NEWS
author nipkow
Wed Aug 17 14:19:17 2005 +0200 (2005-08-17)
changeset 17092 16971afe75f6
parent 17047 e2e2d75bb37b
child 17095 669005f73b81
permissions -rw-r--r--
*** empty log message ***
     1 Isabelle NEWS -- history user-relevant changes
     2 ==============================================
     3 
     4 New in this Isabelle release
     5 ----------------------------
     6 
     7 *** General ***
     8 
     9 * Theory headers: the new header syntax for Isar theories is
    10 
    11   theory <name>
    12   imports <theory1> ... <theoryN>
    13   uses <file1> ... <fileM>
    14   begin
    15 
    16 where the 'uses' part is optional.  The previous syntax
    17 
    18   theory <name> = <theory1> + ... + <theoryN>:
    19 
    20 will disappear in the next release.  Use isatool fixheaders to convert
    21 existing theory files.  Note that there is no change in ancient
    22 non-Isar theories.
    23 
    24 * Theory loader: parent theories can now also be referred to via
    25 relative and absolute paths.
    26 
    27 * Improved version of thms_containing searches for a list of criteria
    28 instead of a list of constants. Known criteria are: intro, elim, dest,
    29 name:string, simp:term, and any term. Criteria can be preceded by '-'
    30 to select theorems that do not match. Intro, elim, dest select
    31 theorems that match the current goal, name:s selects theorems whose
    32 fully qualified name contain s, and simp:term selects all
    33 simplification rules whose lhs match term.  Any other term is
    34 interpreted as pattern and selects all theorems matching the
    35 pattern. Available in ProofGeneral under 'ProofGeneral -> Find
    36 Theorems' or C-c C-f.  Example:
    37 
    38   C-c C-f (100) "(_::nat) + _ + _" intro -name:"HOL."
    39 
    40 prints the last 100 theorems matching the pattern "(_::nat) + _ + _",
    41 matching the current goal as introduction rule and not having "HOL."
    42 in their name (i.e. not being defined in theory HOL).
    43 
    44 
    45 *** Document preparation ***
    46 
    47 * Commands 'display_drafts' and 'print_drafts' perform simple output
    48 of raw sources.  Only those symbols that do not require additional
    49 LaTeX packages (depending on comments in isabellesym.sty) are
    50 displayed properly, everything else is left verbatim.  isatool display
    51 and isatool print are used as front ends (these are subject to the
    52 DVI/PDF_VIEWER and PRINT_COMMAND settings, respectively).
    53 
    54 * Command tags control specific markup of certain regions of text,
    55 notably folding and hiding.  Predefined tags include "theory" (for
    56 theory begin and end), "proof" for proof commands, and "ML" for
    57 commands involving ML code; the additional tags "visible" and
    58 "invisible" are unused by default.  Users may give explicit tag
    59 specifications in the text, e.g. ''by %invisible (auto)''.  The
    60 interpretation of tags is determined by the LaTeX job during document
    61 preparation: see option -V of isatool usedir, or options -n and -t of
    62 isatool document, or even the LaTeX macros \isakeeptag, \isafoldtag,
    63 \isadroptag.
    64 
    65 Several document versions may be produced at the same time via isatool
    66 usedir (the generated index.html will link all of them).  Typical
    67 specifications include ''-V document=theory,proof,ML'' to present
    68 theory/proof/ML parts faithfully, ''-V outline=/proof,/ML'' to fold
    69 proof and ML commands, and ''-V mutilated=-theory,-proof,-ML'' to omit
    70 these parts without any formal replacement text.  The Isabelle site
    71 default settings produce ''document'' and ''outline'' versions as
    72 specified above.
    73 
    74 * Several new antiquotation:
    75 
    76   @{term_type term} prints a term with its type annotated;
    77 
    78   @{typeof term} prints the type of a term;
    79 
    80   @{const const} is the same as @{term const}, but checks that the
    81   argument is a known logical constant;
    82 
    83   @{term_style style term} and @{thm_style style thm} print a term or
    84   theorem applying a "style" to it
    85 
    86 Predefined styles are 'lhs' and 'rhs' printing the lhs/rhs of
    87 definitions, equations, inequations etc., 'concl' printing only the
    88 conclusion of a meta-logical statement theorem, and 'prem1' .. 'prem9'
    89 to print the specified premise.  TermStyle.add_style provides an ML
    90 interface for introducing further styles.  See also the "LaTeX Sugar"
    91 document practical applications.
    92 
    93 
    94 *** Pure ***
    95 
    96 * Considerably improved version of 'constdefs' command.  Now performs
    97 automatic type-inference of declared constants; additional support for
    98 local structure declarations (cf. locales and HOL records), see also
    99 isar-ref manual.  Potential INCOMPATIBILITY: need to observe strictly
   100 sequential dependencies of definitions within a single 'constdefs'
   101 section; moreover, the declared name needs to be an identifier.  If
   102 all fails, consider to fall back on 'consts' and 'defs' separately.
   103 
   104 * Improved indexed syntax and implicit structures.  First of all,
   105 indexed syntax provides a notational device for subscripted
   106 application, using the new syntax \<^bsub>term\<^esub> for arbitrary
   107 expressions.  Secondly, in a local context with structure
   108 declarations, number indexes \<^sub>n or the empty index (default
   109 number 1) refer to a certain fixed variable implicitly; option
   110 show_structs controls printing of implicit structures.  Typical
   111 applications of these concepts involve record types and locales.
   112 
   113 * New command 'no_syntax' removes grammar declarations (and
   114 translations) resulting from the given syntax specification, which is
   115 interpreted in the same manner as for the 'syntax' command.
   116 
   117 * 'Advanced' translation functions (parse_translation etc.) may depend
   118 on the signature of the theory context being presently used for
   119 parsing/printing, see also isar-ref manual.
   120 
   121 * Improved 'oracle' command provides a type-safe interface to turn an
   122 ML expression of type theory -> T -> term into a primitive rule of
   123 type theory -> T -> thm (i.e. the functionality of Thm.invoke_oracle
   124 is already included here); see also FOL/ex/IffExample.thy;
   125 INCOMPATIBILITY.
   126 
   127 * Improved internal renaming of symbolic identifiers -- attach primes
   128 instead of base 26 numbers.
   129 
   130 * New flag show_question_marks controls printing of leading question
   131 marks in schematic variable names.
   132 
   133 * In schematic variable names, *any* symbol following \<^isub> or
   134 \<^isup> is now treated as part of the base name.  For example, the
   135 following works without printing of awkward ".0" indexes:
   136 
   137   lemma "x\<^isub>1 = x\<^isub>2 ==> x\<^isub>2 = x\<^isub>1"
   138     by simp
   139 
   140 * Inner syntax includes (*(*nested*) comments*).
   141 
   142 * Pretty pinter now supports unbreakable blocks, specified in mixfix
   143 annotations as "(00...)".
   144 
   145 * Clear separation of logical types and nonterminals, where the latter
   146 may only occur in 'syntax' specifications or type abbreviations.
   147 Before that distinction was only partially implemented via type class
   148 "logic" vs. "{}".  Potential INCOMPATIBILITY in rare cases of improper
   149 use of 'types'/'consts' instead of 'nonterminals'/'syntax'.  Some very
   150 exotic syntax specifications may require further adaption
   151 (e.g. Cube/Base.thy).
   152 
   153 * Removed obsolete type class "logic", use the top sort {} instead.
   154 Note that non-logical types should be declared as 'nonterminals'
   155 rather than 'types'.  INCOMPATIBILITY for new object-logic
   156 specifications.
   157 
   158 * Simplifier: can now control the depth to which conditional rewriting
   159 is traced via the PG menu Isabelle -> Settings -> Trace Simp Depth
   160 Limit.
   161 
   162 * Simplifier: simplification procedures may now take the current
   163 simpset into account (cf. Simplifier.simproc(_i) / mk_simproc
   164 interface), which is very useful for calling the Simplifier
   165 recursively.  Minor INCOMPATIBILITY: the 'prems' argument of simprocs
   166 is gone -- use prems_of_ss on the simpset instead.  Moreover, the
   167 low-level mk_simproc no longer applies Logic.varify internally, to
   168 allow for use in a context of fixed variables.
   169 
   170 * thin_tac now works even if the assumption being deleted contains !!
   171 or ==>.  More generally, erule now works even if the major premise of
   172 the elimination rule contains !! or ==>.
   173 
   174 * Reorganized bootstrapping of the Pure theories; CPure is now derived
   175 from Pure, which contains all common declarations already.  Both
   176 theories are defined via plain Isabelle/Isar .thy files.
   177 INCOMPATIBILITY: elements of CPure (such as the CPure.intro /
   178 CPure.elim / CPure.dest attributes) now appear in the Pure name space;
   179 use isatool fixcpure to adapt your theory and ML sources.
   180 
   181 * New syntax 'name(i-j, i-, i, ...)' for referring to specific
   182 selections of theorems in named facts via index ranges.
   183 
   184 * More efficient treatment of intermediate checkpoints in interactive
   185 theory development.
   186 
   187 
   188 *** Locales ***
   189   
   190 * New commands for the interpretation of locale expressions in
   191 theories ('interpretation') and proof contexts ('interpret').  These
   192 take an instantiation of the locale parameters and compute proof
   193 obligations from the instantiated specification.  After the
   194 obligations have been discharged, the instantiated theorems of the
   195 locale are added to the theory or proof context.  Interpretation is
   196 smart in that already active interpretations do not occur in proof
   197 obligations, neither are instantiated theorems stored in duplicate.
   198 Use print_interps to inspect active interpretations of a particular
   199 locale.  For details, see the Isar Reference manual.
   200 
   201 INCOMPATIBILITY: former 'instantiate' has been withdrawn, use
   202 'interpret' instead.
   203 
   204 * Proper static binding of attribute syntax -- i.e. types / terms /
   205 facts mentioned as arguments are always those of the locale definition
   206 context, independently of the context of later invocations.  Moreover,
   207 locale operations (renaming and type / term instantiation) are applied
   208 to attribute arguments as expected.
   209 
   210 INCOMPATIBILITY of the ML interface: always pass Attrib.src instead of
   211 actual attributes; rare situations may require Attrib.attribute to
   212 embed those attributes into Attrib.src that lack concrete syntax.
   213 Attribute implementations need to cooperate properly with the static
   214 binding mechanism.  Basic parsers Args.XXX_typ/term/prop and
   215 Attrib.XXX_thm etc. already do the right thing without further
   216 intervention.  Only unusual applications -- such as "where" or "of"
   217 (cf. src/Pure/Isar/attrib.ML), which process arguments depending both
   218 on the context and the facts involved -- may have to assign parsed
   219 values to argument tokens explicitly.
   220 
   221 * New context element "constrains" adds type constraints to parameters --
   222 there is no logical significance.
   223 
   224 * Context expressions: renaming parameters permits syntax
   225 redeclaration as well.
   226 
   227 * Locale definition: 'includes' now disallowed.
   228 
   229 * Changed parameter management in theorem generation for long goal
   230 statements with 'includes'.  INCOMPATIBILITY: produces a different
   231 theorem statement in rare situations.
   232 
   233 * Attributes 'induct' and 'cases': type or set names may now be
   234 locally fixed variables as well.
   235 
   236 * Antiquotations now provide the option 'locale=NAME' to specify an
   237 alternative context used for evaluating and printing the subsequent
   238 argument, as in @{thm [locale=LC] fold_commute}, for example.
   239 
   240 
   241 *** Provers ***
   242 
   243 * Provers/hypsubst.ML: improved version of the subst method, for
   244 single-step rewriting: it now works in bound variable contexts. New is
   245 'subst (asm)', for rewriting an assumption.  INCOMPATIBILITY: may
   246 rewrite a different subterm than the original subst method, which is
   247 still available as 'simplesubst'.
   248 
   249 * Provers/quasi.ML: new transitivity reasoners for transitivity only
   250 and quasi orders.
   251 
   252 * Provers/trancl.ML: new transitivity reasoner for transitive and
   253 reflexive-transitive closure of relations.
   254 
   255 * Provers/blast.ML: new reference depth_limit to make blast's depth
   256 limit (previously hard-coded with a value of 20) user-definable.
   257 
   258 * Provers/simplifier.ML has been moved to Pure, where Simplifier.setup
   259 is peformed already.  Object-logics merely need to finish their
   260 initial simpset configuration as before.  INCOMPATIBILITY.
   261 
   262 
   263 *** HOL ***
   264 
   265 * Symbolic syntax of Hilbert Choice Operator is now as follows:
   266 
   267   syntax (epsilon)
   268     "_Eps" :: "[pttrn, bool] => 'a"    ("(3\<some>_./ _)" [0, 10] 10)
   269 
   270 The symbol \<some> is displayed as the alternative epsilon of LaTeX
   271 and x-symbol; use option '-m epsilon' to get it actually printed.
   272 Moreover, the mathematically important symbolic identifier \<epsilon>
   273 becomes available as variable, constant etc.  INCOMPATIBILITY,
   274 
   275 * "x > y" abbreviates "y < x" and "x >= y" abbreviates "y <= x".
   276 Similarly for all quantifiers: "ALL x > y" etc.  The x-symbol for >=
   277 is \<ge>. New transitivity rules have been added to HOL/Orderings.thy to 
   278 support corresponding Isar calculations.
   279 
   280 * "{x:A. P}" abbreviates "{x. x:A & P}", and similarly for "\<in>"
   281 instead of ":".
   282 
   283 * theory SetInterval: changed the syntax for open intervals:
   284 
   285   Old       New
   286   {..n(}    {..<n}
   287   {)n..}    {n<..}
   288   {m..n(}   {m..<n}
   289   {)m..n}   {m<..n}
   290   {)m..n(}  {m<..<n}
   291 
   292 The old syntax is still supported but will disappear in the next
   293 release.  For conversion use the following Emacs search and replace
   294 patterns (these are not perfect but work quite well):
   295 
   296   {)\([^\.]*\)\.\.  ->  {\1<\.\.}
   297   \.\.\([^(}]*\)(}  ->  \.\.<\1}
   298 
   299 * theory Finite_Set: changed the syntax for 'setsum', summation over
   300 finite sets: "setsum (%x. e) A", which used to be "\<Sum>x:A. e", is
   301 now either "SUM x:A. e" or "\<Sum>x \<in> A. e".
   302 
   303 Some new syntax forms are available:
   304 
   305   "\<Sum>x | P. e"      for     "setsum (%x. e) {x. P}"
   306   "\<Sum>x = a..b. e"   for     "setsum (%x. e) {a..b}"
   307   "\<Sum>x = a..<b. e"  for     "setsum (%x. e) {a..<b}"
   308   "\<Sum>x < k. e"      for     "setsum (%x. e) {..<k}"
   309 
   310 The latter form "\<Sum>x < k. e" used to be based on a separate
   311 function "Summation", which has been discontinued.
   312 
   313 * theory Finite_Set: in structured induction proofs, the insert case
   314 is now 'case (insert x F)' instead of the old counterintuitive 'case
   315 (insert F x)'.
   316 
   317 * The 'refute' command has been extended to support a much larger
   318 fragment of HOL, including axiomatic type classes, constdefs and
   319 typedefs, inductive datatypes and recursion.
   320 
   321 * Datatype induction via method 'induct' now preserves the name of the
   322 induction variable. For example, when proving P(xs::'a list) by
   323 induction on xs, the induction step is now P(xs) ==> P(a#xs) rather
   324 than P(list) ==> P(a#list) as previously.  Potential INCOMPATIBILITY
   325 in unstructured proof scripts.
   326 
   327 * Reworked implementation of records.  Improved scalability for
   328 records with many fields, avoiding performance problems for type
   329 inference. Records are no longer composed of nested field types, but
   330 of nested extension types. Therefore the record type only grows linear
   331 in the number of extensions and not in the number of fields.  The
   332 top-level (users) view on records is preserved.  Potential
   333 INCOMPATIBILITY only in strange cases, where the theory depends on the
   334 old record representation. The type generated for a record is called
   335 <record_name>_ext_type.
   336 
   337 Flag record_quick_and_dirty_sensitive can be enabled to skip the
   338 proofs triggered by a record definition or a simproc (if
   339 quick_and_dirty is enabled).  Definitions of large records can take
   340 quite long.
   341 
   342 New simproc record_upd_simproc for simplification of multiple record
   343 updates enabled by default.  Moreover, trivial updates are also
   344 removed: r(|x := x r|) = r.  INCOMPATIBILITY: old proofs break
   345 occasionally, since simplification is more powerful by default.
   346 
   347 * Simplifier: automatically reasons about transitivity chains
   348 involving "trancl" (r^+) and "rtrancl" (r^*) by setting up tactics
   349 provided by Provers/trancl.ML as additional solvers.  INCOMPATIBILITY:
   350 old proofs break occasionally as simplification may now solve more
   351 goals than previously.
   352 
   353 * Simplifier: converts x <= y into x = y if assumption y <= x is
   354 present.  Works for all partial orders (class "order"), in particular
   355 numbers and sets.  For linear orders (e.g. numbers) it treats ~ x < y
   356 just like y <= x.
   357 
   358 * Simplifier: new simproc for "let x = a in f x".  If a is a free or
   359 bound variable or a constant then the let is unfolded.  Otherwise
   360 first a is simplified to b, and then f b is simplified to g. If
   361 possible we abstract b from g arriving at "let x = b in h x",
   362 otherwise we unfold the let and arrive at g.  The simproc can be
   363 enabled/disabled by the reference use_let_simproc.  Potential
   364 INCOMPATIBILITY since simplification is more powerful by default.
   365 
   366 * Classical reasoning: the meson method now accepts theorems as arguments.
   367 
   368 * Theory OrderedGroup and Ring_and_Field: various additions and
   369 improvements to faciliate calculations involving equalities and
   370 inequalities.
   371 
   372 The following theorems have been eliminated or modified
   373 (INCOMPATIBILITY):
   374 
   375   abs_eq             now named abs_of_nonneg
   376   abs_of_ge_0        now named abs_of_nonneg 
   377   abs_minus_eq       now named abs_of_nonpos  
   378   imp_abs_id         now named abs_of_nonneg
   379   imp_abs_neg_id     now named abs_of_nonpos
   380   mult_pos           now named mult_pos_pos
   381   mult_pos_le        now named mult_nonneg_nonneg
   382   mult_pos_neg_le    now named mult_nonneg_nonpos
   383   mult_pos_neg2_le   now named mult_nonneg_nonpos2
   384   mult_neg           now named mult_neg_neg
   385   mult_neg_le        now named mult_nonpos_nonpos
   386 
   387 * Theory Parity: added rules for simplifying exponents.
   388 
   389 * Theory List:
   390 
   391 The following theorems have been eliminated or modified
   392 (INCOMPATIBILITY):
   393 
   394   list_all_Nil       now named list_all.simps(1)
   395   list_all_Cons      now named list_all.simps(2)
   396   list_all_conv      now named list_all_iff
   397   set_mem_eq         now named mem_iff
   398 
   399 * Theories SetsAndFunctions and BigO (see HOL/Library) support
   400 asymptotic "big O" calculations.  See the notes in BigO.thy.
