NEWS
author huffman
Sun Nov 06 00:35:24 2005 +0100 (2005-11-06)
changeset 18096 574aa0487069
parent 18051 dba086ed50cb
child 18145 6757627acf59
permissions -rw-r--r--
use consts for infix syntax
     1 Isabelle NEWS -- history user-relevant changes
     2 ==============================================
     3 
     4 New in this Isabelle release
     5 ----------------------------
     6 
     7 *** General ***
     8 
     9 * Theory syntax: the header format ``theory A = B + C:'' has been
    10 discontinued in favour of ``theory A imports B C begin''.  Use isatool
    11 fixheaders to convert existing theory files.  INCOMPATIBILITY.
    12 
    13 * Theory syntax: the old non-Isar theory file format has been
    14 discontinued altogether.  Note that ML proof scripts may still be used
    15 with Isar theories; migration is usually quite simple with the ML
    16 function use_legacy_bindings.  INCOMPATIBILITY.
    17 
    18 * Legacy goal package: reduced interface to the bare minimum required
    19 to keep existing proof scripts running.  Most other user-level
    20 functions are now part of the OldGoals structure, which is *not* open
    21 by default (consider isatool expandshort before open OldGoals).
    22 Removed top_sg, prin, printyp, pprint_term/typ altogether, because
    23 these tend to cause confusion about the actual goal (!) context being
    24 used here, which is not necessarily the same as the_context().
    25 
    26 * Command 'find_theorems': support "*" wildcard in "name:" criterion.
    27 
    28 
    29 *** Document preparation ***
    30 
    31 * Added antiquotations @{ML_type text} and @{ML_struct text} which
    32 check the given source text as ML type/structure, printing verbatim.
    33 
    34 
    35 *** Pure ***
    36 
    37 * Isar: improper proof element 'guess' is like 'obtain', but derives
    38 the obtained context from the course of reasoning!  For example:
    39 
    40   assume "EX x y. A x & B y"   -- "any previous fact"
    41   then guess x and y by clarify
    42 
    43 This technique is potentially adventurous, depending on the facts and
    44 proof tools being involved here.
    45 
    46 * Isar: known facts from the proof context may be specified as literal
    47 propositions, using ASCII back-quote syntax.  This works wherever
    48 named facts used to be allowed so far, in proof commands, proof
    49 methods, attributes etc.  Literal facts are retrieved from the context
    50 according to unification of type and term parameters.  For example,
    51 provided that "A" and "A ==> B" and "!!x. P x ==> Q x" are known
    52 theorems in the current context, then these are valid literal facts:
    53 `A` and `A ==> B` and `!!x. P x ==> Q x" as well as `P a ==> Q a` etc.
    54 
    55 There is also a proof method "fact" which does the same composition
    56 for explicit goal states, e.g. the following proof texts coincide with
    57 certain special cases of literal facts:
    58 
    59   have "A" by fact                 ==  note `A`
    60   have "A ==> B" by fact           ==  note `A ==> B`
    61   have "!!x. P x ==> Q x" by fact  ==  note `!!x. P x ==> Q x`
    62   have "P a ==> Q a" by fact       ==  note `P a ==> Q a`
    63 
    64 * Input syntax now supports dummy variable binding "%_. b", where the
    65 body does not mention the bound variable.  Note that dummy patterns
    66 implicitly depend on their context of bounds, which makes "{_. _}"
    67 match any set comprehension as expected.  Potential INCOMPATIBILITY --
    68 parse translations need to cope with syntactic constant "_idtdummy" in
    69 the binding position.
    70 
    71 * Removed obsolete syntactic constant "_K" and its associated parse
    72 translation.  INCOMPATIBILITY -- use dummy abstraction instead, for
    73 example "A -> B" => "Pi A (%_. B)".
    74 
    75 
    76 *** HOL ***
    77 
    78 * Alternative iff syntax "A <-> B" for equality on bool (with priority
    79 25 like -->); output depends on the "iff" print_mode, the default is
    80 "A = B" (with priority 50).
