstate.el Isamode/elisp/isa-proofstate.el
  2067 181c181
  2068 < (defconst proofstate-proofstart-regexp "^Level [0-9]+$"
  2069 ---
  2070 > (defconst proofstate-proofstart-regexp "^Level [0-9]+"
  2071 
  2072 * function bind_thms stores lists of theorems (cf. bind_thm);
  2073 
  2074 * new shorthand tactics ftac, eatac, datac, fatac;
  2075 
  2076 * qed (and friends) now accept "" as result name; in that case the
  2077 theorem is not stored, but proper checks and presentation of the
  2078 result still apply;
  2079 
  2080 * theorem database now also indexes constants "Trueprop", "all",
  2081 "==>", "=="; thus thms_containing, findI etc. may retrieve more rules;
  2082 
  2083 
  2084 *** HOL ***
  2085 
  2086 ** HOL arithmetic **
  2087 
  2088 * There are now decision procedures for linear arithmetic over nat and
  2089 int:
  2090 
  2091 1. arith_tac copes with arbitrary formulae involving `=', `<', `<=',
  2092 `+', `-', `Suc', `min', `max' and numerical constants; other subterms
  2093 are treated as atomic; subformulae not involving type `nat' or `int'
  2094 are ignored; quantified subformulae are ignored unless they are
  2095 positive universal or negative existential. The tactic has to be
  2096 invoked by hand and can be a little bit slow. In particular, the
  2097 running time is exponential in the number of occurrences of `min' and
  2098 `max', and `-' on `nat'.
  2099 
  2100 2. fast_arith_tac is a cut-down version of arith_tac: it only takes
  2101 (negated) (in)equalities among the premises and the conclusion into
  2102 account (i.e. no compound formulae) and does not know about `min' and
  2103 `max', and `-' on `nat'. It is fast and is used automatically by the
  2104 simplifier.
  2105 
  2106 NB: At the moment, these decision procedures do not cope with mixed
  2107 nat/int formulae where the two parts interact, such as `m < n ==>
  2108 int(m) < int(n)'.
  2109 
  2110 * HOL/Numeral provides a generic theory of numerals (encoded
  2111 efficiently as bit strings); setup for types nat/int/real is in place;
  2112 INCOMPATIBILITY: since numeral syntax is now polymorphic, rather than
  2113 int, existing theories and proof scripts may require a few additional
  2114 type constraints;
  2115 
  2116 * integer division and remainder can now be performed on constant
  2117 arguments;
  2118 
  2119 * many properties of integer multiplication, division and remainder
  2120 are now available;
  2121 
  2122 * An interface to the Stanford Validity Checker (SVC) is available through the
  2123 tactic svc_tac.  Propositional tautologies and theorems of linear arithmetic
  2124 are proved automatically.  SVC must be installed separately, and its results
  2125 must be TAKEN ON TRUST (Isabelle does not check the proofs, but tags any
  2126 invocation of the underlying oracle).  For SVC see
  2127   http://verify.stanford.edu/SVC
  2128 
  2129 * IsaMakefile: the HOL-Real target now builds an actual image;
  2130 
  2131 
  2132 ** HOL misc **
  2133 
  2134 * HOL/Real/HahnBanach: the Hahn-Banach theorem for real vector spaces
  2135 (in Isabelle/Isar) -- by Gertrud Bauer;
  2136 
  2137 * HOL/BCV: generic model of bytecode verification, i.e. data-flow
  2138 analysis for assembly languages with subtypes;
  2139 
  2140 * HOL/TLA (Lamport's Temporal Logic of Actions): major reorganization
  2141 -- avoids syntactic ambiguities and treats state, transition, and
  2142 temporal levels more uniformly; introduces INCOMPATIBILITIES due to
  2143 changed syntax and (many) tactics;
  2144 
  2145 * HOL/inductive: Now also handles more general introduction rules such
  2146   as "ALL y. (y, x) : r --> y : acc r ==> x : acc r"; monotonicity
  2147   theorems are now maintained within the theory (maintained via the
  2148   "mono" attribute);
  2149 
  2150 * HOL/datatype: Now also handles arbitrarily branching datatypes
  2151   (using function types) such as
  2152 
  2153   datatype 'a tree = Atom 'a | Branch "nat => 'a tree"
  2154 
  2155 * HOL/record: record_simproc (part of the default simpset) takes care
  2156 of selectors applied to updated records; record_split_tac is no longer
  2157 part of the default claset; update_defs may now be removed from the
  2158 simpset in many cases; COMPATIBILITY: old behavior achieved by
  2159 
  2160   claset_ref () := claset() addSWrapper record_split_wrapper;
  2161   Delsimprocs [record_simproc]
  2162 
  2163 * HOL/typedef: fixed type inference for representing set; type
  2164 arguments now have to occur explicitly on the rhs as type constraints;
  2165 
  2166 * HOL/recdef (TFL): 'congs' syntax now expects comma separated list of theorem
  2167 names rather than an ML expression;
  2168 
  2169 * HOL/defer_recdef (TFL): like recdef but the well-founded relation can be
  2170 supplied later.  Program schemes can be defined, such as
  2171     "While B C s = (if B s then While B C (C s) else s)"
  2172 where the well-founded relation can be chosen after B and C have been given.
