NEWS
author wenzelm
Fri Sep 23 22:21:49 2005 +0200 (2005-09-23)
changeset 17609 5156b731ebc8
parent 17597 dac8dd2272cd
child 17619 026f7bbc8a0f
permissions -rw-r--r--
Provers/cancel_sums.ML: Simplifier.inherit_bounds;
     1 Isabelle NEWS -- history user-relevant changes
     2 ==============================================
     3 
     4 New in Isabelle2005 (September 2005)
     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 now, but these will disappear soon.
    23 
    24 * Theory loader: parent theories can now also be referred to via
    25 relative and absolute paths.
    26 
    27 * Command 'find_theorems' searches for a list of criteria instead of a
    28 list of constants. Known criteria are: intro, elim, dest, name:string,
    29 simp:term, and any term. Criteria can be preceded by '-' to select
    30 theorems that do not match. Intro, elim, dest select theorems that
    31 match the current goal, name:s selects theorems whose fully qualified
    32 name contain s, and simp:term selects all simplification rules whose
    33 lhs match term.  Any other term is interpreted as pattern and selects
    34 all theorems matching the pattern. Available in ProofGeneral under
    35 'ProofGeneral -> Find Theorems' or C-c C-f.  Example:
    36 
    37   C-c C-f (100) "(_::nat) + _ + _" intro -name: "HOL."
    38 
    39 prints the last 100 theorems matching the pattern "(_::nat) + _ + _",
    40 matching the current goal as introduction rule and not having "HOL."
    41 in their name (i.e. not being defined in theory HOL).
    42 
    43 * Command 'thms_containing' has been discontinued in favour of
    44 'find_theorems'; INCOMPATIBILITY.
    45 
    46 * Communication with Proof General is now 8bit clean, which means that
    47 Unicode text in UTF-8 encoding may be used within theory texts (both
    48 formal and informal parts).  Cf. option -U of the Isabelle Proof
    49 General interface.  Here are some simple examples (cf. src/HOL/ex):
    50 
    51   http://isabelle.in.tum.de/library/HOL/ex/Hebrew.html
    52   http://isabelle.in.tum.de/library/HOL/ex/Chinese.html
    53 
    54 * Improved efficiency of the Simplifier and, to a lesser degree, the
    55 Classical Reasoner.  Typical big applications run around 2 times
    56 faster.
    57 
    58 * ProofGeneral interface: the default settings no longer prefer xemacs
    59 over GNU emacs.  Users typically need to experiment with various
    60 variations on PROOFGENERAL_OPTIONS="... -p emacs" to find the most
    61 stable Emacs version on their platform.
    62 
    63 
    64 *** Document preparation ***
    65 
    66 * Commands 'display_drafts' and 'print_drafts' perform simple output
    67 of raw sources.  Only those symbols that do not require additional
    68 LaTeX packages (depending on comments in isabellesym.sty) are
    69 displayed properly, everything else is left verbatim.  isatool display
    70 and isatool print are used as front ends (these are subject to the
    71 DVI/PDF_VIEWER and PRINT_COMMAND settings, respectively).
    72 
    73 * Command tags control specific markup of certain regions of text,
    74 notably folding and hiding.  Predefined tags include "theory" (for
    75 theory begin and end), "proof" for proof commands, and "ML" for
    76 commands involving ML code; the additional tags "visible" and
    77 "invisible" are unused by default.  Users may give explicit tag
    78 specifications in the text, e.g. ''by %invisible (auto)''.  The
    79 interpretation of tags is determined by the LaTeX job during document
    80 preparation: see option -V of isatool usedir, or options -n and -t of
    81 isatool document, or even the LaTeX macros \isakeeptag, \isafoldtag,
    82 \isadroptag.
    83 
    84 Several document versions may be produced at the same time via isatool
    85 usedir (the generated index.html will link all of them).  Typical
    86 specifications include ''-V document=theory,proof,ML'' to present
    87 theory/proof/ML parts faithfully, ''-V outline=/proof,/ML'' to fold
    88 proof and ML commands, and ''-V mutilated=-theory,-proof,-ML'' to omit
    89 these parts without any formal replacement text.  The Isabelle site
    90 default settings produce ''document'' and ''outline'' versions as
    91 specified above.
    92 
    93 * Several new antiquotations:
    94 
    95   @{term_type term} prints a term with its type annotated;
    96 
    97   @{typeof term} prints the type of a term;
    98 
    99   @{const const} is the same as @{term const}, but checks that the
   100   argument is a known logical constant;
   101 
   102   @{term_style style term} and @{thm_style style thm} print a term or
   103   theorem applying a "style" to it
   104 
   105   @{ML text}
   106 
   107 Predefined styles are 'lhs' and 'rhs' printing the lhs/rhs of
   108 definitions, equations, inequations etc., 'concl' printing only the
   109 conclusion of a meta-logical statement theorem, and 'prem1' .. 'prem19'
   110 to print the specified premise.  TermStyle.add_style provides an ML
   111 interface for introducing further styles.  See also the "LaTeX Sugar"
   112 document practical applications.  The ML antiquotation prints
   113 type-checked ML expressions verbatim.
   114 
   115 * Markup commands 'chapter', 'section', 'subsection', 'subsubsection',
   116 and 'text' support optional locale specification '(in loc)', which
   117 specifies the default context for interpreting antiquotations.  For
   118 example: 'text (in lattice) {* @{thm inf_assoc}*}'.
   119 
   120 * Option 'locale=NAME' of antiquotations specifies an alternative
   121 context interpreting the subsequent argument.  For example: @{thm
   122 [locale=lattice] inf_assoc}.
   123 
   124 * Proper output of proof terms (@{prf ...} and @{full_prf ...}) within
   125 a proof context.
   126 
   127 * Proper output of antiquotations for theory commands involving a
   128 proof context (such as 'locale' or 'theorem (in loc) ...').
   129 
   130 * Delimiters of outer tokens (string etc.) now produce separate LaTeX
   131 macros (\isachardoublequoteopen, isachardoublequoteclose etc.).
   132 
   133 * isatool usedir: new option -C (default true) controls whether option
   134 -D should include a copy of the original document directory; -C false
   135 prevents unwanted effects such as copying of administrative CVS data.
   136 
   137 
   138 *** Pure ***
   139 
   140 * Considerably improved version of 'constdefs' command.  Now performs
   141 automatic type-inference of declared constants; additional support for
   142 local structure declarations (cf. locales and HOL records), see also
   143 isar-ref manual.  Potential INCOMPATIBILITY: need to observe strictly
   144 sequential dependencies of definitions within a single 'constdefs'
   145 section; moreover, the declared name needs to be an identifier.  If
   146 all fails, consider to fall back on 'consts' and 'defs' separately.
   147 
   148 * Improved indexed syntax and implicit structures.  First of all,
   149 indexed syntax provides a notational device for subscripted
   150 application, using the new syntax \<^bsub>term\<^esub> for arbitrary
   151 expressions.  Secondly, in a local context with structure
   152 declarations, number indexes \<^sub>n or the empty index (default
   153 number 1) refer to a certain fixed variable implicitly; option
   154 show_structs controls printing of implicit structures.  Typical
   155 applications of these concepts involve record types and locales.
   156 
   157 * New command 'no_syntax' removes grammar declarations (and
   158 translations) resulting from the given syntax specification, which is
   159 interpreted in the same manner as for the 'syntax' command.
   160 
   161 * 'Advanced' translation functions (parse_translation etc.) may depend
   162 on the signature of the theory context being presently used for
   163 parsing/printing, see also isar-ref manual.
   164 
   165 * Improved 'oracle' command provides a type-safe interface to turn an
   166 ML expression of type theory -> T -> term into a primitive rule of
   167 type theory -> T -> thm (i.e. the functionality of Thm.invoke_oracle
   168 is already included here); see also FOL/ex/IffExample.thy;
   169 INCOMPATIBILITY.
   170 
   171 * axclass: name space prefix for class "c" is now "c_class" (was "c"
   172 before); "cI" is no longer bound, use "c.intro" instead.
   173 INCOMPATIBILITY.  This change avoids clashes of fact bindings for
   174 axclasses vs. locales.
   175 
   176 * Improved internal renaming of symbolic identifiers -- attach primes
   177 instead of base 26 numbers.
   178 
   179 * New flag show_question_marks controls printing of leading question
   180 marks in schematic variable names.
   181 
   182 * In schematic variable names, *any* symbol following \<^isub> or
   183 \<^isup> is now treated as part of the base name.  For example, the
   184 following works without printing of awkward ".0" indexes:
   185 
   186   lemma "x\<^isub>1 = x\<^isub>2 ==> x\<^isub>2 = x\<^isub>1"
   187     by simp
   188 
   189 * Inner syntax includes (*(*nested*) comments*).
   190 
   191 * Pretty printer now supports unbreakable blocks, specified in mixfix
   192 annotations as "(00...)".
   193 
   194 * Clear separation of logical types and nonterminals, where the latter
   195 may only occur in 'syntax' specifications or type abbreviations.
   196 Before that distinction was only partially implemented via type class
   197 "logic" vs. "{}".  Potential INCOMPATIBILITY in rare cases of improper
   198 use of 'types'/'consts' instead of 'nonterminals'/'syntax'.  Some very
   199 exotic syntax specifications may require further adaption
   200 (e.g. Cube/Base.thy).
   201 
   202 * Removed obsolete type class "logic", use the top sort {} instead.
   203 Note that non-logical types should be declared as 'nonterminals'
   204 rather than 'types'.  INCOMPATIBILITY for new object-logic
   205 specifications.
   206 
   207 * 'defs': more well-formedness checks of overloaded definitions.
   208 
   209 * Attributes 'induct' and 'cases': type or set names may now be
   210 locally fixed variables as well.
   211 
   212 * Simplifier: can now control the depth to which conditional rewriting
   213 is traced via the PG menu Isabelle -> Settings -> Trace Simp Depth
   214 Limit.
   215 
   216 * Simplifier: simplification procedures may now take the current
   217 simpset into account (cf. Simplifier.simproc(_i) / mk_simproc
   218 interface), which is very useful for calling the Simplifier
   219 recursively.  Minor INCOMPATIBILITY: the 'prems' argument of simprocs
   220 is gone -- use prems_of_ss on the simpset instead.  Moreover, the
   221 low-level mk_simproc no longer applies Logic.varify internally, to
   222 allow for use in a context of fixed variables.
   223 
   224 * thin_tac now works even if the assumption being deleted contains !!
   225 or ==>.  More generally, erule now works even if the major premise of
   226 the elimination rule contains !! or ==>.
   227 
   228 * Method 'rules' has been renamed to 'iprover'. INCOMPATIBILITY.
   229 
   230 * Reorganized bootstrapping of the Pure theories; CPure is now derived
   231 from Pure, which contains all common declarations already.  Both
   232 theories are defined via plain Isabelle/Isar .thy files.
   233 INCOMPATIBILITY: elements of CPure (such as the CPure.intro /
   234 CPure.elim / CPure.dest attributes) now appear in the Pure name space;
   235 use isatool fixcpure to adapt your theory and ML sources.
   236 
   237 * New syntax 'name(i-j, i-, i, ...)' for referring to specific
   238 selections of theorems in named facts via index ranges.
   239 
   240 * 'print_theorems': in theory mode, really print the difference
   241 wrt. the last state (works for interactive theory development only),
   242 in proof mode print all local facts (cf. 'print_facts');
   243 
   244 * 'hide': option '(open)' hides only base names.
   245 
   246 * More efficient treatment of intermediate checkpoints in interactive
   247 theory development.
   248 
   249 
   250 *** Locales ***
   251 
   252 * New commands for the interpretation of locale expressions in
   253 theories (1), locales (2) and proof contexts (3).  These generate
   254 proof obligations from the expression specification.  After the
   255 obligations have been discharged, theorems of the expression are added
   256 to the theory, target locale or proof context.  The synopsis of the
   257 commands is a follows:
   258 
   259   (1) interpretation expr inst
   260   (2) interpretation target < expr
   261   (3) interpret expr inst
   262 
   263 Interpretation in theories and proof contexts require a parameter
   264 instantiation of terms from the current context.  This is applied to
   265 specifications and theorems of the interpreted expression.
   266 Interpretation in locales only permits parameter renaming through the
   267 locale expression.  Interpretation is smart in that interpretations
   268 that are active already do not occur in proof obligations, neither are
   269 instantiated theorems stored in duplicate.  Use 'print_interps' to
   270 inspect active interpretations of a particular locale.  For details,
   271 see the Isar Reference manual.  Examples can be found in
   272 HOL/Finite_Set.thy and HOL/Algebra/UnivPoly.thy.
   273 
   274 INCOMPATIBILITY: former 'instantiate' has been withdrawn, use
   275 'interpret' instead.
   276 
   277 * New context element 'constrains' for adding type constraints to
   278 parameters.
   279 
   280 * Context expressions: renaming of parameters with syntax
   281 redeclaration.
   282 
   283 * Locale declaration: 'includes' disallowed.
   284 
   285 * Proper static binding of attribute syntax -- i.e. types / terms /
   286 facts mentioned as arguments are always those of the locale definition
   287 context, independently of the context of later invocations.  Moreover,
   288 locale operations (renaming and type / term instantiation) are applied
   289 to attribute arguments as expected.
   290 
   291 INCOMPATIBILITY of the ML interface: always pass Attrib.src instead of
   292 actual attributes; rare situations may require Attrib.attribute to
   293 embed those attributes into Attrib.src that lack concrete syntax.
   294 Attribute implementations need to cooperate properly with the static
   295 binding mechanism.  Basic parsers Args.XXX_typ/term/prop and
   296 Attrib.XXX_thm etc. already do the right thing without further
   297 intervention.  Only unusual applications -- such as "where" or "of"
   298 (cf. src/Pure/Isar/attrib.ML), which process arguments depending both
   299 on the context and the facts involved -- may have to assign parsed
   300 values to argument tokens explicitly.
   301 
   302 * Changed parameter management in theorem generation for long goal
   303 statements with 'includes'.  INCOMPATIBILITY: produces a different
   304 theorem statement in rare situations.
   305 
   306 * Locale inspection command 'print_locale' omits notes elements.  Use
   307 'print_locale!' to have them included in the output.
   308 
   309 
   310 *** Provers ***
   311 
   312 * Provers/hypsubst.ML: improved version of the subst method, for
   313 single-step rewriting: it now works in bound variable contexts. New is
   314 'subst (asm)', for rewriting an assumption.  INCOMPATIBILITY: may
   315 rewrite a different subterm than the original subst method, which is
   316 still available as 'simplesubst'.
   317 
   318 * Provers/quasi.ML: new transitivity reasoners for transitivity only
   319 and quasi orders.
   320 
   321 * Provers/trancl.ML: new transitivity reasoner for transitive and
   322 reflexive-transitive closure of relations.
   323 
   324 * Provers/blast.ML: new reference depth_limit to make blast's depth
   325 limit (previously hard-coded with a value of 20) user-definable.
   326 
   327 * Provers/simplifier.ML has been moved to Pure, where Simplifier.setup
   328 is peformed already.  Object-logics merely need to finish their
   329 initial simpset configuration as before.  INCOMPATIBILITY.
   330 
   331 
   332 *** HOL ***
   333 
   334 * Symbolic syntax of Hilbert Choice Operator is now as follows:
   335 
   336   syntax (epsilon)
   337     "_Eps" :: "[pttrn, bool] => 'a"    ("(3\<some>_./ _)" [0, 10] 10)
   338 
   339 The symbol \<some> is displayed as the alternative epsilon of LaTeX
   340 and x-symbol; use option '-m epsilon' to get it actually printed.
   341 Moreover, the mathematically important symbolic identifier \<epsilon>
   342 becomes available as variable, constant etc.  INCOMPATIBILITY,
   343 
   344 * "x > y" abbreviates "y < x" and "x >= y" abbreviates "y <= x".
   345 Similarly for all quantifiers: "ALL x > y" etc.  The x-symbol for >=
   346 is \<ge>. New transitivity rules have been added to HOL/Orderings.thy to
   347 support corresponding Isar calculations.
   348 
   349 * "{x:A. P}" abbreviates "{x. x:A & P}", and similarly for "\<in>"
   350 instead of ":".
   351 
   352 * theory SetInterval: changed the syntax for open intervals:
   353 
   354   Old       New
   355   {..n(}    {..<n}
   356   {)n..}    {n<..}
   357   {m..n(}   {m..<n}
   358   {)m..n}   {m<..n}
   359   {)m..n(}  {m<..<n}
   360 
   361 The old syntax is still supported but will disappear in the next
   362 release.  For conversion use the following Emacs search and replace
   363 patterns (these are not perfect but work quite well):
   364 
   365   {)\([^\.]*\)\.\.  ->  {\1<\.\.}
   366   \.\.\([^(}]*\)(}  ->  \.\.<\1}
   367 
   368 * Theory Commutative_Ring (in Library): method comm_ring for proving
   369 equalities in commutative rings; method 'algebra' provides a generic
   370 interface.
   371 
   372 * Theory Finite_Set: changed the syntax for 'setsum', summation over
   373 finite sets: "setsum (%x. e) A", which used to be "\<Sum>x:A. e", is
   374 now either "SUM x:A. e" or "\<Sum>x \<in> A. e". The bound variable can
   375 be a tuple pattern.
   376 
   377 Some new syntax forms are available:
   378 
   379   "\<Sum>x | P. e"      for     "setsum (%x. e) {x. P}"
   380   "\<Sum>x = a..b. e"   for     "setsum (%x. e) {a..b}"
   381   "\<Sum>x = a..<b. e"  for     "setsum (%x. e) {a..<b}"
   382   "\<Sum>x < k. e"      for     "setsum (%x. e) {..<k}"
   383 
   384 The latter form "\<Sum>x < k. e" used to be based on a separate
   385 function "Summation", which has been discontinued.
   386 
   387 * theory Finite_Set: in structured induction proofs, the insert case
   388 is now 'case (insert x F)' instead of the old counterintuitive 'case
   389 (insert F x)'.
   390 
   391 * The 'refute' command has been extended to support a much larger
   392 fragment of HOL, including axiomatic type classes, constdefs and
   393 typedefs, inductive datatypes and recursion.
   394 
   395 * Datatype induction via method 'induct' now preserves the name of the
   396 induction variable. For example, when proving P(xs::'a list) by
   397 induction on xs, the induction step is now P(xs) ==> P(a#xs) rather
   398 than P(list) ==> P(a#list) as previously.  Potential INCOMPATIBILITY
   399 in unstructured proof scripts.
   400 
   401 * Reworked implementation of records.  Improved scalability for
   402 records with many fields, avoiding performance problems for type
   403 inference. Records are no longer composed of nested field types, but
   404 of nested extension types. Therefore the record type only grows linear
   405 in the number of extensions and not in the number of fields.  The
   406 top-level (users) view on records is preserved.  Potential
   407 INCOMPATIBILITY only in strange cases, where the theory depends on the
   408 old record representation. The type generated for a record is called
   409 <record_name>_ext_type.
   410 
   411 Flag record_quick_and_dirty_sensitive can be enabled to skip the
   412 proofs triggered by a record definition or a simproc (if
   413 quick_and_dirty is enabled).  Definitions of large records can take
   414 quite long.
   415 
   416 New simproc record_upd_simproc for simplification of multiple record
   417 updates enabled by default.  Moreover, trivial updates are also
   418 removed: r(|x := x r|) = r.  INCOMPATIBILITY: old proofs break
   419 occasionally, since simplification is more powerful by default.
   420 
   421 * typedef: proper support for polymorphic sets, which contain extra
   422 type-variables in the term.
   423 
   424 * Simplifier: automatically reasons about transitivity chains
   425 involving "trancl" (r^+) and "rtrancl" (r^*) by setting up tactics
   426 provided by Provers/trancl.ML as additional solvers.  INCOMPATIBILITY:
   427 old proofs break occasionally as simplification may now solve more
   428 goals than previously.
   429 
   430 * Simplifier: converts x <= y into x = y if assumption y <= x is
   431 present.  Works for all partial orders (class "order"), in particular
   432 numbers and sets.  For linear orders (e.g. numbers) it treats ~ x < y
   433 just like y <= x.
   434 
   435 * Simplifier: new simproc for "let x = a in f x".  If a is a free or
   436 bound variable or a constant then the let is unfolded.  Otherwise
   437 first a is simplified to b, and then f b is simplified to g. If
   438 possible we abstract b from g arriving at "let x = b in h x",
   439 otherwise we unfold the let and arrive at g.  The simproc can be
   440 enabled/disabled by the reference use_let_simproc.  Potential
   441 INCOMPATIBILITY since simplification is more powerful by default.
   442 
   443 * Classical reasoning: the meson method now accepts theorems as arguments.
   444 
   445 * Prover support: pre-release of the Isabelle-ATP linkup, which runs background
   446 jobs to provide advice on the provability of subgoals.
   447 
   448 * Theory OrderedGroup and Ring_and_Field: various additions and
   449 improvements to faciliate calculations involving equalities and
   450 inequalities.