   401 
   402 
   403 *** HOL-Complex ***
   404 
   405 * Theory RealDef: better support for embedding natural numbers and
   406 integers in the reals.
   407 
   408 The following theorems have been eliminated or modified
   409 (INCOMPATIBILITY):
   410 
   411   exp_ge_add_one_self  now requires no hypotheses
   412   real_of_int_add      reversed direction of equality (use [symmetric])
   413   real_of_int_minus    reversed direction of equality (use [symmetric])
   414   real_of_int_diff     reversed direction of equality (use [symmetric])
   415   real_of_int_mult     reversed direction of equality (use [symmetric])
   416 
   417 * Theory RComplete: expanded support for floor and ceiling functions.
   418 
   419 * Theory Ln is new, with properties of the natural logarithm
   420 
   421 
   422 *** HOLCF ***
   423 
   424 * HOLCF: discontinued special version of 'constdefs' (which used to
   425 support continuous functions) in favor of the general Pure one with
   426 full type-inference.
   427 
   428 
   429 *** ZF ***
   430 
   431 * ZF/ex: theories Group and Ring provide examples in abstract algebra,
   432 including the First Isomorphism Theorem (on quotienting by the kernel
   433 of a homomorphism).
   434 
   435 * ZF/Simplifier: install second copy of type solver that actually
   436 makes use of TC rules declared to Isar proof contexts (or locales);
   437 the old version is still required for ML proof scripts.
   438 
   439 
   440 *** ML ***
   441 
   442 * Pure/library.ML no longer defines its own option datatype, but uses
   443 that of the SML basis, which has constructors NONE and SOME instead of
   444 None and Some, as well as exception Option.Option instead of OPTION.
   445 The functions the, if_none, is_some, is_none have been adapted
   446 accordingly, while Option.map replaces apsome.
   447 
   448 * Pure/library.ML: the exception LIST has been given up in favour of
   449 the standard exceptions Empty and Subscript, as well as
   450 Library.UnequalLengths.  Function like Library.hd and Library.tl are
   451 superceded by the standard hd and tl functions etc.
   452 
   453 A number of basic list functions are no longer exported to the ML
   454 toplevel, as they are variants of predefined functions.  The following
   455 suggests how one can translate existing code:
   456 
   457     rev_append xs ys = List.revAppend (xs, ys)
   458     nth_elem (i, xs) = List.nth (xs, i)
   459     last_elem xs = List.last xs
   460     flat xss = List.concat xss
   461     seq fs = List.app fs
   462     partition P xs = List.partition P xs
   463     mapfilter f xs = List.mapPartial f xs
   464 
   465 * Pure/library.ML: several combinators for linear functional
   466 transformations, notably reverse application and composition:
   467 
   468   x |> f		f #> g
   469   (x, y) |-> f		f #-> g
   470 
   471 * Pure/library.ML: canonical list combinators fold, fold_rev, and
   472 fold_map support linear functional transformations and nesting.  For
   473 example:
   474 
   475   fold f [x1, ..., xN] y =
   476     y |> f x1 |> ... |> f xN
   477 
   478   (fold o fold) f [xs1, ..., xsN] y =
   479     y |> fold f xs1 |> ... |> fold f xsN
   480 
   481   fold f [x1, ..., xN] =
   482     f x1 #> ... #> f xN
   483 
   484   (fold o fold) f [xs1, ..., xsN] =
   485     fold f xs1 #> ... #> fold f xsN
   486 
   487 * Pure/term.ML: combinators fold_atyps, fold_aterms, fold_term_types,
   488 fold_types traverse types/terms from left to right, observing
   489 canonical argument order.  Supercedes previous foldl_XXX versions,
   490 add_frees, add_vars etc. have been adapted as well: INCOMPATIBILITY.
   491 
   492 * Pure: output via the Isabelle channels of writeln/warning/error
   493 etc. is now passed through Output.output, with a hook for arbitrary
   494 transformations depending on the print_mode (cf. Output.add_mode --
   495 the first active mode that provides a output function wins).  Already
   496 formatted output may be embedded into further text via Output.raw; the
   497 result of Pretty.string_of/str_of and derived functions
   498 (string_of_term/cterm/thm etc.) is already marked raw to accommodate
   499 easy composition of diagnostic messages etc.  Programmers rarely need
   500 to care about Output.output or Output.raw at all, with some notable
   501 exceptions: Output.output is required when bypassing the standard
   502 channels (writeln etc.), or in token translations to produce properly
   503 formatted results; Output.raw is required when capturing already
   504 output material that will eventually be presented to the user a second
   505 time.  For the default print mode, both Output.output and Output.raw
   506 have no effect.
   507 
   508 * Pure: Output.time_accumulator NAME creates an operator ('a -> 'b) ->
   509 'a -> 'b to measure runtime and count invocations; the cumulative
   510 results are displayed at the end of a batch session.
   511 
   512 * Isar toplevel: improved diagnostics, mostly for Poly/ML only.
   513 Reference Toplevel.debug (default false) controls detailed printing
   514 and tracing of low-level exceptions; Toplevel.profiling (default 0)
   515 controls execution profiling -- set to 1 for time and 2 for space
   516 (both increase the runtime).
   517 
   518 * Isar session: The initial use of ROOT.ML is now always timed,
   519 i.e. the log will show the actual process times, in contrast to the
   520 elapsed wall-clock time that the outer shell wrapper produces.
   521  
   522 * Pure: structure OrdList (cf. Pure/General/ord_list.ML) provides a
   523 reasonably efficient light-weight implementation of sets as lists.
   524 
   525 * Pure: more efficient orders for basic syntactic entities: added
   526 fast_string_ord, fast_indexname_ord, fast_term_ord; changed sort_ord
   527 and typ_ord to use fast_string_ord and fast_indexname_ord (term_ord is
   528 NOT affected); structures Symtab, Vartab, Typtab, Termtab use the fast
   529 orders now -- potential INCOMPATIBILITY for code that depends on a
   530 particular order for Symtab.keys, Symtab.dest, etc. (consider using
   531 Library.sort_strings on result).
   532 
   533 * Pure: name spaces have been refined, with significant changes of the
   534 internal interfaces -- INCOMPATIBILITY.  Renamed cond_extern(_table)
   535 to extern(_table).  The plain name entry path is superceded by a
   536 general 'naming' context, which also includes the 'policy' to produce
   537 a fully qualified name and external accesses of a fully qualified
   538 name; NameSpace.extend is superceded by context dependent
   539 Sign.declare_name.  Several theory and proof context operations modify
   540 the naming context.  Especially note Theory.restore_naming and
   541 ProofContext.restore_naming to get back to a sane state; note that
   542 Theory.add_path is no longer sufficient to recover from
   543 Theory.absolute_path in particular.
   544 
   545 * Pure: new flags short_names (default false) and unique_names
   546 (default true) for controlling output of qualified names.  If
   547 short_names is set, names are printed unqualified.  If unique_names is
   548 reset, the name prefix is reduced to the minimum required to achieve
   549 the original result when interning again, even if there is an overlap
   550 with earlier declarations.
   551 
   552 * Pure/TheoryDataFun: change of the argument structure; 'prep_ext' is
   553 now 'extend', and 'merge' gets an additional Pretty.pp argument
   554 (useful for printing error messages).  INCOMPATIBILITY.
   555 
   556 * Pure: major reorganization of the theory context.  Type Sign.sg and
   557 Theory.theory are now identified, referring to the universal
   558 Context.theory (see Pure/context.ML).  Actual signature and theory
   559 content is managed as theory data.  The old code and interfaces were
   560 spread over many files and structures; the new arrangement introduces
   561 considerable INCOMPATIBILITY to gain more clarity:
   562 
   563   Context -- theory management operations (name, identity, inclusion,
   564     parents, ancestors, merge, etc.), plus generic theory data;
   565 
   566   Sign -- logical signature and syntax operations (declaring consts,
   567     types, etc.), plus certify/read for common entities;
   568 
   569   Theory -- logical theory operations (stating axioms, definitions,
   570     oracles), plus a copy of logical signature operations (consts,
   571     types, etc.); also a few basic management operations (Theory.copy,
   572     Theory.merge, etc.)
   573 
   574 The most basic sign_of operations (Theory.sign_of, Thm.sign_of_thm
   575 etc.) as well as the sign field in Thm.rep_thm etc. have been retained
   576 for convenience -- they merely return the theory.
   577 
   578 * Pure: the Isar proof context type is already defined early in Pure
   579 as Context.proof (note that ProofContext.context and Proof.context are
   580 aliases, where the latter is the preferred name).  This enables other
   581 Isabelle components to refer to that type even before Isar is present.
   582 
   583 * Pure/sign/theory: discontinued named name spaces (i.e. classK,
   584 typeK, constK, axiomK, oracleK), but provide explicit operations for
   585 any of these kinds.  For example, Sign.intern typeK is now
   586 Sign.intern_type, Theory.hide_space Sign.typeK is now
   587 Theory.hide_types.  Also note that former
   588 Theory.hide_classes/types/consts are now
   589 Theory.hide_classes_i/types_i/consts_i, while the non '_i' versions
   590 internalize their arguments!  INCOMPATIBILITY.
   591 
   592 * Pure: get_thm interface (of PureThy and ProofContext) expects
   593 datatype thmref (with constructors Name and NameSelection) instead of
   594 plain string -- INCOMPATIBILITY;
   595 
   596 * Pure: cases produced by proof methods specify options, where NONE
   597 means to remove case bindings -- INCOMPATIBILITY in
   598 (RAW_)METHOD_CASES.
   599 
   600 * Pure: the following operations retrieve axioms or theorems from a
   601 theory node or theory hierarchy, respectively:
   602 
   603   Theory.axioms_of: theory -> (string * term) list
   604   Theory.all_axioms_of: theory -> (string * term) list
   605   PureThy.thms_of: theory -> (string * thm) list
   606   PureThy.all_thms_of: theory -> (string * thm) list
   607 
   608 * Pure: print_tac now outputs the goal through the trace channel.
   609 
   610 * Pure/Simplifier: improved handling of bound variables (nameless
   611 representation, avoid allocating new strings).  Simprocs that invoke
   612 the Simplifier recursively should use Simplifier.inherit_bounds to
   613 avoid local name clashes.
   614 
   615 * Pure/Provers: Simplifier and Classical Reasoner now support proof
   616 context dependent plug-ins (simprocs, solvers, wrappers etc.).  These
   617 extra components are stored in the theory and patched into the
   618 simpset/claset when used in an Isar proof context.  Context dependent
   619 components are maintained by the following theory operations:
   620 
   621   Simplifier.add_context_simprocs
   622   Simplifier.del_context_simprocs
   623   Simplifier.set_context_subgoaler
   624   Simplifier.reset_context_subgoaler
   625   Simplifier.add_context_looper
   626   Simplifier.del_context_looper
   627   Simplifier.add_context_unsafe_solver
   628   Simplifier.add_context_safe_solver
   629 
   630   Classical.add_context_safe_wrapper
   631   Classical.del_context_safe_wrapper
   632   Classical.add_context_unsafe_wrapper
   633   Classical.del_context_unsafe_wrapper
   634 
   635 IMPORTANT NOTE: proof tools (methods etc.) need to use
   636 local_simpset_of and local_claset_of to instead of the primitive
   637 Simplifier.get_local_simpset and Classical.get_local_claset,
   638 respectively, in order to see the context dependent fields!
   639 
   640 * File.sysify_path and File.quote_sysify path have been replaced by
   641 File.platform_path and File.shell_path (with appropriate hooks).  This
   642 provides a clean interface for unusual systems where the internal and
   643 external process view of file names are different.
   644 
   645 
   646 *** System ***
   647 
   648 * Allow symlinks to all proper Isabelle executables (Isabelle,
   649 isabelle, isatool etc.).
   650 
   651 * ISABELLE_DOC_FORMAT setting specifies preferred document format (for
   652 isatool doc, isatool mkdir, display_drafts etc.).
   653 
   654 * isatool usedir: option -f allows specification of the ML file to be
   655 used by Isabelle; default is ROOT.ML.
   656 
   657 * New isatool version outputs the version identifier of the Isabelle
   658 distribution being used.
   659 
   660 * HOL: new isatool dimacs2hol converts files in DIMACS CNF format
   661 (containing Boolean satisfiability problems) into Isabelle/HOL
   662 theories.
   663 
   664 
   665 
   666 New in Isabelle2004 (April 2004)
   667 --------------------------------
   668 
   669 *** General ***
   670 
   671 * Provers/order.ML:  new efficient reasoner for partial and linear orders.
   672   Replaces linorder.ML.
   673 
   674 * Pure: Greek letters (except small lambda, \<lambda>), as well as Gothic
   675   (\<aa>...\<zz>\<AA>...\<ZZ>), calligraphic (\<A>...\<Z>), and Euler
   676   (\<a>...\<z>), are now considered normal letters, and can therefore
   677   be used anywhere where an ASCII letter (a...zA...Z) has until
   678   now. COMPATIBILITY: This obviously changes the parsing of some
   679   terms, especially where a symbol has been used as a binder, say
   680   '\<Pi>x. ...', which is now a type error since \<Pi>x will be parsed
   681   as an identifier.  Fix it by inserting a space around former
   682   symbols.  Call 'isatool fixgreek' to try to fix parsing errors in
   683   existing theory and ML files.
   684 
   685 * Pure: Macintosh and Windows line-breaks are now allowed in theory files.
   686 
   687 * Pure: single letter sub/superscripts (\<^isub> and \<^isup>) are now
   688   allowed in identifiers. Similar to Greek letters \<^isub> is now considered
   689   a normal (but invisible) letter. For multiple letter subscripts repeat
   690   \<^isub> like this: x\<^isub>1\<^isub>2.
   691 
   692 * Pure: There are now sub-/superscripts that can span more than one
   693   character. Text between \<^bsub> and \<^esub> is set in subscript in
   694   ProofGeneral and LaTeX, text between \<^bsup> and \<^esup> in
   695   superscript. The new control characters are not identifier parts.
   696 
   697 * Pure: Control-symbols of the form \<^raw:...> will literally print the
   698   content of "..." to the latex file instead of \isacntrl... . The "..."
   699   may consist of any printable characters excluding the end bracket >.
   700 
   701 * Pure: Using new Isar command "finalconsts" (or the ML functions
   702   Theory.add_finals or Theory.add_finals_i) it is now possible to
   703   declare constants "final", which prevents their being given a definition
   704   later.  It is useful for constants whose behaviour is fixed axiomatically
   705   rather than definitionally, such as the meta-logic connectives.
   706 
   707 * Pure: 'instance' now handles general arities with general sorts
   708   (i.e. intersections of classes),
   709 
   710 * Presentation: generated HTML now uses a CSS style sheet to make layout
   711   (somewhat) independent of content. It is copied from lib/html/isabelle.css.
   712   It can be changed to alter the colors/layout of generated pages.
   713 
   714 
   715 *** Isar ***
   716 
   717 * Tactic emulation methods rule_tac, erule_tac, drule_tac, frule_tac,
   718   cut_tac, subgoal_tac and thin_tac:
   719   - Now understand static (Isar) contexts.  As a consequence, users of Isar
   720     locales are no longer forced to write Isar proof scripts.
   721     For details see Isar Reference Manual, paragraph 4.3.2: Further tactic
   722     emulations.
   723   - INCOMPATIBILITY: names of variables to be instantiated may no
   724     longer be enclosed in quotes.  Instead, precede variable name with `?'.
   725     This is consistent with the instantiation attribute "where".
   726 
   727 * Attributes "where" and "of":
   728   - Now take type variables of instantiated theorem into account when reading
   729     the instantiation string.  This fixes a bug that caused instantiated
   730     theorems to have too special types in some circumstances.
   731   - "where" permits explicit instantiations of type variables.
   732 
   733 * Calculation commands "moreover" and "also" no longer interfere with
   734   current facts ("this"), admitting arbitrary combinations with "then"
   735   and derived forms.
   736 
   737 * Locales:
   738   - Goal statements involving the context element "includes" no longer
   739     generate theorems with internal delta predicates (those ending on
   740     "_axioms") in the premise.
   741     Resolve particular premise with <locale>.intro to obtain old form.
   742   - Fixed bug in type inference ("unify_frozen") that prevented mix of target
   743     specification and "includes" elements in goal statement.
   744   - Rule sets <locale>.intro and <locale>.axioms no longer declared as
   745     [intro?] and [elim?] (respectively) by default.
   746   - Experimental command for instantiation of locales in proof contexts:
   747         instantiate <label>[<attrs>]: <loc>
   748     Instantiates locale <loc> and adds all its theorems to the current context
   749     taking into account their attributes.  Label and attrs are optional
   750     modifiers, like in theorem declarations.  If present, names of
   751     instantiated theorems are qualified with <label>, and the attributes
   752     <attrs> are applied after any attributes these theorems might have already.
   753       If the locale has assumptions, a chained fact of the form
   754     "<loc> t1 ... tn" is expected from which instantiations of the parameters
   755     are derived.  The command does not support old-style locales declared
   756     with "locale (open)".
   757       A few (very simple) examples can be found in FOL/ex/LocaleInst.thy.
   758 
   759 * HOL: Tactic emulation methods induct_tac and case_tac understand static
   760   (Isar) contexts.
   761 
   762 
   763 *** HOL ***
   764 
   765 * Proof import: new image HOL4 contains the imported library from
   766   the HOL4 system with about 2500 theorems. It is imported by
   767   replaying proof terms produced by HOL4 in Isabelle. The HOL4 image
   768   can be used like any other Isabelle image.  See
   769   HOL/Import/HOL/README for more information.
   770 
   771 * Simplifier:
   772   - Much improved handling of linear and partial orders.
   773     Reasoners for linear and partial orders are set up for type classes
   774     "linorder" and "order" respectively, and are added to the default simpset
   775     as solvers.  This means that the simplifier can build transitivity chains
   776     to solve goals from the assumptions.
   777   - INCOMPATIBILITY: old proofs break occasionally.  Typically, applications
   778     of blast or auto after simplification become unnecessary because the goal
   779     is solved by simplification already.
   780 
   781 * Numerics: new theory Ring_and_Field contains over 250 basic numerical laws,
   782     all proved in axiomatic type classes for semirings, rings and fields.
   783 
   784 * Numerics:
   785   - Numeric types (nat, int, and in HOL-Complex rat, real, complex, etc.) are
   786     now formalized using the Ring_and_Field theory mentioned above.
   787   - INCOMPATIBILITY: simplification and arithmetic behaves somewhat differently
   788     than before, because now they are set up once in a generic manner.
   789   - INCOMPATIBILITY: many type-specific arithmetic laws have gone.
   790     Look for the general versions in Ring_and_Field (and Power if they concern
   791     exponentiation).
   792 
   793 * Type "rat" of the rational numbers is now available in HOL-Complex.