  2173 
  2174 * HOL/List: the constructors of type list are now Nil and Cons;
  2175 INCOMPATIBILITY: while [] and infix # syntax is still there, of
  2176 course, ML tools referring to List.list.op # etc. have to be adapted;
  2177 
  2178 * HOL_quantifiers flag superseded by "HOL" print mode, which is
  2179 disabled by default; run isabelle with option -m HOL to get back to
  2180 the original Gordon/HOL-style output;
  2181 
  2182 * HOL/Ord.thy: new bounded quantifier syntax (input only): ALL x<y. P,
  2183 ALL x<=y. P, EX x<y. P, EX x<=y. P;
  2184 
  2185 * HOL basic syntax simplified (more orthogonal): all variants of
  2186 All/Ex now support plain / symbolic / HOL notation; plain syntax for
  2187 Eps operator is provided as well: "SOME x. P[x]";
  2188 
  2189 * HOL/Sum.thy: sum_case has been moved to HOL/Datatype;
  2190 
  2191 * HOL/Univ.thy: infix syntax <*>, <+>, <**>, <+> eliminated and made
  2192 thus available for user theories;
  2193 
  2194 * HOLCF/IOA/Sequents: renamed 'Cons' to 'Consq' to avoid clash with
  2195 HOL/List; hardly an INCOMPATIBILITY since '>>' syntax is used all the
  2196 time;
  2197 
  2198 * HOL: new tactic smp_tac: int -> int -> tactic, which applies spec
  2199 several times and then mp;
  2200 
  2201 
  2202 *** LK ***
  2203 
  2204 * the notation <<...>> is now available as a notation for sequences of
  2205 formulas;
  2206 
  2207 * the simplifier is now installed
  2208 
  2209 * the axiom system has been generalized (thanks to Soren Heilmann)
  2210 
  2211 * the classical reasoner now has a default rule database
  2212 
  2213 
  2214 *** ZF ***
  2215 
  2216 * new primrec section allows primitive recursive functions to be given
  2217 directly (as in HOL) over datatypes and the natural numbers;
  2218 
  2219 * new tactics induct_tac and exhaust_tac for induction (or case
  2220 analysis) over datatypes and the natural numbers;
  2221 
  2222 * the datatype declaration of type T now defines the recursor T_rec;
  2223 
  2224 * simplification automatically does freeness reasoning for datatype
  2225 constructors;
  2226 
  2227 * automatic type-inference, with AddTCs command to insert new
  2228 type-checking rules;
  2229 
  2230 * datatype introduction rules are now added as Safe Introduction rules
  2231 to the claset;
  2232 
  2233 * the syntax "if P then x else y" is now available in addition to
  2234 if(P,x,y);
  2235 
  2236 
  2237 *** Internal programming interfaces ***
  2238 
  2239 * tuned simplifier trace output; new flag debug_simp;
  2240 
  2241 * structures Vartab / Termtab (instances of TableFun) offer efficient
  2242 tables indexed by indexname_ord / term_ord (compatible with aconv);
  2243 
  2244 * AxClass.axclass_tac lost the theory argument;
  2245 
  2246 * tuned current_goals_markers semantics: begin / end goal avoids
  2247 printing empty lines;
  2248 
  2249 * removed prs and prs_fn hook, which was broken because it did not
  2250 include \n in its semantics, forcing writeln to add one
  2251 uncoditionally; replaced prs_fn by writeln_fn; consider std_output:
  2252 string -> unit if you really want to output text without newline;
  2253 
  2254 * Symbol.output subject to print mode; INCOMPATIBILITY: defaults to
  2255 plain output, interface builders may have to enable 'isabelle_font'
  2256 mode to get Isabelle font glyphs as before;
  2257 
  2258 * refined token_translation interface; INCOMPATIBILITY: output length
  2259 now of type real instead of int;
  2260 
  2261 * theory loader actions may be traced via new ThyInfo.add_hook
  2262 interface (see src/Pure/Thy/thy_info.ML); example application: keep
  2263 your own database of information attached to *whole* theories -- as
  2264 opposed to intra-theory data slots offered via TheoryDataFun;
  2265 
  2266 * proper handling of dangling sort hypotheses (at last!);
  2267 Thm.strip_shyps and Drule.strip_shyps_warning take care of removing
  2268 extra sort hypotheses that can be witnessed from the type signature;
  2269 the force_strip_shyps flag is gone, any remaining shyps are simply
  2270 left in the theorem (with a warning issued by strip_shyps_warning);
  2271 
  2272 
  2273 
  2274 New in Isabelle98-1 (October 1998)
  2275 ----------------------------------
  2276 
  2277 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  2278 
  2279 * several changes of automated proof tools;
  2280 
  2281 * HOL: major changes to the inductive and datatype packages, including
  2282 some minor incompatibilities of theory syntax;
  2283 
  2284 * HOL: renamed r^-1 to 'converse' from 'inverse'; 'inj_onto' is now
  2285 called `inj_on';
  2286 
  2287 * HOL: removed duplicate thms in Arith:
  2288   less_imp_add_less  should be replaced by  trans_less_add1
  2289   le_imp_add_le      should be replaced by  trans_le_add1
  2290 
  2291 * HOL: unary minus is now overloaded (new type constraints may be
  2292 required);
  2293 
  2294 * HOL and ZF: unary minus for integers is now #- instead of #~.  In
  2295 ZF, expressions such as n#-1 must be changed to n#- 1, since #-1 is
  2296 now taken as an integer constant.
  2297 
  2298 * Pure: ML function 'theory_of' renamed to 'theory';
  2299 
  2300 
  2301 *** Proof tools ***
  2302 
  2303 * Simplifier:
  2304   1. Asm_full_simp_tac is now more aggressive.
  2305      1. It will sometimes reorient premises if that increases their power to
  2306         simplify.
  2307      2. It does no longer proceed strictly from left to right but may also
  2308         rotate premises to achieve further simplification.
  2309      For compatibility reasons there is now Asm_lr_simp_tac which is like the
  2310      old Asm_full_simp_tac in that it does not rotate premises.
  2311   2. The simplifier now knows a little bit about nat-arithmetic.
  2312 
  2313 * Classical reasoner: wrapper mechanism for the classical reasoner now
  2314 allows for selected deletion of wrappers, by introduction of names for
  2315 wrapper functionals.  This implies that addbefore, addSbefore,
  2316 addaltern, and addSaltern now take a pair (name, tactic) as argument,
  2317 and that adding two tactics with the same name overwrites the first
  2318 one (emitting a warning).