   451 
   452 The following theorems have been eliminated or modified
   453 (INCOMPATIBILITY):
   454 
   455   abs_eq             now named abs_of_nonneg
   456   abs_of_ge_0        now named abs_of_nonneg
   457   abs_minus_eq       now named abs_of_nonpos
   458   imp_abs_id         now named abs_of_nonneg
   459   imp_abs_neg_id     now named abs_of_nonpos
   460   mult_pos           now named mult_pos_pos
   461   mult_pos_le        now named mult_nonneg_nonneg
   462   mult_pos_neg_le    now named mult_nonneg_nonpos
   463   mult_pos_neg2_le   now named mult_nonneg_nonpos2
   464   mult_neg           now named mult_neg_neg
   465   mult_neg_le        now named mult_nonpos_nonpos
   466 
   467 * Theory Parity: added rules for simplifying exponents.
   468 
   469 * Theory List:
   470 
   471 The following theorems have been eliminated or modified
   472 (INCOMPATIBILITY):
   473 
   474   list_all_Nil       now named list_all.simps(1)
   475   list_all_Cons      now named list_all.simps(2)
   476   list_all_conv      now named list_all_iff
   477   set_mem_eq         now named mem_iff
   478 
   479 * Theories SetsAndFunctions and BigO (see HOL/Library) support
   480 asymptotic "big O" calculations.  See the notes in BigO.thy.
   481 
   482 
   483 *** HOL-Complex ***
   484 
   485 * Theory RealDef: better support for embedding natural numbers and
   486 integers in the reals.
   487 
   488 The following theorems have been eliminated or modified
   489 (INCOMPATIBILITY):
   490 
   491   exp_ge_add_one_self  now requires no hypotheses
   492   real_of_int_add      reversed direction of equality (use [symmetric])
   493   real_of_int_minus    reversed direction of equality (use [symmetric])
   494   real_of_int_diff     reversed direction of equality (use [symmetric])
   495   real_of_int_mult     reversed direction of equality (use [symmetric])
   496 
   497 * Theory RComplete: expanded support for floor and ceiling functions.
   498 
   499 * Theory Ln is new, with properties of the natural logarithm
   500 
   501 * Hyperreal: There is a new type constructor "star" for making
   502 nonstandard types.  The old type names are now type synonyms:
   503 
   504   hypreal = real star
   505   hypnat = nat star
   506   hcomplex = complex star
   507 
   508 * Hyperreal: Many groups of similarly-defined constants have been
   509 replaced by polymorphic versions (INCOMPATIBILITY):
   510 
   511   star_of <-- hypreal_of_real, hypnat_of_nat, hcomplex_of_complex
   512 
   513   starset      <-- starsetNat, starsetC
   514   *s*          <-- *sNat*, *sc*
   515   starset_n    <-- starsetNat_n, starsetC_n
   516   *sn*         <-- *sNatn*, *scn*
   517   InternalSets <-- InternalNatSets, InternalCSets
   518 
   519   starfun      <-- starfun{Nat,Nat2,C,RC,CR}
   520   *f*          <-- *fNat*, *fNat2*, *fc*, *fRc*, *fcR*
   521   starfun_n    <-- starfun{Nat,Nat2,C,RC,CR}_n
   522   *fn*         <-- *fNatn*, *fNat2n*, *fcn*, *fRcn*, *fcRn*
   523   InternalFuns <-- InternalNatFuns, InternalNatFuns2, Internal{C,RC,CR}Funs
   524 
   525 * Hyperreal: Many type-specific theorems have been removed in favor of
   526 theorems specific to various axiomatic type classes (INCOMPATIBILITY):
   527 
   528   add_commute <-- {hypreal,hypnat,hcomplex}_add_commute
   529   add_assoc   <-- {hypreal,hypnat,hcomplex}_add_assocs
   530   OrderedGroup.add_0 <-- {hypreal,hypnat,hcomplex}_add_zero_left
   531   OrderedGroup.add_0_right <-- {hypreal,hcomplex}_add_zero_right
   532   right_minus <-- hypreal_add_minus
   533   left_minus <-- {hypreal,hcomplex}_add_minus_left
   534   mult_commute <-- {hypreal,hypnat,hcomplex}_mult_commute
   535   mult_assoc <-- {hypreal,hypnat,hcomplex}_mult_assoc
   536   mult_1_left <-- {hypreal,hypnat}_mult_1, hcomplex_mult_one_left
   537   mult_1_right <-- hcomplex_mult_one_right
   538   mult_zero_left <-- hcomplex_mult_zero_left
   539   left_distrib <-- {hypreal,hypnat,hcomplex}_add_mult_distrib
   540   right_distrib <-- hypnat_add_mult_distrib2
   541   zero_neq_one <-- {hypreal,hypnat,hcomplex}_zero_not_eq_one
   542   right_inverse <-- hypreal_mult_inverse
   543   left_inverse <-- hypreal_mult_inverse_left, hcomplex_mult_inv_left
   544   order_refl <-- {hypreal,hypnat}_le_refl
   545   order_trans <-- {hypreal,hypnat}_le_trans
   546   order_antisym <-- {hypreal,hypnat}_le_anti_sym
   547   order_less_le <-- {hypreal,hypnat}_less_le
   548   linorder_linear <-- {hypreal,hypnat}_le_linear
   549   add_left_mono <-- {hypreal,hypnat}_add_left_mono
   550   mult_strict_left_mono <-- {hypreal,hypnat}_mult_less_mono2
   551   add_nonneg_nonneg <-- hypreal_le_add_order
   552 
   553 * Hyperreal: Separate theorems having to do with type-specific
   554 versions of constants have been merged into theorems that apply to the
   555 new polymorphic constants (INCOMPATIBILITY):
   556 
   557   STAR_UNIV_set <-- {STAR_real,NatStar_real,STARC_complex}_set
   558   STAR_empty_set <-- {STAR,NatStar,STARC}_empty_set
   559   STAR_Un <-- {STAR,NatStar,STARC}_Un
   560   STAR_Int <-- {STAR,NatStar,STARC}_Int
   561   STAR_Compl <-- {STAR,NatStar,STARC}_Compl
   562   STAR_subset <-- {STAR,NatStar,STARC}_subset
   563   STAR_mem <-- {STAR,NatStar,STARC}_mem
   564   STAR_mem_Compl <-- {STAR,STARC}_mem_Compl
   565   STAR_diff <-- {STAR,STARC}_diff
   566   STAR_star_of_image_subset <-- {STAR_hypreal_of_real, NatStar_hypreal_of_real,
   567     STARC_hcomplex_of_complex}_image_subset
   568   starset_n_Un <-- starset{Nat,C}_n_Un
   569   starset_n_Int <-- starset{Nat,C}_n_Int
   570   starset_n_Compl <-- starset{Nat,C}_n_Compl
   571   starset_n_diff <-- starset{Nat,C}_n_diff
   572   InternalSets_Un <-- Internal{Nat,C}Sets_Un
   573   InternalSets_Int <-- Internal{Nat,C}Sets_Int
   574   InternalSets_Compl <-- Internal{Nat,C}Sets_Compl
   575   InternalSets_diff <-- Internal{Nat,C}Sets_diff
   576   InternalSets_UNIV_diff <-- Internal{Nat,C}Sets_UNIV_diff
   577   InternalSets_starset_n <-- Internal{Nat,C}Sets_starset{Nat,C}_n
   578   starset_starset_n_eq <-- starset{Nat,C}_starset{Nat,C}_n_eq
   579   starset_n_starset <-- starset{Nat,C}_n_starset{Nat,C}
   580   starfun_n_starfun <-- starfun{Nat,Nat2,C,RC,CR}_n_starfun{Nat,Nat2,C,RC,CR}
   581   starfun <-- starfun{Nat,Nat2,C,RC,CR}
   582   starfun_mult <-- starfun{Nat,Nat2,C,RC,CR}_mult
   583   starfun_add <-- starfun{Nat,Nat2,C,RC,CR}_add
   584   starfun_minus <-- starfun{Nat,Nat2,C,RC,CR}_minus
   585   starfun_diff <-- starfun{C,RC,CR}_diff
   586   starfun_o <-- starfun{NatNat2,Nat2,_stafunNat,C,C_starfunRC,_starfunCR}_o
   587   starfun_o2 <-- starfun{NatNat2,_stafunNat,C,C_starfunRC,_starfunCR}_o2
   588   starfun_const_fun <-- starfun{Nat,Nat2,C,RC,CR}_const_fun
   589   starfun_inverse <-- starfun{Nat,C,RC,CR}_inverse
   590   starfun_eq <-- starfun{Nat,Nat2,C,RC,CR}_eq
   591   starfun_eq_iff <-- starfun{C,RC,CR}_eq_iff
   592   starfun_Id <-- starfunC_Id
   593   starfun_approx <-- starfun{Nat,CR}_approx
   594   starfun_capprox <-- starfun{C,RC}_capprox
   595   starfun_abs <-- starfunNat_rabs
   596   starfun_lambda_cancel <-- starfun{C,CR,RC}_lambda_cancel
   597   starfun_lambda_cancel2 <-- starfun{C,CR,RC}_lambda_cancel2
   598   starfun_mult_HFinite_approx <-- starfunCR_mult_HFinite_capprox
   599   starfun_mult_CFinite_capprox <-- starfun{C,RC}_mult_CFinite_capprox
   600   starfun_add_capprox <-- starfun{C,RC}_add_capprox
   601   starfun_add_approx <-- starfunCR_add_approx
   602   starfun_inverse_inverse <-- starfunC_inverse_inverse
   603   starfun_divide <-- starfun{C,CR,RC}_divide
   604   starfun_n <-- starfun{Nat,C}_n
   605   starfun_n_mult <-- starfun{Nat,C}_n_mult
   606   starfun_n_add <-- starfun{Nat,C}_n_add
   607   starfun_n_add_minus <-- starfunNat_n_add_minus
   608   starfun_n_const_fun <-- starfun{Nat,C}_n_const_fun
   609   starfun_n_minus <-- starfun{Nat,C}_n_minus
   610   starfun_n_eq <-- starfun{Nat,C}_n_eq
   611 
   612   star_n_add <-- {hypreal,hypnat,hcomplex}_add
   613   star_n_minus <-- {hypreal,hcomplex}_minus
   614   star_n_diff <-- {hypreal,hcomplex}_diff
   615   star_n_mult <-- {hypreal,hcomplex}_mult
   616   star_n_inverse <-- {hypreal,hcomplex}_inverse
   617   star_n_le <-- {hypreal,hypnat}_le
   618   star_n_less <-- {hypreal,hypnat}_less
   619   star_n_zero_num <-- {hypreal,hypnat,hcomplex}_zero_num
   620   star_n_one_num <-- {hypreal,hypnat,hcomplex}_one_num
   621   star_n_abs <-- hypreal_hrabs
   622   star_n_divide <-- hcomplex_divide
   623 
   624   star_of_add <-- {hypreal_of_real,hypnat_of_nat,hcomplex_of_complex}_add
   625   star_of_minus <-- {hypreal_of_real,hcomplex_of_complex}_minus
   626   star_of_diff <-- hypreal_of_real_diff
   627   star_of_mult <-- {hypreal_of_real,hypnat_of_nat,hcomplex_of_complex}_mult
   628   star_of_one <-- {hypreal_of_real,hcomplex_of_complex}_one
   629   star_of_zero <-- {hypreal_of_real,hypnat_of_nat,hcomplex_of_complex}_zero
   630   star_of_le <-- {hypreal_of_real,hypnat_of_nat}_le_iff
   631   star_of_less <-- {hypreal_of_real,hypnat_of_nat}_less_iff
   632   star_of_eq <-- {hypreal_of_real,hypnat_of_nat,hcomplex_of_complex}_eq_iff
   633   star_of_inverse <-- {hypreal_of_real,hcomplex_of_complex}_inverse
   634   star_of_divide <-- {hypreal_of_real,hcomplex_of_complex}_divide
   635   star_of_of_nat <-- {hypreal_of_real,hcomplex_of_complex}_of_nat
   636   star_of_of_int <-- {hypreal_of_real,hcomplex_of_complex}_of_int
   637   star_of_number_of <-- {hypreal,hcomplex}_number_of
   638   star_of_number_less <-- number_of_less_hypreal_of_real_iff
   639   star_of_number_le <-- number_of_le_hypreal_of_real_iff
   640   star_of_eq_number <-- hypreal_of_real_eq_number_of_iff
   641   star_of_less_number <-- hypreal_of_real_less_number_of_iff
   642   star_of_le_number <-- hypreal_of_real_le_number_of_iff
   643   star_of_power <-- hypreal_of_real_power
   644   star_of_eq_0 <-- hcomplex_of_complex_zero_iff
   645 
   646 * Hyperreal: new method "transfer" that implements the transfer
   647 principle of nonstandard analysis. With a subgoal that mentions
   648 nonstandard types like "'a star", the command "apply transfer"
   649 replaces it with an equivalent one that mentions only standard types.
   650 To be successful, all free variables must have standard types; non-
   651 standard variables must have explicit universal quantifiers.
   652 
   653 
   654 *** HOLCF ***
   655 
   656 * Discontinued special version of 'constdefs' (which used to support
   657 continuous functions) in favor of the general Pure one with full
   658 type-inference.
   659 
   660 * New simplification procedure for solving continuity conditions; it
   661 is much faster on terms with many nested lambda abstractions (cubic
   662 instead of exponential time).
   663 
   664 * New syntax for domain package: selector names are now optional.
   665 Parentheses should be omitted unless argument is lazy, for example:
   666 
   667   domain 'a stream = cons "'a" (lazy "'a stream")
   668 
   669 * New command 'fixrec' for defining recursive functions with pattern
   670 matching; defining multiple functions with mutual recursion is also
   671 supported.  Patterns may include the constants cpair, spair, up, sinl,
   672 sinr, or any data constructor defined by the domain package. The given
   673 equations are proven as rewrite rules. See HOLCF/ex/Fixrec_ex.thy for
   674 syntax and examples.
   675 
   676 * New commands 'cpodef' and 'pcpodef' for defining predicate subtypes
   677 of cpo and pcpo types. Syntax is exactly like the 'typedef' command,
   678 but the proof obligation additionally includes an admissibility
   679 requirement. The packages generate instances of class cpo or pcpo,
   680 with continuity and strictness theorems for Rep and Abs.
   681 
   682 * HOLCF: Many theorems have been renamed according to a more standard naming
   683 scheme (INCOMPATIBILITY):
   684 
   685   foo_inject:  "foo$x = foo$y ==> x = y"
   686   foo_eq:      "(foo$x = foo$y) = (x = y)"
   687   foo_less:    "(foo$x << foo$y) = (x << y)"
   688   foo_strict:  "foo$UU = UU"
   689   foo_defined: "... ==> foo$x ~= UU"
   690   foo_defined_iff: "(foo$x = UU) = (x = UU)"
   691 
   692 
   693 *** ZF ***
   694 
   695 * ZF/ex: theories Group and Ring provide examples in abstract algebra,
   696 including the First Isomorphism Theorem (on quotienting by the kernel
   697 of a homomorphism).
   698 
   699 * ZF/Simplifier: install second copy of type solver that actually
   700 makes use of TC rules declared to Isar proof contexts (or locales);
   701 the old version is still required for ML proof scripts.
   702 
   703 
   704 *** Cube ***
   705 
   706 * Converted to Isar theory format; use locales instead of axiomatic
   707 theories.
   708 
   709 
   710 *** ML ***
   711 
   712 * Pure/library.ML no longer defines its own option datatype, but uses
   713 that of the SML basis, which has constructors NONE and SOME instead of
   714 None and Some, as well as exception Option.Option instead of OPTION.
   715 The functions the, if_none, is_some, is_none have been adapted
   716 accordingly, while Option.map replaces apsome.
   717 
   718 * Pure/library.ML: the exception LIST has been given up in favour of
   719 the standard exceptions Empty and Subscript, as well as
   720 Library.UnequalLengths.  Function like Library.hd and Library.tl are
   721 superceded by the standard hd and tl functions etc.
   722 
   723 A number of basic list functions are no longer exported to the ML
   724 toplevel, as they are variants of predefined functions.  The following
   725 suggests how one can translate existing code:
   726 
   727     rev_append xs ys = List.revAppend (xs, ys)
   728     nth_elem (i, xs) = List.nth (xs, i)
   729     last_elem xs = List.last xs
   730     flat xss = List.concat xss
   731     seq fs = List.app fs
   732     partition P xs = List.partition P xs
   733     mapfilter f xs = List.mapPartial f xs
   734 
   735 * Pure/library.ML: several combinators for linear functional
   736 transformations, notably reverse application and composition:
   737 
   738   x |> f                f #> g
   739   (x, y) |-> f          f #-> g
   740 
   741 * Pure/library.ML: introduced/changed precedence of infix operators:
   742 
   743   infix 1 |> |-> ||> ||>> |>> |>>> #> #->;
   744   infix 2 ?;
   745   infix 3 o oo ooo oooo;
   746   infix 4 ~~ upto downto;
   747 
   748 Maybe INCOMPATIBILITY when any of those is used in conjunction with other
   749 infix operators.
   750 
   751 * Pure/library.ML: natural list combinators fold, fold_rev, and
   752 fold_map support linear functional transformations and nesting.  For
   753 example:
   754 
   755   fold f [x1, ..., xN] y =
   756     y |> f x1 |> ... |> f xN
   757 
   758   (fold o fold) f [xs1, ..., xsN] y =
   759     y |> fold f xs1 |> ... |> fold f xsN
   760 
   761   fold f [x1, ..., xN] =
   762     f x1 #> ... #> f xN
   763 
   764   (fold o fold) f [xs1, ..., xsN] =
   765     fold f xs1 #> ... #> fold f xsN
   766 
   767 * Pure/library.ML: the following selectors on type 'a option are
   768 available:
   769 
   770   the:               'a option -> 'a  (*partial*)
   771   these:             'a option -> 'a  where 'a = 'b list
   772   the_default: 'a -> 'a option -> 'a
   773   the_list:          'a option -> 'a list
   774 
   775 * Pure/General: structure AList (cf. Pure/General/alist.ML) provides
   776 basic operations for association lists, following natural argument
   777 order; moreover the explicit equality predicate passed here avoids
   778 potentially expensive polymorphic runtime equality checks.
   779 The old functions may be expressed as follows:
   780 
   781   assoc = uncurry (AList.lookup (op =))
   782   assocs = these oo AList.lookup (op =)
   783   overwrite = uncurry (AList.update (op =)) o swap
   784 
   785 * Pure/General: structure AList (cf. Pure/General/alist.ML) provides
   786 
   787   val make: ('a -> 'b) -> 'a list -> ('a * 'b) list
   788   val find: ('a * 'b -> bool) -> ('c * 'b) list -> 'a -> 'c list
   789 
   790 replacing make_keylist and keyfilter (occassionally used)
   791 Naive rewrites:
   792 
   793   make_keylist = AList.make
   794   keyfilter = AList.find (op =)
   795 
   796 * eq_fst and eq_snd now take explicit equality parameter, thus
   797   avoiding eqtypes. Naive rewrites:
   798 
   799     eq_fst = eq_fst (op =)
   800     eq_snd = eq_snd (op =)
   801 
   802 * Removed deprecated apl and apr (rarely used).
   803   Naive rewrites:
   804 
   805     apl (n, op) =>>= curry op n
   806     apr (op, m) =>>= fn n => op (n, m)
   807 
   808 * Pure/General: structure OrdList (cf. Pure/General/ord_list.ML)
   809 provides a reasonably efficient light-weight implementation of sets as
   810 lists.
   811 
   812 * Pure/General: generic tables (cf. Pure/General/table.ML) provide a
   813 few new operations; existing lookup and update are now curried to
   814 follow natural argument order (for use with fold etc.);
   815 INCOMPATIBILITY, use (uncurry Symtab.lookup) etc. as last resort.
   816 
   817 * Pure/General: output via the Isabelle channels of
   818 writeln/warning/error etc. is now passed through Output.output, with a
   819 hook for arbitrary transformations depending on the print_mode
   820 (cf. Output.add_mode -- the first active mode that provides a output
   821 function wins).  Already formatted output may be embedded into further
   822 text via Output.raw; the result of Pretty.string_of/str_of and derived
   823 functions (string_of_term/cterm/thm etc.) is already marked raw to
   824 accommodate easy composition of diagnostic messages etc.  Programmers
   825 rarely need to care about Output.output or Output.raw at all, with
   826 some notable exceptions: Output.output is required when bypassing the
   827 standard channels (writeln etc.), or in token translations to produce
   828 properly formatted results; Output.raw is required when capturing
   829 already output material that will eventually be presented to the user
   830 a second time.  For the default print mode, both Output.output and
   831 Output.raw have no effect.
   832 
   833 * Pure/General: Output.time_accumulator NAME creates an operator ('a
   834 -> 'b) -> 'a -> 'b to measure runtime and count invocations; the
   835 cumulative results are displayed at the end of a batch session.
   836 
   837 * Pure/General: File.sysify_path and File.quote_sysify path have been
   838 replaced by File.platform_path and File.shell_path (with appropriate
   839 hooks).  This provides a clean interface for unusual systems where the
   840 internal and external process view of file names are different.
   841 
   842 * Pure: more efficient orders for basic syntactic entities: added
   843 fast_string_ord, fast_indexname_ord, fast_term_ord; changed sort_ord
   844 and typ_ord to use fast_string_ord and fast_indexname_ord (term_ord is
   845 NOT affected); structures Symtab, Vartab, Typtab, Termtab use the fast
   846 orders now -- potential INCOMPATIBILITY for code that depends on a
   847 particular order for Symtab.keys, Symtab.dest, etc. (consider using
   848 Library.sort_strings on result).
   849 
   850 * Pure/term.ML: combinators fold_atyps, fold_aterms, fold_term_types,
   851 fold_types traverse types/terms from left to right, observing natural
   852 argument order.  Supercedes previous foldl_XXX versions, add_frees,
   853 add_vars etc. have been adapted as well: INCOMPATIBILITY.