    81 
    82 * In the context of the assumption "~(s = t)" the Simplifier rewrites
    83 "t = s" to False (by simproc "neq_simproc").  For backward
    84 compatibility this can be disabled by ML "reset use_neq_simproc".
    85 
    86 * Tactics 'sat' and 'satx' reimplemented, several improvements: goals
    87 no longer need to be stated as "<prems> ==> False", equivalences (i.e.
    88 "=" on type bool) are handled, variable names of the form "lit_<n>"
    89 are no longer reserved, significant speedup.
    90 
    91 
    92 *** ML ***
    93 
    94 * Library: new module Pure/General/rat.ML implementing rational numbers,
    95 replacing the former functions in the Isabelle library.
    96 
    97 * Library: indexed lists - some functions in the Isabelle library
    98 treating lists over 'a as finite mappings from [0...n] to 'a
    99 have been given more convenient names and signatures reminiscent
   100 of similar functions for alists, tables, etc:
   101 
   102   val nth: 'a list -> int -> 'a 
   103   val nth_update: int * 'a -> 'a list -> 'a list
   104   val nth_map: int -> ('a -> 'a) -> 'a list -> 'a list
   105   val fold_index: (int * 'a -> 'b -> 'b) -> 'a list -> 'b -> 'b
   106 
   107 Note that fold_index starts counting at index 0, not 1 like foldln used to.
   108 
   109 * Pure: primitive rule lift_rule now takes goal cterm instead of an
   110 actual goal state (thm).  Use Thm.lift_rule (Thm.cgoal_of st i) to
   111 achieve the old behaviour.
   112 
   113 * Pure: the "Goal" constant is now called "prop", supporting a
   114 slightly more general idea of ``protecting'' meta-level rule
   115 statements.
   116 
   117 * Internal goals: structure Goal provides simple interfaces for
   118 init/conclude/finish and tactical prove operations (replacing former
   119 Tactic.prove).  Note that OldGoals.prove_goalw_cterm has long been
   120 obsolete, it is ill-behaved in a local proof context (e.g. with local
   121 fixes/assumes or in a locale context).
   122 
   123 * Simplifier: the simpset of a running simplification process now
   124 contains a proof context (cf. Simplifier.the_context), which is the
   125 very context that the initial simpset has been retrieved from (by
   126 simpset_of/local_simpset_of).  Consequently, all plug-in components
   127 (solver, looper etc.) may depend on arbitrary proof data.
   128 
   129 * Simplifier.inherit_context inherits the proof context (plus the
   130 local bounds) of the current simplification process; any simproc
   131 etc. that calls the Simplifier recursively should do this!  Removed
   132 former Simplifier.inherit_bounds, which is already included here --
   133 INCOMPATIBILITY.  Tools based on low-level rewriting may even have to
   134 specify an explicit context using Simplifier.context/theory_context.
   135 
   136 * Simplifier/Classical Reasoner: more abstract interfaces
   137 change_simpset/claset for modifying the simpset/claset reference of a
   138 theory; raw versions simpset/claset_ref etc. have been discontinued --
   139 INCOMPATIBILITY.
   140 
   141 
   142 
   143 New in Isabelle2005 (October 2005)
   144 ----------------------------------
   145 
   146 *** General ***
   147 
   148 * Theory headers: the new header syntax for Isar theories is
   149 
   150   theory <name>
   151   imports <theory1> ... <theoryN>
   152   uses <file1> ... <fileM>
   153   begin
   154 
   155 where the 'uses' part is optional.  The previous syntax
   156 
   157   theory <name> = <theory1> + ... + <theoryN>:
   158 
   159 will disappear in the next release.  Use isatool fixheaders to convert
   160 existing theory files.  Note that there is no change in ancient
   161 non-Isar theories now, but these will disappear soon.
   162 
   163 * Theory loader: parent theories can now also be referred to via
   164 relative and absolute paths.