  2319   type wrapper = (int -> tactic) -> (int -> tactic)
  2320   setWrapper, setSWrapper, compWrapper and compSWrapper are replaced by
  2321   addWrapper, addSWrapper: claset * (string * wrapper) -> claset
  2322   delWrapper, delSWrapper: claset *  string            -> claset
  2323   getWrapper is renamed to appWrappers, getSWrapper to appSWrappers;
  2324 
  2325 * Classical reasoner: addbefore/addSbefore now have APPEND/ORELSE
  2326 semantics; addbefore now affects only the unsafe part of step_tac
  2327 etc.; this affects addss/auto_tac/force_tac, so EXISTING PROOFS MAY
  2328 FAIL, but proofs should be fixable easily, e.g. by replacing Auto_tac
  2329 by Force_tac;
  2330 
  2331 * Classical reasoner: setwrapper to setWrapper and compwrapper to
  2332 compWrapper; added safe wrapper (and access functions for it);
  2333 
  2334 * HOL/split_all_tac is now much faster and fails if there is nothing
  2335 to split.  Some EXISTING PROOFS MAY REQUIRE ADAPTION because the order
  2336 and the names of the automatically generated variables have changed.
  2337 split_all_tac has moved within claset() from unsafe wrappers to safe
  2338 wrappers, which means that !!-bound variables are split much more
  2339 aggressively, and safe_tac and clarify_tac now split such variables.
  2340 If this splitting is not appropriate, use delSWrapper "split_all_tac".
  2341 Note: the same holds for record_split_tac, which does the job of
  2342 split_all_tac for record fields.
  2343 
  2344 * HOL/Simplifier: Rewrite rules for case distinctions can now be added
  2345 permanently to the default simpset using Addsplits just like
  2346 Addsimps. They can be removed via Delsplits just like
  2347 Delsimps. Lower-case versions are also available.
  2348 
  2349 * HOL/Simplifier: The rule split_if is now part of the default
  2350 simpset. This means that the simplifier will eliminate all occurrences
  2351 of if-then-else in the conclusion of a goal. To prevent this, you can
  2352 either remove split_if completely from the default simpset by
  2353 `Delsplits [split_if]' or remove it in a specific call of the
  2354 simplifier using `... delsplits [split_if]'.  You can also add/delete
  2355 other case splitting rules to/from the default simpset: every datatype
  2356 generates suitable rules `split_t_case' and `split_t_case_asm' (where
  2357 t is the name of the datatype).
  2358 
  2359 * Classical reasoner / Simplifier combination: new force_tac (and
  2360 derivatives Force_tac, force) combines rewriting and classical
  2361 reasoning (and whatever other tools) similarly to auto_tac, but is
  2362 aimed to solve the given subgoal completely.
  2363 
  2364 
  2365 *** General ***
  2366 
  2367 * new top-level commands `Goal' and `Goalw' that improve upon `goal'
  2368 and `goalw': the theory is no longer needed as an explicit argument -
  2369 the current theory context is used; assumptions are no longer returned
  2370 at the ML-level unless one of them starts with ==> or !!; it is
  2371 recommended to convert to these new commands using isatool fixgoal
  2372 (backup your sources first!);
  2373 
  2374 * new top-level commands 'thm' and 'thms' for retrieving theorems from
  2375 the current theory context, and 'theory' to lookup stored theories;
  2376 
  2377 * new theory section 'locale' for declaring constants, assumptions and
  2378 definitions that have local scope;
  2379 
  2380 * new theory section 'nonterminals' for purely syntactic types;
  2381 
  2382 * new theory section 'setup' for generic ML setup functions
  2383 (e.g. package initialization);
  2384 
  2385 * the distribution now includes Isabelle icons: see
  2386 lib/logo/isabelle-{small,tiny}.xpm;
  2387 
  2388 * isatool install - install binaries with absolute references to
  2389 ISABELLE_HOME/bin;
  2390 
  2391 * isatool logo -- create instances of the Isabelle logo (as EPS);
  2392 
  2393 * print mode 'emacs' reserved for Isamode;
  2394 
  2395 * support multiple print (ast) translations per constant name;
  2396 
  2397 * theorems involving oracles are now printed with a suffixed [!];
  2398 
  2399 
  2400 *** HOL ***
  2401 
  2402 * there is now a tutorial on Isabelle/HOL (do 'isatool doc tutorial');
  2403 
  2404 * HOL/inductive package reorganized and improved: now supports mutual
  2405 definitions such as
  2406 
  2407   inductive EVEN ODD
  2408     intrs
  2409       null "0 : EVEN"
  2410       oddI "n : EVEN ==> Suc n : ODD"
  2411       evenI "n : ODD ==> Suc n : EVEN"
  2412 
  2413 new theorem list "elims" contains an elimination rule for each of the
  2414 recursive sets; inductive definitions now handle disjunctive premises
  2415 correctly (also ZF);
  2416 
  2417 INCOMPATIBILITIES: requires Inductive as an ancestor; component
  2418 "mutual_induct" no longer exists - the induction rule is always
  2419 contained in "induct";
  2420 
  2421 
  2422 * HOL/datatype package re-implemented and greatly improved: now
  2423 supports mutually recursive datatypes such as
  2424 
  2425   datatype
  2426     'a aexp = IF_THEN_ELSE ('a bexp) ('a aexp) ('a aexp)
  2427             | SUM ('a aexp) ('a aexp)
  2428             | DIFF ('a aexp) ('a aexp)
  2429             | NUM 'a
  2430   and
  2431     'a bexp = LESS ('a aexp) ('a aexp)
  2432             | AND ('a bexp) ('a bexp)
  2433             | OR ('a bexp) ('a bexp)
  2434 
  2435 as well as indirectly recursive datatypes such as
  2436 
  2437   datatype
  2438     ('a, 'b) term = Var 'a
  2439                   | App 'b ((('a, 'b) term) list)
  2440 
  2441 The new tactic  mutual_induct_tac [<var_1>, ..., <var_n>] i  performs
  2442 induction on mutually / indirectly recursive datatypes.
  2443 
  2444 Primrec equations are now stored in theory and can be accessed via
  2445 <function_name>.simps.
  2446 
  2447 INCOMPATIBILITIES:
  2448 
  2449   - Theories using datatypes must now have theory Datatype as an
  2450     ancestor.
  2451   - The specific <typename>.induct_tac no longer exists - use the
  2452     generic induct_tac instead.
  2453   - natE has been renamed to nat.exhaust - use exhaust_tac
  2454     instead of res_inst_tac ... natE. Note that the variable
  2455     names in nat.exhaust differ from the names in natE, this
  2456     may cause some "fragile" proofs to fail.