   794 
   795 * Records:
   796   - Record types are now by default printed with their type abbreviation
   797     instead of the list of all field types. This can be configured via
   798     the reference "print_record_type_abbr".
   799   - Simproc "record_upd_simproc" for simplification of multiple updates added
   800     (not enabled by default).
   801   - Simproc "record_ex_sel_eq_simproc" to simplify EX x. sel r = x resp.
   802     EX x. x = sel r to True (not enabled by default).
   803   - Tactic "record_split_simp_tac" to split and simplify records added.
   804 
   805 * 'specification' command added, allowing for definition by
   806   specification.  There is also an 'ax_specification' command that
   807   introduces the new constants axiomatically.
   808 
   809 * arith(_tac) is now able to generate counterexamples for reals as well.
   810 
   811 * HOL-Algebra: new locale "ring" for non-commutative rings.
   812 
   813 * HOL-ex: InductiveInvariant_examples illustrates advanced recursive function
   814   definitions, thanks to Sava Krsti\'{c} and John Matthews.
   815 
   816 * HOL-Matrix: a first theory for matrices in HOL with an application of
   817   matrix theory to linear programming.
   818 
   819 * Unions and Intersections:
   820   The latex output syntax of UN and INT has been changed
   821   from "\Union x \in A. B" to "\Union_{x \in A} B"
   822   i.e. the index formulae has become a subscript.
   823   Similarly for "\Union x. B", and for \Inter instead of \Union.
   824 
   825 * Unions and Intersections over Intervals:
   826   There is new short syntax "UN i<=n. A" for "UN i:{0..n}. A". There is
   827   also an x-symbol version with subscripts "\<Union>\<^bsub>i <= n\<^esub>. A"
   828   like in normal math, and corresponding versions for < and for intersection.
   829 
   830 * HOL/List: Ordering "lexico" is renamed "lenlex" and the standard
   831   lexicographic dictonary ordering has been added as "lexord".
   832 
   833 * ML: the legacy theory structures Int and List have been removed. They had
   834   conflicted with ML Basis Library structures having the same names.
   835 
   836 * 'refute' command added to search for (finite) countermodels.  Only works
   837   for a fragment of HOL.  The installation of an external SAT solver is
   838   highly recommended.  See "HOL/Refute.thy" for details.
   839 
   840 * 'quickcheck' command: Allows to find counterexamples by evaluating
   841   formulae under an assignment of free variables to random values.
   842   In contrast to 'refute', it can deal with inductive datatypes,
   843   but cannot handle quantifiers. See "HOL/ex/Quickcheck_Examples.thy"
   844   for examples.
   845 
   846 
   847 *** HOLCF ***
   848 
   849 * Streams now come with concatenation and are part of the HOLCF image
   850 
   851 
   852 
   853 New in Isabelle2003 (May 2003)
   854 ------------------------------
   855 
   856 *** General ***
   857 
   858 * Provers/simplifier:
   859 
   860   - Completely reimplemented method simp (ML: Asm_full_simp_tac):
   861     Assumptions are now subject to complete mutual simplification,
   862     not just from left to right. The simplifier now preserves
   863     the order of assumptions.
   864 
   865     Potential INCOMPATIBILITY:
   866 
   867     -- simp sometimes diverges where the old version did
   868        not, e.g. invoking simp on the goal
   869 
   870         [| P (f x); y = x; f x = f y |] ==> Q
   871 
   872        now gives rise to the infinite reduction sequence
   873 
   874         P(f x) --(f x = f y)--> P(f y) --(y = x)--> P(f x) --(f x = f y)--> ...
   875 
   876        Using "simp (asm_lr)" (ML: Asm_lr_simp_tac) instead often solves this
   877        kind of problem.
   878 
   879     -- Tactics combining classical reasoner and simplification (such as auto)
   880        are also affected by this change, because many of them rely on
   881        simp. They may sometimes diverge as well or yield a different numbers
   882        of subgoals. Try to use e.g. force, fastsimp, or safe instead of auto
   883        in case of problems. Sometimes subsequent calls to the classical
   884        reasoner will fail because a preceeding call to the simplifier too
   885        eagerly simplified the goal, e.g. deleted redundant premises.
   886 
   887   - The simplifier trace now shows the names of the applied rewrite rules
   888 
   889   - You can limit the number of recursive invocations of the simplifier
   890     during conditional rewriting (where the simplifie tries to solve the
   891     conditions before applying the rewrite rule):
   892     ML "simp_depth_limit := n"
   893     where n is an integer. Thus you can force termination where previously
   894     the simplifier would diverge.
   895 
   896   - Accepts free variables as head terms in congruence rules.  Useful in Isar.
   897 
   898   - No longer aborts on failed congruence proof.  Instead, the
   899     congruence is ignored.
   900 
   901 * Pure: New generic framework for extracting programs from constructive
   902   proofs. See HOL/Extraction.thy for an example instantiation, as well
   903   as HOL/Extraction for some case studies.
   904 
   905 * Pure: The main goal of the proof state is no longer shown by default, only
   906 the subgoals. This behaviour is controlled by a new flag.
   907    PG menu: Isabelle/Isar -> Settings -> Show Main Goal
   908 (ML: Proof.show_main_goal).
   909 
   910 * Pure: You can find all matching introduction rules for subgoal 1, i.e. all
   911 rules whose conclusion matches subgoal 1:
   912       PG menu: Isabelle/Isar -> Show me -> matching rules
   913 The rules are ordered by how closely they match the subgoal.
   914 In particular, rules that solve a subgoal outright are displayed first
   915 (or rather last, the way they are printed).
   916 (ML: ProofGeneral.print_intros())
   917 
   918 * Pure: New flag trace_unify_fail causes unification to print
   919 diagnostic information (PG: in trace buffer) when it fails. This is
   920 useful for figuring out why single step proofs like rule, erule or
   921 assumption failed.
   922 
   923 * Pure: Locale specifications now produce predicate definitions
   924 according to the body of text (covering assumptions modulo local
   925 definitions); predicate "loc_axioms" covers newly introduced text,
   926 while "loc" is cumulative wrt. all included locale expressions; the
   927 latter view is presented only on export into the global theory
   928 context; potential INCOMPATIBILITY, use "(open)" option to fall back
   929 on the old view without predicates;
   930 
   931 * Pure: predefined locales "var" and "struct" are useful for sharing
   932 parameters (as in CASL, for example); just specify something like
   933 ``var x + var y + struct M'' as import;
   934 
   935 * Pure: improved thms_containing: proper indexing of facts instead of
   936 raw theorems; check validity of results wrt. current name space;
   937 include local facts of proof configuration (also covers active
   938 locales), cover fixed variables in index; may use "_" in term
   939 specification; an optional limit for the number of printed facts may
   940 be given (the default is 40);
   941 
   942 * Pure: disallow duplicate fact bindings within new-style theory files
   943 (batch-mode only);
   944 
   945 * Provers: improved induct method: assumptions introduced by case
   946 "foo" are split into "foo.hyps" (from the rule) and "foo.prems" (from
   947 the goal statement); "foo" still refers to all facts collectively;
   948 
   949 * Provers: the function blast.overloaded has been removed: all constants
   950 are regarded as potentially overloaded, which improves robustness in exchange
   951 for slight decrease in efficiency;
   952 
   953 * Provers/linorder: New generic prover for transitivity reasoning over
   954 linear orders.  Note: this prover is not efficient!
   955 
   956 * Isar: preview of problems to finish 'show' now produce an error
   957 rather than just a warning (in interactive mode);
   958 
   959 
   960 *** HOL ***
   961 
   962 * arith(_tac)
   963 
   964  - Produces a counter example if it cannot prove a goal.
   965    Note that the counter example may be spurious if the goal is not a formula
   966    of quantifier-free linear arithmetic.
   967    In ProofGeneral the counter example appears in the trace buffer.
   968 
   969  - Knows about div k and mod k where k is a numeral of type nat or int.
   970 
   971  - Calls full Presburger arithmetic (by Amine Chaieb) if quantifier-free
   972    linear arithmetic fails. This takes account of quantifiers and divisibility.
   973    Presburger arithmetic can also be called explicitly via presburger(_tac).
   974 
   975 * simp's arithmetic capabilities have been enhanced a bit: it now
   976 takes ~= in premises into account (by performing a case split);
   977 
   978 * simp reduces "m*(n div m) + n mod m" to n, even if the two summands
   979 are distributed over a sum of terms;
   980 
   981 * New tactic "trans_tac" and method "trans" instantiate
   982 Provers/linorder.ML for axclasses "order" and "linorder" (predicates
   983 "<=", "<" and "=").
   984 
   985 * function INCOMPATIBILITIES: Pi-sets have been redefined and moved from main
   986 HOL to Library/FuncSet; constant "Fun.op o" is now called "Fun.comp";
   987 
   988 * 'typedef' command has new option "open" to suppress the set
   989 definition;
   990 
   991 * functions Min and Max on finite sets have been introduced (theory
   992 Finite_Set);
   993 
   994 * attribute [symmetric] now works for relations as well; it turns
   995 (x,y) : R^-1 into (y,x) : R, and vice versa;
   996 
   997 * induct over a !!-quantified statement (say !!x1..xn):
   998   each "case" automatically performs "fix x1 .. xn" with exactly those names.
   999 
  1000 * Map: `empty' is no longer a constant but a syntactic abbreviation for
  1001 %x. None. Warning: empty_def now refers to the previously hidden definition
  1002 of the empty set.
  1003 
  1004 * Algebra: formalization of classical algebra.  Intended as base for
  1005 any algebraic development in Isabelle.  Currently covers group theory
  1006 (up to Sylow's theorem) and ring theory (Universal Property of
  1007 Univariate Polynomials).  Contributions welcome;
  1008 
  1009 * GroupTheory: deleted, since its material has been moved to Algebra;
  1010 
  1011 * Complex: new directory of the complex numbers with numeric constants,
  1012 nonstandard complex numbers, and some complex analysis, standard and
  1013 nonstandard (Jacques Fleuriot);
  1014 
  1015 * HOL-Complex: new image for analysis, replacing HOL-Real and HOL-Hyperreal;
  1016 
  1017 * Hyperreal: introduced Gauge integration and hyperreal logarithms (Jacques
  1018 Fleuriot);
  1019 
  1020 * Real/HahnBanach: updated and adapted to locales;
  1021 
  1022 * NumberTheory: added Gauss's law of quadratic reciprocity (by Avigad,
  1023 Gray and Kramer);
  1024 
  1025 * UNITY: added the Meier-Sanders theory of progress sets;
  1026 
  1027 * MicroJava: bytecode verifier and lightweight bytecode verifier
  1028 as abstract algorithms, instantiated to the JVM;
  1029 
  1030 * Bali: Java source language formalization. Type system, operational
  1031 semantics, axiomatic semantics. Supported language features:
  1032 classes, interfaces, objects,virtual methods, static methods,
  1033 static/instance fields, arrays, access modifiers, definite
  1034 assignment, exceptions.
  1035 
  1036 
  1037 *** ZF ***
  1038 
  1039 * ZF/Constructible: consistency proof for AC (Gdel's constructible
  1040 universe, etc.);
  1041 
  1042 * Main ZF: virtually all theories converted to new-style format;
  1043 
  1044 
  1045 *** ML ***
  1046 
  1047 * Pure: Tactic.prove provides sane interface for internal proofs;
  1048 omits the infamous "standard" operation, so this is more appropriate
  1049 than prove_goalw_cterm in many situations (e.g. in simprocs);
  1050 
  1051 * Pure: improved error reporting of simprocs;
  1052 
  1053 * Provers: Simplifier.simproc(_i) provides sane interface for setting
  1054 up simprocs;
  1055 
  1056 
  1057 *** Document preparation ***
  1058 
  1059 * uses \par instead of \\ for line breaks in theory text. This may
  1060 shift some page breaks in large documents. To get the old behaviour
  1061 use \renewcommand{\isanewline}{\mbox{}\\\mbox{}} in root.tex.
  1062 
  1063 * minimized dependencies of isabelle.sty and isabellesym.sty on
  1064 other packages
  1065 
  1066 * \<euro> now needs package babel/greek instead of marvosym (which
  1067 broke \Rightarrow)
  1068 
  1069 * normal size for \<zero>...\<nine> (uses \mathbf instead of
  1070 textcomp package)
  1071 
  1072 
  1073 
  1074 New in Isabelle2002 (March 2002)
  1075 --------------------------------
  1076 
  1077 *** Document preparation ***
  1078 
  1079 * greatly simplified document preparation setup, including more
  1080 graceful interpretation of isatool usedir -i/-d/-D options, and more
  1081 instructive isatool mkdir; users should basically be able to get
  1082 started with "isatool mkdir HOL Test && isatool make"; alternatively,
  1083 users may run a separate document processing stage manually like this:
  1084 "isatool usedir -D output HOL Test && isatool document Test/output";
  1085 
  1086 * theory dependency graph may now be incorporated into documents;
  1087 isatool usedir -g true will produce session_graph.eps/.pdf for use
  1088 with \includegraphics of LaTeX;
  1089 
  1090 * proper spacing of consecutive markup elements, especially text
  1091 blocks after section headings;
  1092 
  1093 * support bold style (for single symbols only), input syntax is like
  1094 this: "\<^bold>\<alpha>" or "\<^bold>A";
  1095 
  1096 * \<bullet> is now output as bold \cdot by default, which looks much
  1097 better in printed text;
  1098 
  1099 * added default LaTeX bindings for \<tturnstile> and \<TTurnstile>;
  1100 note that these symbols are currently unavailable in Proof General /
  1101 X-Symbol; new symbols \<zero>, \<one>, ..., \<nine>, and \<euro>;
  1102 
  1103 * isatool latex no longer depends on changed TEXINPUTS, instead
  1104 isatool document copies the Isabelle style files to the target
  1105 location;
  1106 
  1107 
  1108 *** Isar ***
  1109 
  1110 * Pure/Provers: improved proof by cases and induction;
  1111   - 'case' command admits impromptu naming of parameters (such as
  1112     "case (Suc n)");
  1113   - 'induct' method divinates rule instantiation from the inductive
  1114     claim; no longer requires excessive ?P bindings for proper
  1115     instantiation of cases;
  1116   - 'induct' method properly enumerates all possibilities of set/type
  1117     rules; as a consequence facts may be also passed through *type*
  1118     rules without further ado;
  1119   - 'induct' method now derives symbolic cases from the *rulified*
  1120     rule (before it used to rulify cases stemming from the internal
  1121     atomized version); this means that the context of a non-atomic
  1122     statement becomes is included in the hypothesis, avoiding the
  1123     slightly cumbersome show "PROP ?case" form;
  1124   - 'induct' may now use elim-style induction rules without chaining
  1125     facts, using ``missing'' premises from the goal state; this allows
  1126     rules stemming from inductive sets to be applied in unstructured
  1127     scripts, while still benefitting from proper handling of non-atomic
  1128     statements; NB: major inductive premises need to be put first, all
  1129     the rest of the goal is passed through the induction;
  1130   - 'induct' proper support for mutual induction involving non-atomic
  1131     rule statements (uses the new concept of simultaneous goals, see
  1132     below);
  1133   - append all possible rule selections, but only use the first
  1134     success (no backtracking);
  1135   - removed obsolete "(simplified)" and "(stripped)" options of methods;
  1136   - undeclared rule case names default to numbers 1, 2, 3, ...;
  1137   - added 'print_induct_rules' (covered by help item in recent Proof
  1138     General versions);
  1139   - moved induct/cases attributes to Pure, methods to Provers;
  1140   - generic method setup instantiated for FOL and HOL;
  1141 
  1142 * Pure: support multiple simultaneous goal statements, for example
  1143 "have a: A and b: B" (same for 'theorem' etc.); being a pure
  1144 meta-level mechanism, this acts as if several individual goals had
  1145 been stated separately; in particular common proof methods need to be
  1146 repeated in order to cover all claims; note that a single elimination
  1147 step is *not* sufficient to establish the two conjunctions, so this
  1148 fails:
  1149 
  1150   assume "A & B" then have A and B ..   (*".." fails*)
  1151 
  1152 better use "obtain" in situations as above; alternative refer to
  1153 multi-step methods like 'auto', 'simp_all', 'blast+' etc.;
  1154 
  1155 * Pure: proper integration with ``locales''; unlike the original
  1156 version by Florian Kammller, Isar locales package high-level proof
  1157 contexts rather than raw logical ones (e.g. we admit to include
  1158 attributes everywhere); operations on locales include merge and
  1159 rename; support for implicit arguments (``structures''); simultaneous
  1160 type-inference over imports and text; see also HOL/ex/Locales.thy for
  1161 some examples;
  1162 
  1163 * Pure: the following commands have been ``localized'', supporting a
  1164 target locale specification "(in name)": 'lemma', 'theorem',
  1165 'corollary', 'lemmas', 'theorems', 'declare'; the results will be
  1166 stored both within the locale and at the theory level (exported and
  1167 qualified by the locale name);
  1168 
  1169 * Pure: theory goals may now be specified in ``long'' form, with
  1170 ad-hoc contexts consisting of arbitrary locale elements. for example
  1171 ``lemma foo: fixes x assumes "A x" shows "B x"'' (local syntax and
  1172 definitions may be given, too); the result is a meta-level rule with
  1173 the context elements being discharged in the obvious way;
  1174 
  1175 * Pure: new proof command 'using' allows to augment currently used
  1176 facts after a goal statement ('using' is syntactically analogous to
  1177 'apply', but acts on the goal's facts only); this allows chained facts
  1178 to be separated into parts given before and after a claim, as in
  1179 ``from a and b have C using d and e <proof>'';
  1180 
  1181 * Pure: renamed "antecedent" case to "rule_context";
  1182 
  1183 * Pure: new 'judgment' command records explicit information about the
  1184 object-logic embedding (used by several tools internally); no longer
  1185 use hard-wired "Trueprop";
  1186 
  1187 * Pure: added 'corollary' command;
  1188 
  1189 * Pure: fixed 'token_translation' command;
  1190 
  1191 * Pure: removed obsolete 'exported' attribute;
  1192 
  1193 * Pure: dummy pattern "_" in is/let is now automatically lifted over
  1194 bound variables: "ALL x. P x --> Q x" (is "ALL x. _ --> ?C x")
  1195 supersedes more cumbersome ... (is "ALL x. _ x --> ?C x");
  1196 
  1197 * Pure: method 'atomize' presents local goal premises as object-level
  1198 statements (atomic meta-level propositions); setup controlled via
  1199 rewrite rules declarations of 'atomize' attribute; example
  1200 application: 'induct' method with proper rule statements in improper
  1201 proof *scripts*;
  1202 
  1203 * Pure: emulation of instantiation tactics (rule_tac, cut_tac, etc.)