   165 
   166 * Command 'find_theorems' searches for a list of criteria instead of a
   167 list of constants. Known criteria are: intro, elim, dest, name:string,
   168 simp:term, and any term. Criteria can be preceded by '-' to select
   169 theorems that do not match. Intro, elim, dest select theorems that
   170 match the current goal, name:s selects theorems whose fully qualified
   171 name contain s, and simp:term selects all simplification rules whose
   172 lhs match term.  Any other term is interpreted as pattern and selects
   173 all theorems matching the pattern. Available in ProofGeneral under
   174 'ProofGeneral -> Find Theorems' or C-c C-f.  Example:
   175 
   176   C-c C-f (100) "(_::nat) + _ + _" intro -name: "HOL."
   177 
   178 prints the last 100 theorems matching the pattern "(_::nat) + _ + _",
   179 matching the current goal as introduction rule and not having "HOL."
   180 in their name (i.e. not being defined in theory HOL).
   181 
   182 * Command 'thms_containing' has been discontinued in favour of
   183 'find_theorems'; INCOMPATIBILITY.
   184 
   185 * Communication with Proof General is now 8bit clean, which means that
   186 Unicode text in UTF-8 encoding may be used within theory texts (both
   187 formal and informal parts).  Cf. option -U of the Isabelle Proof
   188 General interface.  Here are some simple examples (cf. src/HOL/ex):
   189 
   190   http://isabelle.in.tum.de/library/HOL/ex/Hebrew.html
   191   http://isabelle.in.tum.de/library/HOL/ex/Chinese.html
   192 
   193 * Improved efficiency of the Simplifier and, to a lesser degree, the
   194 Classical Reasoner.  Typical big applications run around 2 times
   195 faster.
   196 
   197 
   198 *** Document preparation ***
   199 
   200 * Commands 'display_drafts' and 'print_drafts' perform simple output
   201 of raw sources.  Only those symbols that do not require additional
   202 LaTeX packages (depending on comments in isabellesym.sty) are
   203 displayed properly, everything else is left verbatim.  isatool display
   204 and isatool print are used as front ends (these are subject to the
   205 DVI/PDF_VIEWER and PRINT_COMMAND settings, respectively).
   206 
   207 * Command tags control specific markup of certain regions of text,
   208 notably folding and hiding.  Predefined tags include "theory" (for
   209 theory begin and end), "proof" for proof commands, and "ML" for
   210 commands involving ML code; the additional tags "visible" and
   211 "invisible" are unused by default.  Users may give explicit tag
   212 specifications in the text, e.g. ''by %invisible (auto)''.  The
   213 interpretation of tags is determined by the LaTeX job during document
   214 preparation: see option -V of isatool usedir, or options -n and -t of
   215 isatool document, or even the LaTeX macros \isakeeptag, \isafoldtag,
   216 \isadroptag.
   217 
   218 Several document versions may be produced at the same time via isatool
   219 usedir (the generated index.html will link all of them).  Typical
   220 specifications include ''-V document=theory,proof,ML'' to present
   221 theory/proof/ML parts faithfully, ''-V outline=/proof,/ML'' to fold
   222 proof and ML commands, and ''-V mutilated=-theory,-proof,-ML'' to omit
   223 these parts without any formal replacement text.  The Isabelle site
   224 default settings produce ''document'' and ''outline'' versions as
   225 specified above.
   226 
   227 * Several new antiquotations:
   228 
   229   @{term_type term} prints a term with its type annotated;
   230 
   231   @{typeof term} prints the type of a term;
   232 
   233   @{const const} is the same as @{term const}, but checks that the
   234   argument is a known logical constant;
   235 
   236   @{term_style style term} and @{thm_style style thm} print a term or
   237   theorem applying a "style" to it
   238 
   239   @{ML text}
   240 
   241 Predefined styles are 'lhs' and 'rhs' printing the lhs/rhs of
   242 definitions, equations, inequations etc., 'concl' printing only the
   243 conclusion of a meta-logical statement theorem, and 'prem1' .. 'prem19'
   244 to print the specified premise.  TermStyle.add_style provides an ML
   245 interface for introducing further styles.  See also the "LaTeX Sugar"
   246 document practical applications.  The ML antiquotation prints
   247 type-checked ML expressions verbatim.