  2457   - The theorems split_<typename>_case and split_<typename>_case_asm
  2458     have been renamed to <typename>.split and <typename>.split_asm.
  2459   - Since default sorts of type variables are now handled correctly,
  2460     some datatype definitions may have to be annotated with explicit
  2461     sort constraints.
  2462   - Primrec definitions no longer require function name and type
  2463     of recursive argument.
  2464 
  2465 Consider using isatool fixdatatype to adapt your theories and proof
  2466 scripts to the new package (backup your sources first!).
  2467 
  2468 
  2469 * HOL/record package: considerably improved implementation; now
  2470 includes concrete syntax for record types, terms, updates; theorems
  2471 for surjective pairing and splitting !!-bound record variables; proof
  2472 support is as follows:
  2473 
  2474   1) standard conversions (selectors or updates applied to record
  2475 constructor terms) are part of the standard simpset;
  2476 
  2477   2) inject equations of the form ((x, y) = (x', y')) == x=x' & y=y' are
  2478 made part of standard simpset and claset via addIffs;
  2479 
  2480   3) a tactic for record field splitting (record_split_tac) is part of
  2481 the standard claset (addSWrapper);
  2482 
  2483 To get a better idea about these rules you may retrieve them via
  2484 something like 'thms "foo.simps"' or 'thms "foo.iffs"', where "foo" is
  2485 the name of your record type.
  2486 
  2487 The split tactic 3) conceptually simplifies by the following rule:
  2488 
  2489   "(!!x. PROP ?P x) == (!!a b. PROP ?P (a, b))"
  2490 
  2491 Thus any record variable that is bound by meta-all will automatically
  2492 blow up into some record constructor term, consequently the
  2493 simplifications of 1), 2) apply.  Thus force_tac, auto_tac etc. shall
  2494 solve record problems automatically.
  2495 
  2496 
  2497 * reorganized the main HOL image: HOL/Integ and String loaded by
  2498 default; theory Main includes everything;
  2499 
  2500 * automatic simplification of integer sums and comparisons, using cancellation;
  2501 
  2502 * added option_map_eq_Some and not_Some_eq to the default simpset and claset;
  2503 
  2504 * added disj_not1 = "(~P | Q) = (P --> Q)" to the default simpset;
  2505 
  2506 * many new identities for unions, intersections, set difference, etc.;
  2507 
  2508 * expand_if, expand_split, expand_sum_case and expand_nat_case are now
  2509 called split_if, split_split, split_sum_case and split_nat_case (to go
  2510 with add/delsplits);
  2511 
  2512 * HOL/Prod introduces simplification procedure unit_eq_proc rewriting
  2513 (?x::unit) = (); this is made part of the default simpset, which COULD
  2514 MAKE EXISTING PROOFS FAIL under rare circumstances (consider
  2515 'Delsimprocs [unit_eq_proc];' as last resort); also note that
  2516 unit_abs_eta_conv is added in order to counter the effect of
  2517 unit_eq_proc on (%u::unit. f u), replacing it by f rather than by
  2518 %u.f();
  2519 
  2520 * HOL/Fun INCOMPATIBILITY: `inj_onto' is now called `inj_on' (which
  2521 makes more sense);
  2522 
  2523 * HOL/Set INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
  2524   It and 'sym RS equals0D' are now in the default  claset, giving automatic
  2525   disjointness reasoning but breaking a few old proofs.
  2526 
  2527 * HOL/Relation INCOMPATIBILITY: renamed the relational operator r^-1
  2528 to 'converse' from 'inverse' (for compatibility with ZF and some
  2529 literature);
  2530 
  2531 * HOL/recdef can now declare non-recursive functions, with {} supplied as
  2532 the well-founded relation;
  2533 
  2534 * HOL/Set INCOMPATIBILITY: the complement of set A is now written -A instead of
  2535     Compl A.  The "Compl" syntax remains available as input syntax for this
  2536     release ONLY.
  2537 
  2538 * HOL/Update: new theory of function updates:
  2539     f(a:=b) == %x. if x=a then b else f x
  2540 may also be iterated as in f(a:=b,c:=d,...);
  2541 
  2542 * HOL/Vimage: new theory for inverse image of a function, syntax f-``B;
  2543 
  2544 * HOL/List:
  2545   - new function list_update written xs[i:=v] that updates the i-th
  2546     list position. May also be iterated as in xs[i:=a,j:=b,...].
  2547   - new function `upt' written [i..j(] which generates the list
  2548     [i,i+1,...,j-1], i.e. the upper bound is excluded. To include the upper
  2549     bound write [i..j], which is a shorthand for [i..j+1(].
  2550   - new lexicographic orderings and corresponding wellfoundedness theorems.
  2551 
  2552 * HOL/Arith:
  2553   - removed 'pred' (predecessor) function;
  2554   - generalized some theorems about n-1;
  2555   - many new laws about "div" and "mod";
  2556   - new laws about greatest common divisors (see theory ex/Primes);
  2557 
  2558 * HOL/Relation: renamed the relational operator r^-1 "converse"
  2559 instead of "inverse";
  2560 
  2561 * HOL/Induct/Multiset: a theory of multisets, including the wellfoundedness
  2562   of the multiset ordering;
  2563 
  2564 * directory HOL/Real: a construction of the reals using Dedekind cuts
  2565   (not included by default);
  2566 
  2567 * directory HOL/UNITY: Chandy and Misra's UNITY formalism;
  2568 
  2569 * directory HOL/Hoare: a new version of Hoare logic which permits many-sorted
  2570   programs, i.e. different program variables may have different types.
  2571 
  2572 * calling (stac rew i) now fails if "rew" has no effect on the goal
  2573   [previously, this check worked only if the rewrite rule was unconditional]
  2574   Now rew can involve either definitions or equalities (either == or =).
  2575 
  2576 
  2577 *** ZF ***
  2578 
  2579 * theory Main includes everything; INCOMPATIBILITY: theory ZF.thy contains
  2580   only the theorems proved on ZF.ML;
  2581 
  2582 * ZF INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
  2583   It and 'sym RS equals0D' are now in the default  claset, giving automatic
  2584   disjointness reasoning but breaking a few old proofs.