   854 
   855 * Pure: name spaces have been refined, with significant changes of the
   856 internal interfaces -- INCOMPATIBILITY.  Renamed cond_extern(_table)
   857 to extern(_table).  The plain name entry path is superceded by a
   858 general 'naming' context, which also includes the 'policy' to produce
   859 a fully qualified name and external accesses of a fully qualified
   860 name; NameSpace.extend is superceded by context dependent
   861 Sign.declare_name.  Several theory and proof context operations modify
   862 the naming context.  Especially note Theory.restore_naming and
   863 ProofContext.restore_naming to get back to a sane state; note that
   864 Theory.add_path is no longer sufficient to recover from
   865 Theory.absolute_path in particular.
   866 
   867 * Pure: new flags short_names (default false) and unique_names
   868 (default true) for controlling output of qualified names.  If
   869 short_names is set, names are printed unqualified.  If unique_names is
   870 reset, the name prefix is reduced to the minimum required to achieve
   871 the original result when interning again, even if there is an overlap
   872 with earlier declarations.
   873 
   874 * Pure/TheoryDataFun: change of the argument structure; 'prep_ext' is
   875 now 'extend', and 'merge' gets an additional Pretty.pp argument
   876 (useful for printing error messages).  INCOMPATIBILITY.
   877 
   878 * Pure: major reorganization of the theory context.  Type Sign.sg and
   879 Theory.theory are now identified, referring to the universal
   880 Context.theory (see Pure/context.ML).  Actual signature and theory
   881 content is managed as theory data.  The old code and interfaces were
   882 spread over many files and structures; the new arrangement introduces
   883 considerable INCOMPATIBILITY to gain more clarity:
   884 
   885   Context -- theory management operations (name, identity, inclusion,
   886     parents, ancestors, merge, etc.), plus generic theory data;
   887 
   888   Sign -- logical signature and syntax operations (declaring consts,
   889     types, etc.), plus certify/read for common entities;
   890 
   891   Theory -- logical theory operations (stating axioms, definitions,
   892     oracles), plus a copy of logical signature operations (consts,
   893     types, etc.); also a few basic management operations (Theory.copy,
   894     Theory.merge, etc.)
   895 
   896 The most basic sign_of operations (Theory.sign_of, Thm.sign_of_thm
   897 etc.) as well as the sign field in Thm.rep_thm etc. have been retained
   898 for convenience -- they merely return the theory.
   899 
   900 * Pure: type Type.tsig is superceded by theory in most interfaces.
   901 
   902 * Pure: the Isar proof context type is already defined early in Pure
   903 as Context.proof (note that ProofContext.context and Proof.context are
   904 aliases, where the latter is the preferred name).  This enables other
   905 Isabelle components to refer to that type even before Isar is present.
   906 
   907 * Pure/sign/theory: discontinued named name spaces (i.e. classK,
   908 typeK, constK, axiomK, oracleK), but provide explicit operations for
   909 any of these kinds.  For example, Sign.intern typeK is now
   910 Sign.intern_type, Theory.hide_space Sign.typeK is now
   911 Theory.hide_types.  Also note that former
   912 Theory.hide_classes/types/consts are now
   913 Theory.hide_classes_i/types_i/consts_i, while the non '_i' versions
   914 internalize their arguments!  INCOMPATIBILITY.
   915 
   916 * Pure: get_thm interface (of PureThy and ProofContext) expects
   917 datatype thmref (with constructors Name and NameSelection) instead of
   918 plain string -- INCOMPATIBILITY;
   919 
   920 * Pure: cases produced by proof methods specify options, where NONE
   921 means to remove case bindings -- INCOMPATIBILITY in
   922 (RAW_)METHOD_CASES.
   923 
   924 * Pure: the following operations retrieve axioms or theorems from a
   925 theory node or theory hierarchy, respectively:
   926 
   927   Theory.axioms_of: theory -> (string * term) list
   928   Theory.all_axioms_of: theory -> (string * term) list
   929   PureThy.thms_of: theory -> (string * thm) list
   930   PureThy.all_thms_of: theory -> (string * thm) list
   931 
   932 * Pure: print_tac now outputs the goal through the trace channel.
   933 
   934 * Isar toplevel: improved diagnostics, mostly for Poly/ML only.
   935 Reference Toplevel.debug (default false) controls detailed printing
   936 and tracing of low-level exceptions; Toplevel.profiling (default 0)
   937 controls execution profiling -- set to 1 for time and 2 for space
   938 (both increase the runtime).
   939 
   940 * Isar session: The initial use of ROOT.ML is now always timed,
   941 i.e. the log will show the actual process times, in contrast to the
   942 elapsed wall-clock time that the outer shell wrapper produces.
   943 
   944 * Simplifier: improved handling of bound variables (nameless
   945 representation, avoid allocating new strings).  Simprocs that invoke
   946 the Simplifier recursively should use Simplifier.inherit_bounds to
   947 avoid local name clashes.
   948 
   949 * Provers: Simplifier and Classical Reasoner now support proof context
   950 dependent plug-ins (simprocs, solvers, wrappers etc.).  These extra
   951 components are stored in the theory and patched into the
   952 simpset/claset when used in an Isar proof context.  Context dependent
   953 components are maintained by the following theory operations:
   954 
   955   Simplifier.add_context_simprocs
   956   Simplifier.del_context_simprocs
   957   Simplifier.set_context_subgoaler
   958   Simplifier.reset_context_subgoaler
   959   Simplifier.add_context_looper
   960   Simplifier.del_context_looper
   961   Simplifier.add_context_unsafe_solver
   962   Simplifier.add_context_safe_solver
   963 
   964   Classical.add_context_safe_wrapper
   965   Classical.del_context_safe_wrapper
   966   Classical.add_context_unsafe_wrapper
   967   Classical.del_context_unsafe_wrapper
   968 
   969 IMPORTANT NOTE: proof tools (methods etc.) need to use
   970 local_simpset_of and local_claset_of to instead of the primitive
   971 Simplifier.get_local_simpset and Classical.get_local_claset,
   972 respectively, in order to see the context dependent fields!
   973 
   974 * ML functions legacy_bindings and use_legacy_bindings produce ML fact
   975 bindings for all theorems stored within a given theory; this may help
   976 in porting non-Isar theories to Isar ones, while keeping ML proof
   977 scripts for the time being.
   978 
   979 * ML operator HTML.with_charset specifies the charset begin used for
   980 generated HTML files.  For example:
   981 
   982   HTML.with_charset "utf-8" use_thy "Hebrew";
   983   HTML.with_charset "utf-8" use_thy "Chinese";
   984 
   985 
   986 *** System ***
   987 
   988 * Allow symlinks to all proper Isabelle executables (Isabelle,
   989 isabelle, isatool etc.).
   990 
   991 * ISABELLE_DOC_FORMAT setting specifies preferred document format (for
   992 isatool doc, isatool mkdir, display_drafts etc.).
   993 
   994 * isatool usedir: option -f allows specification of the ML file to be
   995 used by Isabelle; default is ROOT.ML.
   996 
   997 * New isatool version outputs the version identifier of the Isabelle
   998 distribution being used.
   999 
  1000 * HOL: new isatool dimacs2hol converts files in DIMACS CNF format
  1001 (containing Boolean satisfiability problems) into Isabelle/HOL
  1002 theories.
  1003 
  1004 
  1005 
  1006 New in Isabelle2004 (April 2004)
  1007 --------------------------------
  1008 
  1009 *** General ***
  1010 
  1011 * Provers/order.ML:  new efficient reasoner for partial and linear orders.
  1012   Replaces linorder.ML.
  1013 
  1014 * Pure: Greek letters (except small lambda, \<lambda>), as well as Gothic
  1015   (\<aa>...\<zz>\<AA>...\<ZZ>), calligraphic (\<A>...\<Z>), and Euler
  1016   (\<a>...\<z>), are now considered normal letters, and can therefore
  1017   be used anywhere where an ASCII letter (a...zA...Z) has until
  1018   now. COMPATIBILITY: This obviously changes the parsing of some
  1019   terms, especially where a symbol has been used as a binder, say
  1020   '\<Pi>x. ...', which is now a type error since \<Pi>x will be parsed
  1021   as an identifier.  Fix it by inserting a space around former
  1022   symbols.  Call 'isatool fixgreek' to try to fix parsing errors in
  1023   existing theory and ML files.
  1024 
  1025 * Pure: Macintosh and Windows line-breaks are now allowed in theory files.
  1026 
  1027 * Pure: single letter sub/superscripts (\<^isub> and \<^isup>) are now
  1028   allowed in identifiers. Similar to Greek letters \<^isub> is now considered
  1029   a normal (but invisible) letter. For multiple letter subscripts repeat
  1030   \<^isub> like this: x\<^isub>1\<^isub>2.
  1031 
  1032 * Pure: There are now sub-/superscripts that can span more than one
  1033   character. Text between \<^bsub> and \<^esub> is set in subscript in
  1034   ProofGeneral and LaTeX, text between \<^bsup> and \<^esup> in
  1035   superscript. The new control characters are not identifier parts.
  1036 
  1037 * Pure: Control-symbols of the form \<^raw:...> will literally print the
  1038   content of "..." to the latex file instead of \isacntrl... . The "..."
  1039   may consist of any printable characters excluding the end bracket >.
  1040 
  1041 * Pure: Using new Isar command "finalconsts" (or the ML functions
  1042   Theory.add_finals or Theory.add_finals_i) it is now possible to
  1043   declare constants "final", which prevents their being given a definition
  1044   later.  It is useful for constants whose behaviour is fixed axiomatically
  1045   rather than definitionally, such as the meta-logic connectives.
  1046 
  1047 * Pure: 'instance' now handles general arities with general sorts
  1048   (i.e. intersections of classes),
  1049 
  1050 * Presentation: generated HTML now uses a CSS style sheet to make layout
  1051   (somewhat) independent of content. It is copied from lib/html/isabelle.css.
  1052   It can be changed to alter the colors/layout of generated pages.
  1053 
  1054 
  1055 *** Isar ***
  1056 
  1057 * Tactic emulation methods rule_tac, erule_tac, drule_tac, frule_tac,
  1058   cut_tac, subgoal_tac and thin_tac:
  1059   - Now understand static (Isar) contexts.  As a consequence, users of Isar
  1060     locales are no longer forced to write Isar proof scripts.
  1061     For details see Isar Reference Manual, paragraph 4.3.2: Further tactic
  1062     emulations.
  1063   - INCOMPATIBILITY: names of variables to be instantiated may no
  1064     longer be enclosed in quotes.  Instead, precede variable name with `?'.
  1065     This is consistent with the instantiation attribute "where".
  1066 
  1067 * Attributes "where" and "of":
  1068   - Now take type variables of instantiated theorem into account when reading
  1069     the instantiation string.  This fixes a bug that caused instantiated
  1070     theorems to have too special types in some circumstances.
  1071   - "where" permits explicit instantiations of type variables.
  1072 
  1073 * Calculation commands "moreover" and "also" no longer interfere with
  1074   current facts ("this"), admitting arbitrary combinations with "then"
  1075   and derived forms.
  1076 
  1077 * Locales:
  1078   - Goal statements involving the context element "includes" no longer
  1079     generate theorems with internal delta predicates (those ending on
  1080     "_axioms") in the premise.
  1081     Resolve particular premise with <locale>.intro to obtain old form.
  1082   - Fixed bug in type inference ("unify_frozen") that prevented mix of target
  1083     specification and "includes" elements in goal statement.
  1084   - Rule sets <locale>.intro and <locale>.axioms no longer declared as
  1085     [intro?] and [elim?] (respectively) by default.
  1086   - Experimental command for instantiation of locales in proof contexts:
  1087         instantiate <label>[<attrs>]: <loc>
  1088     Instantiates locale <loc> and adds all its theorems to the current context
  1089     taking into account their attributes.  Label and attrs are optional
  1090     modifiers, like in theorem declarations.  If present, names of
  1091     instantiated theorems are qualified with <label>, and the attributes
  1092     <attrs> are applied after any attributes these theorems might have already.
  1093       If the locale has assumptions, a chained fact of the form
  1094     "<loc> t1 ... tn" is expected from which instantiations of the parameters
  1095     are derived.  The command does not support old-style locales declared
  1096     with "locale (open)".
  1097       A few (very simple) examples can be found in FOL/ex/LocaleInst.thy.
  1098 
  1099 * HOL: Tactic emulation methods induct_tac and case_tac understand static
  1100   (Isar) contexts.
  1101 
  1102 
  1103 *** HOL ***
  1104 
  1105 * Proof import: new image HOL4 contains the imported library from
  1106   the HOL4 system with about 2500 theorems. It is imported by
  1107   replaying proof terms produced by HOL4 in Isabelle. The HOL4 image
  1108   can be used like any other Isabelle image.  See
  1109   HOL/Import/HOL/README for more information.
  1110 
  1111 * Simplifier:
  1112   - Much improved handling of linear and partial orders.
  1113     Reasoners for linear and partial orders are set up for type classes
  1114     "linorder" and "order" respectively, and are added to the default simpset
  1115     as solvers.  This means that the simplifier can build transitivity chains
  1116     to solve goals from the assumptions.
  1117   - INCOMPATIBILITY: old proofs break occasionally.  Typically, applications
  1118     of blast or auto after simplification become unnecessary because the goal
  1119     is solved by simplification already.
  1120 
  1121 * Numerics: new theory Ring_and_Field contains over 250 basic numerical laws,
  1122     all proved in axiomatic type classes for semirings, rings and fields.
  1123 
  1124 * Numerics:
  1125   - Numeric types (nat, int, and in HOL-Complex rat, real, complex, etc.) are
  1126     now formalized using the Ring_and_Field theory mentioned above.
  1127   - INCOMPATIBILITY: simplification and arithmetic behaves somewhat differently
  1128     than before, because now they are set up once in a generic manner.
  1129   - INCOMPATIBILITY: many type-specific arithmetic laws have gone.
  1130     Look for the general versions in Ring_and_Field (and Power if they concern
  1131     exponentiation).
  1132 
  1133 * Type "rat" of the rational numbers is now available in HOL-Complex.
  1134 
  1135 * Records:
  1136   - Record types are now by default printed with their type abbreviation
  1137     instead of the list of all field types. This can be configured via
  1138     the reference "print_record_type_abbr".
  1139   - Simproc "record_upd_simproc" for simplification of multiple updates added
  1140     (not enabled by default).
  1141   - Simproc "record_ex_sel_eq_simproc" to simplify EX x. sel r = x resp.
  1142     EX x. x = sel r to True (not enabled by default).
  1143   - Tactic "record_split_simp_tac" to split and simplify records added.
  1144 
  1145 * 'specification' command added, allowing for definition by
  1146   specification.  There is also an 'ax_specification' command that
  1147   introduces the new constants axiomatically.
  1148 
  1149 * arith(_tac) is now able to generate counterexamples for reals as well.
  1150 
  1151 * HOL-Algebra: new locale "ring" for non-commutative rings.
  1152 
  1153 * HOL-ex: InductiveInvariant_examples illustrates advanced recursive function
  1154   definitions, thanks to Sava Krsti\'{c} and John Matthews.
  1155 
  1156 * HOL-Matrix: a first theory for matrices in HOL with an application of
  1157   matrix theory to linear programming.
  1158 
  1159 * Unions and Intersections:
  1160   The latex output syntax of UN and INT has been changed
  1161   from "\Union x \in A. B" to "\Union_{x \in A} B"
  1162   i.e. the index formulae has become a subscript.
  1163   Similarly for "\Union x. B", and for \Inter instead of \Union.
  1164 
  1165 * Unions and Intersections over Intervals:
  1166   There is new short syntax "UN i<=n. A" for "UN i:{0..n}. A". There is
  1167   also an x-symbol version with subscripts "\<Union>\<^bsub>i <= n\<^esub>. A"
  1168   like in normal math, and corresponding versions for < and for intersection.
  1169 
  1170 * HOL/List: Ordering "lexico" is renamed "lenlex" and the standard
  1171   lexicographic dictonary ordering has been added as "lexord".
  1172 
  1173 * ML: the legacy theory structures Int and List have been removed. They had
  1174   conflicted with ML Basis Library structures having the same names.
  1175 
  1176 * 'refute' command added to search for (finite) countermodels.  Only works
  1177   for a fragment of HOL.  The installation of an external SAT solver is
  1178   highly recommended.  See "HOL/Refute.thy" for details.
  1179 
  1180 * 'quickcheck' command: Allows to find counterexamples by evaluating
  1181   formulae under an assignment of free variables to random values.
  1182   In contrast to 'refute', it can deal with inductive datatypes,
  1183   but cannot handle quantifiers. See "HOL/ex/Quickcheck_Examples.thy"
  1184   for examples.
  1185 
  1186 
  1187 *** HOLCF ***
  1188 
  1189 * Streams now come with concatenation and are part of the HOLCF image
  1190 
  1191 
  1192 
  1193 New in Isabelle2003 (May 2003)
  1194 ------------------------------
  1195 
  1196 *** General ***
  1197 
  1198 * Provers/simplifier:
  1199 
  1200   - Completely reimplemented method simp (ML: Asm_full_simp_tac):
  1201     Assumptions are now subject to complete mutual simplification,
  1202     not just from left to right. The simplifier now preserves
  1203     the order of assumptions.
  1204 
  1205     Potential INCOMPATIBILITY:
  1206 
  1207     -- simp sometimes diverges where the old version did
  1208        not, e.g. invoking simp on the goal
  1209 
  1210         [| P (f x); y = x; f x = f y |] ==> Q
  1211 
  1212        now gives rise to the infinite reduction sequence
  1213 
  1214         P(f x) --(f x = f y)--> P(f y) --(y = x)--> P(f x) --(f x = f y)--> ...
  1215 
  1216        Using "simp (asm_lr)" (ML: Asm_lr_simp_tac) instead often solves this
  1217        kind of problem.
  1218 
  1219     -- Tactics combining classical reasoner and simplification (such as auto)
  1220        are also affected by this change, because many of them rely on
  1221        simp. They may sometimes diverge as well or yield a different numbers
  1222        of subgoals. Try to use e.g. force, fastsimp, or safe instead of auto
  1223        in case of problems. Sometimes subsequent calls to the classical
  1224        reasoner will fail because a preceeding call to the simplifier too
  1225        eagerly simplified the goal, e.g. deleted redundant premises.
  1226 
  1227   - The simplifier trace now shows the names of the applied rewrite rules
  1228 
  1229   - You can limit the number of recursive invocations of the simplifier
  1230     during conditional rewriting (where the simplifie tries to solve the
  1231     conditions before applying the rewrite rule):
  1232     ML "simp_depth_limit := n"
  1233     where n is an integer. Thus you can force termination where previously
  1234     the simplifier would diverge.
  1235 
  1236   - Accepts free variables as head terms in congruence rules.  Useful in Isar.
  1237 
  1238   - No longer aborts on failed congruence proof.  Instead, the
  1239     congruence is ignored.
  1240 
  1241 * Pure: New generic framework for extracting programs from constructive
  1242   proofs. See HOL/Extraction.thy for an example instantiation, as well
  1243   as HOL/Extraction for some case studies.
  1244 
  1245 * Pure: The main goal of the proof state is no longer shown by default, only
  1246 the subgoals. This behaviour is controlled by a new flag.
  1247    PG menu: Isabelle/Isar -> Settings -> Show Main Goal
  1248 (ML: Proof.show_main_goal).
  1249 
  1250 * Pure: You can find all matching introduction rules for subgoal 1, i.e. all
  1251 rules whose conclusion matches subgoal 1:
  1252       PG menu: Isabelle/Isar -> Show me -> matching rules
  1253 The rules are ordered by how closely they match the subgoal.
  1254 In particular, rules that solve a subgoal outright are displayed first
  1255 (or rather last, the way they are printed).
  1256 (ML: ProofGeneral.print_intros())
  1257 
  1258 * Pure: New flag trace_unify_fail causes unification to print
  1259 diagnostic information (PG: in trace buffer) when it fails. This is
  1260 useful for figuring out why single step proofs like rule, erule or
  1261 assumption failed.
  1262 
  1263 * Pure: Locale specifications now produce predicate definitions
  1264 according to the body of text (covering assumptions modulo local
  1265 definitions); predicate "loc_axioms" covers newly introduced text,
  1266 while "loc" is cumulative wrt. all included locale expressions; the
  1267 latter view is presented only on export into the global theory
  1268 context; potential INCOMPATIBILITY, use "(open)" option to fall back
  1269 on the old view without predicates;
  1270 
  1271 * Pure: predefined locales "var" and "struct" are useful for sharing
  1272 parameters (as in CASL, for example); just specify something like
  1273 ``var x + var y + struct M'' as import;
  1274 
  1275 * Pure: improved thms_containing: proper indexing of facts instead of
  1276 raw theorems; check validity of results wrt. current name space;
  1277 include local facts of proof configuration (also covers active
  1278 locales), cover fixed variables in index; may use "_" in term
  1279 specification; an optional limit for the number of printed facts may
  1280 be given (the default is 40);
  1281 
  1282 * Pure: disallow duplicate fact bindings within new-style theory files
  1283 (batch-mode only);
  1284 
  1285 * Provers: improved induct method: assumptions introduced by case
  1286 "foo" are split into "foo.hyps" (from the rule) and "foo.prems" (from
  1287 the goal statement); "foo" still refers to all facts collectively;
  1288 
  1289 * Provers: the function blast.overloaded has been removed: all constants
  1290 are regarded as potentially overloaded, which improves robustness in exchange
  1291 for slight decrease in efficiency;
  1292 
  1293 * Provers/linorder: New generic prover for transitivity reasoning over
  1294 linear orders.  Note: this prover is not efficient!