  1204 now consider the syntactic context of assumptions, giving a better
  1205 chance to get type-inference of the arguments right (this is
  1206 especially important for locales);
  1207 
  1208 * Pure: "sorry" no longer requires quick_and_dirty in interactive
  1209 mode;
  1210 
  1211 * Pure/obtain: the formal conclusion "thesis", being marked as
  1212 ``internal'', may no longer be reference directly in the text;
  1213 potential INCOMPATIBILITY, may need to use "?thesis" in rare
  1214 situations;
  1215 
  1216 * Pure: generic 'sym' attribute which declares a rule both as pure
  1217 'elim?' and for the 'symmetric' operation;
  1218 
  1219 * Pure: marginal comments ``--'' may now occur just anywhere in the
  1220 text; the fixed correlation with particular command syntax has been
  1221 discontinued;
  1222 
  1223 * Pure: new method 'rules' is particularly well-suited for proof
  1224 search in intuitionistic logic; a bit slower than 'blast' or 'fast',
  1225 but often produces more compact proof terms with less detours;
  1226 
  1227 * Pure/Provers/classical: simplified integration with pure rule
  1228 attributes and methods; the classical "intro?/elim?/dest?"
  1229 declarations coincide with the pure ones; the "rule" method no longer
  1230 includes classically swapped intros; "intro" and "elim" methods no
  1231 longer pick rules from the context; also got rid of ML declarations
  1232 AddXIs/AddXEs/AddXDs; all of this has some potential for
  1233 INCOMPATIBILITY;
  1234 
  1235 * Provers/classical: attribute 'swapped' produces classical inversions
  1236 of introduction rules;
  1237 
  1238 * Provers/simplifier: 'simplified' attribute may refer to explicit
  1239 rules instead of full simplifier context; 'iff' attribute handles
  1240 conditional rules;
  1241 
  1242 * HOL: 'typedef' now allows alternative names for Rep/Abs morphisms;
  1243 
  1244 * HOL: 'recdef' now fails on unfinished automated proofs, use
  1245 "(permissive)" option to recover old behavior;
  1246 
  1247 * HOL: 'inductive' no longer features separate (collective) attributes
  1248 for 'intros' (was found too confusing);
  1249 
  1250 * HOL: properly declared induction rules less_induct and
  1251 wf_induct_rule;
  1252 
  1253 
  1254 *** HOL ***
  1255 
  1256 * HOL: moved over to sane numeral syntax; the new policy is as
  1257 follows:
  1258 
  1259   - 0 and 1 are polymorphic constants, which are defined on any
  1260   numeric type (nat, int, real etc.);
  1261 
  1262   - 2, 3, 4, ... and -1, -2, -3, ... are polymorphic numerals, based
  1263   binary representation internally;
  1264 
  1265   - type nat has special constructor Suc, and generally prefers Suc 0
  1266   over 1::nat and Suc (Suc 0) over 2::nat;
  1267 
  1268 This change may cause significant problems of INCOMPATIBILITY; here
  1269 are some hints on converting existing sources:
  1270 
  1271   - due to the new "num" token, "-0" and "-1" etc. are now atomic
  1272   entities, so expressions involving "-" (unary or binary minus) need
  1273   to be spaced properly;
  1274 
  1275   - existing occurrences of "1" may need to be constraint "1::nat" or
  1276   even replaced by Suc 0; similar for old "2";
  1277 
  1278   - replace "#nnn" by "nnn", and "#-nnn" by "-nnn";
  1279 
  1280   - remove all special provisions on numerals in proofs;
  1281 
  1282 * HOL: simp rules nat_number expand numerals on nat to Suc/0
  1283 representation (depends on bin_arith_simps in the default context);
  1284 
  1285 * HOL: symbolic syntax for x^2 (numeral 2);
  1286 
  1287 * HOL: the class of all HOL types is now called "type" rather than
  1288 "term"; INCOMPATIBILITY, need to adapt references to this type class
  1289 in axclass/classes, instance/arities, and (usually rare) occurrences
  1290 in typings (of consts etc.); internally the class is called
  1291 "HOL.type", ML programs should refer to HOLogic.typeS;
  1292 
  1293 * HOL/record package improvements:
  1294   - new derived operations "fields" to build a partial record section,
  1295     "extend" to promote a fixed record to a record scheme, and
  1296     "truncate" for the reverse; cf. theorems "xxx.defs", which are *not*
  1297     declared as simp by default;
  1298   - shared operations ("more", "fields", etc.) now need to be always
  1299     qualified) --- potential INCOMPATIBILITY;
  1300   - removed "make_scheme" operations (use "make" with "extend") --
  1301     INCOMPATIBILITY;
  1302   - removed "more" class (simply use "term") -- INCOMPATIBILITY;
  1303   - provides cases/induct rules for use with corresponding Isar
  1304     methods (for concrete records, record schemes, concrete more
  1305     parts, and schematic more parts -- in that order);
  1306   - internal definitions directly based on a light-weight abstract
  1307     theory of product types over typedef rather than datatype;
  1308 
  1309 * HOL: generic code generator for generating executable ML code from
  1310 specifications; specific support for HOL constructs such as inductive
  1311 datatypes and sets, as well as recursive functions; can be invoked
  1312 via 'generate_code' theory section;
  1313 
  1314 * HOL: canonical cases/induct rules for n-tuples (n = 3..7);
  1315 
  1316 * HOL: consolidated and renamed several theories.  In particular:
  1317         Ord.thy has been absorbed into HOL.thy
  1318         String.thy has been absorbed into List.thy
  1319 
  1320 * HOL: concrete setsum syntax "\<Sum>i:A. b" == "setsum (%i. b) A"
  1321 (beware of argument permutation!);
  1322 
  1323 * HOL: linorder_less_split superseded by linorder_cases;
  1324 
  1325 * HOL/List: "nodups" renamed to "distinct";
  1326 
  1327 * HOL: added "The" definite description operator; move Hilbert's "Eps"
  1328 to peripheral theory "Hilbert_Choice"; some INCOMPATIBILITIES:
  1329   - Ex_def has changed, now need to use some_eq_ex
  1330 
  1331 * HOL: made split_all_tac safe; EXISTING PROOFS MAY FAIL OR LOOP, so
  1332 in this (rare) case use:
  1333 
  1334   delSWrapper "split_all_tac"
  1335   addSbefore ("unsafe_split_all_tac", unsafe_split_all_tac)
  1336 
  1337 * HOL: added safe wrapper "split_conv_tac" to claset; EXISTING PROOFS
  1338 MAY FAIL;
  1339 
  1340 * HOL: introduced f^n = f o ... o f; warning: due to the limits of
  1341 Isabelle's type classes, ^ on functions and relations has too general
  1342 a domain, namely ('a * 'b) set and 'a => 'b; this means that it may be
  1343 necessary to attach explicit type constraints;
  1344 
  1345 * HOL/Relation: the prefix name of the infix "O" has been changed from
  1346 "comp" to "rel_comp"; INCOMPATIBILITY: a few theorems have been
  1347 renamed accordingly (eg "compI" -> "rel_compI").
  1348 
  1349 * HOL: syntax translations now work properly with numerals and records
  1350 expressions;
  1351 
  1352 * HOL: bounded abstraction now uses syntax "%" / "\<lambda>" instead
  1353 of "lam" -- INCOMPATIBILITY;
  1354 
  1355 * HOL: got rid of some global declarations (potential INCOMPATIBILITY
  1356 for ML tools): const "()" renamed "Product_Type.Unity", type "unit"
  1357 renamed "Product_Type.unit";
  1358 
  1359 * HOL: renamed rtrancl_into_rtrancl2 to converse_rtrancl_into_rtrancl
  1360 
  1361 * HOL: removed obsolete theorem "optionE" (use "option.exhaust", or
  1362 the "cases" method);
  1363 
  1364 * HOL/GroupTheory: group theory examples including Sylow's theorem (by
  1365 Florian Kammller);
  1366 
  1367 * HOL/IMP: updated and converted to new-style theory format; several
  1368 parts turned into readable document, with proper Isar proof texts and
  1369 some explanations (by Gerwin Klein);
  1370 
  1371 * HOL-Real: added Complex_Numbers (by Gertrud Bauer);
  1372 
  1373 * HOL-Hyperreal is now a logic image;
  1374 
  1375 
  1376 *** HOLCF ***
  1377 
  1378 * Isar: consts/constdefs supports mixfix syntax for continuous
  1379 operations;
  1380 
  1381 * Isar: domain package adapted to new-style theory format, e.g. see
  1382 HOLCF/ex/Dnat.thy;
  1383 
  1384 * theory Lift: proper use of rep_datatype lift instead of ML hacks --
  1385 potential INCOMPATIBILITY; now use plain induct_tac instead of former
  1386 lift.induct_tac, always use UU instead of Undef;
  1387 
  1388 * HOLCF/IMP: updated and converted to new-style theory;
  1389 
  1390 
  1391 *** ZF ***
  1392 
  1393 * Isar: proper integration of logic-specific tools and packages,
  1394 including theory commands '(co)inductive', '(co)datatype',
  1395 'rep_datatype', 'inductive_cases', as well as methods 'ind_cases',
  1396 'induct_tac', 'case_tac', and 'typecheck' (with attribute 'TC');
  1397 
  1398 * theory Main no longer includes AC; for the Axiom of Choice, base
  1399 your theory on Main_ZFC;
  1400 
  1401 * the integer library now covers quotients and remainders, with many
  1402 laws relating division to addition, multiplication, etc.;
  1403 
  1404 * ZF/UNITY: Chandy and Misra's UNITY is now available in ZF, giving a
  1405 typeless version of the formalism;
  1406 
  1407 * ZF/AC, Coind, IMP, Resid: updated and converted to new-style theory
  1408 format;
  1409 
  1410 * ZF/Induct: new directory for examples of inductive definitions,
  1411 including theory Multiset for multiset orderings; converted to
  1412 new-style theory format;
  1413 
  1414 * ZF: many new theorems about lists, ordinals, etc.;
  1415 
  1416 
  1417 *** General ***
  1418 
  1419 * Pure/kernel: meta-level proof terms (by Stefan Berghofer); reference
  1420 variable proof controls level of detail: 0 = no proofs (only oracle
  1421 dependencies), 1 = lemma dependencies, 2 = compact proof terms; see
  1422 also ref manual for further ML interfaces;
  1423 
  1424 * Pure/axclass: removed obsolete ML interface
  1425 goal_subclass/goal_arity;
  1426 
  1427 * Pure/syntax: new token syntax "num" for plain numerals (without "#"
  1428 of "xnum"); potential INCOMPATIBILITY, since -0, -1 etc. are now
  1429 separate tokens, so expressions involving minus need to be spaced
  1430 properly;
  1431 
  1432 * Pure/syntax: support non-oriented infixes, using keyword "infix"
  1433 rather than "infixl" or "infixr";
  1434 
  1435 * Pure/syntax: concrete syntax for dummy type variables admits genuine
  1436 sort constraint specifications in type inference; e.g. "x::_::foo"
  1437 ensures that the type of "x" is of sort "foo" (but not necessarily a
  1438 type variable);
  1439 
  1440 * Pure/syntax: print modes "type_brackets" and "no_type_brackets"
  1441 control output of nested => (types); the default behavior is
  1442 "type_brackets";
  1443 
  1444 * Pure/syntax: builtin parse translation for "_constify" turns valued
  1445 tokens into AST constants;
  1446 
  1447 * Pure/syntax: prefer later declarations of translations and print
  1448 translation functions; potential INCOMPATIBILITY: need to reverse
  1449 multiple declarations for same syntax element constant;
  1450 
  1451 * Pure/show_hyps reset by default (in accordance to existing Isar
  1452 practice);
  1453 
  1454 * Provers/classical: renamed addaltern to addafter, addSaltern to
  1455 addSafter;
  1456 
  1457 * Provers/clasimp: ``iff'' declarations now handle conditional rules
  1458 as well;
  1459 
  1460 * system: tested support for MacOS X; should be able to get Isabelle +
  1461 Proof General to work in a plain Terminal after installing Poly/ML
  1462 (e.g. from the Isabelle distribution area) and GNU bash alone
  1463 (e.g. from http://www.apple.com); full X11, XEmacs and X-Symbol
  1464 support requires further installations, e.g. from
  1465 http://fink.sourceforge.net/);
  1466 
  1467 * system: support Poly/ML 4.1.1 (able to manage larger heaps);
  1468 
  1469 * system: reduced base memory usage by Poly/ML (approx. 20 MB instead
  1470 of 40 MB), cf. ML_OPTIONS;
  1471 
  1472 * system: Proof General keywords specification is now part of the
  1473 Isabelle distribution (see etc/isar-keywords.el);
  1474 
  1475 * system: support for persistent Proof General sessions (refrain from
  1476 outdating all loaded theories on startup); user may create writable
  1477 logic images like this: ``isabelle -q HOL Test'';
  1478 
  1479 * system: smart selection of Isabelle process versus Isabelle
  1480 interface, accommodates case-insensitive file systems (e.g. HFS+); may
  1481 run both "isabelle" and "Isabelle" even if file names are badly
  1482 damaged (executable inspects the case of the first letter of its own
  1483 name); added separate "isabelle-process" and "isabelle-interface";
  1484 
  1485 * system: refrain from any attempt at filtering input streams; no
  1486 longer support ``8bit'' encoding of old isabelle font, instead proper
  1487 iso-latin characters may now be used; the related isatools
  1488 "symbolinput" and "nonascii" have disappeared as well;
  1489 
  1490 * system: removed old "xterm" interface (the print modes "xterm" and
  1491 "xterm_color" are still available for direct use in a suitable
  1492 terminal);
  1493 
  1494 
  1495 
  1496 New in Isabelle99-2 (February 2001)
  1497 -----------------------------------
  1498 
  1499 *** Overview of INCOMPATIBILITIES ***
  1500 
  1501 * HOL: please note that theories in the Library and elsewhere often use the
  1502 new-style (Isar) format; to refer to their theorems in an ML script you must
  1503 bind them to ML identifers by e.g.      val thm_name = thm "thm_name";
  1504 
  1505 * HOL: inductive package no longer splits induction rule aggressively,
  1506 but only as far as specified by the introductions given; the old
  1507 format may be recovered via ML function complete_split_rule or attribute
  1508 'split_rule (complete)';
  1509 
  1510 * HOL: induct renamed to lfp_induct, lfp_Tarski to lfp_unfold,
  1511 gfp_Tarski to gfp_unfold;
  1512 
  1513 * HOL: contrapos, contrapos2 renamed to contrapos_nn, contrapos_pp;
  1514 
  1515 * HOL: infix "dvd" now has priority 50 rather than 70 (because it is a
  1516 relation); infix "^^" has been renamed "``"; infix "``" has been
  1517 renamed "`"; "univalent" has been renamed "single_valued";
  1518 
  1519 * HOL/Real: "rinv" and "hrinv" replaced by overloaded "inverse"
  1520 operation;
  1521 
  1522 * HOLCF: infix "`" has been renamed "$"; the symbol syntax is \<cdot>;
  1523 
  1524 * Isar: 'obtain' no longer declares "that" fact as simp/intro;
  1525 
  1526 * Isar/HOL: method 'induct' now handles non-atomic goals; as a
  1527 consequence, it is no longer monotonic wrt. the local goal context
  1528 (which is now passed through the inductive cases);
  1529 
  1530 * Document preparation: renamed standard symbols \<ll> to \<lless> and
  1531 \<gg> to \<ggreater>;
  1532 
  1533 
  1534 *** Document preparation ***
  1535 
  1536 * \isabellestyle{NAME} selects version of Isabelle output (currently
  1537 available: are "it" for near math-mode best-style output, "sl" for
  1538 slanted text style, and "tt" for plain type-writer; if no
  1539 \isabellestyle command is given, output is according to slanted
  1540 type-writer);
  1541 
  1542 * support sub/super scripts (for single symbols only), input syntax is
  1543 like this: "A\<^sup>*" or "A\<^sup>\<star>";
  1544 
  1545 * some more standard symbols; see Appendix A of the system manual for
  1546 the complete list of symbols defined in isabellesym.sty;
  1547 
  1548 * improved isabelle style files; more abstract symbol implementation
  1549 (should now use \isamath{...} and \isatext{...} in custom symbol
  1550 definitions);
  1551 
  1552 * antiquotation @{goals} and @{subgoals} for output of *dynamic* goals
  1553 state; Note that presentation of goal states does not conform to
  1554 actual human-readable proof documents.  Please do not include goal
  1555 states into document output unless you really know what you are doing!