  2585 
  2586 * ZF/Update: new theory of function updates
  2587     with default rewrite rule  f(x:=y) ` z = if(z=x, y, f`z)
  2588   may also be iterated as in f(a:=b,c:=d,...);
  2589 
  2590 * in  let x=t in u(x), neither t nor u(x) has to be an FOL term.
  2591 
  2592 * calling (stac rew i) now fails if "rew" has no effect on the goal
  2593   [previously, this check worked only if the rewrite rule was unconditional]
  2594   Now rew can involve either definitions or equalities (either == or =).
  2595 
  2596 * case_tac provided for compatibility with HOL
  2597     (like the old excluded_middle_tac, but with subgoals swapped)
  2598 
  2599 
  2600 *** Internal programming interfaces ***
  2601 
  2602 * Pure: several new basic modules made available for general use, see
  2603 also src/Pure/README;
  2604 
  2605 * improved the theory data mechanism to support encapsulation (data
  2606 kind name replaced by private Object.kind, acting as authorization
  2607 key); new type-safe user interface via functor TheoryDataFun; generic
  2608 print_data function becomes basically useless;
  2609 
  2610 * removed global_names compatibility flag -- all theory declarations
  2611 are qualified by default;
  2612 
  2613 * module Pure/Syntax now offers quote / antiquote translation
  2614 functions (useful for Hoare logic etc. with implicit dependencies);
  2615 see HOL/ex/Antiquote for an example use;
  2616 
  2617 * Simplifier now offers conversions (asm_)(full_)rewrite: simpset ->
  2618 cterm -> thm;
  2619 
  2620 * new tactical CHANGED_GOAL for checking that a tactic modifies a
  2621 subgoal;
  2622 
  2623 * Display.print_goals function moved to Locale.print_goals;
  2624 
  2625 * standard print function for goals supports current_goals_markers
  2626 variable for marking begin of proof, end of proof, start of goal; the
  2627 default is ("", "", ""); setting current_goals_markers := ("<proof>",
  2628 "</proof>", "<goal>") causes SGML like tagged proof state printing,
  2629 for example;
  2630 
  2631 
  2632 
  2633 New in Isabelle98 (January 1998)
  2634 --------------------------------
  2635 
  2636 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  2637 
  2638 * changed lexical syntax of terms / types: dots made part of long
  2639 identifiers, e.g. "%x.x" no longer possible, should be "%x. x";
  2640 
  2641 * simpset (and claset) reference variable replaced by functions
  2642 simpset / simpset_ref;
  2643 
  2644 * no longer supports theory aliases (via merge) and non-trivial
  2645 implicit merge of thms' signatures;
  2646 
  2647 * most internal names of constants changed due to qualified names;
  2648 
  2649 * changed Pure/Sequence interface (see Pure/seq.ML);
  2650 
  2651 
  2652 *** General Changes ***
  2653 
  2654 * hierachically structured name spaces (for consts, types, axms, thms
  2655 etc.); new lexical class 'longid' (e.g. Foo.bar.x) may render much of
  2656 old input syntactically incorrect (e.g. "%x.x"); COMPATIBILITY:
  2657 isatool fixdots ensures space after dots (e.g. "%x. x"); set
  2658 long_names for fully qualified output names; NOTE: ML programs
  2659 (special tactics, packages etc.) referring to internal names may have
  2660 to be adapted to cope with fully qualified names; in case of severe
  2661 backward campatibility problems try setting 'global_names' at compile
  2662 time to have enrything declared within a flat name space; one may also
  2663 fine tune name declarations in theories via the 'global' and 'local'
  2664 section;
  2665 
  2666 * reimplemented the implicit simpset and claset using the new anytype
  2667 data filed in signatures; references simpset:simpset ref etc. are
  2668 replaced by functions simpset:unit->simpset and
  2669 simpset_ref:unit->simpset ref; COMPATIBILITY: use isatool fixclasimp
  2670 to patch your ML files accordingly;
  2671 
  2672 * HTML output now includes theory graph data for display with Java
  2673 applet or isatool browser; data generated automatically via isatool
  2674 usedir (see -i option, ISABELLE_USEDIR_OPTIONS);
  2675 
  2676 * defs may now be conditional; improved rewrite_goals_tac to handle
  2677 conditional equations;
  2678 
  2679 * defs now admits additional type arguments, using TYPE('a) syntax;
  2680 
  2681 * theory aliases via merge (e.g. M=A+B+C) no longer supported, always
  2682 creates a new theory node; implicit merge of thms' signatures is
  2683 restricted to 'trivial' ones; COMPATIBILITY: one may have to use
  2684 transfer:theory->thm->thm in (rare) cases;
  2685 
  2686 * improved handling of draft signatures / theories; draft thms (and
  2687 ctyps, cterms) are automatically promoted to real ones;
  2688 
  2689 * slightly changed interfaces for oracles: admit many per theory, named
  2690 (e.g. oracle foo = mlfun), additional name argument for invoke_oracle;
  2691 
  2692 * print_goals: optional output of const types (set show_consts and
  2693 show_types);
  2694 
  2695 * improved output of warnings (###) and errors (***);
  2696 
  2697 * subgoal_tac displays a warning if the new subgoal has type variables;
  2698 
  2699 * removed old README and Makefiles;
  2700 
  2701 * replaced print_goals_ref hook by print_current_goals_fn and result_error_fn;
  2702 
  2703 * removed obsolete init_pps and init_database;
  2704 
  2705 * deleted the obsolete tactical STATE, which was declared by
  2706     fun STATE tacfun st = tacfun st st;
  2707 
  2708 * cd and use now support path variables, e.g. $ISABELLE_HOME, or ~
  2709 (which abbreviates $HOME);
  2710 
  2711 * changed Pure/Sequence interface (see Pure/seq.ML); COMPATIBILITY:
  2712 use isatool fixseq to adapt your ML programs (this works for fully
  2713 qualified references to the Sequence structure only!);
  2714 
  2715 * use_thy no longer requires writable current directory; it always
  2716 reloads .ML *and* .thy file, if either one is out of date;
  2717 
  2718 
  2719 *** Classical Reasoner ***
  2720 
  2721 * Clarify_tac, clarify_tac, clarify_step_tac, Clarify_step_tac: new
  2722 tactics that use classical reasoning to simplify a subgoal without
  2723 splitting it into several subgoals;
  2724 
  2725 * Safe_tac: like safe_tac but uses the default claset;
  2726 
  2727 
  2728 *** Simplifier ***
  2729 
  2730 * added simplification meta rules:
  2731     (asm_)(full_)simplify: simpset -> thm -> thm;
  2732 
  2733 * simplifier.ML no longer part of Pure -- has to be loaded by object
  2734 logics (again);
  2735 
  2736 * added prems argument to simplification procedures;
  2737 
  2738 * HOL, FOL, ZF: added infix function `addsplits':
  2739   instead of `<simpset> setloop (split_tac <thms>)'
  2740   you can simply write `<simpset> addsplits <thms>'
  2741 
  2742 
  2743 *** Syntax ***
  2744 
  2745 * TYPE('a) syntax for type reflection terms;
  2746 
  2747 * no longer handles consts with name "" -- declare as 'syntax' instead;
  2748 
  2749 * pretty printer: changed order of mixfix annotation preference (again!);
  2750 
  2751 * Pure: fixed idt/idts vs. pttrn/pttrns syntactic categories;
  2752 
  2753 
  2754 *** HOL ***
  2755 
  2756 * HOL: there is a new splitter `split_asm_tac' that can be used e.g.