   248 
   249 * Markup commands 'chapter', 'section', 'subsection', 'subsubsection',
   250 and 'text' support optional locale specification '(in loc)', which
   251 specifies the default context for interpreting antiquotations.  For
   252 example: 'text (in lattice) {* @{thm inf_assoc}*}'.
   253 
   254 * Option 'locale=NAME' of antiquotations specifies an alternative
   255 context interpreting the subsequent argument.  For example: @{thm
   256 [locale=lattice] inf_assoc}.
   257 
   258 * Proper output of proof terms (@{prf ...} and @{full_prf ...}) within
   259 a proof context.
   260 
   261 * Proper output of antiquotations for theory commands involving a
   262 proof context (such as 'locale' or 'theorem (in loc) ...').
   263 
   264 * Delimiters of outer tokens (string etc.) now produce separate LaTeX
   265 macros (\isachardoublequoteopen, isachardoublequoteclose etc.).
   266 
   267 * isatool usedir: new option -C (default true) controls whether option
   268 -D should include a copy of the original document directory; -C false
   269 prevents unwanted effects such as copying of administrative CVS data.
   270 
   271 
   272 *** Pure ***
   273 
   274 * Considerably improved version of 'constdefs' command.  Now performs
   275 automatic type-inference of declared constants; additional support for
   276 local structure declarations (cf. locales and HOL records), see also
   277 isar-ref manual.  Potential INCOMPATIBILITY: need to observe strictly
   278 sequential dependencies of definitions within a single 'constdefs'
   279 section; moreover, the declared name needs to be an identifier.  If
   280 all fails, consider to fall back on 'consts' and 'defs' separately.
   281 
   282 * Improved indexed syntax and implicit structures.  First of all,
   283 indexed syntax provides a notational device for subscripted
   284 application, using the new syntax \<^bsub>term\<^esub> for arbitrary
   285 expressions.  Secondly, in a local context with structure
   286 declarations, number indexes \<^sub>n or the empty index (default
   287 number 1) refer to a certain fixed variable implicitly; option
   288 show_structs controls printing of implicit structures.  Typical
   289 applications of these concepts involve record types and locales.
   290 
   291 * New command 'no_syntax' removes grammar declarations (and
   292 translations) resulting from the given syntax specification, which is
   293 interpreted in the same manner as for the 'syntax' command.
   294 
   295 * 'Advanced' translation functions (parse_translation etc.) may depend
   296 on the signature of the theory context being presently used for
   297 parsing/printing, see also isar-ref manual.
   298 
   299 * Improved 'oracle' command provides a type-safe interface to turn an
   300 ML expression of type theory -> T -> term into a primitive rule of
   301 type theory -> T -> thm (i.e. the functionality of Thm.invoke_oracle
   302 is already included here); see also FOL/ex/IffExample.thy;
   303 INCOMPATIBILITY.
   304 
   305 * axclass: name space prefix for class "c" is now "c_class" (was "c"
   306 before); "cI" is no longer bound, use "c.intro" instead.
   307 INCOMPATIBILITY.  This change avoids clashes of fact bindings for
   308 axclasses vs. locales.
   309 
   310 * Improved internal renaming of symbolic identifiers -- attach primes
   311 instead of base 26 numbers.
   312 
   313 * New flag show_question_marks controls printing of leading question
   314 marks in schematic variable names.
   315 
   316 * In schematic variable names, *any* symbol following \<^isub> or
   317 \<^isup> is now treated as part of the base name.  For example, the
   318 following works without printing of awkward ".0" indexes:
   319 
   320   lemma "x\<^isub>1 = x\<^isub>2 ==> x\<^isub>2 = x\<^isub>1"
   321     by simp
   322 
   323 * Inner syntax includes (*(*nested*) comments*).
   324 
   325 * Pretty printer now supports unbreakable blocks, specified in mixfix
   326 annotations as "(00...)".
   327 
   328 * Clear separation of logical types and nonterminals, where the latter
   329 may only occur in 'syntax' specifications or type abbreviations.