  1556 
  1557 * proper indentation of antiquoted output with proportional LaTeX
  1558 fonts;
  1559 
  1560 * no_document ML operator temporarily disables LaTeX document
  1561 generation;
  1562 
  1563 * isatool unsymbolize tunes sources for plain ASCII communication;
  1564 
  1565 
  1566 *** Isar ***
  1567 
  1568 * Pure: Isar now suffers initial goal statements to contain unbound
  1569 schematic variables (this does not conform to actual readable proof
  1570 documents, due to unpredictable outcome and non-compositional proof
  1571 checking); users who know what they are doing may use schematic goals
  1572 for Prolog-style synthesis of proven results;
  1573 
  1574 * Pure: assumption method (an implicit finishing) now handles actual
  1575 rules as well;
  1576 
  1577 * Pure: improved 'obtain' --- moved to Pure, insert "that" into
  1578 initial goal, declare "that" only as Pure intro (only for single
  1579 steps); the "that" rule assumption may now be involved in implicit
  1580 finishing, thus ".." becomes a feasible for trivial obtains;
  1581 
  1582 * Pure: default proof step now includes 'intro_classes'; thus trivial
  1583 instance proofs may be performed by "..";
  1584 
  1585 * Pure: ?thesis / ?this / "..." now work for pure meta-level
  1586 statements as well;
  1587 
  1588 * Pure: more robust selection of calculational rules;
  1589 
  1590 * Pure: the builtin notion of 'finished' goal now includes the ==-refl
  1591 rule (as well as the assumption rule);
  1592 
  1593 * Pure: 'thm_deps' command visualizes dependencies of theorems and
  1594 lemmas, using the graph browser tool;
  1595 
  1596 * Pure: predict failure of "show" in interactive mode;
  1597 
  1598 * Pure: 'thms_containing' now takes actual terms as arguments;
  1599 
  1600 * HOL: improved method 'induct' --- now handles non-atomic goals
  1601 (potential INCOMPATIBILITY); tuned error handling;
  1602 
  1603 * HOL: cases and induct rules now provide explicit hints about the
  1604 number of facts to be consumed (0 for "type" and 1 for "set" rules);
  1605 any remaining facts are inserted into the goal verbatim;
  1606 
  1607 * HOL: local contexts (aka cases) may now contain term bindings as
  1608 well; the 'cases' and 'induct' methods new provide a ?case binding for
  1609 the result to be shown in each case;
  1610 
  1611 * HOL: added 'recdef_tc' command;
  1612 
  1613 * isatool convert assists in eliminating legacy ML scripts;
  1614 
  1615 
  1616 *** HOL ***
  1617 
  1618 * HOL/Library: a collection of generic theories to be used together
  1619 with main HOL; the theory loader path already includes this directory
  1620 by default; the following existing theories have been moved here:
  1621 HOL/Induct/Multiset, HOL/Induct/Acc (as Accessible_Part), HOL/While
  1622 (as While_Combinator), HOL/Lex/Prefix (as List_Prefix);
  1623 
  1624 * HOL/Unix: "Some aspects of Unix file-system security", a typical
  1625 modelling and verification task performed in Isabelle/HOL +
  1626 Isabelle/Isar + Isabelle document preparation (by Markus Wenzel).
  1627 
  1628 * HOL/Algebra: special summation operator SUM no longer exists, it has
  1629 been replaced by setsum; infix 'assoc' now has priority 50 (like
  1630 'dvd'); axiom 'one_not_zero' has been moved from axclass 'ring' to
  1631 'domain', this makes the theory consistent with mathematical
  1632 literature;
  1633 
  1634 * HOL basics: added overloaded operations "inverse" and "divide"
  1635 (infix "/"), syntax for generic "abs" operation, generic summation
  1636 operator \<Sum>;
  1637 
  1638 * HOL/typedef: simplified package, provide more useful rules (see also
  1639 HOL/subset.thy);
  1640 
  1641 * HOL/datatype: induction rule for arbitrarily branching datatypes is
  1642 now expressed as a proper nested rule (old-style tactic scripts may
  1643 require atomize_strip_tac to cope with non-atomic premises);
  1644 
  1645 * HOL: renamed theory "Prod" to "Product_Type", renamed "split" rule
  1646 to "split_conv" (old name still available for compatibility);
  1647 
  1648 * HOL: improved concrete syntax for strings (e.g. allows translation
  1649 rules with string literals);
  1650 
  1651 * HOL-Real-Hyperreal: this extends HOL-Real with the hyperreals
  1652  and Fleuriot's mechanization of analysis, including the transcendental
  1653  functions for the reals;
  1654 
  1655 * HOL/Real, HOL/Hyperreal: improved arithmetic simplification;
  1656 
  1657 
  1658 *** CTT ***
  1659 
  1660 * CTT: x-symbol support for Pi, Sigma, -->, : (membership); note that
  1661 "lam" is displayed as TWO lambda-symbols
  1662 
  1663 * CTT: theory Main now available, containing everything (that is, Bool
  1664 and Arith);
  1665 
  1666 
  1667 *** General ***
  1668 
  1669 * Pure: the Simplifier has been implemented properly as a derived rule
  1670 outside of the actual kernel (at last!); the overall performance
  1671 penalty in practical applications is about 50%, while reliability of
  1672 the Isabelle inference kernel has been greatly improved;
  1673 
  1674 * print modes "brackets" and "no_brackets" control output of nested =>
  1675 (types) and ==> (props); the default behaviour is "brackets";
  1676 
  1677 * Provers: fast_tac (and friends) now handle actual object-logic rules
  1678 as assumptions as well;
  1679 
  1680 * system: support Poly/ML 4.0;
  1681 
  1682 * system: isatool install handles KDE version 1 or 2;
  1683 
  1684 
  1685 
  1686 New in Isabelle99-1 (October 2000)
  1687 ----------------------------------
  1688 
  1689 *** Overview of INCOMPATIBILITIES ***
  1690 
  1691 * HOL: simplification of natural numbers is much changed; to partly
  1692 recover the old behaviour (e.g. to prevent n+n rewriting to #2*n)
  1693 issue the following ML commands:
  1694 
  1695   Delsimprocs Nat_Numeral_Simprocs.cancel_numerals;
  1696   Delsimprocs [Nat_Numeral_Simprocs.combine_numerals];
  1697 
  1698 * HOL: simplification no longer dives into case-expressions; this is
  1699 controlled by "t.weak_case_cong" for each datatype t;
  1700 
  1701 * HOL: nat_less_induct renamed to less_induct;
  1702 
  1703 * HOL: systematic renaming of the SOME (Eps) rules, may use isatool
  1704 fixsome to patch .thy and .ML sources automatically;
  1705 
  1706   select_equality  -> some_equality
  1707   select_eq_Ex     -> some_eq_ex
  1708   selectI2EX       -> someI2_ex
  1709   selectI2         -> someI2
  1710   selectI          -> someI
  1711   select1_equality -> some1_equality
  1712   Eps_sym_eq       -> some_sym_eq_trivial
  1713   Eps_eq           -> some_eq_trivial
  1714 
  1715 * HOL: exhaust_tac on datatypes superceded by new generic case_tac;
  1716 
  1717 * HOL: removed obsolete theorem binding expand_if (refer to split_if
  1718 instead);
  1719 
  1720 * HOL: the recursion equations generated by 'recdef' are now called
  1721 f.simps instead of f.rules;
  1722 
  1723 * HOL: qed_spec_mp now also handles bounded ALL as well;
  1724 
  1725 * HOL: 0 is now overloaded, so the type constraint ":: nat" may
  1726 sometimes be needed;
  1727 
  1728 * HOL: the constant for "f``x" is now "image" rather than "op ``";
  1729 
  1730 * HOL: the constant for "f-``x" is now "vimage" rather than "op -``";
  1731 
  1732 * HOL: the disjoint sum is now "<+>" instead of "Plus"; the cartesian
  1733 product is now "<*>" instead of "Times"; the lexicographic product is
  1734 now "<*lex*>" instead of "**";
  1735 
  1736 * HOL: theory Sexp is now in HOL/Induct examples (it used to be part
  1737 of main HOL, but was unused); better use HOL's datatype package;
  1738 
  1739 * HOL: removed "symbols" syntax for constant "override" of theory Map;
  1740 the old syntax may be recovered as follows:
  1741 
  1742   syntax (symbols)
  1743     override  :: "('a ~=> 'b) => ('a ~=> 'b) => ('a ~=> 'b)"
  1744       (infixl "\\<oplus>" 100)
  1745 
  1746 * HOL/Real: "rabs" replaced by overloaded "abs" function;
  1747 
  1748 * HOL/ML: even fewer consts are declared as global (see theories Ord,
  1749 Lfp, Gfp, WF); this only affects ML packages that refer to const names
  1750 internally;
  1751 
  1752 * HOL and ZF: syntax for quotienting wrt an equivalence relation
  1753 changed from A/r to A//r;
  1754 
  1755 * ZF: new treatment of arithmetic (nat & int) may break some old
  1756 proofs;
  1757 
  1758 * Isar: renamed some attributes (RS -> THEN, simplify -> simplified,
  1759 rulify -> rule_format, elimify -> elim_format, ...);
  1760 
  1761 * Isar/Provers: intro/elim/dest attributes changed; renamed
  1762 intro/intro!/intro!! flags to intro!/intro/intro? (in most cases, one
  1763 should have to change intro!! to intro? only); replaced "delrule" by
  1764 "rule del";
  1765 
  1766 * Isar/HOL: renamed "intrs" to "intros" in inductive definitions;
  1767 
  1768 * Provers: strengthened force_tac by using new first_best_tac;
  1769 
  1770 * LaTeX document preparation: several changes of isabelle.sty (see
  1771 lib/texinputs);
  1772 
  1773 
  1774 *** Document preparation ***
  1775 
  1776 * formal comments (text blocks etc.) in new-style theories may now
  1777 contain antiquotations of thm/prop/term/typ/text to be presented
  1778 according to latex print mode; concrete syntax is like this:
  1779 @{term[show_types] "f(x) = a + x"};
  1780 
  1781 * isatool mkdir provides easy setup of Isabelle session directories,
  1782 including proper document sources;
  1783 
  1784 * generated LaTeX sources are now deleted after successful run
  1785 (isatool document -c); may retain a copy somewhere else via -D option
  1786 of isatool usedir;
  1787 
  1788 * isatool usedir -D now lets isatool latex -o sty update the Isabelle
  1789 style files, achieving self-contained LaTeX sources and simplifying
  1790 LaTeX debugging;
  1791 
  1792 * old-style theories now produce (crude) LaTeX output as well;
  1793 
  1794 * browser info session directories are now self-contained (may be put
  1795 on WWW server seperately); improved graphs of nested sessions; removed
  1796 graph for 'all sessions';
  1797 
  1798 * several improvements in isabelle style files; \isabellestyle{it}
  1799 produces fake math mode output; \isamarkupheader is now \section by
  1800 default; see lib/texinputs/isabelle.sty etc.;
  1801 
  1802 
  1803 *** Isar ***
  1804 
  1805 * Isar/Pure: local results and corresponding term bindings are now
  1806 subject to Hindley-Milner polymorphism (similar to ML); this
  1807 accommodates incremental type-inference very nicely;
  1808 
  1809 * Isar/Pure: new derived language element 'obtain' supports
  1810 generalized existence reasoning;
  1811 
  1812 * Isar/Pure: new calculational elements 'moreover' and 'ultimately'
  1813 support accumulation of results, without applying any rules yet;
  1814 useful to collect intermediate results without explicit name
  1815 references, and for use with transitivity rules with more than 2
  1816 premises;
  1817 
  1818 * Isar/Pure: scalable support for case-analysis type proofs: new
  1819 'case' language element refers to local contexts symbolically, as
  1820 produced by certain proof methods; internally, case names are attached
  1821 to theorems as "tags";
  1822 
  1823 * Isar/Pure: theory command 'hide' removes declarations from
  1824 class/type/const name spaces;
  1825 
  1826 * Isar/Pure: theory command 'defs' supports option "(overloaded)" to
  1827 indicate potential overloading;
  1828 
  1829 * Isar/Pure: changed syntax of local blocks from {{ }} to { };
  1830 
  1831 * Isar/Pure: syntax of sorts made 'inner', i.e. have to write
  1832 "{a,b,c}" instead of {a,b,c};
  1833 
  1834 * Isar/Pure now provides its own version of intro/elim/dest
  1835 attributes; useful for building new logics, but beware of confusion
  1836 with the version in Provers/classical;
  1837 
  1838 * Isar/Pure: the local context of (non-atomic) goals is provided via
  1839 case name 'antecedent';
  1840 
  1841 * Isar/Pure: removed obsolete 'transfer' attribute (transfer of thms
  1842 to the current context is now done automatically);
  1843 
  1844 * Isar/Pure: theory command 'method_setup' provides a simple interface
  1845 for definining proof methods in ML;
  1846 
  1847 * Isar/Provers: intro/elim/dest attributes changed; renamed
  1848 intro/intro!/intro!! flags to intro!/intro/intro? (INCOMPATIBILITY, in
  1849 most cases, one should have to change intro!! to intro? only);
  1850 replaced "delrule" by "rule del";
  1851 
  1852 * Isar/Provers: new 'hypsubst' method, plain 'subst' method and
  1853 'symmetric' attribute (the latter supercedes [RS sym]);
  1854 
  1855 * Isar/Provers: splitter support (via 'split' attribute and 'simp'
  1856 method modifier); 'simp' method: 'only:' modifier removes loopers as
  1857 well (including splits);
  1858 
  1859 * Isar/Provers: Simplifier and Classical methods now support all kind
  1860 of modifiers used in the past, including 'cong', 'iff', etc.
  1861 
  1862 * Isar/Provers: added 'fastsimp' and 'clarsimp' methods (combination
  1863 of Simplifier and Classical reasoner);
  1864 
  1865 * Isar/HOL: new proof method 'cases' and improved version of 'induct'
  1866 now support named cases; major packages (inductive, datatype, primrec,
  1867 recdef) support case names and properly name parameters;
  1868 
  1869 * Isar/HOL: new transitivity rules for substitution in inequalities --
  1870 monotonicity conditions are extracted to be proven at end of
  1871 calculations;
  1872 
  1873 * Isar/HOL: removed 'case_split' thm binding, should use 'cases' proof
  1874 method anyway;
  1875 
  1876 * Isar/HOL: removed old expand_if = split_if; theorems if_splits =
  1877 split_if split_if_asm; datatype package provides theorems foo.splits =
  1878 foo.split foo.split_asm for each datatype;
  1879 
  1880 * Isar/HOL: tuned inductive package, rename "intrs" to "intros"
  1881 (potential INCOMPATIBILITY), emulation of mk_cases feature for proof
  1882 scripts: new 'inductive_cases' command and 'ind_cases' method; (Note:
  1883 use "(cases (simplified))" method in proper proof texts);
  1884 
  1885 * Isar/HOL: added global 'arith_split' attribute for 'arith' method;
  1886 
  1887 * Isar: names of theorems etc. may be natural numbers as well;
  1888 
  1889 * Isar: 'pr' command: optional arguments for goals_limit and
  1890 ProofContext.prems_limit; no longer prints theory contexts, but only
  1891 proof states;
  1892 
  1893 * Isar: diagnostic commands 'pr', 'thm', 'prop', 'term', 'typ' admit
  1894 additional print modes to be specified; e.g. "pr(latex)" will print
  1895 proof state according to the Isabelle LaTeX style;
  1896 
  1897 * Isar: improved support for emulating tactic scripts, including proof
  1898 methods 'rule_tac' etc., 'cut_tac', 'thin_tac', 'subgoal_tac',
  1899 'rename_tac', 'rotate_tac', 'tactic', and 'case_tac' / 'induct_tac'
  1900 (for HOL datatypes);
  1901 
  1902 * Isar: simplified (more robust) goal selection of proof methods: 1st
  1903 goal, all goals, or explicit goal specifier (tactic emulation); thus
  1904 'proof method scripts' have to be in depth-first order;
  1905 
  1906 * Isar: tuned 'let' syntax: replaced 'as' keyword by 'and';
  1907 
  1908 * Isar: removed 'help' command, which hasn't been too helpful anyway;
  1909 should instead use individual commands for printing items
  1910 (print_commands, print_methods etc.);
  1911 
  1912 * Isar: added 'nothing' --- the empty list of theorems;
  1913 
  1914 
  1915 *** HOL ***
  1916 
  1917 * HOL/MicroJava: formalization of a fragment of Java, together with a
  1918 corresponding virtual machine and a specification of its bytecode
  1919 verifier and a lightweight bytecode verifier, including proofs of
  1920 type-safety; by Gerwin Klein, Tobias Nipkow, David von Oheimb, and
  1921 Cornelia Pusch (see also the homepage of project Bali at
  1922 http://isabelle.in.tum.de/Bali/);
  1923 
  1924 * HOL/Algebra: new theory of rings and univariate polynomials, by
  1925 Clemens Ballarin;
  1926 
  1927 * HOL/NumberTheory: fundamental Theorem of Arithmetic, Chinese
  1928 Remainder Theorem, Fermat/Euler Theorem, Wilson's Theorem, by Thomas M
  1929 Rasmussen;
  1930 
  1931 * HOL/Lattice: fundamental concepts of lattice theory and order
  1932 structures, including duals, properties of bounds versus algebraic
  1933 laws, lattice operations versus set-theoretic ones, the Knaster-Tarski
  1934 Theorem for complete lattices etc.; may also serve as a demonstration
  1935 for abstract algebraic reasoning using axiomatic type classes, and
  1936 mathematics-style proof in Isabelle/Isar; by Markus Wenzel;
  1937 
  1938 * HOL/Prolog: a (bare-bones) implementation of Lambda-Prolog, by David
  1939 von Oheimb;
  1940 
  1941 * HOL/IMPP: extension of IMP with local variables and mutually
  1942 recursive procedures, by David von Oheimb;
  1943 
  1944 * HOL/Lambda: converted into new-style theory and document;
  1945 
  1946 * HOL/ex/Multiquote: example of multiple nested quotations and
  1947 anti-quotations -- basically a generalized version of de-Bruijn
  1948 representation; very useful in avoiding lifting of operations;
  1949 
  1950 * HOL/record: added general record equality rule to simpset; fixed
  1951 select-update simplification procedure to handle extended records as
  1952 well; admit "r" as field name;
  1953 
  1954 * HOL: 0 is now overloaded over the new sort "zero", allowing its use with
  1955 other numeric types and also as the identity of groups, rings, etc.;
  1956 
  1957 * HOL: new axclass plus_ac0 for addition with the AC-laws and 0 as identity.
  1958 Types nat and int belong to this axclass;
  1959 
  1960 * HOL: greatly improved simplification involving numerals of type nat, int, real:
  1961    (i + #8 + j) = Suc k simplifies to  #7 + (i + j) = k
  1962    i*j + k + j*#3*i     simplifies to  #4*(i*j) + k
  1963   two terms #m*u and #n*u are replaced by #(m+n)*u
  1964     (where #m, #n and u can implicitly be 1; this is simproc combine_numerals)
  1965   and the term/formula #m*u+x ~~ #n*u+y simplifies simplifies to #(m-n)+x ~~ y
  1966     or x ~~ #(n-m)+y, where ~~ is one of = < <= or - (simproc cancel_numerals);
  1967 
  1968 * HOL: meson_tac is available (previously in ex/meson.ML); it is a
  1969 powerful prover for predicate logic but knows nothing of clasets; see
  1970 ex/mesontest.ML and ex/mesontest2.ML for example applications;
  1971 
  1972 * HOL: new version of "case_tac" subsumes both boolean case split and
  1973 "exhaust_tac" on datatypes; INCOMPATIBILITY: exhaust_tac no longer
  1974 exists, may define val exhaust_tac = case_tac for ad-hoc portability;
  1975 
  1976 * HOL: simplification no longer dives into case-expressions: only the
  1977 selector expression is simplified, but not the remaining arms; to
  1978 enable full simplification of case-expressions for datatype t, you may
  1979 remove t.weak_case_cong from the simpset, either globally (Delcongs
  1980 [thm"t.weak_case_cong"];) or locally (delcongs [...]).
  1981 
  1982 * HOL/recdef: the recursion equations generated by 'recdef' for
  1983 function 'f' are now called f.simps instead of f.rules; if all
  1984 termination conditions are proved automatically, these simplification
  1985 rules are added to the simpset, as in primrec; rules may be named
  1986 individually as well, resulting in a separate list of theorems for
  1987 each equation;
  1988 
  1989 * HOL/While is a new theory that provides a while-combinator. It
  1990 permits the definition of tail-recursive functions without the
  1991 provision of a termination measure. The latter is necessary once the
  1992 invariant proof rule for while is applied.
  1993 
  1994 * HOL: new (overloaded) notation for the set of elements below/above
  1995 some element: {..u}, {..u(}, {l..}, {)l..}. See theory SetInterval.