  1295 
  1296 * Isar: preview of problems to finish 'show' now produce an error
  1297 rather than just a warning (in interactive mode);
  1298 
  1299 
  1300 *** HOL ***
  1301 
  1302 * arith(_tac)
  1303 
  1304  - Produces a counter example if it cannot prove a goal.
  1305    Note that the counter example may be spurious if the goal is not a formula
  1306    of quantifier-free linear arithmetic.
  1307    In ProofGeneral the counter example appears in the trace buffer.
  1308 
  1309  - Knows about div k and mod k where k is a numeral of type nat or int.
  1310 
  1311  - Calls full Presburger arithmetic (by Amine Chaieb) if quantifier-free
  1312    linear arithmetic fails. This takes account of quantifiers and divisibility.
  1313    Presburger arithmetic can also be called explicitly via presburger(_tac).
  1314 
  1315 * simp's arithmetic capabilities have been enhanced a bit: it now
  1316 takes ~= in premises into account (by performing a case split);
  1317 
  1318 * simp reduces "m*(n div m) + n mod m" to n, even if the two summands
  1319 are distributed over a sum of terms;
  1320 
  1321 * New tactic "trans_tac" and method "trans" instantiate
  1322 Provers/linorder.ML for axclasses "order" and "linorder" (predicates
  1323 "<=", "<" and "=").
  1324 
  1325 * function INCOMPATIBILITIES: Pi-sets have been redefined and moved from main
  1326 HOL to Library/FuncSet; constant "Fun.op o" is now called "Fun.comp";
  1327 
  1328 * 'typedef' command has new option "open" to suppress the set
  1329 definition;
  1330 
  1331 * functions Min and Max on finite sets have been introduced (theory
  1332 Finite_Set);
  1333 
  1334 * attribute [symmetric] now works for relations as well; it turns
  1335 (x,y) : R^-1 into (y,x) : R, and vice versa;
  1336 
  1337 * induct over a !!-quantified statement (say !!x1..xn):
  1338   each "case" automatically performs "fix x1 .. xn" with exactly those names.
  1339 
  1340 * Map: `empty' is no longer a constant but a syntactic abbreviation for
  1341 %x. None. Warning: empty_def now refers to the previously hidden definition
  1342 of the empty set.
  1343 
  1344 * Algebra: formalization of classical algebra.  Intended as base for
  1345 any algebraic development in Isabelle.  Currently covers group theory
  1346 (up to Sylow's theorem) and ring theory (Universal Property of
  1347 Univariate Polynomials).  Contributions welcome;
  1348 
  1349 * GroupTheory: deleted, since its material has been moved to Algebra;
  1350 
  1351 * Complex: new directory of the complex numbers with numeric constants,
  1352 nonstandard complex numbers, and some complex analysis, standard and
  1353 nonstandard (Jacques Fleuriot);
  1354 
  1355 * HOL-Complex: new image for analysis, replacing HOL-Real and HOL-Hyperreal;
  1356 
  1357 * Hyperreal: introduced Gauge integration and hyperreal logarithms (Jacques
  1358 Fleuriot);
  1359 
  1360 * Real/HahnBanach: updated and adapted to locales;
  1361 
  1362 * NumberTheory: added Gauss's law of quadratic reciprocity (by Avigad,
  1363 Gray and Kramer);
  1364 
  1365 * UNITY: added the Meier-Sanders theory of progress sets;
  1366 
  1367 * MicroJava: bytecode verifier and lightweight bytecode verifier
  1368 as abstract algorithms, instantiated to the JVM;
  1369 
  1370 * Bali: Java source language formalization. Type system, operational
  1371 semantics, axiomatic semantics. Supported language features:
  1372 classes, interfaces, objects,virtual methods, static methods,
  1373 static/instance fields, arrays, access modifiers, definite
  1374 assignment, exceptions.
  1375 
  1376 
  1377 *** ZF ***
  1378 
  1379 * ZF/Constructible: consistency proof for AC (Gdel's constructible
  1380 universe, etc.);
  1381 
  1382 * Main ZF: virtually all theories converted to new-style format;
  1383 
  1384 
  1385 *** ML ***
  1386 
  1387 * Pure: Tactic.prove provides sane interface for internal proofs;
  1388 omits the infamous "standard" operation, so this is more appropriate
  1389 than prove_goalw_cterm in many situations (e.g. in simprocs);
  1390 
  1391 * Pure: improved error reporting of simprocs;
  1392 
  1393 * Provers: Simplifier.simproc(_i) provides sane interface for setting
  1394 up simprocs;
  1395 
  1396 
  1397 *** Document preparation ***
  1398 
  1399 * uses \par instead of \\ for line breaks in theory text. This may
  1400 shift some page breaks in large documents. To get the old behaviour
  1401 use \renewcommand{\isanewline}{\mbox{}\\\mbox{}} in root.tex.
  1402 
  1403 * minimized dependencies of isabelle.sty and isabellesym.sty on
  1404 other packages
  1405 
  1406 * \<euro> now needs package babel/greek instead of marvosym (which
  1407 broke \Rightarrow)
  1408 
  1409 * normal size for \<zero>...\<nine> (uses \mathbf instead of
  1410 textcomp package)
  1411 
  1412 
  1413 
  1414 New in Isabelle2002 (March 2002)
  1415 --------------------------------
  1416 
  1417 *** Document preparation ***
  1418 
  1419 * greatly simplified document preparation setup, including more
  1420 graceful interpretation of isatool usedir -i/-d/-D options, and more
  1421 instructive isatool mkdir; users should basically be able to get
  1422 started with "isatool mkdir HOL Test && isatool make"; alternatively,
  1423 users may run a separate document processing stage manually like this:
  1424 "isatool usedir -D output HOL Test && isatool document Test/output";
  1425 
  1426 * theory dependency graph may now be incorporated into documents;
  1427 isatool usedir -g true will produce session_graph.eps/.pdf for use
  1428 with \includegraphics of LaTeX;
  1429 
  1430 * proper spacing of consecutive markup elements, especially text
  1431 blocks after section headings;
  1432 
  1433 * support bold style (for single symbols only), input syntax is like
  1434 this: "\<^bold>\<alpha>" or "\<^bold>A";
  1435 
  1436 * \<bullet> is now output as bold \cdot by default, which looks much
  1437 better in printed text;
  1438 
  1439 * added default LaTeX bindings for \<tturnstile> and \<TTurnstile>;
  1440 note that these symbols are currently unavailable in Proof General /
  1441 X-Symbol; new symbols \<zero>, \<one>, ..., \<nine>, and \<euro>;
  1442 
  1443 * isatool latex no longer depends on changed TEXINPUTS, instead
  1444 isatool document copies the Isabelle style files to the target
  1445 location;
  1446 
  1447 
  1448 *** Isar ***
  1449 
  1450 * Pure/Provers: improved proof by cases and induction;
  1451   - 'case' command admits impromptu naming of parameters (such as
  1452     "case (Suc n)");
  1453   - 'induct' method divinates rule instantiation from the inductive
  1454     claim; no longer requires excessive ?P bindings for proper
  1455     instantiation of cases;
  1456   - 'induct' method properly enumerates all possibilities of set/type
  1457     rules; as a consequence facts may be also passed through *type*
  1458     rules without further ado;
  1459   - 'induct' method now derives symbolic cases from the *rulified*
  1460     rule (before it used to rulify cases stemming from the internal
  1461     atomized version); this means that the context of a non-atomic
  1462     statement becomes is included in the hypothesis, avoiding the
  1463     slightly cumbersome show "PROP ?case" form;
  1464   - 'induct' may now use elim-style induction rules without chaining
  1465     facts, using ``missing'' premises from the goal state; this allows
  1466     rules stemming from inductive sets to be applied in unstructured
  1467     scripts, while still benefitting from proper handling of non-atomic
  1468     statements; NB: major inductive premises need to be put first, all
  1469     the rest of the goal is passed through the induction;
  1470   - 'induct' proper support for mutual induction involving non-atomic
  1471     rule statements (uses the new concept of simultaneous goals, see
  1472     below);
  1473   - append all possible rule selections, but only use the first
  1474     success (no backtracking);
  1475   - removed obsolete "(simplified)" and "(stripped)" options of methods;
  1476   - undeclared rule case names default to numbers 1, 2, 3, ...;
  1477   - added 'print_induct_rules' (covered by help item in recent Proof
  1478     General versions);
  1479   - moved induct/cases attributes to Pure, methods to Provers;
  1480   - generic method setup instantiated for FOL and HOL;
  1481 
  1482 * Pure: support multiple simultaneous goal statements, for example
  1483 "have a: A and b: B" (same for 'theorem' etc.); being a pure
  1484 meta-level mechanism, this acts as if several individual goals had
  1485 been stated separately; in particular common proof methods need to be
  1486 repeated in order to cover all claims; note that a single elimination
  1487 step is *not* sufficient to establish the two conjunctions, so this
  1488 fails:
  1489 
  1490   assume "A & B" then have A and B ..   (*".." fails*)
  1491 
  1492 better use "obtain" in situations as above; alternative refer to
  1493 multi-step methods like 'auto', 'simp_all', 'blast+' etc.;
  1494 
  1495 * Pure: proper integration with ``locales''; unlike the original
  1496 version by Florian Kammller, Isar locales package high-level proof
  1497 contexts rather than raw logical ones (e.g. we admit to include
  1498 attributes everywhere); operations on locales include merge and
  1499 rename; support for implicit arguments (``structures''); simultaneous
  1500 type-inference over imports and text; see also HOL/ex/Locales.thy for
  1501 some examples;
  1502 
  1503 * Pure: the following commands have been ``localized'', supporting a
  1504 target locale specification "(in name)": 'lemma', 'theorem',
  1505 'corollary', 'lemmas', 'theorems', 'declare'; the results will be
  1506 stored both within the locale and at the theory level (exported and
  1507 qualified by the locale name);
  1508 
  1509 * Pure: theory goals may now be specified in ``long'' form, with
  1510 ad-hoc contexts consisting of arbitrary locale elements. for example
  1511 ``lemma foo: fixes x assumes "A x" shows "B x"'' (local syntax and
  1512 definitions may be given, too); the result is a meta-level rule with
  1513 the context elements being discharged in the obvious way;
  1514 
  1515 * Pure: new proof command 'using' allows to augment currently used
  1516 facts after a goal statement ('using' is syntactically analogous to
  1517 'apply', but acts on the goal's facts only); this allows chained facts
  1518 to be separated into parts given before and after a claim, as in
  1519 ``from a and b have C using d and e <proof>'';
  1520 
  1521 * Pure: renamed "antecedent" case to "rule_context";
  1522 
  1523 * Pure: new 'judgment' command records explicit information about the
  1524 object-logic embedding (used by several tools internally); no longer
  1525 use hard-wired "Trueprop";
  1526 
  1527 * Pure: added 'corollary' command;
  1528 
  1529 * Pure: fixed 'token_translation' command;
  1530 
  1531 * Pure: removed obsolete 'exported' attribute;
  1532 
  1533 * Pure: dummy pattern "_" in is/let is now automatically lifted over
  1534 bound variables: "ALL x. P x --> Q x" (is "ALL x. _ --> ?C x")
  1535 supersedes more cumbersome ... (is "ALL x. _ x --> ?C x");
  1536 
  1537 * Pure: method 'atomize' presents local goal premises as object-level
  1538 statements (atomic meta-level propositions); setup controlled via
  1539 rewrite rules declarations of 'atomize' attribute; example
  1540 application: 'induct' method with proper rule statements in improper
  1541 proof *scripts*;
  1542 
  1543 * Pure: emulation of instantiation tactics (rule_tac, cut_tac, etc.)
  1544 now consider the syntactic context of assumptions, giving a better
  1545 chance to get type-inference of the arguments right (this is
  1546 especially important for locales);
  1547 
  1548 * Pure: "sorry" no longer requires quick_and_dirty in interactive
  1549 mode;
  1550 
  1551 * Pure/obtain: the formal conclusion "thesis", being marked as
  1552 ``internal'', may no longer be reference directly in the text;
  1553 potential INCOMPATIBILITY, may need to use "?thesis" in rare
  1554 situations;
  1555 
  1556 * Pure: generic 'sym' attribute which declares a rule both as pure
  1557 'elim?' and for the 'symmetric' operation;
  1558 
  1559 * Pure: marginal comments ``--'' may now occur just anywhere in the
  1560 text; the fixed correlation with particular command syntax has been
  1561 discontinued;
  1562 
  1563 * Pure: new method 'rules' is particularly well-suited for proof
  1564 search in intuitionistic logic; a bit slower than 'blast' or 'fast',
  1565 but often produces more compact proof terms with less detours;
  1566 
  1567 * Pure/Provers/classical: simplified integration with pure rule
  1568 attributes and methods; the classical "intro?/elim?/dest?"
  1569 declarations coincide with the pure ones; the "rule" method no longer
  1570 includes classically swapped intros; "intro" and "elim" methods no
  1571 longer pick rules from the context; also got rid of ML declarations
  1572 AddXIs/AddXEs/AddXDs; all of this has some potential for
  1573 INCOMPATIBILITY;
  1574 
  1575 * Provers/classical: attribute 'swapped' produces classical inversions
  1576 of introduction rules;
  1577 
  1578 * Provers/simplifier: 'simplified' attribute may refer to explicit
  1579 rules instead of full simplifier context; 'iff' attribute handles
  1580 conditional rules;
  1581 
  1582 * HOL: 'typedef' now allows alternative names for Rep/Abs morphisms;
  1583 
  1584 * HOL: 'recdef' now fails on unfinished automated proofs, use
  1585 "(permissive)" option to recover old behavior;
  1586 
  1587 * HOL: 'inductive' no longer features separate (collective) attributes
  1588 for 'intros' (was found too confusing);
  1589 
  1590 * HOL: properly declared induction rules less_induct and
  1591 wf_induct_rule;
  1592 
  1593 
  1594 *** HOL ***
  1595 
  1596 * HOL: moved over to sane numeral syntax; the new policy is as
  1597 follows:
  1598 
  1599   - 0 and 1 are polymorphic constants, which are defined on any
  1600   numeric type (nat, int, real etc.);
  1601 
  1602   - 2, 3, 4, ... and -1, -2, -3, ... are polymorphic numerals, based
  1603   binary representation internally;
  1604 
  1605   - type nat has special constructor Suc, and generally prefers Suc 0
  1606   over 1::nat and Suc (Suc 0) over 2::nat;
  1607 
  1608 This change may cause significant problems of INCOMPATIBILITY; here
  1609 are some hints on converting existing sources:
  1610 
  1611   - due to the new "num" token, "-0" and "-1" etc. are now atomic
  1612   entities, so expressions involving "-" (unary or binary minus) need
  1613   to be spaced properly;
  1614 
  1615   - existing occurrences of "1" may need to be constraint "1::nat" or
  1616   even replaced by Suc 0; similar for old "2";
  1617 
  1618   - replace "#nnn" by "nnn", and "#-nnn" by "-nnn";
  1619 
  1620   - remove all special provisions on numerals in proofs;
  1621 
  1622 * HOL: simp rules nat_number expand numerals on nat to Suc/0
  1623 representation (depends on bin_arith_simps in the default context);
  1624 
  1625 * HOL: symbolic syntax for x^2 (numeral 2);
  1626 
  1627 * HOL: the class of all HOL types is now called "type" rather than
  1628 "term"; INCOMPATIBILITY, need to adapt references to this type class
  1629 in axclass/classes, instance/arities, and (usually rare) occurrences
  1630 in typings (of consts etc.); internally the class is called
  1631 "HOL.type", ML programs should refer to HOLogic.typeS;
  1632 
  1633 * HOL/record package improvements:
  1634   - new derived operations "fields" to build a partial record section,
  1635     "extend" to promote a fixed record to a record scheme, and
  1636     "truncate" for the reverse; cf. theorems "xxx.defs", which are *not*
  1637     declared as simp by default;
  1638   - shared operations ("more", "fields", etc.) now need to be always
  1639     qualified) --- potential INCOMPATIBILITY;
  1640   - removed "make_scheme" operations (use "make" with "extend") --
  1641     INCOMPATIBILITY;
  1642   - removed "more" class (simply use "term") -- INCOMPATIBILITY;
  1643   - provides cases/induct rules for use with corresponding Isar
  1644     methods (for concrete records, record schemes, concrete more
  1645     parts, and schematic more parts -- in that order);
  1646   - internal definitions directly based on a light-weight abstract
  1647     theory of product types over typedef rather than datatype;
  1648 
  1649 * HOL: generic code generator for generating executable ML code from
  1650 specifications; specific support for HOL constructs such as inductive
  1651 datatypes and sets, as well as recursive functions; can be invoked
  1652 via 'generate_code' theory section;
  1653 
  1654 * HOL: canonical cases/induct rules for n-tuples (n = 3..7);
  1655 
  1656 * HOL: consolidated and renamed several theories.  In particular:
  1657         Ord.thy has been absorbed into HOL.thy
  1658         String.thy has been absorbed into List.thy
  1659 
  1660 * HOL: concrete setsum syntax "\<Sum>i:A. b" == "setsum (%i. b) A"
  1661 (beware of argument permutation!);
  1662 
  1663 * HOL: linorder_less_split superseded by linorder_cases;
  1664 
  1665 * HOL/List: "nodups" renamed to "distinct";
  1666 
  1667 * HOL: added "The" definite description operator; move Hilbert's "Eps"
  1668 to peripheral theory "Hilbert_Choice"; some INCOMPATIBILITIES:
  1669   - Ex_def has changed, now need to use some_eq_ex
  1670 
  1671 * HOL: made split_all_tac safe; EXISTING PROOFS MAY FAIL OR LOOP, so
  1672 in this (rare) case use:
  1673 
  1674   delSWrapper "split_all_tac"
  1675   addSbefore ("unsafe_split_all_tac", unsafe_split_all_tac)
  1676 
  1677 * HOL: added safe wrapper "split_conv_tac" to claset; EXISTING PROOFS
  1678 MAY FAIL;
  1679 
  1680 * HOL: introduced f^n = f o ... o f; warning: due to the limits of
  1681 Isabelle's type classes, ^ on functions and relations has too general
  1682 a domain, namely ('a * 'b) set and 'a => 'b; this means that it may be
  1683 necessary to attach explicit type constraints;
  1684 
  1685 * HOL/Relation: the prefix name of the infix "O" has been changed from
  1686 "comp" to "rel_comp"; INCOMPATIBILITY: a few theorems have been
  1687 renamed accordingly (eg "compI" -> "rel_compI").