  2757   with `addloop' of the simplifier to faciliate case splitting in premises.
  2758 
  2759 * HOL/TLA: Stephan Merz's formalization of Lamport's Temporal Logic of Actions;
  2760 
  2761 * HOL/Auth: new protocol proofs including some for the Internet
  2762   protocol TLS;
  2763 
  2764 * HOL/Map: new theory of `maps' a la VDM;
  2765 
  2766 * HOL/simplifier: simplification procedures nat_cancel_sums for
  2767 cancelling out common nat summands from =, <, <= (in)equalities, or
  2768 differences; simplification procedures nat_cancel_factor for
  2769 cancelling common factor from =, <, <= (in)equalities over natural
  2770 sums; nat_cancel contains both kinds of procedures, it is installed by
  2771 default in Arith.thy -- this COULD MAKE EXISTING PROOFS FAIL;
  2772 
  2773 * HOL/simplifier: terms of the form
  2774   `? x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x)'  (or t=x)
  2775   are rewritten to
  2776   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t)',
  2777   and those of the form
  2778   `! x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x) --> R(x)'  (or t=x)
  2779   are rewritten to
  2780   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t) --> R(t)',
  2781 
  2782 * HOL/datatype
  2783   Each datatype `t' now comes with a theorem `split_t_case' of the form
  2784 
  2785   P(t_case f1 ... fn x) =
  2786      ( (!y1 ... ym1. x = C1 y1 ... ym1 --> P(f1 y1 ... ym1)) &
  2787         ...
  2788        (!y1 ... ymn. x = Cn y1 ... ymn --> P(f1 y1 ... ymn))
  2789      )
  2790 
  2791   and a theorem `split_t_case_asm' of the form
  2792 
  2793   P(t_case f1 ... fn x) =
  2794     ~( (? y1 ... ym1. x = C1 y1 ... ym1 & ~P(f1 y1 ... ym1)) |
  2795         ...
  2796        (? y1 ... ymn. x = Cn y1 ... ymn & ~P(f1 y1 ... ymn))
  2797      )
  2798   which can be added to a simpset via `addsplits'. The existing theorems
  2799   expand_list_case and expand_option_case have been renamed to
  2800   split_list_case and split_option_case.
  2801 
  2802 * HOL/Arithmetic:
  2803   - `pred n' is automatically converted to `n-1'.
  2804     Users are strongly encouraged not to use `pred' any longer,
  2805     because it will disappear altogether at some point.
  2806   - Users are strongly encouraged to write "0 < n" rather than
  2807     "n ~= 0". Theorems and proof tools have been modified towards this
  2808     `standard'.
  2809 
  2810 * HOL/Lists:
  2811   the function "set_of_list" has been renamed "set" (and its theorems too);
  2812   the function "nth" now takes its arguments in the reverse order and
  2813   has acquired the infix notation "!" as in "xs!n".
  2814 
  2815 * HOL/Set: UNIV is now a constant and is no longer translated to Compl{};
  2816 
  2817 * HOL/Set: The operator (UN x.B x) now abbreviates (UN x:UNIV. B x) and its
  2818   specialist theorems (like UN1_I) are gone.  Similarly for (INT x.B x);
  2819 
  2820 * HOL/record: extensible records with schematic structural subtyping
  2821 (single inheritance); EXPERIMENTAL version demonstrating the encoding,
  2822 still lacks various theorems and concrete record syntax;
  2823 
  2824 
  2825 *** HOLCF ***
  2826 
  2827 * removed "axioms" and "generated by" sections;
  2828 
  2829 * replaced "ops" section by extended "consts" section, which is capable of
  2830   handling the continuous function space "->" directly;
  2831 
  2832 * domain package:
  2833   . proves theorems immediately and stores them in the theory,
  2834   . creates hierachical name space,
  2835   . now uses normal mixfix annotations (instead of cinfix...),
  2836   . minor changes to some names and values (for consistency),
  2837   . e.g. cases -> casedist, dists_eq -> dist_eqs, [take_lemma] -> take_lemmas,
  2838   . separator between mutual domain defs: changed "," to "and",
  2839   . improved handling of sort constraints;  now they have to
  2840     appear on the left-hand side of the equations only;
  2841 
  2842 * fixed LAM <x,y,zs>.b syntax;
  2843 
  2844 * added extended adm_tac to simplifier in HOLCF -- can now discharge
  2845 adm (%x. P (t x)), where P is chainfinite and t continuous;
  2846 
  2847 
  2848 *** FOL and ZF ***
  2849 
  2850 * FOL: there is a new splitter `split_asm_tac' that can be used e.g.