  1996 
  1997 * HOL: theorems impI, allI, ballI bound as "strip";
  1998 
  1999 * HOL: new tactic induct_thm_tac: thm -> string -> int -> tactic
  2000 induct_tac th "x1 ... xn" expects th to have a conclusion of the form
  2001 P v1 ... vn and abbreviates res_inst_tac [("v1","x1"),...,("vn","xn")] th;
  2002 
  2003 * HOL/Real: "rabs" replaced by overloaded "abs" function;
  2004 
  2005 * HOL: theory Sexp now in HOL/Induct examples (it used to be part of
  2006 main HOL, but was unused);
  2007 
  2008 * HOL: fewer consts declared as global (e.g. have to refer to
  2009 "Lfp.lfp" instead of "lfp" internally; affects ML packages only);
  2010 
  2011 * HOL: tuned AST representation of nested pairs, avoiding bogus output
  2012 in case of overlap with user translations (e.g. judgements over
  2013 tuples); (note that the underlying logical represenation is still
  2014 bogus);
  2015 
  2016 
  2017 *** ZF ***
  2018 
  2019 * ZF: simplification automatically cancels common terms in arithmetic
  2020 expressions over nat and int;
  2021 
  2022 * ZF: new treatment of nat to minimize type-checking: all operators
  2023 coerce their operands to a natural number using the function natify,
  2024 making the algebraic laws unconditional;
  2025 
  2026 * ZF: as above, for int: operators coerce their operands to an integer
  2027 using the function intify;
  2028 
  2029 * ZF: the integer library now contains many of the usual laws for the
  2030 orderings, including $<=, and monotonicity laws for $+ and $*;
  2031 
  2032 * ZF: new example ZF/ex/NatSum to demonstrate integer arithmetic
  2033 simplification;
  2034 
  2035 * FOL and ZF: AddIffs now available, giving theorems of the form P<->Q
  2036 to the simplifier and classical reasoner simultaneously;
  2037 
  2038 
  2039 *** General ***
  2040 
  2041 * Provers: blast_tac now handles actual object-logic rules as
  2042 assumptions; note that auto_tac uses blast_tac internally as well;
  2043 
  2044 * Provers: new functions rulify/rulify_no_asm: thm -> thm for turning
  2045 outer -->/All/Ball into ==>/!!; qed_spec_mp now uses rulify_no_asm;
  2046 
  2047 * Provers: delrules now handles destruct rules as well (no longer need
  2048 explicit make_elim);
  2049 
  2050 * Provers: Blast_tac now warns of and ignores "weak elimination rules" e.g.
  2051   [| inj ?f;          ?f ?x = ?f ?y; ?x = ?y ==> ?W |] ==> ?W
  2052 use instead the strong form,
  2053   [| inj ?f; ~ ?W ==> ?f ?x = ?f ?y; ?x = ?y ==> ?W |] ==> ?W
  2054 in HOL, FOL and ZF the function cla_make_elim will create such rules
  2055 from destruct-rules;
  2056 
  2057 * Provers: Simplifier.easy_setup provides a fast path to basic
  2058 Simplifier setup for new object-logics;
  2059 
  2060 * Pure: AST translation rules no longer require constant head on LHS;
  2061 
  2062 * Pure: improved name spaces: ambiguous output is qualified; support
  2063 for hiding of names;
  2064 
  2065 * system: smart setup of canonical ML_HOME, ISABELLE_INTERFACE, and
  2066 XSYMBOL_HOME; no longer need to do manual configuration in most
  2067 situations;
  2068 
  2069 * system: compression of ML heaps images may now be controlled via -c
  2070 option of isabelle and isatool usedir (currently only observed by
  2071 Poly/ML);
  2072 
  2073 * system: isatool installfonts may handle X-Symbol fonts as well (very
  2074 useful for remote X11);
  2075 
  2076 * system: provide TAGS file for Isabelle sources;
  2077 
  2078 * ML: infix 'OF' is a version of 'MRS' with more appropriate argument
  2079 order;
  2080 
  2081 * ML: renamed flags Syntax.trace_norm_ast to Syntax.trace_ast; global
  2082 timing flag supersedes proof_timing and Toplevel.trace;
  2083 
  2084 * ML: new combinators |>> and |>>> for incremental transformations
  2085 with secondary results (e.g. certain theory extensions):
  2086 
  2087 * ML: PureThy.add_defs gets additional argument to indicate potential
  2088 overloading (usually false);
  2089 
  2090 * ML: PureThy.add_thms/add_axioms/add_defs now return theorems as
  2091 results;
  2092 
  2093 
  2094 
  2095 New in Isabelle99 (October 1999)
  2096 --------------------------------
  2097 
  2098 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  2099 
  2100 * HOL: The THEN and ELSE parts of conditional expressions (if P then x else y)
  2101 are no longer simplified.  (This allows the simplifier to unfold recursive
  2102 functional programs.)  To restore the old behaviour, declare
  2103 
  2104     Delcongs [if_weak_cong];
  2105 
  2106 * HOL: Removed the obsolete syntax "Compl A"; use -A for set
  2107 complement;
  2108 
  2109 * HOL: the predicate "inj" is now defined by translation to "inj_on";
  2110 
  2111 * HOL/datatype: mutual_induct_tac no longer exists --
  2112   use induct_tac "x_1 ... x_n" instead of mutual_induct_tac ["x_1", ..., "x_n"]
  2113 
  2114 * HOL/typedef: fixed type inference for representing set; type
  2115 arguments now have to occur explicitly on the rhs as type constraints;
  2116 
  2117 * ZF: The con_defs part of an inductive definition may no longer refer
  2118 to constants declared in the same theory;
  2119 
  2120 * HOL, ZF: the function mk_cases, generated by the inductive
  2121 definition package, has lost an argument.  To simplify its result, it
  2122 uses the default simpset instead of a supplied list of theorems.
  2123 
  2124 * HOL/List: the constructors of type list are now Nil and Cons;
  2125 
  2126 * Simplifier: the type of the infix ML functions
  2127         setSSolver addSSolver setSolver addSolver
  2128 is now  simpset * solver -> simpset  where `solver' is a new abstract type
  2129 for packaging solvers. A solver is created via
  2130         mk_solver: string -> (thm list -> int -> tactic) -> solver
  2131 where the string argument is only a comment.
  2132 
  2133 
  2134 *** Proof tools ***
  2135 
  2136 * Provers/Arith/fast_lin_arith.ML contains a functor for creating a
  2137 decision procedure for linear arithmetic. Currently it is used for
  2138 types `nat', `int', and `real' in HOL (see below); it can, should and
  2139 will be instantiated for other types and logics as well.
  2140 
  2141 * The simplifier now accepts rewrite rules with flexible heads, eg
  2142      hom ?f ==> ?f(?x+?y) = ?f ?x + ?f ?y
  2143   They are applied like any rule with a non-pattern lhs, i.e. by first-order
  2144   matching.
  2145 
  2146 
  2147 *** General ***
  2148 
  2149 * New Isabelle/Isar subsystem provides an alternative to traditional
  2150 tactical theorem proving; together with the ProofGeneral/isar user
  2151 interface it offers an interactive environment for developing human
  2152 readable proof documents (Isar == Intelligible semi-automated
  2153 reasoning); for further information see isatool doc isar-ref,
  2154 src/HOL/Isar_examples and http://isabelle.in.tum.de/Isar/
  2155 
  2156 * improved and simplified presentation of theories: better HTML markup
  2157 (including colors), graph views in several sizes; isatool usedir now
  2158 provides a proper interface for user theories (via -P option); actual
  2159 document preparation based on (PDF)LaTeX is available as well (for
  2160 new-style theories only); see isatool doc system for more information;
  2161 
  2162 * native support for Proof General, both for classic Isabelle and
  2163 Isabelle/Isar;
  2164 
  2165 * ML function thm_deps visualizes dependencies of theorems and lemmas,
  2166 using the graph browser tool;
  2167 
  2168 * Isabelle manuals now also available as PDF;
  2169 
  2170 * theory loader rewritten from scratch (may not be fully
  2171 bug-compatible); old loadpath variable has been replaced by show_path,
  2172 add_path, del_path, reset_path functions; new operations such as
  2173 update_thy, touch_thy, remove_thy, use/update_thy_only (see also
  2174 isatool doc ref);
  2175 
  2176 * improved isatool install: option -k creates KDE application icon,
  2177 option -p DIR installs standalone binaries;
  2178 
  2179 * added ML_PLATFORM setting (useful for cross-platform installations);
  2180 more robust handling of platform specific ML images for SML/NJ;
  2181 
  2182 * the settings environment is now statically scoped, i.e. it is never
  2183 created again in sub-processes invoked from isabelle, isatool, or
  2184 Isabelle;
  2185 
  2186 * path element specification '~~' refers to '$ISABELLE_HOME';
  2187 
  2188 * in locales, the "assumes" and "defines" parts may be omitted if
  2189 empty;
  2190 
  2191 * new print_mode "xsymbols" for extended symbol support (e.g. genuine
  2192 long arrows);
  2193 
  2194 * new print_mode "HTML";
  2195 
  2196 * new flag show_tags controls display of tags of theorems (which are
  2197 basically just comments that may be attached by some tools);
  2198 
  2199 * Isamode 2.6 requires patch to accomodate change of Isabelle font
  2200 mode and goal output format:
  2201 
  2202 diff -r Isamode-2.6/elisp/isa-load.el Isamode/elisp/isa-load.el
  2203 244c244
  2204 <       (list (isa-getenv "ISABELLE") "-msymbols" logic-name)
  2205 ---
  2206 >       (list (isa-getenv "ISABELLE") "-misabelle_font" "-msymbols" logic-name)
  2207 diff -r Isabelle-2.6/elisp/isa-proofstate.el Isamode/elisp/isa-proofstate.el
  2208 181c181
  2209 < (defconst proofstate-proofstart-regexp "^Level [0-9]+$"
  2210 ---
  2211 > (defconst proofstate-proofstart-regexp "^Level [0-9]+"
  2212 
  2213 * function bind_thms stores lists of theorems (cf. bind_thm);
  2214 
  2215 * new shorthand tactics ftac, eatac, datac, fatac;
  2216 
  2217 * qed (and friends) now accept "" as result name; in that case the
  2218 theorem is not stored, but proper checks and presentation of the
  2219 result still apply;
  2220 
  2221 * theorem database now also indexes constants "Trueprop", "all",
  2222 "==>", "=="; thus thms_containing, findI etc. may retrieve more rules;
  2223 
  2224 
  2225 *** HOL ***
  2226 
  2227 ** HOL arithmetic **
  2228 
  2229 * There are now decision procedures for linear arithmetic over nat and
  2230 int:
  2231 
  2232 1. arith_tac copes with arbitrary formulae involving `=', `<', `<=',
  2233 `+', `-', `Suc', `min', `max' and numerical constants; other subterms
  2234 are treated as atomic; subformulae not involving type `nat' or `int'
  2235 are ignored; quantified subformulae are ignored unless they are
  2236 positive universal or negative existential. The tactic has to be
  2237 invoked by hand and can be a little bit slow. In particular, the
  2238 running time is exponential in the number of occurrences of `min' and
  2239 `max', and `-' on `nat'.
  2240 
  2241 2. fast_arith_tac is a cut-down version of arith_tac: it only takes
  2242 (negated) (in)equalities among the premises and the conclusion into
  2243 account (i.e. no compound formulae) and does not know about `min' and
  2244 `max', and `-' on `nat'. It is fast and is used automatically by the
  2245 simplifier.
  2246 
  2247 NB: At the moment, these decision procedures do not cope with mixed
  2248 nat/int formulae where the two parts interact, such as `m < n ==>
  2249 int(m) < int(n)'.
  2250 
  2251 * HOL/Numeral provides a generic theory of numerals (encoded
  2252 efficiently as bit strings); setup for types nat/int/real is in place;
  2253 INCOMPATIBILITY: since numeral syntax is now polymorphic, rather than
  2254 int, existing theories and proof scripts may require a few additional
  2255 type constraints;
  2256 
  2257 * integer division and remainder can now be performed on constant
  2258 arguments;
  2259 
  2260 * many properties of integer multiplication, division and remainder
  2261 are now available;
  2262 
  2263 * An interface to the Stanford Validity Checker (SVC) is available through the
  2264 tactic svc_tac.  Propositional tautologies and theorems of linear arithmetic
  2265 are proved automatically.  SVC must be installed separately, and its results
  2266 must be TAKEN ON TRUST (Isabelle does not check the proofs, but tags any
  2267 invocation of the underlying oracle).  For SVC see
  2268   http://verify.stanford.edu/SVC
  2269 
  2270 * IsaMakefile: the HOL-Real target now builds an actual image;
  2271 
  2272 
  2273 ** HOL misc **
  2274 
  2275 * HOL/Real/HahnBanach: the Hahn-Banach theorem for real vector spaces
  2276 (in Isabelle/Isar) -- by Gertrud Bauer;
  2277 
  2278 * HOL/BCV: generic model of bytecode verification, i.e. data-flow
  2279 analysis for assembly languages with subtypes;
  2280 
  2281 * HOL/TLA (Lamport's Temporal Logic of Actions): major reorganization
  2282 -- avoids syntactic ambiguities and treats state, transition, and
  2283 temporal levels more uniformly; introduces INCOMPATIBILITIES due to
  2284 changed syntax and (many) tactics;
  2285 
  2286 * HOL/inductive: Now also handles more general introduction rules such
  2287   as "ALL y. (y, x) : r --> y : acc r ==> x : acc r"; monotonicity
  2288   theorems are now maintained within the theory (maintained via the
  2289   "mono" attribute);
  2290 
  2291 * HOL/datatype: Now also handles arbitrarily branching datatypes
  2292   (using function types) such as
  2293 
  2294   datatype 'a tree = Atom 'a | Branch "nat => 'a tree"
  2295 
  2296 * HOL/record: record_simproc (part of the default simpset) takes care
  2297 of selectors applied to updated records; record_split_tac is no longer
  2298 part of the default claset; update_defs may now be removed from the
  2299 simpset in many cases; COMPATIBILITY: old behavior achieved by
  2300 
  2301   claset_ref () := claset() addSWrapper record_split_wrapper;
  2302   Delsimprocs [record_simproc]
  2303 
  2304 * HOL/typedef: fixed type inference for representing set; type
  2305 arguments now have to occur explicitly on the rhs as type constraints;
  2306 
  2307 * HOL/recdef (TFL): 'congs' syntax now expects comma separated list of theorem
  2308 names rather than an ML expression;
  2309 
  2310 * HOL/defer_recdef (TFL): like recdef but the well-founded relation can be
  2311 supplied later.  Program schemes can be defined, such as
  2312     "While B C s = (if B s then While B C (C s) else s)"
  2313 where the well-founded relation can be chosen after B and C have been given.
  2314 
  2315 * HOL/List: the constructors of type list are now Nil and Cons;
  2316 INCOMPATIBILITY: while [] and infix # syntax is still there, of
  2317 course, ML tools referring to List.list.op # etc. have to be adapted;
  2318 
  2319 * HOL_quantifiers flag superseded by "HOL" print mode, which is
  2320 disabled by default; run isabelle with option -m HOL to get back to
  2321 the original Gordon/HOL-style output;
  2322 
  2323 * HOL/Ord.thy: new bounded quantifier syntax (input only): ALL x<y. P,
  2324 ALL x<=y. P, EX x<y. P, EX x<=y. P;
  2325 
  2326 * HOL basic syntax simplified (more orthogonal): all variants of
  2327 All/Ex now support plain / symbolic / HOL notation; plain syntax for
  2328 Eps operator is provided as well: "SOME x. P[x]";
  2329 
  2330 * HOL/Sum.thy: sum_case has been moved to HOL/Datatype;
  2331 
  2332 * HOL/Univ.thy: infix syntax <*>, <+>, <**>, <+> eliminated and made
  2333 thus available for user theories;
  2334 
  2335 * HOLCF/IOA/Sequents: renamed 'Cons' to 'Consq' to avoid clash with
  2336 HOL/List; hardly an INCOMPATIBILITY since '>>' syntax is used all the
  2337 time;
  2338 
  2339 * HOL: new tactic smp_tac: int -> int -> tactic, which applies spec
  2340 several times and then mp;
  2341 
  2342 
  2343 *** LK ***
  2344 
  2345 * the notation <<...>> is now available as a notation for sequences of
  2346 formulas;
  2347 
  2348 * the simplifier is now installed
  2349 
  2350 * the axiom system has been generalized (thanks to Soren Heilmann)
  2351 
  2352 * the classical reasoner now has a default rule database
  2353 
  2354 
  2355 *** ZF ***
  2356 
  2357 * new primrec section allows primitive recursive functions to be given
  2358 directly (as in HOL) over datatypes and the natural numbers;
  2359 
  2360 * new tactics induct_tac and exhaust_tac for induction (or case
  2361 analysis) over datatypes and the natural numbers;
  2362 
  2363 * the datatype declaration of type T now defines the recursor T_rec;
  2364 
  2365 * simplification automatically does freeness reasoning for datatype
  2366 constructors;
  2367 
  2368 * automatic type-inference, with AddTCs command to insert new
  2369 type-checking rules;
  2370 
  2371 * datatype introduction rules are now added as Safe Introduction rules
  2372 to the claset;
  2373 
  2374 * the syntax "if P then x else y" is now available in addition to
  2375 if(P,x,y);
  2376 
  2377 
  2378 *** Internal programming interfaces ***
  2379 
  2380 * tuned simplifier trace output; new flag debug_simp;
  2381 
  2382 * structures Vartab / Termtab (instances of TableFun) offer efficient
  2383 tables indexed by indexname_ord / term_ord (compatible with aconv);
  2384 
  2385 * AxClass.axclass_tac lost the theory argument;
  2386 
  2387 * tuned current_goals_markers semantics: begin / end goal avoids
  2388 printing empty lines;
  2389 
  2390 * removed prs and prs_fn hook, which was broken because it did not
  2391 include \n in its semantics, forcing writeln to add one
  2392 uncoditionally; replaced prs_fn by writeln_fn; consider std_output:
  2393 string -> unit if you really want to output text without newline;
  2394 
  2395 * Symbol.output subject to print mode; INCOMPATIBILITY: defaults to
  2396 plain output, interface builders may have to enable 'isabelle_font'
  2397 mode to get Isabelle font glyphs as before;
  2398 
  2399 * refined token_translation interface; INCOMPATIBILITY: output length
  2400 now of type real instead of int;
  2401 
  2402 * theory loader actions may be traced via new ThyInfo.add_hook
  2403 interface (see src/Pure/Thy/thy_info.ML); example application: keep
  2404 your own database of information attached to *whole* theories -- as
  2405 opposed to intra-theory data slots offered via TheoryDataFun;
  2406 
  2407 * proper handling of dangling sort hypotheses (at last!);
  2408 Thm.strip_shyps and Drule.strip_shyps_warning take care of removing
  2409 extra sort hypotheses that can be witnessed from the type signature;
  2410 the force_strip_shyps flag is gone, any remaining shyps are simply
  2411 left in the theorem (with a warning issued by strip_shyps_warning);
  2412 
  2413 
  2414 
  2415 New in Isabelle98-1 (October 1998)
  2416 ----------------------------------
  2417 
  2418 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  2419 
  2420 * several changes of automated proof tools;
  2421 
  2422 * HOL: major changes to the inductive and datatype packages, including
  2423 some minor incompatibilities of theory syntax;
  2424 
  2425 * HOL: renamed r^-1 to 'converse' from 'inverse'; 'inj_onto' is now
  2426 called `inj_on';
  2427 
  2428 * HOL: removed duplicate thms in Arith:
  2429   less_imp_add_less  should be replaced by  trans_less_add1
  2430   le_imp_add_le      should be replaced by  trans_le_add1
  2431 
  2432 * HOL: unary minus is now overloaded (new type constraints may be
  2433 required);
  2434 
  2435 * HOL and ZF: unary minus for integers is now #- instead of #~.  In
  2436 ZF, expressions such as n#-1 must be changed to n#- 1, since #-1 is
  2437 now taken as an integer constant.