  1688 
  1689 * HOL: syntax translations now work properly with numerals and records
  1690 expressions;
  1691 
  1692 * HOL: bounded abstraction now uses syntax "%" / "\<lambda>" instead
  1693 of "lam" -- INCOMPATIBILITY;
  1694 
  1695 * HOL: got rid of some global declarations (potential INCOMPATIBILITY
  1696 for ML tools): const "()" renamed "Product_Type.Unity", type "unit"
  1697 renamed "Product_Type.unit";
  1698 
  1699 * HOL: renamed rtrancl_into_rtrancl2 to converse_rtrancl_into_rtrancl
  1700 
  1701 * HOL: removed obsolete theorem "optionE" (use "option.exhaust", or
  1702 the "cases" method);
  1703 
  1704 * HOL/GroupTheory: group theory examples including Sylow's theorem (by
  1705 Florian Kammller);
  1706 
  1707 * HOL/IMP: updated and converted to new-style theory format; several
  1708 parts turned into readable document, with proper Isar proof texts and
  1709 some explanations (by Gerwin Klein);
  1710 
  1711 * HOL-Real: added Complex_Numbers (by Gertrud Bauer);
  1712 
  1713 * HOL-Hyperreal is now a logic image;
  1714 
  1715 
  1716 *** HOLCF ***
  1717 
  1718 * Isar: consts/constdefs supports mixfix syntax for continuous
  1719 operations;
  1720 
  1721 * Isar: domain package adapted to new-style theory format, e.g. see
  1722 HOLCF/ex/Dnat.thy;
  1723 
  1724 * theory Lift: proper use of rep_datatype lift instead of ML hacks --
  1725 potential INCOMPATIBILITY; now use plain induct_tac instead of former
  1726 lift.induct_tac, always use UU instead of Undef;
  1727 
  1728 * HOLCF/IMP: updated and converted to new-style theory;
  1729 
  1730 
  1731 *** ZF ***
  1732 
  1733 * Isar: proper integration of logic-specific tools and packages,
  1734 including theory commands '(co)inductive', '(co)datatype',
  1735 'rep_datatype', 'inductive_cases', as well as methods 'ind_cases',
  1736 'induct_tac', 'case_tac', and 'typecheck' (with attribute 'TC');
  1737 
  1738 * theory Main no longer includes AC; for the Axiom of Choice, base
  1739 your theory on Main_ZFC;
  1740 
  1741 * the integer library now covers quotients and remainders, with many
  1742 laws relating division to addition, multiplication, etc.;
  1743 
  1744 * ZF/UNITY: Chandy and Misra's UNITY is now available in ZF, giving a
  1745 typeless version of the formalism;
  1746 
  1747 * ZF/AC, Coind, IMP, Resid: updated and converted to new-style theory
  1748 format;
  1749 
  1750 * ZF/Induct: new directory for examples of inductive definitions,
  1751 including theory Multiset for multiset orderings; converted to
  1752 new-style theory format;
  1753 
  1754 * ZF: many new theorems about lists, ordinals, etc.;
  1755 
  1756 
  1757 *** General ***
  1758 
  1759 * Pure/kernel: meta-level proof terms (by Stefan Berghofer); reference
  1760 variable proof controls level of detail: 0 = no proofs (only oracle
  1761 dependencies), 1 = lemma dependencies, 2 = compact proof terms; see
  1762 also ref manual for further ML interfaces;
  1763 
  1764 * Pure/axclass: removed obsolete ML interface
  1765 goal_subclass/goal_arity;
  1766 
  1767 * Pure/syntax: new token syntax "num" for plain numerals (without "#"
  1768 of "xnum"); potential INCOMPATIBILITY, since -0, -1 etc. are now
  1769 separate tokens, so expressions involving minus need to be spaced
  1770 properly;
  1771 
  1772 * Pure/syntax: support non-oriented infixes, using keyword "infix"
  1773 rather than "infixl" or "infixr";
  1774 
  1775 * Pure/syntax: concrete syntax for dummy type variables admits genuine
  1776 sort constraint specifications in type inference; e.g. "x::_::foo"
  1777 ensures that the type of "x" is of sort "foo" (but not necessarily a
  1778 type variable);
  1779 
  1780 * Pure/syntax: print modes "type_brackets" and "no_type_brackets"
  1781 control output of nested => (types); the default behavior is
  1782 "type_brackets";
  1783 
  1784 * Pure/syntax: builtin parse translation for "_constify" turns valued
  1785 tokens into AST constants;
  1786 
  1787 * Pure/syntax: prefer later declarations of translations and print
  1788 translation functions; potential INCOMPATIBILITY: need to reverse
  1789 multiple declarations for same syntax element constant;
  1790 
  1791 * Pure/show_hyps reset by default (in accordance to existing Isar
  1792 practice);
  1793 
  1794 * Provers/classical: renamed addaltern to addafter, addSaltern to
  1795 addSafter;
  1796 
  1797 * Provers/clasimp: ``iff'' declarations now handle conditional rules
  1798 as well;
  1799 
  1800 * system: tested support for MacOS X; should be able to get Isabelle +
  1801 Proof General to work in a plain Terminal after installing Poly/ML
  1802 (e.g. from the Isabelle distribution area) and GNU bash alone
  1803 (e.g. from http://www.apple.com); full X11, XEmacs and X-Symbol
  1804 support requires further installations, e.g. from
  1805 http://fink.sourceforge.net/);
  1806 
  1807 * system: support Poly/ML 4.1.1 (able to manage larger heaps);
  1808 
  1809 * system: reduced base memory usage by Poly/ML (approx. 20 MB instead
  1810 of 40 MB), cf. ML_OPTIONS;
  1811 
  1812 * system: Proof General keywords specification is now part of the
  1813 Isabelle distribution (see etc/isar-keywords.el);
  1814 
  1815 * system: support for persistent Proof General sessions (refrain from
  1816 outdating all loaded theories on startup); user may create writable
  1817 logic images like this: ``isabelle -q HOL Test'';
  1818 
  1819 * system: smart selection of Isabelle process versus Isabelle
  1820 interface, accommodates case-insensitive file systems (e.g. HFS+); may
  1821 run both "isabelle" and "Isabelle" even if file names are badly
  1822 damaged (executable inspects the case of the first letter of its own
  1823 name); added separate "isabelle-process" and "isabelle-interface";
  1824 
  1825 * system: refrain from any attempt at filtering input streams; no
  1826 longer support ``8bit'' encoding of old isabelle font, instead proper
  1827 iso-latin characters may now be used; the related isatools
  1828 "symbolinput" and "nonascii" have disappeared as well;
  1829 
  1830 * system: removed old "xterm" interface (the print modes "xterm" and
  1831 "xterm_color" are still available for direct use in a suitable
  1832 terminal);
  1833 
  1834 
  1835 
  1836 New in Isabelle99-2 (February 2001)
  1837 -----------------------------------
  1838 
  1839 *** Overview of INCOMPATIBILITIES ***
  1840 
  1841 * HOL: please note that theories in the Library and elsewhere often use the
  1842 new-style (Isar) format; to refer to their theorems in an ML script you must
  1843 bind them to ML identifers by e.g.      val thm_name = thm "thm_name";
  1844 
  1845 * HOL: inductive package no longer splits induction rule aggressively,
  1846 but only as far as specified by the introductions given; the old
  1847 format may be recovered via ML function complete_split_rule or attribute
  1848 'split_rule (complete)';
  1849 
  1850 * HOL: induct renamed to lfp_induct, lfp_Tarski to lfp_unfold,
  1851 gfp_Tarski to gfp_unfold;
  1852 
  1853 * HOL: contrapos, contrapos2 renamed to contrapos_nn, contrapos_pp;
  1854 
  1855 * HOL: infix "dvd" now has priority 50 rather than 70 (because it is a
  1856 relation); infix "^^" has been renamed "``"; infix "``" has been
  1857 renamed "`"; "univalent" has been renamed "single_valued";
  1858 
  1859 * HOL/Real: "rinv" and "hrinv" replaced by overloaded "inverse"
  1860 operation;
  1861 
  1862 * HOLCF: infix "`" has been renamed "$"; the symbol syntax is \<cdot>;
  1863 
  1864 * Isar: 'obtain' no longer declares "that" fact as simp/intro;
  1865 
  1866 * Isar/HOL: method 'induct' now handles non-atomic goals; as a
  1867 consequence, it is no longer monotonic wrt. the local goal context
  1868 (which is now passed through the inductive cases);
  1869 
  1870 * Document preparation: renamed standard symbols \<ll> to \<lless> and
  1871 \<gg> to \<ggreater>;
  1872 
  1873 
  1874 *** Document preparation ***
  1875 
  1876 * \isabellestyle{NAME} selects version of Isabelle output (currently
  1877 available: are "it" for near math-mode best-style output, "sl" for
  1878 slanted text style, and "tt" for plain type-writer; if no
  1879 \isabellestyle command is given, output is according to slanted
  1880 type-writer);
  1881 
  1882 * support sub/super scripts (for single symbols only), input syntax is
  1883 like this: "A\<^sup>*" or "A\<^sup>\<star>";
  1884 
  1885 * some more standard symbols; see Appendix A of the system manual for
  1886 the complete list of symbols defined in isabellesym.sty;
  1887 
  1888 * improved isabelle style files; more abstract symbol implementation
  1889 (should now use \isamath{...} and \isatext{...} in custom symbol
  1890 definitions);
  1891 
  1892 * antiquotation @{goals} and @{subgoals} for output of *dynamic* goals
  1893 state; Note that presentation of goal states does not conform to
  1894 actual human-readable proof documents.  Please do not include goal
  1895 states into document output unless you really know what you are doing!
  1896 
  1897 * proper indentation of antiquoted output with proportional LaTeX
  1898 fonts;
  1899 
  1900 * no_document ML operator temporarily disables LaTeX document
  1901 generation;
  1902 
  1903 * isatool unsymbolize tunes sources for plain ASCII communication;
  1904 
  1905 
  1906 *** Isar ***
  1907 
  1908 * Pure: Isar now suffers initial goal statements to contain unbound
  1909 schematic variables (this does not conform to actual readable proof
  1910 documents, due to unpredictable outcome and non-compositional proof
  1911 checking); users who know what they are doing may use schematic goals
  1912 for Prolog-style synthesis of proven results;
  1913 
  1914 * Pure: assumption method (an implicit finishing) now handles actual
  1915 rules as well;
  1916 
  1917 * Pure: improved 'obtain' --- moved to Pure, insert "that" into
  1918 initial goal, declare "that" only as Pure intro (only for single
  1919 steps); the "that" rule assumption may now be involved in implicit
  1920 finishing, thus ".." becomes a feasible for trivial obtains;
  1921 
  1922 * Pure: default proof step now includes 'intro_classes'; thus trivial
  1923 instance proofs may be performed by "..";
  1924 
  1925 * Pure: ?thesis / ?this / "..." now work for pure meta-level
  1926 statements as well;
  1927 
  1928 * Pure: more robust selection of calculational rules;
  1929 
  1930 * Pure: the builtin notion of 'finished' goal now includes the ==-refl
  1931 rule (as well as the assumption rule);
  1932 
  1933 * Pure: 'thm_deps' command visualizes dependencies of theorems and
  1934 lemmas, using the graph browser tool;
  1935 
  1936 * Pure: predict failure of "show" in interactive mode;
  1937 
  1938 * Pure: 'thms_containing' now takes actual terms as arguments;
  1939 
  1940 * HOL: improved method 'induct' --- now handles non-atomic goals
  1941 (potential INCOMPATIBILITY); tuned error handling;
  1942 
  1943 * HOL: cases and induct rules now provide explicit hints about the
  1944 number of facts to be consumed (0 for "type" and 1 for "set" rules);
  1945 any remaining facts are inserted into the goal verbatim;
  1946 
  1947 * HOL: local contexts (aka cases) may now contain term bindings as
  1948 well; the 'cases' and 'induct' methods new provide a ?case binding for
  1949 the result to be shown in each case;
  1950 
  1951 * HOL: added 'recdef_tc' command;
  1952 
  1953 * isatool convert assists in eliminating legacy ML scripts;
  1954 
  1955 
  1956 *** HOL ***
  1957 
  1958 * HOL/Library: a collection of generic theories to be used together
  1959 with main HOL; the theory loader path already includes this directory
  1960 by default; the following existing theories have been moved here:
  1961 HOL/Induct/Multiset, HOL/Induct/Acc (as Accessible_Part), HOL/While
  1962 (as While_Combinator), HOL/Lex/Prefix (as List_Prefix);
  1963 
  1964 * HOL/Unix: "Some aspects of Unix file-system security", a typical
  1965 modelling and verification task performed in Isabelle/HOL +
  1966 Isabelle/Isar + Isabelle document preparation (by Markus Wenzel).
  1967 
  1968 * HOL/Algebra: special summation operator SUM no longer exists, it has
  1969 been replaced by setsum; infix 'assoc' now has priority 50 (like
  1970 'dvd'); axiom 'one_not_zero' has been moved from axclass 'ring' to
  1971 'domain', this makes the theory consistent with mathematical
  1972 literature;
  1973 
  1974 * HOL basics: added overloaded operations "inverse" and "divide"
  1975 (infix "/"), syntax for generic "abs" operation, generic summation
  1976 operator \<Sum>;
  1977 
  1978 * HOL/typedef: simplified package, provide more useful rules (see also
  1979 HOL/subset.thy);
  1980 
  1981 * HOL/datatype: induction rule for arbitrarily branching datatypes is
  1982 now expressed as a proper nested rule (old-style tactic scripts may
  1983 require atomize_strip_tac to cope with non-atomic premises);
  1984 
  1985 * HOL: renamed theory "Prod" to "Product_Type", renamed "split" rule
  1986 to "split_conv" (old name still available for compatibility);
  1987 
  1988 * HOL: improved concrete syntax for strings (e.g. allows translation
  1989 rules with string literals);
  1990 
  1991 * HOL-Real-Hyperreal: this extends HOL-Real with the hyperreals
  1992  and Fleuriot's mechanization of analysis, including the transcendental
  1993  functions for the reals;
  1994 
  1995 * HOL/Real, HOL/Hyperreal: improved arithmetic simplification;
  1996 
  1997 
  1998 *** CTT ***
  1999 
  2000 * CTT: x-symbol support for Pi, Sigma, -->, : (membership); note that
  2001 "lam" is displayed as TWO lambda-symbols
  2002 
  2003 * CTT: theory Main now available, containing everything (that is, Bool
  2004 and Arith);
  2005 
  2006 
  2007 *** General ***
  2008 
  2009 * Pure: the Simplifier has been implemented properly as a derived rule
  2010 outside of the actual kernel (at last!); the overall performance
  2011 penalty in practical applications is about 50%, while reliability of
  2012 the Isabelle inference kernel has been greatly improved;
  2013 
  2014 * print modes "brackets" and "no_brackets" control output of nested =>
  2015 (types) and ==> (props); the default behaviour is "brackets";
  2016 
  2017 * Provers: fast_tac (and friends) now handle actual object-logic rules
  2018 as assumptions as well;
  2019 
  2020 * system: support Poly/ML 4.0;
  2021 
  2022 * system: isatool install handles KDE version 1 or 2;
  2023 
  2024 
  2025 
  2026 New in Isabelle99-1 (October 2000)
  2027 ----------------------------------
  2028 
  2029 *** Overview of INCOMPATIBILITIES ***
  2030 
  2031 * HOL: simplification of natural numbers is much changed; to partly
  2032 recover the old behaviour (e.g. to prevent n+n rewriting to #2*n)
  2033 issue the following ML commands:
  2034 
  2035   Delsimprocs Nat_Numeral_Simprocs.cancel_numerals;
  2036   Delsimprocs [Nat_Numeral_Simprocs.combine_numerals];
  2037 
  2038 * HOL: simplification no longer dives into case-expressions; this is
  2039 controlled by "t.weak_case_cong" for each datatype t;
  2040 
  2041 * HOL: nat_less_induct renamed to less_induct;
  2042 
  2043 * HOL: systematic renaming of the SOME (Eps) rules, may use isatool
  2044 fixsome to patch .thy and .ML sources automatically;
  2045 
  2046   select_equality  -> some_equality
  2047   select_eq_Ex     -> some_eq_ex
  2048   selectI2EX       -> someI2_ex
  2049   selectI2         -> someI2
  2050   selectI          -> someI
  2051   select1_equality -> some1_equality
  2052   Eps_sym_eq       -> some_sym_eq_trivial
  2053   Eps_eq           -> some_eq_trivial
  2054 
  2055 * HOL: exhaust_tac on datatypes superceded by new generic case_tac;
  2056 
  2057 * HOL: removed obsolete theorem binding expand_if (refer to split_if
  2058 instead);
  2059 
  2060 * HOL: the recursion equations generated by 'recdef' are now called
  2061 f.simps instead of f.rules;
  2062 
  2063 * HOL: qed_spec_mp now also handles bounded ALL as well;
  2064 
  2065 * HOL: 0 is now overloaded, so the type constraint ":: nat" may
  2066 sometimes be needed;
  2067 
  2068 * HOL: the constant for "f``x" is now "image" rather than "op ``";
  2069 
  2070 * HOL: the constant for "f-``x" is now "vimage" rather than "op -``";
  2071 
  2072 * HOL: the disjoint sum is now "<+>" instead of "Plus"; the cartesian
  2073 product is now "<*>" instead of "Times"; the lexicographic product is
  2074 now "<*lex*>" instead of "**";
  2075 
  2076 * HOL: theory Sexp is now in HOL/Induct examples (it used to be part
  2077 of main HOL, but was unused); better use HOL's datatype package;
  2078 
  2079 * HOL: removed "symbols" syntax for constant "override" of theory Map;
  2080 the old syntax may be recovered as follows:
  2081 
  2082   syntax (symbols)
  2083     override  :: "('a ~=> 'b) => ('a ~=> 'b) => ('a ~=> 'b)"
  2084       (infixl "\\<oplus>" 100)
  2085 
  2086 * HOL/Real: "rabs" replaced by overloaded "abs" function;
  2087 
  2088 * HOL/ML: even fewer consts are declared as global (see theories Ord,
  2089 Lfp, Gfp, WF); this only affects ML packages that refer to const names
  2090 internally;
  2091 
  2092 * HOL and ZF: syntax for quotienting wrt an equivalence relation
  2093 changed from A/r to A//r;
  2094 
  2095 * ZF: new treatment of arithmetic (nat & int) may break some old
  2096 proofs;
  2097 
  2098 * Isar: renamed some attributes (RS -> THEN, simplify -> simplified,
  2099 rulify -> rule_format, elimify -> elim_format, ...);
  2100 
  2101 * Isar/Provers: intro/elim/dest attributes changed; renamed
  2102 intro/intro!/intro!! flags to intro!/intro/intro? (in most cases, one
  2103 should have to change intro!! to intro? only); replaced "delrule" by
  2104 "rule del";
  2105 
  2106 * Isar/HOL: renamed "intrs" to "intros" in inductive definitions;
  2107 
  2108 * Provers: strengthened force_tac by using new first_best_tac;
  2109 
  2110 * LaTeX document preparation: several changes of isabelle.sty (see
  2111 lib/texinputs);
  2112 
  2113 
  2114 *** Document preparation ***
  2115 
  2116 * formal comments (text blocks etc.) in new-style theories may now
  2117 contain antiquotations of thm/prop/term/typ/text to be presented
  2118 according to latex print mode; concrete syntax is like this:
  2119 @{term[show_types] "f(x) = a + x"};
  2120 
  2121 * isatool mkdir provides easy setup of Isabelle session directories,
  2122 including proper document sources;
  2123 
  2124 * generated LaTeX sources are now deleted after successful run
  2125 (isatool document -c); may retain a copy somewhere else via -D option
  2126 of isatool usedir;
  2127 
  2128 * isatool usedir -D now lets isatool latex -o sty update the Isabelle
  2129 style files, achieving self-contained LaTeX sources and simplifying
  2130 LaTeX debugging;
  2131 
  2132 * old-style theories now produce (crude) LaTeX output as well;
  2133 
  2134 * browser info session directories are now self-contained (may be put
  2135 on WWW server seperately); improved graphs of nested sessions; removed
  2136 graph for 'all sessions';
  2137 
  2138 * several improvements in isabelle style files; \isabellestyle{it}
  2139 produces fake math mode output; \isamarkupheader is now \section by
  2140 default; see lib/texinputs/isabelle.sty etc.;
  2141 
  2142 
  2143 *** Isar ***
  2144 
  2145 * Isar/Pure: local results and corresponding term bindings are now
  2146 subject to Hindley-Milner polymorphism (similar to ML); this
  2147 accommodates incremental type-inference very nicely;
  2148 
  2149 * Isar/Pure: new derived language element 'obtain' supports
  2150 generalized existence reasoning;
  2151 
  2152 * Isar/Pure: new calculational elements 'moreover' and 'ultimately'
  2153 support accumulation of results, without applying any rules yet;
  2154 useful to collect intermediate results without explicit name
  2155 references, and for use with transitivity rules with more than 2
  2156 premises;
  2157 
  2158 * Isar/Pure: scalable support for case-analysis type proofs: new
  2159 'case' language element refers to local contexts symbolically, as
  2160 produced by certain proof methods; internally, case names are attached
  2161 to theorems as "tags";
  2162 
  2163 * Isar/Pure: theory command 'hide' removes declarations from
  2164 class/type/const name spaces;
  2165 
  2166 * Isar/Pure: theory command 'defs' supports option "(overloaded)" to
  2167 indicate potential overloading;
  2168 
  2169 * Isar/Pure: changed syntax of local blocks from {{ }} to { };
  2170 
  2171 * Isar/Pure: syntax of sorts made 'inner', i.e. have to write
  2172 "{a,b,c}" instead of {a,b,c};
  2173 
  2174 * Isar/Pure now provides its own version of intro/elim/dest
  2175 attributes; useful for building new logics, but beware of confusion
  2176 with the version in Provers/classical;
  2177 
  2178 * Isar/Pure: the local context of (non-atomic) goals is provided via
  2179 case name 'antecedent';
  2180 
  2181 * Isar/Pure: removed obsolete 'transfer' attribute (transfer of thms
  2182 to the current context is now done automatically);
  2183 
  2184 * Isar/Pure: theory command 'method_setup' provides a simple interface
  2185 for definining proof methods in ML;
  2186 
  2187 * Isar/Provers: intro/elim/dest attributes changed; renamed
  2188 intro/intro!/intro!! flags to intro!/intro/intro? (INCOMPATIBILITY, in
  2189 most cases, one should have to change intro!! to intro? only);
  2190 replaced "delrule" by "rule del";
  2191 
  2192 * Isar/Provers: new 'hypsubst' method, plain 'subst' method and
  2193 'symmetric' attribute (the latter supercedes [RS sym]);
  2194 
  2195 * Isar/Provers: splitter support (via 'split' attribute and 'simp'
  2196 method modifier); 'simp' method: 'only:' modifier removes loopers as
  2197 well (including splits);
  2198 
  2199 * Isar/Provers: Simplifier and Classical methods now support all kind
  2200 of modifiers used in the past, including 'cong', 'iff', etc.