   330 Before that distinction was only partially implemented via type class
   331 "logic" vs. "{}".  Potential INCOMPATIBILITY in rare cases of improper
   332 use of 'types'/'consts' instead of 'nonterminals'/'syntax'.  Some very
   333 exotic syntax specifications may require further adaption
   334 (e.g. Cube/Cube.thy).
   335 
   336 * Removed obsolete type class "logic", use the top sort {} instead.
   337 Note that non-logical types should be declared as 'nonterminals'
   338 rather than 'types'.  INCOMPATIBILITY for new object-logic
   339 specifications.
   340 
   341 * Attributes 'induct' and 'cases': type or set names may now be
   342 locally fixed variables as well.
   343 
   344 * Simplifier: can now control the depth to which conditional rewriting
   345 is traced via the PG menu Isabelle -> Settings -> Trace Simp Depth
   346 Limit.
   347 
   348 * Simplifier: simplification procedures may now take the current
   349 simpset into account (cf. Simplifier.simproc(_i) / mk_simproc
   350 interface), which is very useful for calling the Simplifier
   351 recursively.  Minor INCOMPATIBILITY: the 'prems' argument of simprocs
   352 is gone -- use prems_of_ss on the simpset instead.  Moreover, the
   353 low-level mk_simproc no longer applies Logic.varify internally, to
   354 allow for use in a context of fixed variables.
   355 
   356 * thin_tac now works even if the assumption being deleted contains !!
   357 or ==>.  More generally, erule now works even if the major premise of
   358 the elimination rule contains !! or ==>.
   359 
   360 * Method 'rules' has been renamed to 'iprover'. INCOMPATIBILITY.
   361 
   362 * Reorganized bootstrapping of the Pure theories; CPure is now derived
   363 from Pure, which contains all common declarations already.  Both
   364 theories are defined via plain Isabelle/Isar .thy files.
   365 INCOMPATIBILITY: elements of CPure (such as the CPure.intro /
   366 CPure.elim / CPure.dest attributes) now appear in the Pure name space;
   367 use isatool fixcpure to adapt your theory and ML sources.
   368 
   369 * New syntax 'name(i-j, i-, i, ...)' for referring to specific
   370 selections of theorems in named facts via index ranges.
   371 
   372 * 'print_theorems': in theory mode, really print the difference
   373 wrt. the last state (works for interactive theory development only),
   374 in proof mode print all local facts (cf. 'print_facts');
   375 
   376 * 'hide': option '(open)' hides only base names.
   377 
   378 * More efficient treatment of intermediate checkpoints in interactive
   379 theory development.
   380 
   381 * Code generator is now invoked via code_module (incremental code
   382 generation) and code_library (modular code generation, ML structures
   383 for each theory).  INCOMPATIBILITY: new keywords 'file' and 'contains'
   384 must be quoted when used as identifiers.
   385 
   386 * New 'value' command for reading, evaluating and printing terms using
   387 the code generator.  INCOMPATIBILITY: command keyword 'value' must be
   388 quoted when used as identifier.
   389 
   390 
   391 *** Locales ***
   392 
   393 * New commands for the interpretation of locale expressions in
   394 theories (1), locales (2) and proof contexts (3).  These generate
   395 proof obligations from the expression specification.  After the
   396 obligations have been discharged, theorems of the expression are added
   397 to the theory, target locale or proof context.  The synopsis of the
   398 commands is a follows:
   399 
   400   (1) interpretation expr inst
   401   (2) interpretation target < expr
   402   (3) interpret expr inst
   403 
   404 Interpretation in theories and proof contexts require a parameter
   405 instantiation of terms from the current context.  This is applied to
   406 specifications and theorems of the interpreted expression.
   407 Interpretation in locales only permits parameter renaming through the
   408 locale expression.  Interpretation is smart in that interpretations
   409 that are active already do not occur in proof obligations, neither are
   410 instantiated theorems stored in duplicate.  Use 'print_interps' to
   411 inspect active interpretations of a particular locale.  For details,
   412 see the Isar Reference manual.  Examples can be found in
   413 HOL/Finite_Set.thy and HOL/Algebra/UnivPoly.thy.
   414 
   415 INCOMPATIBILITY: former 'instantiate' has been withdrawn, use
   416 'interpret' instead.