  2438 
  2439 * Pure: ML function 'theory_of' renamed to 'theory';
  2440 
  2441 
  2442 *** Proof tools ***
  2443 
  2444 * Simplifier:
  2445   1. Asm_full_simp_tac is now more aggressive.
  2446      1. It will sometimes reorient premises if that increases their power to
  2447         simplify.
  2448      2. It does no longer proceed strictly from left to right but may also
  2449         rotate premises to achieve further simplification.
  2450      For compatibility reasons there is now Asm_lr_simp_tac which is like the
  2451      old Asm_full_simp_tac in that it does not rotate premises.
  2452   2. The simplifier now knows a little bit about nat-arithmetic.
  2453 
  2454 * Classical reasoner: wrapper mechanism for the classical reasoner now
  2455 allows for selected deletion of wrappers, by introduction of names for
  2456 wrapper functionals.  This implies that addbefore, addSbefore,
  2457 addaltern, and addSaltern now take a pair (name, tactic) as argument,
  2458 and that adding two tactics with the same name overwrites the first
  2459 one (emitting a warning).
  2460   type wrapper = (int -> tactic) -> (int -> tactic)
  2461   setWrapper, setSWrapper, compWrapper and compSWrapper are replaced by
  2462   addWrapper, addSWrapper: claset * (string * wrapper) -> claset
  2463   delWrapper, delSWrapper: claset *  string            -> claset
  2464   getWrapper is renamed to appWrappers, getSWrapper to appSWrappers;
  2465 
  2466 * Classical reasoner: addbefore/addSbefore now have APPEND/ORELSE
  2467 semantics; addbefore now affects only the unsafe part of step_tac
  2468 etc.; this affects addss/auto_tac/force_tac, so EXISTING PROOFS MAY
  2469 FAIL, but proofs should be fixable easily, e.g. by replacing Auto_tac
  2470 by Force_tac;
  2471 
  2472 * Classical reasoner: setwrapper to setWrapper and compwrapper to
  2473 compWrapper; added safe wrapper (and access functions for it);
  2474 
  2475 * HOL/split_all_tac is now much faster and fails if there is nothing
  2476 to split.  Some EXISTING PROOFS MAY REQUIRE ADAPTION because the order
  2477 and the names of the automatically generated variables have changed.
  2478 split_all_tac has moved within claset() from unsafe wrappers to safe
  2479 wrappers, which means that !!-bound variables are split much more
  2480 aggressively, and safe_tac and clarify_tac now split such variables.
  2481 If this splitting is not appropriate, use delSWrapper "split_all_tac".
  2482 Note: the same holds for record_split_tac, which does the job of
  2483 split_all_tac for record fields.
  2484 
  2485 * HOL/Simplifier: Rewrite rules for case distinctions can now be added
  2486 permanently to the default simpset using Addsplits just like
  2487 Addsimps. They can be removed via Delsplits just like
  2488 Delsimps. Lower-case versions are also available.
  2489 
  2490 * HOL/Simplifier: The rule split_if is now part of the default
  2491 simpset. This means that the simplifier will eliminate all occurrences
  2492 of if-then-else in the conclusion of a goal. To prevent this, you can
  2493 either remove split_if completely from the default simpset by
  2494 `Delsplits [split_if]' or remove it in a specific call of the
  2495 simplifier using `... delsplits [split_if]'.  You can also add/delete
  2496 other case splitting rules to/from the default simpset: every datatype
  2497 generates suitable rules `split_t_case' and `split_t_case_asm' (where
  2498 t is the name of the datatype).
  2499 
  2500 * Classical reasoner / Simplifier combination: new force_tac (and
  2501 derivatives Force_tac, force) combines rewriting and classical
  2502 reasoning (and whatever other tools) similarly to auto_tac, but is
  2503 aimed to solve the given subgoal completely.
  2504 
  2505 
  2506 *** General ***
  2507 
  2508 * new top-level commands `Goal' and `Goalw' that improve upon `goal'
  2509 and `goalw': the theory is no longer needed as an explicit argument -
  2510 the current theory context is used; assumptions are no longer returned
  2511 at the ML-level unless one of them starts with ==> or !!; it is
  2512 recommended to convert to these new commands using isatool fixgoal
  2513 (backup your sources first!);
  2514 
  2515 * new top-level commands 'thm' and 'thms' for retrieving theorems from
  2516 the current theory context, and 'theory' to lookup stored theories;
  2517 
  2518 * new theory section 'locale' for declaring constants, assumptions and
  2519 definitions that have local scope;
  2520 
  2521 * new theory section 'nonterminals' for purely syntactic types;
  2522 
  2523 * new theory section 'setup' for generic ML setup functions
  2524 (e.g. package initialization);
  2525 
  2526 * the distribution now includes Isabelle icons: see
  2527 lib/logo/isabelle-{small,tiny}.xpm;
  2528 
  2529 * isatool install - install binaries with absolute references to
  2530 ISABELLE_HOME/bin;
  2531 
  2532 * isatool logo -- create instances of the Isabelle logo (as EPS);
  2533 
  2534 * print mode 'emacs' reserved for Isamode;
  2535 
  2536 * support multiple print (ast) translations per constant name;
  2537 
  2538 * theorems involving oracles are now printed with a suffixed [!];
  2539 
  2540 
  2541 *** HOL ***
  2542 
  2543 * there is now a tutorial on Isabelle/HOL (do 'isatool doc tutorial');
  2544 
  2545 * HOL/inductive package reorganized and improved: now supports mutual
  2546 definitions such as
  2547 
  2548   inductive EVEN ODD
  2549     intrs
  2550       null "0 : EVEN"
  2551       oddI "n : EVEN ==> Suc n : ODD"
  2552       evenI "n : ODD ==> Suc n : EVEN"
  2553 
  2554 new theorem list "elims" contains an elimination rule for each of the
  2555 recursive sets; inductive definitions now handle disjunctive premises
  2556 correctly (also ZF);
  2557 
  2558 INCOMPATIBILITIES: requires Inductive as an ancestor; component
  2559 "mutual_induct" no longer exists - the induction rule is always
  2560 contained in "induct";
  2561 
  2562 
  2563 * HOL/datatype package re-implemented and greatly improved: now
  2564 supports mutually recursive datatypes such as
  2565 
  2566   datatype
  2567     'a aexp = IF_THEN_ELSE ('a bexp) ('a aexp) ('a aexp)
  2568             | SUM ('a aexp) ('a aexp)
  2569             | DIFF ('a aexp) ('a aexp)
  2570             | NUM 'a
  2571   and
  2572     'a bexp = LESS ('a aexp) ('a aexp)
  2573             | AND ('a bexp) ('a bexp)
  2574             | OR ('a bexp) ('a bexp)
  2575 
  2576 as well as indirectly recursive datatypes such as
  2577 
  2578   datatype
  2579     ('a, 'b) term = Var 'a
  2580                   | App 'b ((('a, 'b) term) list)
  2581 
  2582 The new tactic  mutual_induct_tac [<var_1>, ..., <var_n>] i  performs
  2583 induction on mutually / indirectly recursive datatypes.
  2584 
  2585 Primrec equations are now stored in theory and can be accessed via
  2586 <function_name>.simps.
  2587 
  2588 INCOMPATIBILITIES:
  2589 
  2590   - Theories using datatypes must now have theory Datatype as an
  2591     ancestor.
  2592   - The specific <typename>.induct_tac no longer exists - use the
  2593     generic induct_tac instead.
  2594   - natE has been renamed to nat.exhaust - use exhaust_tac
  2595     instead of res_inst_tac ... natE. Note that the variable
  2596     names in nat.exhaust differ from the names in natE, this
  2597     may cause some "fragile" proofs to fail.
  2598   - The theorems split_<typename>_case and split_<typename>_case_asm
  2599     have been renamed to <typename>.split and <typename>.split_asm.
  2600   - Since default sorts of type variables are now handled correctly,
  2601     some datatype definitions may have to be annotated with explicit
  2602     sort constraints.
  2603   - Primrec definitions no longer require function name and type
  2604     of recursive argument.
  2605 
  2606 Consider using isatool fixdatatype to adapt your theories and proof
  2607 scripts to the new package (backup your sources first!).
  2608 
  2609 
  2610 * HOL/record package: considerably improved implementation; now
  2611 includes concrete syntax for record types, terms, updates; theorems
  2612 for surjective pairing and splitting !!-bound record variables; proof
  2613 support is as follows:
  2614 
  2615   1) standard conversions (selectors or updates applied to record
  2616 constructor terms) are part of the standard simpset;
  2617 
  2618   2) inject equations of the form ((x, y) = (x', y')) == x=x' & y=y' are
  2619 made part of standard simpset and claset via addIffs;
  2620 
  2621   3) a tactic for record field splitting (record_split_tac) is part of
  2622 the standard claset (addSWrapper);
  2623 
  2624 To get a better idea about these rules you may retrieve them via
  2625 something like 'thms "foo.simps"' or 'thms "foo.iffs"', where "foo" is
  2626 the name of your record type.
  2627 
  2628 The split tactic 3) conceptually simplifies by the following rule:
  2629 
  2630   "(!!x. PROP ?P x) == (!!a b. PROP ?P (a, b))"
  2631 
  2632 Thus any record variable that is bound by meta-all will automatically
  2633 blow up into some record constructor term, consequently the
  2634 simplifications of 1), 2) apply.  Thus force_tac, auto_tac etc. shall
  2635 solve record problems automatically.
  2636 
  2637 
  2638 * reorganized the main HOL image: HOL/Integ and String loaded by
  2639 default; theory Main includes everything;
  2640 
  2641 * automatic simplification of integer sums and comparisons, using cancellation;
  2642 
  2643 * added option_map_eq_Some and not_Some_eq to the default simpset and claset;
  2644 
  2645 * added disj_not1 = "(~P | Q) = (P --> Q)" to the default simpset;
  2646 
  2647 * many new identities for unions, intersections, set difference, etc.;
  2648 
  2649 * expand_if, expand_split, expand_sum_case and expand_nat_case are now
  2650 called split_if, split_split, split_sum_case and split_nat_case (to go
  2651 with add/delsplits);
  2652 
  2653 * HOL/Prod introduces simplification procedure unit_eq_proc rewriting
  2654 (?x::unit) = (); this is made part of the default simpset, which COULD
  2655 MAKE EXISTING PROOFS FAIL under rare circumstances (consider
  2656 'Delsimprocs [unit_eq_proc];' as last resort); also note that
  2657 unit_abs_eta_conv is added in order to counter the effect of
  2658 unit_eq_proc on (%u::unit. f u), replacing it by f rather than by
  2659 %u.f();
  2660 
  2661 * HOL/Fun INCOMPATIBILITY: `inj_onto' is now called `inj_on' (which
  2662 makes more sense);
  2663 
  2664 * HOL/Set INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
  2665   It and 'sym RS equals0D' are now in the default  claset, giving automatic
  2666   disjointness reasoning but breaking a few old proofs.
  2667 
  2668 * HOL/Relation INCOMPATIBILITY: renamed the relational operator r^-1
  2669 to 'converse' from 'inverse' (for compatibility with ZF and some
  2670 literature);
  2671 
  2672 * HOL/recdef can now declare non-recursive functions, with {} supplied as
  2673 the well-founded relation;
  2674 
  2675 * HOL/Set INCOMPATIBILITY: the complement of set A is now written -A instead of
  2676     Compl A.  The "Compl" syntax remains available as input syntax for this
  2677     release ONLY.
  2678 
  2679 * HOL/Update: new theory of function updates:
  2680     f(a:=b) == %x. if x=a then b else f x
  2681 may also be iterated as in f(a:=b,c:=d,...);
  2682 
  2683 * HOL/Vimage: new theory for inverse image of a function, syntax f-``B;
  2684 
  2685 * HOL/List:
  2686   - new function list_update written xs[i:=v] that updates the i-th
  2687     list position. May also be iterated as in xs[i:=a,j:=b,...].
  2688   - new function `upt' written [i..j(] which generates the list
  2689     [i,i+1,...,j-1], i.e. the upper bound is excluded. To include the upper
  2690     bound write [i..j], which is a shorthand for [i..j+1(].
  2691   - new lexicographic orderings and corresponding wellfoundedness theorems.
  2692 
  2693 * HOL/Arith:
  2694   - removed 'pred' (predecessor) function;
  2695   - generalized some theorems about n-1;
  2696   - many new laws about "div" and "mod";
  2697   - new laws about greatest common divisors (see theory ex/Primes);
  2698 
  2699 * HOL/Relation: renamed the relational operator r^-1 "converse"
  2700 instead of "inverse";
  2701 
  2702 * HOL/Induct/Multiset: a theory of multisets, including the wellfoundedness
  2703   of the multiset ordering;
  2704 
  2705 * directory HOL/Real: a construction of the reals using Dedekind cuts
  2706   (not included by default);
  2707 
  2708 * directory HOL/UNITY: Chandy and Misra's UNITY formalism;
  2709 
  2710 * directory HOL/Hoare: a new version of Hoare logic which permits many-sorted
  2711   programs, i.e. different program variables may have different types.
  2712 
  2713 * calling (stac rew i) now fails if "rew" has no effect on the goal
  2714   [previously, this check worked only if the rewrite rule was unconditional]
  2715   Now rew can involve either definitions or equalities (either == or =).
  2716 
  2717 
  2718 *** ZF ***
  2719 
  2720 * theory Main includes everything; INCOMPATIBILITY: theory ZF.thy contains
  2721   only the theorems proved on ZF.ML;
  2722 
  2723 * ZF INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
  2724   It and 'sym RS equals0D' are now in the default  claset, giving automatic
  2725   disjointness reasoning but breaking a few old proofs.
  2726 
  2727 * ZF/Update: new theory of function updates
  2728     with default rewrite rule  f(x:=y) ` z = if(z=x, y, f`z)
  2729   may also be iterated as in f(a:=b,c:=d,...);
  2730 
  2731 * in  let x=t in u(x), neither t nor u(x) has to be an FOL term.
  2732 
  2733 * calling (stac rew i) now fails if "rew" has no effect on the goal
  2734   [previously, this check worked only if the rewrite rule was unconditional]
  2735   Now rew can involve either definitions or equalities (either == or =).
  2736 
  2737 * case_tac provided for compatibility with HOL
  2738     (like the old excluded_middle_tac, but with subgoals swapped)
  2739 
  2740 
  2741 *** Internal programming interfaces ***
  2742 
  2743 * Pure: several new basic modules made available for general use, see
  2744 also src/Pure/README;
  2745 
  2746 * improved the theory data mechanism to support encapsulation (data
  2747 kind name replaced by private Object.kind, acting as authorization
  2748 key); new type-safe user interface via functor TheoryDataFun; generic
  2749 print_data function becomes basically useless;
  2750 
  2751 * removed global_names compatibility flag -- all theory declarations
  2752 are qualified by default;
  2753 
  2754 * module Pure/Syntax now offers quote / antiquote translation
  2755 functions (useful for Hoare logic etc. with implicit dependencies);
  2756 see HOL/ex/Antiquote for an example use;
  2757 
  2758 * Simplifier now offers conversions (asm_)(full_)rewrite: simpset ->
  2759 cterm -> thm;
  2760 
  2761 * new tactical CHANGED_GOAL for checking that a tactic modifies a
  2762 subgoal;
  2763 
  2764 * Display.print_goals function moved to Locale.print_goals;
  2765 
  2766 * standard print function for goals supports current_goals_markers
  2767 variable for marking begin of proof, end of proof, start of goal; the
  2768 default is ("", "", ""); setting current_goals_markers := ("<proof>",
  2769 "</proof>", "<goal>") causes SGML like tagged proof state printing,
  2770 for example;
  2771 
  2772 
  2773 
  2774 New in Isabelle98 (January 1998)
  2775 --------------------------------
  2776 
  2777 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  2778 
  2779 * changed lexical syntax of terms / types: dots made part of long
  2780 identifiers, e.g. "%x.x" no longer possible, should be "%x. x";
  2781 
  2782 * simpset (and claset) reference variable replaced by functions
  2783 simpset / simpset_ref;
  2784 
  2785 * no longer supports theory aliases (via merge) and non-trivial
  2786 implicit merge of thms' signatures;
  2787 
  2788 * most internal names of constants changed due to qualified names;
  2789 
  2790 * changed Pure/Sequence interface (see Pure/seq.ML);
  2791 
  2792 
  2793 *** General Changes ***
  2794 
  2795 * hierachically structured name spaces (for consts, types, axms, thms
  2796 etc.); new lexical class 'longid' (e.g. Foo.bar.x) may render much of
  2797 old input syntactically incorrect (e.g. "%x.x"); COMPATIBILITY:
  2798 isatool fixdots ensures space after dots (e.g. "%x. x"); set
  2799 long_names for fully qualified output names; NOTE: ML programs
  2800 (special tactics, packages etc.) referring to internal names may have
  2801 to be adapted to cope with fully qualified names; in case of severe
  2802 backward campatibility problems try setting 'global_names' at compile
  2803 time to have enrything declared within a flat name space; one may also
  2804 fine tune name declarations in theories via the 'global' and 'local'
  2805 section;
  2806 
  2807 * reimplemented the implicit simpset and claset using the new anytype
  2808 data filed in signatures; references simpset:simpset ref etc. are
  2809 replaced by functions simpset:unit->simpset and
  2810 simpset_ref:unit->simpset ref; COMPATIBILITY: use isatool fixclasimp
  2811 to patch your ML files accordingly;
  2812 
  2813 * HTML output now includes theory graph data for display with Java
  2814 applet or isatool browser; data generated automatically via isatool
  2815 usedir (see -i option, ISABELLE_USEDIR_OPTIONS);
  2816 
  2817 * defs may now be conditional; improved rewrite_goals_tac to handle
  2818 conditional equations;
  2819 
  2820 * defs now admits additional type arguments, using TYPE('a) syntax;
  2821 
  2822 * theory aliases via merge (e.g. M=A+B+C) no longer supported, always
  2823 creates a new theory node; implicit merge of thms' signatures is
  2824 restricted to 'trivial' ones; COMPATIBILITY: one may have to use
  2825 transfer:theory->thm->thm in (rare) cases;
  2826 
  2827 * improved handling of draft signatures / theories; draft thms (and
  2828 ctyps, cterms) are automatically promoted to real ones;
  2829 
  2830 * slightly changed interfaces for oracles: admit many per theory, named
  2831 (e.g. oracle foo = mlfun), additional name argument for invoke_oracle;
  2832 
  2833 * print_goals: optional output of const types (set show_consts and
  2834 show_types);
  2835 
  2836 * improved output of warnings (###) and errors (***);
  2837 
  2838 * subgoal_tac displays a warning if the new subgoal has type variables;
  2839 
  2840 * removed old README and Makefiles;
  2841 
  2842 * replaced print_goals_ref hook by print_current_goals_fn and result_error_fn;
  2843 
  2844 * removed obsolete init_pps and init_database;
  2845 
  2846 * deleted the obsolete tactical STATE, which was declared by
  2847     fun STATE tacfun st = tacfun st st;
  2848 
  2849 * cd and use now support path variables, e.g. $ISABELLE_HOME, or ~
  2850 (which abbreviates $HOME);
  2851 
  2852 * changed Pure/Sequence interface (see Pure/seq.ML); COMPATIBILITY:
  2853 use isatool fixseq to adapt your ML programs (this works for fully
  2854 qualified references to the Sequence structure only!);
  2855 
  2856 * use_thy no longer requires writable current directory; it always
  2857 reloads .ML *and* .thy file, if either one is out of date;
  2858 
  2859 
  2860 *** Classical Reasoner ***
  2861 
  2862 * Clarify_tac, clarify_tac, clarify_step_tac, Clarify_step_tac: new
  2863 tactics that use classical reasoning to simplify a subgoal without
  2864 splitting it into several subgoals;
  2865 
  2866 * Safe_tac: like safe_tac but uses the default claset;
  2867 
  2868 
  2869 *** Simplifier ***
  2870 
  2871 * added simplification meta rules:
  2872     (asm_)(full_)simplify: simpset -> thm -> thm;
  2873 
  2874 * simplifier.ML no longer part of Pure -- has to be loaded by object
  2875 logics (again);
  2876 
  2877 * added prems argument to simplification procedures;
  2878 
  2879 * HOL, FOL, ZF: added infix function `addsplits':
  2880   instead of `<simpset> setloop (split_tac <thms>)'
  2881   you can simply write `<simpset> addsplits <thms>'
  2882 
  2883 
  2884 *** Syntax ***
  2885 
  2886 * TYPE('a) syntax for type reflection terms;
  2887 
  2888 * no longer handles consts with name "" -- declare as 'syntax' instead;
  2889 
  2890 * pretty printer: changed order of mixfix annotation preference (again!);
  2891 
  2892 * Pure: fixed idt/idts vs. pttrn/pttrns syntactic categories;
  2893 
  2894 
  2895 *** HOL ***
  2896 
  2897 * HOL: there is a new splitter `split_asm_tac' that can be used e.g.