  2201 
  2202 * Isar/Provers: added 'fastsimp' and 'clarsimp' methods (combination
  2203 of Simplifier and Classical reasoner);
  2204 
  2205 * Isar/HOL: new proof method 'cases' and improved version of 'induct'
  2206 now support named cases; major packages (inductive, datatype, primrec,
  2207 recdef) support case names and properly name parameters;
  2208 
  2209 * Isar/HOL: new transitivity rules for substitution in inequalities --
  2210 monotonicity conditions are extracted to be proven at end of
  2211 calculations;
  2212 
  2213 * Isar/HOL: removed 'case_split' thm binding, should use 'cases' proof
  2214 method anyway;
  2215 
  2216 * Isar/HOL: removed old expand_if = split_if; theorems if_splits =
  2217 split_if split_if_asm; datatype package provides theorems foo.splits =
  2218 foo.split foo.split_asm for each datatype;
  2219 
  2220 * Isar/HOL: tuned inductive package, rename "intrs" to "intros"
  2221 (potential INCOMPATIBILITY), emulation of mk_cases feature for proof
  2222 scripts: new 'inductive_cases' command and 'ind_cases' method; (Note:
  2223 use "(cases (simplified))" method in proper proof texts);
  2224 
  2225 * Isar/HOL: added global 'arith_split' attribute for 'arith' method;
  2226 
  2227 * Isar: names of theorems etc. may be natural numbers as well;
  2228 
  2229 * Isar: 'pr' command: optional arguments for goals_limit and
  2230 ProofContext.prems_limit; no longer prints theory contexts, but only
  2231 proof states;
  2232 
  2233 * Isar: diagnostic commands 'pr', 'thm', 'prop', 'term', 'typ' admit
  2234 additional print modes to be specified; e.g. "pr(latex)" will print
  2235 proof state according to the Isabelle LaTeX style;
  2236 
  2237 * Isar: improved support for emulating tactic scripts, including proof
  2238 methods 'rule_tac' etc., 'cut_tac', 'thin_tac', 'subgoal_tac',
  2239 'rename_tac', 'rotate_tac', 'tactic', and 'case_tac' / 'induct_tac'
  2240 (for HOL datatypes);
  2241 
  2242 * Isar: simplified (more robust) goal selection of proof methods: 1st
  2243 goal, all goals, or explicit goal specifier (tactic emulation); thus
  2244 'proof method scripts' have to be in depth-first order;
  2245 
  2246 * Isar: tuned 'let' syntax: replaced 'as' keyword by 'and';
  2247 
  2248 * Isar: removed 'help' command, which hasn't been too helpful anyway;
  2249 should instead use individual commands for printing items
  2250 (print_commands, print_methods etc.);
  2251 
  2252 * Isar: added 'nothing' --- the empty list of theorems;
  2253 
  2254 
  2255 *** HOL ***
  2256 
  2257 * HOL/MicroJava: formalization of a fragment of Java, together with a
  2258 corresponding virtual machine and a specification of its bytecode
  2259 verifier and a lightweight bytecode verifier, including proofs of
  2260 type-safety; by Gerwin Klein, Tobias Nipkow, David von Oheimb, and
  2261 Cornelia Pusch (see also the homepage of project Bali at
  2262 http://isabelle.in.tum.de/Bali/);
  2263 
  2264 * HOL/Algebra: new theory of rings and univariate polynomials, by
  2265 Clemens Ballarin;
  2266 
  2267 * HOL/NumberTheory: fundamental Theorem of Arithmetic, Chinese
  2268 Remainder Theorem, Fermat/Euler Theorem, Wilson's Theorem, by Thomas M
  2269 Rasmussen;
  2270 
  2271 * HOL/Lattice: fundamental concepts of lattice theory and order
  2272 structures, including duals, properties of bounds versus algebraic
  2273 laws, lattice operations versus set-theoretic ones, the Knaster-Tarski
  2274 Theorem for complete lattices etc.; may also serve as a demonstration
  2275 for abstract algebraic reasoning using axiomatic type classes, and
  2276 mathematics-style proof in Isabelle/Isar; by Markus Wenzel;
  2277 
  2278 * HOL/Prolog: a (bare-bones) implementation of Lambda-Prolog, by David
  2279 von Oheimb;
  2280 
  2281 * HOL/IMPP: extension of IMP with local variables and mutually
  2282 recursive procedures, by David von Oheimb;
  2283 
  2284 * HOL/Lambda: converted into new-style theory and document;
  2285 
  2286 * HOL/ex/Multiquote: example of multiple nested quotations and
  2287 anti-quotations -- basically a generalized version of de-Bruijn
  2288 representation; very useful in avoiding lifting of operations;
  2289 
  2290 * HOL/record: added general record equality rule to simpset; fixed
  2291 select-update simplification procedure to handle extended records as
  2292 well; admit "r" as field name;
  2293 
  2294 * HOL: 0 is now overloaded over the new sort "zero", allowing its use with
  2295 other numeric types and also as the identity of groups, rings, etc.;
  2296 
  2297 * HOL: new axclass plus_ac0 for addition with the AC-laws and 0 as identity.
  2298 Types nat and int belong to this axclass;
  2299 
  2300 * HOL: greatly improved simplification involving numerals of type nat, int, real:
  2301    (i + #8 + j) = Suc k simplifies to  #7 + (i + j) = k
  2302    i*j + k + j*#3*i     simplifies to  #4*(i*j) + k
  2303   two terms #m*u and #n*u are replaced by #(m+n)*u
  2304     (where #m, #n and u can implicitly be 1; this is simproc combine_numerals)
  2305   and the term/formula #m*u+x ~~ #n*u+y simplifies simplifies to #(m-n)+x ~~ y
  2306     or x ~~ #(n-m)+y, where ~~ is one of = < <= or - (simproc cancel_numerals);
  2307 
  2308 * HOL: meson_tac is available (previously in ex/meson.ML); it is a
  2309 powerful prover for predicate logic but knows nothing of clasets; see
  2310 ex/mesontest.ML and ex/mesontest2.ML for example applications;
  2311 
  2312 * HOL: new version of "case_tac" subsumes both boolean case split and
  2313 "exhaust_tac" on datatypes; INCOMPATIBILITY: exhaust_tac no longer
  2314 exists, may define val exhaust_tac = case_tac for ad-hoc portability;
  2315 
  2316 * HOL: simplification no longer dives into case-expressions: only the
  2317 selector expression is simplified, but not the remaining arms; to
  2318 enable full simplification of case-expressions for datatype t, you may
  2319 remove t.weak_case_cong from the simpset, either globally (Delcongs
  2320 [thm"t.weak_case_cong"];) or locally (delcongs [...]).
  2321 
  2322 * HOL/recdef: the recursion equations generated by 'recdef' for
  2323 function 'f' are now called f.simps instead of f.rules; if all
  2324 termination conditions are proved automatically, these simplification
  2325 rules are added to the simpset, as in primrec; rules may be named
  2326 individually as well, resulting in a separate list of theorems for
  2327 each equation;
  2328 
  2329 * HOL/While is a new theory that provides a while-combinator. It
  2330 permits the definition of tail-recursive functions without the
  2331 provision of a termination measure. The latter is necessary once the
  2332 invariant proof rule for while is applied.
  2333 
  2334 * HOL: new (overloaded) notation for the set of elements below/above
  2335 some element: {..u}, {..u(}, {l..}, {)l..}. See theory SetInterval.
  2336 
  2337 * HOL: theorems impI, allI, ballI bound as "strip";
  2338 
  2339 * HOL: new tactic induct_thm_tac: thm -> string -> int -> tactic
  2340 induct_tac th "x1 ... xn" expects th to have a conclusion of the form
  2341 P v1 ... vn and abbreviates res_inst_tac [("v1","x1"),...,("vn","xn")] th;
  2342 
  2343 * HOL/Real: "rabs" replaced by overloaded "abs" function;
  2344 
  2345 * HOL: theory Sexp now in HOL/Induct examples (it used to be part of
  2346 main HOL, but was unused);
  2347 
  2348 * HOL: fewer consts declared as global (e.g. have to refer to
  2349 "Lfp.lfp" instead of "lfp" internally; affects ML packages only);
  2350 
  2351 * HOL: tuned AST representation of nested pairs, avoiding bogus output
  2352 in case of overlap with user translations (e.g. judgements over
  2353 tuples); (note that the underlying logical represenation is still
  2354 bogus);
  2355 
  2356 
  2357 *** ZF ***
  2358 
  2359 * ZF: simplification automatically cancels common terms in arithmetic
  2360 expressions over nat and int;
  2361 
  2362 * ZF: new treatment of nat to minimize type-checking: all operators
  2363 coerce their operands to a natural number using the function natify,
  2364 making the algebraic laws unconditional;
  2365 
  2366 * ZF: as above, for int: operators coerce their operands to an integer
  2367 using the function intify;
  2368 
  2369 * ZF: the integer library now contains many of the usual laws for the
  2370 orderings, including $<=, and monotonicity laws for $+ and $*;
  2371 
  2372 * ZF: new example ZF/ex/NatSum to demonstrate integer arithmetic
  2373 simplification;
  2374 
  2375 * FOL and ZF: AddIffs now available, giving theorems of the form P<->Q
  2376 to the simplifier and classical reasoner simultaneously;
  2377 
  2378 
  2379 *** General ***
  2380 
  2381 * Provers: blast_tac now handles actual object-logic rules as
  2382 assumptions; note that auto_tac uses blast_tac internally as well;
  2383 
  2384 * Provers: new functions rulify/rulify_no_asm: thm -> thm for turning
  2385 outer -->/All/Ball into ==>/!!; qed_spec_mp now uses rulify_no_asm;
  2386 
  2387 * Provers: delrules now handles destruct rules as well (no longer need
  2388 explicit make_elim);
  2389 
  2390 * Provers: Blast_tac now warns of and ignores "weak elimination rules" e.g.
  2391   [| inj ?f;          ?f ?x = ?f ?y; ?x = ?y ==> ?W |] ==> ?W
  2392 use instead the strong form,
  2393   [| inj ?f; ~ ?W ==> ?f ?x = ?f ?y; ?x = ?y ==> ?W |] ==> ?W
  2394 in HOL, FOL and ZF the function cla_make_elim will create such rules
  2395 from destruct-rules;
  2396 
  2397 * Provers: Simplifier.easy_setup provides a fast path to basic
  2398 Simplifier setup for new object-logics;
  2399 
  2400 * Pure: AST translation rules no longer require constant head on LHS;
  2401 
  2402 * Pure: improved name spaces: ambiguous output is qualified; support
  2403 for hiding of names;
  2404 
  2405 * system: smart setup of canonical ML_HOME, ISABELLE_INTERFACE, and
  2406 XSYMBOL_HOME; no longer need to do manual configuration in most
  2407 situations;
  2408 
  2409 * system: compression of ML heaps images may now be controlled via -c
  2410 option of isabelle and isatool usedir (currently only observed by
  2411 Poly/ML);
  2412 
  2413 * system: isatool installfonts may handle X-Symbol fonts as well (very
  2414 useful for remote X11);
  2415 
  2416 * system: provide TAGS file for Isabelle sources;
  2417 
  2418 * ML: infix 'OF' is a version of 'MRS' with more appropriate argument
  2419 order;
  2420 
  2421 * ML: renamed flags Syntax.trace_norm_ast to Syntax.trace_ast; global
  2422 timing flag supersedes proof_timing and Toplevel.trace;
  2423 
  2424 * ML: new combinators |>> and |>>> for incremental transformations
  2425 with secondary results (e.g. certain theory extensions):
  2426 
  2427 * ML: PureThy.add_defs gets additional argument to indicate potential
  2428 overloading (usually false);
  2429 
  2430 * ML: PureThy.add_thms/add_axioms/add_defs now return theorems as
  2431 results;
  2432 
  2433 
  2434 
  2435 New in Isabelle99 (October 1999)
  2436 --------------------------------
  2437 
  2438 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  2439 
  2440 * HOL: The THEN and ELSE parts of conditional expressions (if P then x else y)
  2441 are no longer simplified.  (This allows the simplifier to unfold recursive
  2442 functional programs.)  To restore the old behaviour, declare
  2443 
  2444     Delcongs [if_weak_cong];
  2445 
  2446 * HOL: Removed the obsolete syntax "Compl A"; use -A for set
  2447 complement;
  2448 
  2449 * HOL: the predicate "inj" is now defined by translation to "inj_on";
  2450 
  2451 * HOL/datatype: mutual_induct_tac no longer exists --
  2452   use induct_tac "x_1 ... x_n" instead of mutual_induct_tac ["x_1", ..., "x_n"]
  2453 
  2454 * HOL/typedef: fixed type inference for representing set; type
  2455 arguments now have to occur explicitly on the rhs as type constraints;
  2456 
  2457 * ZF: The con_defs part of an inductive definition may no longer refer
  2458 to constants declared in the same theory;
  2459 
  2460 * HOL, ZF: the function mk_cases, generated by the inductive
  2461 definition package, has lost an argument.  To simplify its result, it
  2462 uses the default simpset instead of a supplied list of theorems.
  2463 
  2464 * HOL/List: the constructors of type list are now Nil and Cons;
  2465 
  2466 * Simplifier: the type of the infix ML functions
  2467         setSSolver addSSolver setSolver addSolver
  2468 is now  simpset * solver -> simpset  where `solver' is a new abstract type
  2469 for packaging solvers. A solver is created via
  2470         mk_solver: string -> (thm list -> int -> tactic) -> solver
  2471 where the string argument is only a comment.
  2472 
  2473 
  2474 *** Proof tools ***
  2475 
  2476 * Provers/Arith/fast_lin_arith.ML contains a functor for creating a
  2477 decision procedure for linear arithmetic. Currently it is used for
  2478 types `nat', `int', and `real' in HOL (see below); it can, should and
  2479 will be instantiated for other types and logics as well.
  2480 
  2481 * The simplifier now accepts rewrite rules with flexible heads, eg
  2482      hom ?f ==> ?f(?x+?y) = ?f ?x + ?f ?y
  2483   They are applied like any rule with a non-pattern lhs, i.e. by first-order
  2484   matching.
  2485 
  2486 
  2487 *** General ***
  2488 
  2489 * New Isabelle/Isar subsystem provides an alternative to traditional
  2490 tactical theorem proving; together with the ProofGeneral/isar user
  2491 interface it offers an interactive environment for developing human
  2492 readable proof documents (Isar == Intelligible semi-automated
  2493 reasoning); for further information see isatool doc isar-ref,
  2494 src/HOL/Isar_examples and http://isabelle.in.tum.de/Isar/
  2495 
  2496 * improved and simplified presentation of theories: better HTML markup
  2497 (including colors), graph views in several sizes; isatool usedir now
  2498 provides a proper interface for user theories (via -P option); actual
  2499 document preparation based on (PDF)LaTeX is available as well (for
  2500 new-style theories only); see isatool doc system for more information;
  2501 
  2502 * native support for Proof General, both for classic Isabelle and
  2503 Isabelle/Isar;
  2504 
  2505 * ML function thm_deps visualizes dependencies of theorems and lemmas,
  2506 using the graph browser tool;
  2507 
  2508 * Isabelle manuals now also available as PDF;
  2509 
  2510 * theory loader rewritten from scratch (may not be fully
  2511 bug-compatible); old loadpath variable has been replaced by show_path,
  2512 add_path, del_path, reset_path functions; new operations such as
  2513 update_thy, touch_thy, remove_thy, use/update_thy_only (see also
  2514 isatool doc ref);
  2515 
  2516 * improved isatool install: option -k creates KDE application icon,
  2517 option -p DIR installs standalone binaries;
  2518 
  2519 * added ML_PLATFORM setting (useful for cross-platform installations);
  2520 more robust handling of platform specific ML images for SML/NJ;
  2521 
  2522 * the settings environment is now statically scoped, i.e. it is never
  2523 created again in sub-processes invoked from isabelle, isatool, or
  2524 Isabelle;
  2525 
  2526 * path element specification '~~' refers to '$ISABELLE_HOME';
  2527 
  2528 * in locales, the "assumes" and "defines" parts may be omitted if
  2529 empty;
  2530 
  2531 * new print_mode "xsymbols" for extended symbol support (e.g. genuine
  2532 long arrows);
  2533 
  2534 * new print_mode "HTML";
  2535 
  2536 * new flag show_tags controls display of tags of theorems (which are
  2537 basically just comments that may be attached by some tools);
  2538 
  2539 * Isamode 2.6 requires patch to accomodate change of Isabelle font
  2540 mode and goal output format:
  2541 
  2542 diff -r Isamode-2.6/elisp/isa-load.el Isamode/elisp/isa-load.el
  2543 244c244
  2544 <       (list (isa-getenv "ISABELLE") "-msymbols" logic-name)
  2545 ---
  2546 >       (list (isa-getenv "ISABELLE") "-misabelle_font" "-msymbols" logic-name)
  2547 diff -r Isabelle-2.6/elisp/isa-proofstate.el Isamode/elisp/isa-proofstate.el
  2548 181c181
  2549 < (defconst proofstate-proofstart-regexp "^Level [0-9]+$"
  2550 ---
  2551 > (defconst proofstate-proofstart-regexp "^Level [0-9]+"
  2552 
  2553 * function bind_thms stores lists of theorems (cf. bind_thm);
  2554 
  2555 * new shorthand tactics ftac, eatac, datac, fatac;
  2556 
  2557 * qed (and friends) now accept "" as result name; in that case the
  2558 theorem is not stored, but proper checks and presentation of the
  2559 result still apply;
  2560 
  2561 * theorem database now also indexes constants "Trueprop", "all",
  2562 "==>", "=="; thus thms_containing, findI etc. may retrieve more rules;
  2563 
  2564 
  2565 *** HOL ***
  2566 
  2567 ** HOL arithmetic **
  2568 
  2569 * There are now decision procedures for linear arithmetic over nat and
  2570 int:
  2571 
  2572 1. arith_tac copes with arbitrary formulae involving `=', `<', `<=',
  2573 `+', `-', `Suc', `min', `max' and numerical constants; other subterms
  2574 are treated as atomic; subformulae not involving type `nat' or `int'
  2575 are ignored; quantified subformulae are ignored unless they are
  2576 positive universal or negative existential. The tactic has to be
  2577 invoked by hand and can be a little bit slow. In particular, the
  2578 running time is exponential in the number of occurrences of `min' and
  2579 `max', and `-' on `nat'.
  2580 
  2581 2. fast_arith_tac is a cut-down version of arith_tac: it only takes
  2582 (negated) (in)equalities among the premises and the conclusion into
  2583 account (i.e. no compound formulae) and does not know about `min' and
  2584 `max', and `-' on `nat'. It is fast and is used automatically by the
  2585 simplifier.
  2586 
  2587 NB: At the moment, these decision procedures do not cope with mixed
  2588 nat/int formulae where the two parts interact, such as `m < n ==>
  2589 int(m) < int(n)'.
  2590 
  2591 * HOL/Numeral provides a generic theory of numerals (encoded
  2592 efficiently as bit strings); setup for types nat/int/real is in place;
  2593 INCOMPATIBILITY: since numeral syntax is now polymorphic, rather than
  2594 int, existing theories and proof scripts may require a few additional
  2595 type constraints;
  2596 
  2597 * integer division and remainder can now be performed on constant
  2598 arguments;
  2599 
  2600 * many properties of integer multiplication, division and remainder
  2601 are now available;
  2602 
  2603 * An interface to the Stanford Validity Checker (SVC) is available through the
  2604 tactic svc_tac.  Propositional tautologies and theorems of linear arithmetic
  2605 are proved automatically.  SVC must be installed separately, and its results
  2606 must be TAKEN ON TRUST (Isabelle does not check the proofs, but tags any
  2607 invocation of the underlying oracle).  For SVC see
  2608   http://verify.stanford.edu/SVC
  2609 
  2610 * IsaMakefile: the HOL-Real target now builds an actual image;
  2611 
  2612 
  2613 ** HOL misc **
  2614 
  2615 * HOL/Real/HahnBanach: the Hahn-Banach theorem for real vector spaces
  2616 (in Isabelle/Isar) -- by Gertrud Bauer;
  2617 
  2618 * HOL/BCV: generic model of bytecode verification, i.e. data-flow
  2619 analysis for assembly languages with subtypes;
  2620 
  2621 * HOL/TLA (Lamport's Temporal Logic of Actions): major reorganization
  2622 -- avoids syntactic ambiguities and treats state, transition, and
  2623 temporal levels more uniformly; introduces INCOMPATIBILITIES due to
  2624 changed syntax and (many) tactics;
  2625 
  2626 * HOL/inductive: Now also handles more general introduction rules such
  2627   as "ALL y. (y, x) : r --> y : acc r ==> x : acc r"; monotonicity
  2628   theorems are now maintained within the theory (maintained via the
  2629   "mono" attribute);
  2630 
  2631 * HOL/datatype: Now also handles arbitrarily branching datatypes
  2632   (using function types) such as
  2633 
  2634   datatype 'a tree = Atom 'a | Branch "nat => 'a tree"
  2635 
  2636 * HOL/record: record_simproc (part of the default simpset) takes care
  2637 of selectors applied to updated records; record_split_tac is no longer
  2638 part of the default claset; update_defs may now be removed from the
  2639 simpset in many cases; COMPATIBILITY: old behavior achieved by
  2640 
  2641   claset_ref () := claset() addSWrapper record_split_wrapper;
  2642   Delsimprocs [record_simproc]
  2643 
  2644 * HOL/typedef: fixed type inference for representing set; type
  2645 arguments now have to occur explicitly on the rhs as type constraints;
  2646 
  2647 * HOL/recdef (TFL): 'congs' syntax now expects comma separated list of theorem
  2648 names rather than an ML expression;
  2649 
  2650 * HOL/defer_recdef (TFL): like recdef but the well-founded relation can be
  2651 supplied later.  Program schemes can be defined, such as
  2652     "While B C s = (if B s then While B C (C s) else s)"
  2653 where the well-founded relation can be chosen after B and C have been given.