   417 
   418 * New context element 'constrains' for adding type constraints to
   419 parameters.
   420 
   421 * Context expressions: renaming of parameters with syntax
   422 redeclaration.
   423 
   424 * Locale declaration: 'includes' disallowed.
   425 
   426 * Proper static binding of attribute syntax -- i.e. types / terms /
   427 facts mentioned as arguments are always those of the locale definition
   428 context, independently of the context of later invocations.  Moreover,
   429 locale operations (renaming and type / term instantiation) are applied
   430 to attribute arguments as expected.
   431 
   432 INCOMPATIBILITY of the ML interface: always pass Attrib.src instead of
   433 actual attributes; rare situations may require Attrib.attribute to
   434 embed those attributes into Attrib.src that lack concrete syntax.
   435 Attribute implementations need to cooperate properly with the static
   436 binding mechanism.  Basic parsers Args.XXX_typ/term/prop and
   437 Attrib.XXX_thm etc. already do the right thing without further
   438 intervention.  Only unusual applications -- such as "where" or "of"
   439 (cf. src/Pure/Isar/attrib.ML), which process arguments depending both
   440 on the context and the facts involved -- may have to assign parsed
   441 values to argument tokens explicitly.
   442 
   443 * Changed parameter management in theorem generation for long goal
   444 statements with 'includes'.  INCOMPATIBILITY: produces a different
   445 theorem statement in rare situations.
   446 
   447 * Locale inspection command 'print_locale' omits notes elements.  Use
   448 'print_locale!' to have them included in the output.
   449 
   450 
   451 *** Provers ***
   452 
   453 * Provers/hypsubst.ML: improved version of the subst method, for
   454 single-step rewriting: it now works in bound variable contexts. New is
   455 'subst (asm)', for rewriting an assumption.  INCOMPATIBILITY: may
   456 rewrite a different subterm than the original subst method, which is
   457 still available as 'simplesubst'.
   458 
   459 * Provers/quasi.ML: new transitivity reasoners for transitivity only
   460 and quasi orders.
   461 
   462 * Provers/trancl.ML: new transitivity reasoner for transitive and
   463 reflexive-transitive closure of relations.
   464 
   465 * Provers/blast.ML: new reference depth_limit to make blast's depth
   466 limit (previously hard-coded with a value of 20) user-definable.
   467 
   468 * Provers/simplifier.ML has been moved to Pure, where Simplifier.setup
   469 is peformed already.  Object-logics merely need to finish their
   470 initial simpset configuration as before.  INCOMPATIBILITY.
   471 
   472 
   473 *** HOL ***
   474 
   475 * Symbolic syntax of Hilbert Choice Operator is now as follows:
   476 
   477   syntax (epsilon)
   478     "_Eps" :: "[pttrn, bool] => 'a"    ("(3\<some>_./ _)" [0, 10] 10)
   479 
   480 The symbol \<some> is displayed as the alternative epsilon of LaTeX
   481 and x-symbol; use option '-m epsilon' to get it actually printed.
   482 Moreover, the mathematically important symbolic identifier \<epsilon>
   483 becomes available as variable, constant etc.  INCOMPATIBILITY,
   484 
   485 * "x > y" abbreviates "y < x" and "x >= y" abbreviates "y <= x".
   486 Similarly for all quantifiers: "ALL x > y" etc.  The x-symbol for >=
   487 is \<ge>. New transitivity rules have been added to HOL/Orderings.thy to
   488 support corresponding Isar calculations.
   489 
   490 * "{x:A. P}" abbreviates "{x. x:A & P}", and similarly for "\<in>"
   491 instead of ":".