  2851   with `addloop' of the simplifier to faciliate case splitting in premises.
  2852 
  2853 * qed_spec_mp, qed_goal_spec_mp, qed_goalw_spec_mp are available, as
  2854 in HOL, they strip ALL and --> from proved theorems;
  2855 
  2856 
  2857 
  2858 New in Isabelle94-8 (May 1997)
  2859 ------------------------------
  2860 
  2861 *** General Changes ***
  2862 
  2863 * new utilities to build / run / maintain Isabelle etc. (in parts
  2864 still somewhat experimental); old Makefiles etc. still functional;
  2865 
  2866 * new 'Isabelle System Manual';
  2867 
  2868 * INSTALL text, together with ./configure and ./build scripts;
  2869 
  2870 * reimplemented type inference for greater efficiency, better error
  2871 messages and clean internal interface;
  2872 
  2873 * prlim command for dealing with lots of subgoals (an easier way of
  2874 setting goals_limit);
  2875 
  2876 
  2877 *** Syntax ***
  2878 
  2879 * supports alternative (named) syntax tables (parser and pretty
  2880 printer); internal interface is provided by add_modesyntax(_i);
  2881 
  2882 * Pure, FOL, ZF, HOL, HOLCF now support symbolic input and output; to
  2883 be used in conjunction with the Isabelle symbol font; uses the
  2884 "symbols" syntax table;
  2885 
  2886 * added token_translation interface (may translate name tokens in
  2887 arbitrary ways, dependent on their type (free, bound, tfree, ...) and
  2888 the current print_mode); IMPORTANT: user print translation functions
  2889 are responsible for marking newly introduced bounds
  2890 (Syntax.mark_boundT);
  2891 
  2892 * token translations for modes "xterm" and "xterm_color" that display
  2893 names in bold, underline etc. or colors (which requires a color
  2894 version of xterm);
  2895 
  2896 * infixes may now be declared with names independent of their syntax;
  2897 
  2898 * added typed_print_translation (like print_translation, but may
  2899 access type of constant);
  2900 
  2901 
  2902 *** Classical Reasoner ***
  2903 
  2904 Blast_tac: a new tactic!  It is often more powerful than fast_tac, but has
  2905 some limitations.  Blast_tac...
  2906   + ignores addss, addbefore, addafter; this restriction is intrinsic
  2907   + ignores elimination rules that don't have the correct format
  2908         (the conclusion MUST be a formula variable)
  2909   + ignores types, which can make HOL proofs fail
  2910   + rules must not require higher-order unification, e.g. apply_type in ZF
  2911     [message "Function Var's argument not a bound variable" relates to this]
  2912   + its proof strategy is more general but can actually be slower
  2913 
  2914 * substitution with equality assumptions no longer permutes other
  2915 assumptions;
  2916 
  2917 * minor changes in semantics of addafter (now called addaltern); renamed
  2918 setwrapper to setWrapper and compwrapper to compWrapper; added safe wrapper
  2919 (and access functions for it);
  2920 
  2921 * improved combination of classical reasoner and simplifier:
  2922   + functions for handling clasimpsets
  2923   + improvement of addss: now the simplifier is called _after_ the
  2924     safe steps.
  2925   + safe variant of addss called addSss: uses safe simplifications
  2926     _during_ the safe steps. It is more complete as it allows multiple
  2927     instantiations of unknowns (e.g. with slow_tac).
  2928 
  2929 *** Simplifier ***
  2930 
  2931 * added interface for simplification procedures (functions that
  2932 produce *proven* rewrite rules on the fly, depending on current
  2933 redex);
  2934 
  2935 * ordering on terms as parameter (used for ordered rewriting);
  2936 
  2937 * new functions delcongs, deleqcongs, and Delcongs. richer rep_ss;
  2938 
  2939 * the solver is now split into a safe and an unsafe part.
  2940 This should be invisible for the normal user, except that the
  2941 functions setsolver and addsolver have been renamed to setSolver and
  2942 addSolver; added safe_asm_full_simp_tac;
  2943 
  2944 
  2945 *** HOL ***
  2946 
  2947 * a generic induction tactic `induct_tac' which works for all datatypes and
  2948 also for type `nat';
  2949 
  2950 * a generic case distinction tactic `exhaust_tac' which works for all
  2951 datatypes and also for type `nat';
  2952 
  2953 * each datatype comes with a function `size';
  2954 
  2955 * patterns in case expressions allow tuple patterns as arguments to
  2956 constructors, for example `case x of [] => ... | (x,y,z)#ps => ...';
  2957 
  2958 * primrec now also works with type nat;
  2959 
  2960 * recdef: a new declaration form, allows general recursive functions to be
  2961 defined in theory files.  See HOL/ex/Fib, HOL/ex/Primes, HOL/Subst/Unify.
  2962 
  2963 * the constant for negation has been renamed from "not" to "Not" to
  2964 harmonize with FOL, ZF, LK, etc.;
  2965 
  2966 * HOL/ex/LFilter theory of a corecursive "filter" functional for
  2967 infinite lists;
  2968 
  2969 * HOL/Modelcheck demonstrates invocation of model checker oracle;
  2970 
  2971 * HOL/ex/Ring.thy declares cring_simp, which solves equational
  2972 problems in commutative rings, using axiomatic type classes for + and *;
  2973 
  2974 * more examples in HOL/MiniML and HOL/Auth;
  2975 
  2976 * more default rewrite rules for quantifiers, union/intersection;
  2977 
  2978 * a new constant `arbitrary == @x.False';
  2979 
  2980 * HOLCF/IOA replaces old HOL/IOA;
  2981 
  2982 * HOLCF changes: derived all rules and arities
  2983   + axiomatic type classes instead of classes
  2984   + typedef instead of faking type definitions
  2985   + eliminated the internal constants less_fun, less_cfun, UU_fun, UU_cfun etc.