  2654 
  2655 * HOL/List: the constructors of type list are now Nil and Cons;
  2656 INCOMPATIBILITY: while [] and infix # syntax is still there, of
  2657 course, ML tools referring to List.list.op # etc. have to be adapted;
  2658 
  2659 * HOL_quantifiers flag superseded by "HOL" print mode, which is
  2660 disabled by default; run isabelle with option -m HOL to get back to
  2661 the original Gordon/HOL-style output;
  2662 
  2663 * HOL/Ord.thy: new bounded quantifier syntax (input only): ALL x<y. P,
  2664 ALL x<=y. P, EX x<y. P, EX x<=y. P;
  2665 
  2666 * HOL basic syntax simplified (more orthogonal): all variants of
  2667 All/Ex now support plain / symbolic / HOL notation; plain syntax for
  2668 Eps operator is provided as well: "SOME x. P[x]";
  2669 
  2670 * HOL/Sum.thy: sum_case has been moved to HOL/Datatype;
  2671 
  2672 * HOL/Univ.thy: infix syntax <*>, <+>, <**>, <+> eliminated and made
  2673 thus available for user theories;
  2674 
  2675 * HOLCF/IOA/Sequents: renamed 'Cons' to 'Consq' to avoid clash with
  2676 HOL/List; hardly an INCOMPATIBILITY since '>>' syntax is used all the
  2677 time;
  2678 
  2679 * HOL: new tactic smp_tac: int -> int -> tactic, which applies spec
  2680 several times and then mp;
  2681 
  2682 
  2683 *** LK ***
  2684 
  2685 * the notation <<...>> is now available as a notation for sequences of
  2686 formulas;
  2687 
  2688 * the simplifier is now installed
  2689 
  2690 * the axiom system has been generalized (thanks to Soren Heilmann)
  2691 
  2692 * the classical reasoner now has a default rule database
  2693 
  2694 
  2695 *** ZF ***
  2696 
  2697 * new primrec section allows primitive recursive functions to be given
  2698 directly (as in HOL) over datatypes and the natural numbers;
  2699 
  2700 * new tactics induct_tac and exhaust_tac for induction (or case
  2701 analysis) over datatypes and the natural numbers;
  2702 
  2703 * the datatype declaration of type T now defines the recursor T_rec;
  2704 
  2705 * simplification automatically does freeness reasoning for datatype
  2706 constructors;
  2707 
  2708 * automatic type-inference, with AddTCs command to insert new
  2709 type-checking rules;
  2710 
  2711 * datatype introduction rules are now added as Safe Introduction rules
  2712 to the claset;
  2713 
  2714 * the syntax "if P then x else y" is now available in addition to
  2715 if(P,x,y);
  2716 
  2717 
  2718 *** Internal programming interfaces ***
  2719 
  2720 * tuned simplifier trace output; new flag debug_simp;
  2721 
  2722 * structures Vartab / Termtab (instances of TableFun) offer efficient
  2723 tables indexed by indexname_ord / term_ord (compatible with aconv);
  2724 
  2725 * AxClass.axclass_tac lost the theory argument;
  2726 
  2727 * tuned current_goals_markers semantics: begin / end goal avoids
  2728 printing empty lines;
  2729 
  2730 * removed prs and prs_fn hook, which was broken because it did not
  2731 include \n in its semantics, forcing writeln to add one
  2732 uncoditionally; replaced prs_fn by writeln_fn; consider std_output:
  2733 string -> unit if you really want to output text without newline;
  2734 
  2735 * Symbol.output subject to print mode; INCOMPATIBILITY: defaults to
  2736 plain output, interface builders may have to enable 'isabelle_font'
  2737 mode to get Isabelle font glyphs as before;
  2738 
  2739 * refined token_translation interface; INCOMPATIBILITY: output length
  2740 now of type real instead of int;
  2741 
  2742 * theory loader actions may be traced via new ThyInfo.add_hook
  2743 interface (see src/Pure/Thy/thy_info.ML); example application: keep
  2744 your own database of information attached to *whole* theories -- as
  2745 opposed to intra-theory data slots offered via TheoryDataFun;
  2746 
  2747 * proper handling of dangling sort hypotheses (at last!);
  2748 Thm.strip_shyps and Drule.strip_shyps_warning take care of removing
  2749 extra sort hypotheses that can be witnessed from the type signature;
  2750 the force_strip_shyps flag is gone, any remaining shyps are simply
  2751 left in the theorem (with a warning issued by strip_shyps_warning);
  2752 
  2753 
  2754 
  2755 New in Isabelle98-1 (October 1998)
  2756 ----------------------------------
  2757 
  2758 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  2759 
  2760 * several changes of automated proof tools;
  2761 
  2762 * HOL: major changes to the inductive and datatype packages, including
  2763 some minor incompatibilities of theory syntax;
  2764 
  2765 * HOL: renamed r^-1 to 'converse' from 'inverse'; 'inj_onto' is now
  2766 called `inj_on';
  2767 
  2768 * HOL: removed duplicate thms in Arith:
  2769   less_imp_add_less  should be replaced by  trans_less_add1
  2770   le_imp_add_le      should be replaced by  trans_le_add1
  2771 
  2772 * HOL: unary minus is now overloaded (new type constraints may be
  2773 required);
  2774 
  2775 * HOL and ZF: unary minus for integers is now #- instead of #~.  In
  2776 ZF, expressions such as n#-1 must be changed to n#- 1, since #-1 is
  2777 now taken as an integer constant.
  2778 
  2779 * Pure: ML function 'theory_of' renamed to 'theory';
  2780 
  2781 
  2782 *** Proof tools ***
  2783 
  2784 * Simplifier:
  2785   1. Asm_full_simp_tac is now more aggressive.
  2786      1. It will sometimes reorient premises if that increases their power to
  2787         simplify.
  2788      2. It does no longer proceed strictly from left to right but may also
  2789         rotate premises to achieve further simplification.
  2790      For compatibility reasons there is now Asm_lr_simp_tac which is like the
  2791      old Asm_full_simp_tac in that it does not rotate premises.
  2792   2. The simplifier now knows a little bit about nat-arithmetic.
  2793 
  2794 * Classical reasoner: wrapper mechanism for the classical reasoner now
  2795 allows for selected deletion of wrappers, by introduction of names for
  2796 wrapper functionals.  This implies that addbefore, addSbefore,
  2797 addaltern, and addSaltern now take a pair (name, tactic) as argument,
  2798 and that adding two tactics with the same name overwrites the first
  2799 one (emitting a warning).
  2800   type wrapper = (int -> tactic) -> (int -> tactic)
  2801   setWrapper, setSWrapper, compWrapper and compSWrapper are replaced by
  2802   addWrapper, addSWrapper: claset * (string * wrapper) -> claset
  2803   delWrapper, delSWrapper: claset *  string            -> claset
  2804   getWrapper is renamed to appWrappers, getSWrapper to appSWrappers;
  2805 
  2806 * Classical reasoner: addbefore/addSbefore now have APPEND/ORELSE
  2807 semantics; addbefore now affects only the unsafe part of step_tac
  2808 etc.; this affects addss/auto_tac/force_tac, so EXISTING PROOFS MAY
  2809 FAIL, but proofs should be fixable easily, e.g. by replacing Auto_tac
  2810 by Force_tac;
  2811 
  2812 * Classical reasoner: setwrapper to setWrapper and compwrapper to
  2813 compWrapper; added safe wrapper (and access functions for it);
  2814 
  2815 * HOL/split_all_tac is now much faster and fails if there is nothing
  2816 to split.  Some EXISTING PROOFS MAY REQUIRE ADAPTION because the order
  2817 and the names of the automatically generated variables have changed.
  2818 split_all_tac has moved within claset() from unsafe wrappers to safe
  2819 wrappers, which means that !!-bound variables are split much more
  2820 aggressively, and safe_tac and clarify_tac now split such variables.
  2821 If this splitting is not appropriate, use delSWrapper "split_all_tac".
  2822 Note: the same holds for record_split_tac, which does the job of
  2823 split_all_tac for record fields.
  2824 
  2825 * HOL/Simplifier: Rewrite rules for case distinctions can now be added
  2826 permanently to the default simpset using Addsplits just like
  2827 Addsimps. They can be removed via Delsplits just like
  2828 Delsimps. Lower-case versions are also available.
  2829 
  2830 * HOL/Simplifier: The rule split_if is now part of the default
  2831 simpset. This means that the simplifier will eliminate all occurrences
  2832 of if-then-else in the conclusion of a goal. To prevent this, you can
  2833 either remove split_if completely from the default simpset by
  2834 `Delsplits [split_if]' or remove it in a specific call of the
  2835 simplifier using `... delsplits [split_if]'.  You can also add/delete
  2836 other case splitting rules to/from the default simpset: every datatype
  2837 generates suitable rules `split_t_case' and `split_t_case_asm' (where
  2838 t is the name of the datatype).
  2839 
  2840 * Classical reasoner / Simplifier combination: new force_tac (and
  2841 derivatives Force_tac, force) combines rewriting and classical
  2842 reasoning (and whatever other tools) similarly to auto_tac, but is
  2843 aimed to solve the given subgoal completely.
  2844 
  2845 
  2846 *** General ***
  2847 
  2848 * new top-level commands `Goal' and `Goalw' that improve upon `goal'
  2849 and `goalw': the theory is no longer needed as an explicit argument -
  2850 the current theory context is used; assumptions are no longer returned
  2851 at the ML-level unless one of them starts with ==> or !!; it is
  2852 recommended to convert to these new commands using isatool fixgoal
  2853 (backup your sources first!);
  2854 
  2855 * new top-level commands 'thm' and 'thms' for retrieving theorems from
  2856 the current theory context, and 'theory' to lookup stored theories;
  2857 
  2858 * new theory section 'locale' for declaring constants, assumptions and
  2859 definitions that have local scope;
  2860 
  2861 * new theory section 'nonterminals' for purely syntactic types;
  2862 
  2863 * new theory section 'setup' for generic ML setup functions
  2864 (e.g. package initialization);
  2865 
  2866 * the distribution now includes Isabelle icons: see
  2867 lib/logo/isabelle-{small,tiny}.xpm;
  2868 
  2869 * isatool install - install binaries with absolute references to
  2870 ISABELLE_HOME/bin;
  2871 
  2872 * isatool logo -- create instances of the Isabelle logo (as EPS);
  2873 
  2874 * print mode 'emacs' reserved for Isamode;
  2875 
  2876 * support multiple print (ast) translations per constant name;
  2877 
  2878 * theorems involving oracles are now printed with a suffixed [!];
  2879 
  2880 
  2881 *** HOL ***
  2882 
  2883 * there is now a tutorial on Isabelle/HOL (do 'isatool doc tutorial');
  2884 
  2885 * HOL/inductive package reorganized and improved: now supports mutual
  2886 definitions such as
  2887 
  2888   inductive EVEN ODD
  2889     intrs
  2890       null "0 : EVEN"
  2891       oddI "n : EVEN ==> Suc n : ODD"
  2892       evenI "n : ODD ==> Suc n : EVEN"
  2893 
  2894 new theorem list "elims" contains an elimination rule for each of the
  2895 recursive sets; inductive definitions now handle disjunctive premises
  2896 correctly (also ZF);
  2897 
  2898 INCOMPATIBILITIES: requires Inductive as an ancestor; component
  2899 "mutual_induct" no longer exists - the induction rule is always
  2900 contained in "induct";
  2901 
  2902 
  2903 * HOL/datatype package re-implemented and greatly improved: now
  2904 supports mutually recursive datatypes such as
  2905 
  2906   datatype
  2907     'a aexp = IF_THEN_ELSE ('a bexp) ('a aexp) ('a aexp)
  2908             | SUM ('a aexp) ('a aexp)
  2909             | DIFF ('a aexp) ('a aexp)
  2910             | NUM 'a
  2911   and
  2912     'a bexp = LESS ('a aexp) ('a aexp)
  2913             | AND ('a bexp) ('a bexp)
  2914             | OR ('a bexp) ('a bexp)
  2915 
  2916 as well as indirectly recursive datatypes such as
  2917 
  2918   datatype
  2919     ('a, 'b) term = Var 'a
  2920                   | App 'b ((('a, 'b) term) list)
  2921 
  2922 The new tactic  mutual_induct_tac [<var_1>, ..., <var_n>] i  performs
  2923 induction on mutually / indirectly recursive datatypes.
  2924 
  2925 Primrec equations are now stored in theory and can be accessed via
  2926 <function_name>.simps.
  2927 
  2928 INCOMPATIBILITIES:
  2929 
  2930   - Theories using datatypes must now have theory Datatype as an
  2931     ancestor.
  2932   - The specific <typename>.induct_tac no longer exists - use the
  2933     generic induct_tac instead.
  2934   - natE has been renamed to nat.exhaust - use exhaust_tac
  2935     instead of res_inst_tac ... natE. Note that the variable
  2936     names in nat.exhaust differ from the names in natE, this
  2937     may cause some "fragile" proofs to fail.
  2938   - The theorems split_<typename>_case and split_<typename>_case_asm
  2939     have been renamed to <typename>.split and <typename>.split_asm.
  2940   - Since default sorts of type variables are now handled correctly,
  2941     some datatype definitions may have to be annotated with explicit
  2942     sort constraints.
  2943   - Primrec definitions no longer require function name and type
  2944     of recursive argument.
  2945 
  2946 Consider using isatool fixdatatype to adapt your theories and proof
  2947 scripts to the new package (backup your sources first!).
  2948 
  2949 
  2950 * HOL/record package: considerably improved implementation; now
  2951 includes concrete syntax for record types, terms, updates; theorems
  2952 for surjective pairing and splitting !!-bound record variables; proof
  2953 support is as follows:
  2954 
  2955   1) standard conversions (selectors or updates applied to record
  2956 constructor terms) are part of the standard simpset;
  2957 
  2958   2) inject equations of the form ((x, y) = (x', y')) == x=x' & y=y' are
  2959 made part of standard simpset and claset via addIffs;
  2960 
  2961   3) a tactic for record field splitting (record_split_tac) is part of
  2962 the standard claset (addSWrapper);
  2963 
  2964 To get a better idea about these rules you may retrieve them via
  2965 something like 'thms "foo.simps"' or 'thms "foo.iffs"', where "foo" is
  2966 the name of your record type.
  2967 
  2968 The split tactic 3) conceptually simplifies by the following rule:
  2969 
  2970   "(!!x. PROP ?P x) == (!!a b. PROP ?P (a, b))"
  2971 
  2972 Thus any record variable that is bound by meta-all will automatically
  2973 blow up into some record constructor term, consequently the
  2974 simplifications of 1), 2) apply.  Thus force_tac, auto_tac etc. shall
  2975 solve record problems automatically.
  2976 
  2977 
  2978 * reorganized the main HOL image: HOL/Integ and String loaded by
  2979 default; theory Main includes everything;
  2980 
  2981 * automatic simplification of integer sums and comparisons, using cancellation;
  2982 
  2983 * added option_map_eq_Some and not_Some_eq to the default simpset and claset;
  2984 
  2985 * added disj_not1 = "(~P | Q) = (P --> Q)" to the default simpset;
  2986 
  2987 * many new identities for unions, intersections, set difference, etc.;
  2988 
  2989 * expand_if, expand_split, expand_sum_case and expand_nat_case are now
  2990 called split_if, split_split, split_sum_case and split_nat_case (to go
  2991 with add/delsplits);
  2992 
  2993 * HOL/Prod introduces simplification procedure unit_eq_proc rewriting
  2994 (?x::unit) = (); this is made part of the default simpset, which COULD
  2995 MAKE EXISTING PROOFS FAIL under rare circumstances (consider
  2996 'Delsimprocs [unit_eq_proc];' as last resort); also note that
  2997 unit_abs_eta_conv is added in order to counter the effect of
  2998 unit_eq_proc on (%u::unit. f u), replacing it by f rather than by
  2999 %u.f();
  3000 
  3001 * HOL/Fun INCOMPATIBILITY: `inj_onto' is now called `inj_on' (which
  3002 makes more sense);
  3003 
  3004 * HOL/Set INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
  3005   It and 'sym RS equals0D' are now in the default  claset, giving automatic
  3006   disjointness reasoning but breaking a few old proofs.
  3007 
  3008 * HOL/Relation INCOMPATIBILITY: renamed the relational operator r^-1
  3009 to 'converse' from 'inverse' (for compatibility with ZF and some
  3010 literature);
  3011 
  3012 * HOL/recdef can now declare non-recursive functions, with {} supplied as
  3013 the well-founded relation;
  3014 
  3015 * HOL/Set INCOMPATIBILITY: the complement of set A is now written -A instead of
  3016     Compl A.  The "Compl" syntax remains available as input syntax for this
  3017     release ONLY.
  3018 
  3019 * HOL/Update: new theory of function updates:
  3020     f(a:=b) == %x. if x=a then b else f x
  3021 may also be iterated as in f(a:=b,c:=d,...);
  3022 
  3023 * HOL/Vimage: new theory for inverse image of a function, syntax f-``B;
  3024 
  3025 * HOL/List:
  3026   - new function list_update written xs[i:=v] that updates the i-th
  3027     list position. May also be iterated as in xs[i:=a,j:=b,...].
  3028   - new function `upt' written [i..j(] which generates the list
  3029     [i,i+1,...,j-1], i.e. the upper bound is excluded. To include the upper
  3030     bound write [i..j], which is a shorthand for [i..j+1(].
  3031   - new lexicographic orderings and corresponding wellfoundedness theorems.
  3032 
  3033 * HOL/Arith:
  3034   - removed 'pred' (predecessor) function;
  3035   - generalized some theorems about n-1;
  3036   - many new laws about "div" and "mod";
  3037   - new laws about greatest common divisors (see theory ex/Primes);
  3038 
  3039 * HOL/Relation: renamed the relational operator r^-1 "converse"
  3040 instead of "inverse";
  3041 
  3042 * HOL/Induct/Multiset: a theory of multisets, including the wellfoundedness
  3043   of the multiset ordering;
  3044 
  3045 * directory HOL/Real: a construction of the reals using Dedekind cuts
  3046   (not included by default);
  3047 
  3048 * directory HOL/UNITY: Chandy and Misra's UNITY formalism;
  3049 
  3050 * directory HOL/Hoare: a new version of Hoare logic which permits many-sorted
  3051   programs, i.e. different program variables may have different types.
  3052 
  3053 * calling (stac rew i) now fails if "rew" has no effect on the goal
  3054   [previously, this check worked only if the rewrite rule was unconditional]
  3055   Now rew can involve either definitions or equalities (either == or =).
  3056 
  3057 
  3058 *** ZF ***
  3059 
  3060 * theory Main includes everything; INCOMPATIBILITY: theory ZF.thy contains
  3061   only the theorems proved on ZF.ML;
  3062 
  3063 * ZF INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
  3064   It and 'sym RS equals0D' are now in the default  claset, giving automatic
  3065   disjointness reasoning but breaking a few old proofs.
  3066 
  3067 * ZF/Update: new theory of function updates
  3068     with default rewrite rule  f(x:=y) ` z = if(z=x, y, f`z)
  3069   may also be iterated as in f(a:=b,c:=d,...);
  3070 
  3071 * in  let x=t in u(x), neither t nor u(x) has to be an FOL term.