   492 
   493 * theory SetInterval: changed the syntax for open intervals:
   494 
   495   Old       New
   496   {..n(}    {..<n}
   497   {)n..}    {n<..}
   498   {m..n(}   {m..<n}
   499   {)m..n}   {m<..n}
   500   {)m..n(}  {m<..<n}
   501 
   502 The old syntax is still supported but will disappear in the next
   503 release.  For conversion use the following Emacs search and replace
   504 patterns (these are not perfect but work quite well):
   505 
   506   {)\([^\.]*\)\.\.  ->  {\1<\.\.}
   507   \.\.\([^(}]*\)(}  ->  \.\.<\1}
   508 
   509 * Theory Commutative_Ring (in Library): method comm_ring for proving
   510 equalities in commutative rings; method 'algebra' provides a generic
   511 interface.
   512 
   513 * Theory Finite_Set: changed the syntax for 'setsum', summation over
   514 finite sets: "setsum (%x. e) A", which used to be "\<Sum>x:A. e", is
   515 now either "SUM x:A. e" or "\<Sum>x \<in> A. e". The bound variable can
   516 be a tuple pattern.
   517 
   518 Some new syntax forms are available:
   519 
   520   "\<Sum>x | P. e"      for     "setsum (%x. e) {x. P}"
   521   "\<Sum>x = a..b. e"   for     "setsum (%x. e) {a..b}"
   522   "\<Sum>x = a..<b. e"  for     "setsum (%x. e) {a..<b}"
   523   "\<Sum>x < k. e"      for     "setsum (%x. e) {..<k}"
   524 
   525 The latter form "\<Sum>x < k. e" used to be based on a separate
   526 function "Summation", which has been discontinued.
   527 
   528 * theory Finite_Set: in structured induction proofs, the insert case
   529 is now 'case (insert x F)' instead of the old counterintuitive 'case
   530 (insert F x)'.
   531 
   532 * The 'refute' command has been extended to support a much larger
   533 fragment of HOL, including axiomatic type classes, constdefs and
   534 typedefs, inductive datatypes and recursion.
   535 
   536 * New tactics 'sat' and 'satx' to prove propositional tautologies.
   537 Requires zChaff with proof generation to be installed.  See
   538 HOL/ex/SAT_Examples.thy for examples.
   539 
   540 * Datatype induction via method 'induct' now preserves the name of the
   541 induction variable. For example, when proving P(xs::'a list) by
   542 induction on xs, the induction step is now P(xs) ==> P(a#xs) rather
   543 than P(list) ==> P(a#list) as previously.  Potential INCOMPATIBILITY
   544 in unstructured proof scripts.
   545 
   546 * Reworked implementation of records.  Improved scalability for
   547 records with many fields, avoiding performance problems for type
   548 inference. Records are no longer composed of nested field types, but
   549 of nested extension types. Therefore the record type only grows linear
   550 in the number of extensions and not in the number of fields.  The
   551 top-level (users) view on records is preserved.  Potential
   552 INCOMPATIBILITY only in strange cases, where the theory depends on the
   553 old record representation. The type generated for a record is called
   554 <record_name>_ext_type.
   555 
   556 Flag record_quick_and_dirty_sensitive can be enabled to skip the
   557 proofs triggered by a record definition or a simproc (if
   558 quick_and_dirty is enabled).  Definitions of large records can take
   559 quite long.
   560 
   561 New simproc record_upd_simproc for simplification of multiple record
   562 updates enabled by default.  Moreover, trivial updates are also
   563 removed: r(|x := x r|) = r.  INCOMPATIBILITY: old proofs break
   564 occasionally, since simplification is more powerful by default.
   565 
   566 * typedef: proper support for polymorphic sets, which contain extra
   567 type-variables in the term.
   568 
   569 * Simplifier: automatically reasons about transitivity chains
   570 involving "trancl" (r^+) and "rtrancl" (r^*) by setting up tactics
   571 provided by Provers/trancl.ML as additional solvers.  INCOMPATIBILITY:
   572 old proofs break occasionally as simplification may now solve more
   573 goals than previously.
   574 
   575 * Simplifier: converts x <= y into x = y if assumption y <= x is
   576 present.  Works for all partial orders (class "order"), in particular
   577 numbers and sets.  For linear orders (e.g. numbers) it treats ~ x < y
   578 just like y <= x.