  2898   with `addloop' of the simplifier to faciliate case splitting in premises.
  2899 
  2900 * HOL/TLA: Stephan Merz's formalization of Lamport's Temporal Logic of Actions;
  2901 
  2902 * HOL/Auth: new protocol proofs including some for the Internet
  2903   protocol TLS;
  2904 
  2905 * HOL/Map: new theory of `maps' a la VDM;
  2906 
  2907 * HOL/simplifier: simplification procedures nat_cancel_sums for
  2908 cancelling out common nat summands from =, <, <= (in)equalities, or
  2909 differences; simplification procedures nat_cancel_factor for
  2910 cancelling common factor from =, <, <= (in)equalities over natural
  2911 sums; nat_cancel contains both kinds of procedures, it is installed by
  2912 default in Arith.thy -- this COULD MAKE EXISTING PROOFS FAIL;
  2913 
  2914 * HOL/simplifier: terms of the form
  2915   `? x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x)'  (or t=x)
  2916   are rewritten to
  2917   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t)',
  2918   and those of the form
  2919   `! x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x) --> R(x)'  (or t=x)
  2920   are rewritten to
  2921   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t) --> R(t)',
  2922 
  2923 * HOL/datatype
  2924   Each datatype `t' now comes with a theorem `split_t_case' of the form
  2925 
  2926   P(t_case f1 ... fn x) =
  2927      ( (!y1 ... ym1. x = C1 y1 ... ym1 --> P(f1 y1 ... ym1)) &
  2928         ...
  2929        (!y1 ... ymn. x = Cn y1 ... ymn --> P(f1 y1 ... ymn))
  2930      )
  2931 
  2932   and a theorem `split_t_case_asm' of the form
  2933 
  2934   P(t_case f1 ... fn x) =
  2935     ~( (? y1 ... ym1. x = C1 y1 ... ym1 & ~P(f1 y1 ... ym1)) |
  2936         ...
  2937        (? y1 ... ymn. x = Cn y1 ... ymn & ~P(f1 y1 ... ymn))
  2938      )
  2939   which can be added to a simpset via `addsplits'. The existing theorems
  2940   expand_list_case and expand_option_case have been renamed to
  2941   split_list_case and split_option_case.
  2942 
  2943 * HOL/Arithmetic:
  2944   - `pred n' is automatically converted to `n-1'.
  2945     Users are strongly encouraged not to use `pred' any longer,
  2946     because it will disappear altogether at some point.
  2947   - Users are strongly encouraged to write "0 < n" rather than
  2948     "n ~= 0". Theorems and proof tools have been modified towards this
  2949     `standard'.
  2950 
  2951 * HOL/Lists:
  2952   the function "set_of_list" has been renamed "set" (and its theorems too);
  2953   the function "nth" now takes its arguments in the reverse order and
  2954   has acquired the infix notation "!" as in "xs!n".
  2955 
  2956 * HOL/Set: UNIV is now a constant and is no longer translated to Compl{};
  2957 
  2958 * HOL/Set: The operator (UN x.B x) now abbreviates (UN x:UNIV. B x) and its
  2959   specialist theorems (like UN1_I) are gone.  Similarly for (INT x.B x);
  2960 
  2961 * HOL/record: extensible records with schematic structural subtyping
  2962 (single inheritance); EXPERIMENTAL version demonstrating the encoding,
  2963 still lacks various theorems and concrete record syntax;
  2964 
  2965 
  2966 *** HOLCF ***
  2967 
  2968 * removed "axioms" and "generated by" sections;
  2969 
  2970 * replaced "ops" section by extended "consts" section, which is capable of
  2971   handling the continuous function space "->" directly;
  2972 
  2973 * domain package:
  2974   . proves theorems immediately and stores them in the theory,
  2975   . creates hierachical name space,
  2976   . now uses normal mixfix annotations (instead of cinfix...),
  2977   . minor changes to some names and values (for consistency),
  2978   . e.g. cases -> casedist, dists_eq -> dist_eqs, [take_lemma] -> take_lemmas,
  2979   . separator between mutual domain defs: changed "," to "and",
  2980   . improved handling of sort constraints;  now they have to
  2981     appear on the left-hand side of the equations only;
  2982 
  2983 * fixed LAM <x,y,zs>.b syntax;
  2984 
  2985 * added extended adm_tac to simplifier in HOLCF -- can now discharge
  2986 adm (%x. P (t x)), where P is chainfinite and t continuous;
  2987 
  2988 
  2989 *** FOL and ZF ***
  2990 
  2991 * FOL: there is a new splitter `split_asm_tac' that can be used e.g.
  2992   with `addloop' of the simplifier to faciliate case splitting in premises.
  2993 
  2994 * qed_spec_mp, qed_goal_spec_mp, qed_goalw_spec_mp are available, as
  2995 in HOL, they strip ALL and --> from proved theorems;
  2996 
  2997 
  2998 
  2999 New in Isabelle94-8 (May 1997)
  3000 ------------------------------
  3001 
  3002 *** General Changes ***
  3003 
  3004 * new utilities to build / run / maintain Isabelle etc. (in parts
  3005 still somewhat experimental); old Makefiles etc. still functional;
  3006 
  3007 * new 'Isabelle System Manual';
  3008 
  3009 * INSTALL text, together with ./configure and ./build scripts;
  3010 
  3011 * reimplemented type inference for greater efficiency, better error
  3012 messages and clean internal interface;
  3013 
  3014 * prlim command for dealing with lots of subgoals (an easier way of
  3015 setting goals_limit);
  3016 
  3017 
  3018 *** Syntax ***
  3019 
  3020 * supports alternative (named) syntax tables (parser and pretty
  3021 printer); internal interface is provided by add_modesyntax(_i);
  3022 
  3023 * Pure, FOL, ZF, HOL, HOLCF now support symbolic input and output; to
  3024 be used in conjunction with the Isabelle symbol font; uses the
  3025 "symbols" syntax table;
  3026 
  3027 * added token_translation interface (may translate name tokens in
  3028 arbitrary ways, dependent on their type (free, bound, tfree, ...) and
  3029 the current print_mode); IMPORTANT: user print translation functions
  3030 are responsible for marking newly introduced bounds
  3031 (Syntax.mark_boundT);
  3032 
  3033 * token translations for modes "xterm" and "xterm_color" that display
  3034 names in bold, underline etc. or colors (which requires a color
  3035 version of xterm);
  3036 
  3037 * infixes may now be declared with names independent of their syntax;
  3038 
  3039 * added typed_print_translation (like print_translation, but may
  3040 access type of constant);
  3041 
  3042 
  3043 *** Classical Reasoner ***
  3044 
  3045 Blast_tac: a new tactic!  It is often more powerful than fast_tac, but has
  3046 some limitations.  Blast_tac...
  3047   + ignores addss, addbefore, addafter; this restriction is intrinsic
  3048   + ignores elimination rules that don't have the correct format
  3049         (the conclusion MUST be a formula variable)
  3050   + ignores types, which can make HOL proofs fail
  3051   + rules must not require higher-order unification, e.g. apply_type in ZF
  3052     [message "Function Var's argument not a bound variable" relates to this]
  3053   + its proof strategy is more general but can actually be slower
  3054 
  3055 * substitution with equality assumptions no longer permutes other
  3056 assumptions;
  3057 
  3058 * minor changes in semantics of addafter (now called addaltern); renamed
  3059 setwrapper to setWrapper and compwrapper to compWrapper; added safe wrapper
  3060 (and access functions for it);
  3061 
  3062 * improved combination of classical reasoner and simplifier:
  3063   + functions for handling clasimpsets
  3064   + improvement of addss: now the simplifier is called _after_ the
  3065     safe steps.
  3066   + safe variant of addss called addSss: uses safe simplifications
  3067     _during_ the safe steps. It is more complete as it allows multiple
  3068     instantiations of unknowns (e.g. with slow_tac).
  3069 
  3070 *** Simplifier ***
  3071 
  3072 * added interface for simplification procedures (functions that
  3073 produce *proven* rewrite rules on the fly, depending on current
  3074 redex);
  3075 
  3076 * ordering on terms as parameter (used for ordered rewriting);
  3077 
  3078 * new functions delcongs, deleqcongs, and Delcongs. richer rep_ss;
  3079 
  3080 * the solver is now split into a safe and an unsafe part.
  3081 This should be invisible for the normal user, except that the
  3082 functions setsolver and addsolver have been renamed to setSolver and
  3083 addSolver; added safe_asm_full_simp_tac;
  3084 
  3085 
  3086 *** HOL ***
  3087 
  3088 * a generic induction tactic `induct_tac' which works for all datatypes and
  3089 also for type `nat';
  3090 
  3091 * a generic case distinction tactic `exhaust_tac' which works for all
  3092 datatypes and also for type `nat';
  3093 
  3094 * each datatype comes with a function `size';
  3095 
  3096 * patterns in case expressions allow tuple patterns as arguments to
  3097 constructors, for example `case x of [] => ... | (x,y,z)#ps => ...';
  3098 
  3099 * primrec now also works with type nat;
  3100 
  3101 * recdef: a new declaration form, allows general recursive functions to be
  3102 defined in theory files.  See HOL/ex/Fib, HOL/ex/Primes, HOL/Subst/Unify.
  3103 
  3104 * the constant for negation has been renamed from "not" to "Not" to
  3105 harmonize with FOL, ZF, LK, etc.;
  3106 
  3107 * HOL/ex/LFilter theory of a corecursive "filter" functional for
  3108 infinite lists;
  3109 
  3110 * HOL/Modelcheck demonstrates invocation of model checker oracle;
  3111 
  3112 * HOL/ex/Ring.thy declares cring_simp, which solves equational
  3113 problems in commutative rings, using axiomatic type classes for + and *;
  3114 
  3115 * more examples in HOL/MiniML and HOL/Auth;
  3116 
  3117 * more default rewrite rules for quantifiers, union/intersection;
  3118 
  3119 * a new constant `arbitrary == @x.False';
  3120 
  3121 * HOLCF/IOA replaces old HOL/IOA;
  3122 
  3123 * HOLCF changes: derived all rules and arities
  3124   + axiomatic type classes instead of classes
  3125   + typedef instead of faking type definitions
  3126   + eliminated the internal constants less_fun, less_cfun, UU_fun, UU_cfun etc.
  3127   + new axclasses cpo, chfin, flat with flat < chfin < pcpo < cpo < po
  3128   + eliminated the types void, one, tr
  3129   + use unit lift and bool lift (with translations) instead of one and tr
  3130   + eliminated blift from Lift3.thy (use Def instead of blift)
  3131   all eliminated rules are derived as theorems --> no visible changes ;
  3132 
  3133 
  3134 *** ZF ***
  3135 
  3136 * ZF now has Fast_tac, Simp_tac and Auto_tac.  Union_iff is a now a default
  3137 rewrite rule; this may affect some proofs.  eq_cs is gone but can be put back
  3138 as ZF_cs addSIs [equalityI];
  3139 
  3140 
  3141 
  3142 New in Isabelle94-7 (November 96)
  3143 ---------------------------------
  3144 
  3145 * allowing negative levels (as offsets) in prlev and choplev;
  3146 
  3147 * super-linear speedup for large simplifications;
  3148 
  3149 * FOL, ZF and HOL now use miniscoping: rewriting pushes
  3150 quantifications in as far as possible (COULD MAKE EXISTING PROOFS
  3151 FAIL); can suppress it using the command Delsimps (ex_simps @
  3152 all_simps); De Morgan laws are also now included, by default;
  3153 
  3154 * improved printing of ==>  :  ~:
  3155 
  3156 * new object-logic "Sequents" adds linear logic, while replacing LK
  3157 and Modal (thanks to Sara Kalvala);
  3158 
  3159 * HOL/Auth: correctness proofs for authentication protocols;
  3160 
  3161 * HOL: new auto_tac combines rewriting and classical reasoning (many
  3162 examples on HOL/Auth);
  3163 
  3164 * HOL: new command AddIffs for declaring theorems of the form P=Q to
  3165 the rewriter and classical reasoner simultaneously;
  3166 
  3167 * function uresult no longer returns theorems in "standard" format;
  3168 regain previous version by: val uresult = standard o uresult;
  3169 
  3170 
  3171 
  3172 New in Isabelle94-6
  3173 -------------------
  3174 
  3175 * oracles -- these establish an interface between Isabelle and trusted
  3176 external reasoners, which may deliver results as theorems;
  3177 
  3178 * proof objects (in particular record all uses of oracles);
  3179 
  3180 * Simp_tac, Fast_tac, etc. that refer to implicit simpset / claset;
  3181 
  3182 * "constdefs" section in theory files;
  3183 
  3184 * "primrec" section (HOL) no longer requires names;
  3185 
  3186 * internal type "tactic" now simply "thm -> thm Sequence.seq";
  3187 
  3188 
  3189 
  3190 New in Isabelle94-5
  3191 -------------------
  3192 
  3193 * reduced space requirements;
  3194 
  3195 * automatic HTML generation from theories;
  3196 
  3197 * theory files no longer require "..." (quotes) around most types;
  3198 
  3199 * new examples, including two proofs of the Church-Rosser theorem;
  3200 
  3201 * non-curried (1994) version of HOL is no longer distributed;
  3202 
  3203 
  3204 
  3205 New in Isabelle94-4
  3206 -------------------
  3207 
  3208 * greatly reduced space requirements;
  3209 
  3210 * theory files (.thy) no longer require \...\ escapes at line breaks;
  3211 
  3212 * searchable theorem database (see the section "Retrieving theorems" on
  3213 page 8 of the Reference Manual);
  3214 
  3215 * new examples, including Grabczewski's monumental case study of the
  3216 Axiom of Choice;
  3217 
  3218 * The previous version of HOL renamed to Old_HOL;
  3219 
  3220 * The new version of HOL (previously called CHOL) uses a curried syntax
  3221 for functions.  Application looks like f a b instead of f(a,b);
  3222 
  3223 * Mutually recursive inductive definitions finally work in HOL;
  3224 
  3225 * In ZF, pattern-matching on tuples is now available in all abstractions and
  3226 translates to the operator "split";
  3227 
  3228 
  3229 
  3230 New in Isabelle94-3
  3231 -------------------
  3232 
  3233 * new infix operator, addss, allowing the classical reasoner to
  3234 perform simplification at each step of its search.  Example:
  3235         fast_tac (cs addss ss)
  3236 
  3237 * a new logic, CHOL, the same as HOL, but with a curried syntax
  3238 for functions.  Application looks like f a b instead of f(a,b).  Also pairs
  3239 look like (a,b) instead of <a,b>;
  3240 
  3241 * PLEASE NOTE: CHOL will eventually replace HOL!
  3242 
  3243 * In CHOL, pattern-matching on tuples is now available in all abstractions.
  3244 It translates to the operator "split".  A new theory of integers is available;
  3245 
  3246 * In ZF, integer numerals now denote two's-complement binary integers.
  3247 Arithmetic operations can be performed by rewriting.  See ZF/ex/Bin.ML;
  3248 
  3249 * Many new examples: I/O automata, Church-Rosser theorem, equivalents
  3250 of the Axiom of Choice;
  3251 
  3252 
  3253 
  3254 New in Isabelle94-2
  3255 -------------------
  3256 
  3257 * Significantly faster resolution;
  3258 
  3259 * the different sections in a .thy file can now be mixed and repeated
  3260 freely;
  3261 
  3262 * Database of theorems for FOL, HOL and ZF.  New
  3263 commands including qed, qed_goal and bind_thm store theorems in the database.
  3264 
  3265 * Simple database queries: return a named theorem (get_thm) or all theorems of
  3266 a given theory (thms_of), or find out what theory a theorem was proved in
  3267 (theory_of_thm);
  3268 
  3269 * Bugs fixed in the inductive definition and datatype packages;
  3270 
  3271 * The classical reasoner provides deepen_tac and depth_tac, making FOL_dup_cs
  3272 and HOL_dup_cs obsolete;
  3273 
  3274 * Syntactic ambiguities caused by the new treatment of syntax in Isabelle94-1
  3275 have been removed;
  3276 
  3277 * Simpler definition of function space in ZF;
  3278 
  3279 * new results about cardinal and ordinal arithmetic in ZF;
  3280 
  3281 * 'subtype' facility in HOL for introducing new types as subsets of existing
  3282 types;
  3283 
  3284 
  3285 $Id$