  3072 
  3073 * calling (stac rew i) now fails if "rew" has no effect on the goal
  3074   [previously, this check worked only if the rewrite rule was unconditional]
  3075   Now rew can involve either definitions or equalities (either == or =).
  3076 
  3077 * case_tac provided for compatibility with HOL
  3078     (like the old excluded_middle_tac, but with subgoals swapped)
  3079 
  3080 
  3081 *** Internal programming interfaces ***
  3082 
  3083 * Pure: several new basic modules made available for general use, see
  3084 also src/Pure/README;
  3085 
  3086 * improved the theory data mechanism to support encapsulation (data
  3087 kind name replaced by private Object.kind, acting as authorization
  3088 key); new type-safe user interface via functor TheoryDataFun; generic
  3089 print_data function becomes basically useless;
  3090 
  3091 * removed global_names compatibility flag -- all theory declarations
  3092 are qualified by default;
  3093 
  3094 * module Pure/Syntax now offers quote / antiquote translation
  3095 functions (useful for Hoare logic etc. with implicit dependencies);
  3096 see HOL/ex/Antiquote for an example use;
  3097 
  3098 * Simplifier now offers conversions (asm_)(full_)rewrite: simpset ->
  3099 cterm -> thm;
  3100 
  3101 * new tactical CHANGED_GOAL for checking that a tactic modifies a
  3102 subgoal;
  3103 
  3104 * Display.print_goals function moved to Locale.print_goals;
  3105 
  3106 * standard print function for goals supports current_goals_markers
  3107 variable for marking begin of proof, end of proof, start of goal; the
  3108 default is ("", "", ""); setting current_goals_markers := ("<proof>",
  3109 "</proof>", "<goal>") causes SGML like tagged proof state printing,
  3110 for example;
  3111 
  3112 
  3113 
  3114 New in Isabelle98 (January 1998)
  3115 --------------------------------
  3116 
  3117 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  3118 
  3119 * changed lexical syntax of terms / types: dots made part of long
  3120 identifiers, e.g. "%x.x" no longer possible, should be "%x. x";
  3121 
  3122 * simpset (and claset) reference variable replaced by functions
  3123 simpset / simpset_ref;
  3124 
  3125 * no longer supports theory aliases (via merge) and non-trivial
  3126 implicit merge of thms' signatures;
  3127 
  3128 * most internal names of constants changed due to qualified names;
  3129 
  3130 * changed Pure/Sequence interface (see Pure/seq.ML);
  3131 
  3132 
  3133 *** General Changes ***
  3134 
  3135 * hierachically structured name spaces (for consts, types, axms, thms
  3136 etc.); new lexical class 'longid' (e.g. Foo.bar.x) may render much of
  3137 old input syntactically incorrect (e.g. "%x.x"); COMPATIBILITY:
  3138 isatool fixdots ensures space after dots (e.g. "%x. x"); set
  3139 long_names for fully qualified output names; NOTE: ML programs
  3140 (special tactics, packages etc.) referring to internal names may have
  3141 to be adapted to cope with fully qualified names; in case of severe
  3142 backward campatibility problems try setting 'global_names' at compile
  3143 time to have enrything declared within a flat name space; one may also
  3144 fine tune name declarations in theories via the 'global' and 'local'
  3145 section;
  3146 
  3147 * reimplemented the implicit simpset and claset using the new anytype
  3148 data filed in signatures; references simpset:simpset ref etc. are
  3149 replaced by functions simpset:unit->simpset and
  3150 simpset_ref:unit->simpset ref; COMPATIBILITY: use isatool fixclasimp
  3151 to patch your ML files accordingly;
  3152 
  3153 * HTML output now includes theory graph data for display with Java
  3154 applet or isatool browser; data generated automatically via isatool
  3155 usedir (see -i option, ISABELLE_USEDIR_OPTIONS);
  3156 
  3157 * defs may now be conditional; improved rewrite_goals_tac to handle
  3158 conditional equations;
  3159 
  3160 * defs now admits additional type arguments, using TYPE('a) syntax;
  3161 
  3162 * theory aliases via merge (e.g. M=A+B+C) no longer supported, always
  3163 creates a new theory node; implicit merge of thms' signatures is
  3164 restricted to 'trivial' ones; COMPATIBILITY: one may have to use
  3165 transfer:theory->thm->thm in (rare) cases;
  3166 
  3167 * improved handling of draft signatures / theories; draft thms (and
  3168 ctyps, cterms) are automatically promoted to real ones;
  3169 
  3170 * slightly changed interfaces for oracles: admit many per theory, named
  3171 (e.g. oracle foo = mlfun), additional name argument for invoke_oracle;
  3172 
  3173 * print_goals: optional output of const types (set show_consts and
  3174 show_types);
  3175 
  3176 * improved output of warnings (###) and errors (***);
  3177 
  3178 * subgoal_tac displays a warning if the new subgoal has type variables;
  3179 
  3180 * removed old README and Makefiles;
  3181 
  3182 * replaced print_goals_ref hook by print_current_goals_fn and result_error_fn;
  3183 
  3184 * removed obsolete init_pps and init_database;
  3185 
  3186 * deleted the obsolete tactical STATE, which was declared by
  3187     fun STATE tacfun st = tacfun st st;
  3188 
  3189 * cd and use now support path variables, e.g. $ISABELLE_HOME, or ~
  3190 (which abbreviates $HOME);
  3191 
  3192 * changed Pure/Sequence interface (see Pure/seq.ML); COMPATIBILITY:
  3193 use isatool fixseq to adapt your ML programs (this works for fully
  3194 qualified references to the Sequence structure only!);
  3195 
  3196 * use_thy no longer requires writable current directory; it always
  3197 reloads .ML *and* .thy file, if either one is out of date;
  3198 
  3199 
  3200 *** Classical Reasoner ***
  3201 
  3202 * Clarify_tac, clarify_tac, clarify_step_tac, Clarify_step_tac: new
  3203 tactics that use classical reasoning to simplify a subgoal without
  3204 splitting it into several subgoals;
  3205 
  3206 * Safe_tac: like safe_tac but uses the default claset;
  3207 
  3208 
  3209 *** Simplifier ***
  3210 
  3211 * added simplification meta rules:
  3212     (asm_)(full_)simplify: simpset -> thm -> thm;
  3213 
  3214 * simplifier.ML no longer part of Pure -- has to be loaded by object
  3215 logics (again);
  3216 
  3217 * added prems argument to simplification procedures;
  3218 
  3219 * HOL, FOL, ZF: added infix function `addsplits':
  3220   instead of `<simpset> setloop (split_tac <thms>)'
  3221   you can simply write `<simpset> addsplits <thms>'
  3222 
  3223 
  3224 *** Syntax ***
  3225 
  3226 * TYPE('a) syntax for type reflection terms;
  3227 
  3228 * no longer handles consts with name "" -- declare as 'syntax' instead;
  3229 
  3230 * pretty printer: changed order of mixfix annotation preference (again!);
  3231 
  3232 * Pure: fixed idt/idts vs. pttrn/pttrns syntactic categories;
  3233 
  3234 
  3235 *** HOL ***
  3236 
  3237 * HOL: there is a new splitter `split_asm_tac' that can be used e.g.
  3238   with `addloop' of the simplifier to faciliate case splitting in premises.
  3239 
  3240 * HOL/TLA: Stephan Merz's formalization of Lamport's Temporal Logic of Actions;
  3241 
  3242 * HOL/Auth: new protocol proofs including some for the Internet
  3243   protocol TLS;
  3244 
  3245 * HOL/Map: new theory of `maps' a la VDM;
  3246 
  3247 * HOL/simplifier: simplification procedures nat_cancel_sums for
  3248 cancelling out common nat summands from =, <, <= (in)equalities, or
  3249 differences; simplification procedures nat_cancel_factor for
  3250 cancelling common factor from =, <, <= (in)equalities over natural
  3251 sums; nat_cancel contains both kinds of procedures, it is installed by
  3252 default in Arith.thy -- this COULD MAKE EXISTING PROOFS FAIL;
  3253 
  3254 * HOL/simplifier: terms of the form
  3255   `? x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x)'  (or t=x)
  3256   are rewritten to
  3257   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t)',
  3258   and those of the form
  3259   `! x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x) --> R(x)'  (or t=x)
  3260   are rewritten to
  3261   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t) --> R(t)',
  3262 
  3263 * HOL/datatype
  3264   Each datatype `t' now comes with a theorem `split_t_case' of the form
  3265 
  3266   P(t_case f1 ... fn x) =
  3267      ( (!y1 ... ym1. x = C1 y1 ... ym1 --> P(f1 y1 ... ym1)) &
  3268         ...
  3269        (!y1 ... ymn. x = Cn y1 ... ymn --> P(f1 y1 ... ymn))
  3270      )
  3271 
  3272   and a theorem `split_t_case_asm' of the form
  3273 
  3274   P(t_case f1 ... fn x) =
  3275     ~( (? y1 ... ym1. x = C1 y1 ... ym1 & ~P(f1 y1 ... ym1)) |
  3276         ...
  3277        (? y1 ... ymn. x = Cn y1 ... ymn & ~P(f1 y1 ... ymn))
  3278      )
  3279   which can be added to a simpset via `addsplits'. The existing theorems
  3280   expand_list_case and expand_option_case have been renamed to
  3281   split_list_case and split_option_case.
  3282 
  3283 * HOL/Arithmetic:
  3284   - `pred n' is automatically converted to `n-1'.
  3285     Users are strongly encouraged not to use `pred' any longer,
  3286     because it will disappear altogether at some point.
  3287   - Users are strongly encouraged to write "0 < n" rather than
  3288     "n ~= 0". Theorems and proof tools have been modified towards this
  3289     `standard'.
  3290 
  3291 * HOL/Lists:
  3292   the function "set_of_list" has been renamed "set" (and its theorems too);
  3293   the function "nth" now takes its arguments in the reverse order and
  3294   has acquired the infix notation "!" as in "xs!n".
  3295 
  3296 * HOL/Set: UNIV is now a constant and is no longer translated to Compl{};
  3297 
  3298 * HOL/Set: The operator (UN x.B x) now abbreviates (UN x:UNIV. B x) and its
  3299   specialist theorems (like UN1_I) are gone.  Similarly for (INT x.B x);
  3300 
  3301 * HOL/record: extensible records with schematic structural subtyping
  3302 (single inheritance); EXPERIMENTAL version demonstrating the encoding,
  3303 still lacks various theorems and concrete record syntax;
  3304 
  3305 
  3306 *** HOLCF ***
  3307 
  3308 * removed "axioms" and "generated by" sections;
  3309 
  3310 * replaced "ops" section by extended "consts" section, which is capable of
  3311   handling the continuous function space "->" directly;
  3312 
  3313 * domain package:
  3314   . proves theorems immediately and stores them in the theory,
  3315   . creates hierachical name space,
  3316   . now uses normal mixfix annotations (instead of cinfix...),
  3317   . minor changes to some names and values (for consistency),
  3318   . e.g. cases -> casedist, dists_eq -> dist_eqs, [take_lemma] -> take_lemmas,
  3319   . separator between mutual domain defs: changed "," to "and",
  3320   . improved handling of sort constraints;  now they have to
  3321     appear on the left-hand side of the equations only;
  3322 
  3323 * fixed LAM <x,y,zs>.b syntax;
  3324 
  3325 * added extended adm_tac to simplifier in HOLCF -- can now discharge
  3326 adm (%x. P (t x)), where P is chainfinite and t continuous;
  3327 
  3328 
  3329 *** FOL and ZF ***
  3330 
  3331 * FOL: there is a new splitter `split_asm_tac' that can be used e.g.
  3332   with `addloop' of the simplifier to faciliate case splitting in premises.
  3333 
  3334 * qed_spec_mp, qed_goal_spec_mp, qed_goalw_spec_mp are available, as
  3335 in HOL, they strip ALL and --> from proved theorems;
  3336 
  3337 
  3338 
  3339 New in Isabelle94-8 (May 1997)
  3340 ------------------------------
  3341 
  3342 *** General Changes ***
  3343 
  3344 * new utilities to build / run / maintain Isabelle etc. (in parts
  3345 still somewhat experimental); old Makefiles etc. still functional;
  3346 
  3347 * new 'Isabelle System Manual';
  3348 
  3349 * INSTALL text, together with ./configure and ./build scripts;
  3350 
  3351 * reimplemented type inference for greater efficiency, better error
  3352 messages and clean internal interface;
  3353 
  3354 * prlim command for dealing with lots of subgoals (an easier way of
  3355 setting goals_limit);
  3356 
  3357 
  3358 *** Syntax ***
  3359 
  3360 * supports alternative (named) syntax tables (parser and pretty
  3361 printer); internal interface is provided by add_modesyntax(_i);
  3362 
  3363 * Pure, FOL, ZF, HOL, HOLCF now support symbolic input and output; to
  3364 be used in conjunction with the Isabelle symbol font; uses the
  3365 "symbols" syntax table;
  3366 
  3367 * added token_translation interface (may translate name tokens in
  3368 arbitrary ways, dependent on their type (free, bound, tfree, ...) and
  3369 the current print_mode); IMPORTANT: user print translation functions
  3370 are responsible for marking newly introduced bounds
  3371 (Syntax.mark_boundT);
  3372 
  3373 * token translations for modes "xterm" and "xterm_color" that display
  3374 names in bold, underline etc. or colors (which requires a color
  3375 version of xterm);
  3376 
  3377 * infixes may now be declared with names independent of their syntax;
  3378 
  3379 * added typed_print_translation (like print_translation, but may
  3380 access type of constant);
  3381 
  3382 
  3383 *** Classical Reasoner ***
  3384 
  3385 Blast_tac: a new tactic!  It is often more powerful than fast_tac, but has
  3386 some limitations.  Blast_tac...
  3387   + ignores addss, addbefore, addafter; this restriction is intrinsic
  3388   + ignores elimination rules that don't have the correct format
  3389         (the conclusion MUST be a formula variable)
  3390   + ignores types, which can make HOL proofs fail
  3391   + rules must not require higher-order unification, e.g. apply_type in ZF
  3392     [message "Function Var's argument not a bound variable" relates to this]
  3393   + its proof strategy is more general but can actually be slower
  3394 
  3395 * substitution with equality assumptions no longer permutes other
  3396 assumptions;
  3397 
  3398 * minor changes in semantics of addafter (now called addaltern); renamed
  3399 setwrapper to setWrapper and compwrapper to compWrapper; added safe wrapper
  3400 (and access functions for it);
  3401 
  3402 * improved combination of classical reasoner and simplifier:
  3403   + functions for handling clasimpsets
  3404   + improvement of addss: now the simplifier is called _after_ the
  3405     safe steps.
  3406   + safe variant of addss called addSss: uses safe simplifications
  3407     _during_ the safe steps. It is more complete as it allows multiple
  3408     instantiations of unknowns (e.g. with slow_tac).
  3409 
  3410 *** Simplifier ***
  3411 
  3412 * added interface for simplification procedures (functions that
  3413 produce *proven* rewrite rules on the fly, depending on current
  3414 redex);
  3415 
  3416 * ordering on terms as parameter (used for ordered rewriting);
  3417 
  3418 * new functions delcongs, deleqcongs, and Delcongs. richer rep_ss;
  3419 
  3420 * the solver is now split into a safe and an unsafe part.
  3421 This should be invisible for the normal user, except that the
  3422 functions setsolver and addsolver have been renamed to setSolver and
  3423 addSolver; added safe_asm_full_simp_tac;
  3424 
  3425 
  3426 *** HOL ***
  3427 
  3428 * a generic induction tactic `induct_tac' which works for all datatypes and
  3429 also for type `nat';
  3430 
  3431 * a generic case distinction tactic `exhaust_tac' which works for all
  3432 datatypes and also for type `nat';
  3433 
  3434 * each datatype comes with a function `size';
  3435 
  3436 * patterns in case expressions allow tuple patterns as arguments to
  3437 constructors, for example `case x of [] => ... | (x,y,z)#ps => ...';
  3438 
  3439 * primrec now also works with type nat;
  3440 
  3441 * recdef: a new declaration form, allows general recursive functions to be
  3442 defined in theory files.  See HOL/ex/Fib, HOL/ex/Primes, HOL/Subst/Unify.
  3443 
  3444 * the constant for negation has been renamed from "not" to "Not" to
  3445 harmonize with FOL, ZF, LK, etc.;
  3446 
  3447 * HOL/ex/LFilter theory of a corecursive "filter" functional for
  3448 infinite lists;
  3449 
  3450 * HOL/Modelcheck demonstrates invocation of model checker oracle;
  3451 
  3452 * HOL/ex/Ring.thy declares cring_simp, which solves equational
  3453 problems in commutative rings, using axiomatic type classes for + and *;
  3454 
  3455 * more examples in HOL/MiniML and HOL/Auth;
  3456 
  3457 * more default rewrite rules for quantifiers, union/intersection;
  3458 
  3459 * a new constant `arbitrary == @x.False';
  3460 
  3461 * HOLCF/IOA replaces old HOL/IOA;
  3462 
  3463 * HOLCF changes: derived all rules and arities
  3464   + axiomatic type classes instead of classes
  3465   + typedef instead of faking type definitions
  3466   + eliminated the internal constants less_fun, less_cfun, UU_fun, UU_cfun etc.
  3467   + new axclasses cpo, chfin, flat with flat < chfin < pcpo < cpo < po
  3468   + eliminated the types void, one, tr
  3469   + use unit lift and bool lift (with translations) instead of one and tr
  3470   + eliminated blift from Lift3.thy (use Def instead of blift)
  3471   all eliminated rules are derived as theorems --> no visible changes ;
  3472 
  3473 
  3474 *** ZF ***
  3475 
  3476 * ZF now has Fast_tac, Simp_tac and Auto_tac.  Union_iff is a now a default
  3477 rewrite rule; this may affect some proofs.  eq_cs is gone but can be put back
  3478 as ZF_cs addSIs [equalityI];
  3479 
  3480 
  3481 
  3482 New in Isabelle94-7 (November 96)
  3483 ---------------------------------
  3484 
  3485 * allowing negative levels (as offsets) in prlev and choplev;
  3486 
  3487 * super-linear speedup for large simplifications;
  3488 
  3489 * FOL, ZF and HOL now use miniscoping: rewriting pushes
  3490 quantifications in as far as possible (COULD MAKE EXISTING PROOFS
  3491 FAIL); can suppress it using the command Delsimps (ex_simps @
  3492 all_simps); De Morgan laws are also now included, by default;
  3493 
  3494 * improved printing of ==>  :  ~:
  3495 
  3496 * new object-logic "Sequents" adds linear logic, while replacing LK
  3497 and Modal (thanks to Sara Kalvala);
  3498 
  3499 * HOL/Auth: correctness proofs for authentication protocols;
  3500 
  3501 * HOL: new auto_tac combines rewriting and classical reasoning (many
  3502 examples on HOL/Auth);
  3503 
  3504 * HOL: new command AddIffs for declaring theorems of the form P=Q to
  3505 the rewriter and classical reasoner simultaneously;
  3506 
  3507 * function uresult no longer returns theorems in "standard" format;
  3508 regain previous version by: val uresult = standard o uresult;
  3509 
  3510 
  3511 
  3512 New in Isabelle94-6
  3513 -------------------
  3514 
  3515 * oracles -- these establish an interface between Isabelle and trusted
  3516 external reasoners, which may deliver results as theorems;
  3517 
  3518 * proof objects (in particular record all uses of oracles);
  3519 
  3520 * Simp_tac, Fast_tac, etc. that refer to implicit simpset / claset;
  3521 
  3522 * "constdefs" section in theory files;
  3523 
  3524 * "primrec" section (HOL) no longer requires names;
  3525 
  3526 * internal type "tactic" now simply "thm -> thm Sequence.seq";
  3527 
  3528 
  3529 
  3530 New in Isabelle94-5
  3531 -------------------
  3532 
  3533 * reduced space requirements;
  3534 
  3535 * automatic HTML generation from theories;
  3536 
  3537 * theory files no longer require "..." (quotes) around most types;
  3538 
  3539 * new examples, including two proofs of the Church-Rosser theorem;
  3540 
  3541 * non-curried (1994) version of HOL is no longer distributed;
  3542 
  3543 
  3544 
  3545 New in Isabelle94-4
  3546 -------------------
  3547 
  3548 * greatly reduced space requirements;
  3549 
  3550 * theory files (.thy) no longer require \...\ escapes at line breaks;
  3551 
  3552 * searchable theorem database (see the section "Retrieving theorems" on
  3553 page 8 of the Reference Manual);
  3554 
  3555 * new examples, including Grabczewski's monumental case study of the
  3556 Axiom of Choice;
  3557 
  3558 * The previous version of HOL renamed to Old_HOL;
  3559 
  3560 * The new version of HOL (previously called CHOL) uses a curried syntax
  3561 for functions.  Application looks like f a b instead of f(a,b);
  3562 
  3563 * Mutually recursive inductive definitions finally work in HOL;
  3564 
  3565 * In ZF, pattern-matching on tuples is now available in all abstractions and
  3566 translates to the operator "split";
  3567 
  3568 
  3569 
  3570 New in Isabelle94-3
  3571 -------------------
  3572 
  3573 * new infix operator, addss, allowing the classical reasoner to
  3574 perform simplification at each step of its search.  Example:
  3575         fast_tac (cs addss ss)
  3576 
  3577 * a new logic, CHOL, the same as HOL, but with a curried syntax
  3578 for functions.  Application looks like f a b instead of f(a,b).  Also pairs
  3579 look like (a,b) instead of <a,b>;
  3580 
  3581 * PLEASE NOTE: CHOL will eventually replace HOL!
  3582 
  3583 * In CHOL, pattern-matching on tuples is now available in all abstractions.
  3584 It translates to the operator "split".  A new theory of integers is available;
  3585 
  3586 * In ZF, integer numerals now denote two's-complement binary integers.
  3587 Arithmetic operations can be performed by rewriting.  See ZF/ex/Bin.ML;
  3588 
  3589 * Many new examples: I/O automata, Church-Rosser theorem, equivalents
  3590 of the Axiom of Choice;
  3591 
  3592 
  3593 
  3594 New in Isabelle94-2
  3595 -------------------
  3596 
  3597 * Significantly faster resolution;
  3598 
  3599 * the different sections in a .thy file can now be mixed and repeated
  3600 freely;
  3601 
  3602 * Database of theorems for FOL, HOL and ZF.  New
  3603 commands including qed, qed_goal and bind_thm store theorems in the database.
  3604 
  3605 * Simple database queries: return a named theorem (get_thm) or all theorems of
  3606 a given theory (thms_of), or find out what theory a theorem was proved in
  3607 (theory_of_thm);
  3608 
  3609 * Bugs fixed in the inductive definition and datatype packages;
  3610 
  3611 * The classical reasoner provides deepen_tac and depth_tac, making FOL_dup_cs
  3612 and HOL_dup_cs obsolete;
  3613 
  3614 * Syntactic ambiguities caused by the new treatment of syntax in Isabelle94-1
  3615 have been removed;
  3616 
  3617 * Simpler definition of function space in ZF;
  3618 
  3619 * new results about cardinal and ordinal arithmetic in ZF;
  3620 
  3621 * 'subtype' facility in HOL for introducing new types as subsets of existing
  3622 types;
  3623 
  3624 
  3625 $Id$