  2986   + new axclasses cpo, chfin, flat with flat < chfin < pcpo < cpo < po
  2987   + eliminated the types void, one, tr
  2988   + use unit lift and bool lift (with translations) instead of one and tr
  2989   + eliminated blift from Lift3.thy (use Def instead of blift)
  2990   all eliminated rules are derived as theorems --> no visible changes ;
  2991 
  2992 
  2993 *** ZF ***
  2994 
  2995 * ZF now has Fast_tac, Simp_tac and Auto_tac.  Union_iff is a now a default
  2996 rewrite rule; this may affect some proofs.  eq_cs is gone but can be put back
  2997 as ZF_cs addSIs [equalityI];
  2998 
  2999 
  3000 
  3001 New in Isabelle94-7 (November 96)
  3002 ---------------------------------
  3003 
  3004 * allowing negative levels (as offsets) in prlev and choplev;
  3005 
  3006 * super-linear speedup for large simplifications;
  3007 
  3008 * FOL, ZF and HOL now use miniscoping: rewriting pushes
  3009 quantifications in as far as possible (COULD MAKE EXISTING PROOFS
  3010 FAIL); can suppress it using the command Delsimps (ex_simps @
  3011 all_simps); De Morgan laws are also now included, by default;
  3012 
  3013 * improved printing of ==>  :  ~:
  3014 
  3015 * new object-logic "Sequents" adds linear logic, while replacing LK
  3016 and Modal (thanks to Sara Kalvala);
  3017 
  3018 * HOL/Auth: correctness proofs for authentication protocols;
  3019 
  3020 * HOL: new auto_tac combines rewriting and classical reasoning (many
  3021 examples on HOL/Auth);
  3022 
  3023 * HOL: new command AddIffs for declaring theorems of the form P=Q to
  3024 the rewriter and classical reasoner simultaneously;
  3025 
  3026 * function uresult no longer returns theorems in "standard" format;
  3027 regain previous version by: val uresult = standard o uresult;
  3028 
  3029 
  3030 
  3031 New in Isabelle94-6
  3032 -------------------
  3033 
  3034 * oracles -- these establish an interface between Isabelle and trusted
  3035 external reasoners, which may deliver results as theorems;
  3036 
  3037 * proof objects (in particular record all uses of oracles);
  3038 
  3039 * Simp_tac, Fast_tac, etc. that refer to implicit simpset / claset;
  3040 
  3041 * "constdefs" section in theory files;
  3042 
  3043 * "primrec" section (HOL) no longer requires names;
  3044 
  3045 * internal type "tactic" now simply "thm -> thm Sequence.seq";
  3046 
  3047 
  3048 
  3049 New in Isabelle94-5
  3050 -------------------
  3051 
  3052 * reduced space requirements;
  3053 
  3054 * automatic HTML generation from theories;
  3055 
  3056 * theory files no longer require "..." (quotes) around most types;
  3057 
  3058 * new examples, including two proofs of the Church-Rosser theorem;
  3059 
  3060 * non-curried (1994) version of HOL is no longer distributed;
  3061 
  3062 
  3063 
  3064 New in Isabelle94-4
  3065 -------------------
  3066 
  3067 * greatly reduced space requirements;
  3068 
  3069 * theory files (.thy) no longer require \...\ escapes at line breaks;
  3070 
  3071 * searchable theorem database (see the section "Retrieving theorems" on
  3072 page 8 of the Reference Manual);
  3073 
  3074 * new examples, including Grabczewski's monumental case study of the
  3075 Axiom of Choice;
  3076 
  3077 * The previous version of HOL renamed to Old_HOL;
  3078 
  3079 * The new version of HOL (previously called CHOL) uses a curried syntax
  3080 for functions.  Application looks like f a b instead of f(a,b);
  3081 
  3082 * Mutually recursive inductive definitions finally work in HOL;
  3083 
  3084 * In ZF, pattern-matching on tuples is now available in all abstractions and
  3085 translates to the operator "split";
  3086 
  3087 
  3088 
  3089 New in Isabelle94-3
  3090 -------------------
  3091 
  3092 * new infix operator, addss, allowing the classical reasoner to
  3093 perform simplification at each step of its search.  Example:
  3094         fast_tac (cs addss ss)
  3095 
  3096 * a new logic, CHOL, the same as HOL, but with a curried syntax
  3097 for functions.  Application looks like f a b instead of f(a,b).  Also pairs
  3098 look like (a,b) instead of <a,b>;
  3099 
  3100 * PLEASE NOTE: CHOL will eventually replace HOL!
  3101 
  3102 * In CHOL, pattern-matching on tuples is now available in all abstractions.
  3103 It translates to the operator "split".  A new theory of integers is available;
  3104 
  3105 * In ZF, integer numerals now denote two's-complement binary integers.
  3106 Arithmetic operations can be performed by rewriting.  See ZF/ex/Bin.ML;
  3107 
  3108 * Many new examples: I/O automata, Church-Rosser theorem, equivalents
  3109 of the Axiom of Choice;
  3110 
  3111 
  3112 
  3113 New in Isabelle94-2
  3114 -------------------
  3115 
  3116 * Significantly faster resolution;
  3117 
  3118 * the different sections in a .thy file can now be mixed and repeated
  3119 freely;
  3120 
  3121 * Database of theorems for FOL, HOL and ZF.  New
  3122 commands including qed, qed_goal and bind_thm store theorems in the database.
  3123 
  3124 * Simple database queries: return a named theorem (get_thm) or all theorems of
  3125 a given theory (thms_of), or find out what theory a theorem was proved in
  3126 (theory_of_thm);
  3127 
  3128 * Bugs fixed in the inductive definition and datatype packages;
  3129 
  3130 * The classical reasoner provides deepen_tac and depth_tac, making FOL_dup_cs
  3131 and HOL_dup_cs obsolete;
  3132 
  3133 * Syntactic ambiguities caused by the new treatment of syntax in Isabelle94-1
  3134 have been removed;
  3135 
  3136 * Simpler definition of function space in ZF;
  3137 
  3138 * new results about cardinal and ordinal arithmetic in ZF;
  3139 
  3140 * 'subtype' facility in HOL for introducing new types as subsets of existing
  3141 types;
  3142 
  3143 
  3144 $Id$