   579 
   580 * Simplifier: new simproc for "let x = a in f x".  If a is a free or
   581 bound variable or a constant then the let is unfolded.  Otherwise
   582 first a is simplified to b, and then f b is simplified to g. If
   583 possible we abstract b from g arriving at "let x = b in h x",
   584 otherwise we unfold the let and arrive at g.  The simproc can be
   585 enabled/disabled by the reference use_let_simproc.  Potential
   586 INCOMPATIBILITY since simplification is more powerful by default.
   587 
   588 * Classical reasoning: the meson method now accepts theorems as arguments.
   589 
   590 * Prover support: pre-release of the Isabelle-ATP linkup, which runs background
   591 jobs to provide advice on the provability of subgoals.
   592 
   593 * Theory OrderedGroup and Ring_and_Field: various additions and
   594 improvements to faciliate calculations involving equalities and
   595 inequalities.
   596 
   597 The following theorems have been eliminated or modified
   598 (INCOMPATIBILITY):
   599 
   600   abs_eq             now named abs_of_nonneg
   601   abs_of_ge_0        now named abs_of_nonneg
   602   abs_minus_eq       now named abs_of_nonpos
   603   imp_abs_id         now named abs_of_nonneg
   604   imp_abs_neg_id     now named abs_of_nonpos
   605   mult_pos           now named mult_pos_pos
   606   mult_pos_le        now named mult_nonneg_nonneg
   607   mult_pos_neg_le    now named mult_nonneg_nonpos
   608   mult_pos_neg2_le   now named mult_nonneg_nonpos2
   609   mult_neg           now named mult_neg_neg
   610   mult_neg_le        now named mult_nonpos_nonpos
   611 
   612 * Theory Parity: added rules for simplifying exponents.
   613 
   614 * Theory List:
   615 
   616 The following theorems have been eliminated or modified
   617 (INCOMPATIBILITY):
   618 
   619   list_all_Nil       now named list_all.simps(1)
   620   list_all_Cons      now named list_all.simps(2)
   621   list_all_conv      now named list_all_iff
   622   set_mem_eq         now named mem_iff
   623 
   624 * Theories SetsAndFunctions and BigO (see HOL/Library) support
   625 asymptotic "big O" calculations.  See the notes in BigO.thy.
   626 
   627 
   628 *** HOL-Complex ***
   629 
   630 * Theory RealDef: better support for embedding natural numbers and
   631 integers in the reals.
   632 
   633 The following theorems have been eliminated or modified
   634 (INCOMPATIBILITY):
   635 
   636   exp_ge_add_one_self  now requires no hypotheses
   637   real_of_int_add      reversed direction of equality (use [symmetric])
   638   real_of_int_minus    reversed direction of equality (use [symmetric])
   639   real_of_int_diff     reversed direction of equality (use [symmetric])
   640   real_of_int_mult     reversed direction of equality (use [symmetric])
   641 
   642 * Theory RComplete: expanded support for floor and ceiling functions.
   643 
   644 * Theory Ln is new, with properties of the natural logarithm
   645 
   646 * Hyperreal: There is a new type constructor "star" for making
   647 nonstandard types.  The old type names are now type synonyms:
   648 
   649   hypreal = real star
   650   hypnat = nat star
   651   hcomplex = complex star
   652 
   653 * Hyperreal: Many groups of similarly-defined constants have been
   654 replaced by polymorphic versions (INCOMPATIBILITY):
   655 
   656   star_of <-- hypreal_of_real, hypnat_of_nat, hcomplex_of_complex
   657 
   658   starset      <-- starsetNat, starsetC
   659   *s*          <-- *sNat*, *sc*
   660   starset_n    <-- starsetNat_n, starsetC_n
   661   *sn*         <-- *sNatn*, *scn*
   662   InternalSets <-- InternalNatSets, InternalCSets
   663 
   664   starfun      <-- starfun{Nat,Nat2,C,RC,CR}
   665   *f*          <-- *fNat*, *fNat2*, *fc*, *fRc*, *fcR*
   666   starfun_n    <-- starfun{Nat,Nat2,C,RC,CR}_n
   667   *fn*         <-- *fNatn*, *fNat2n*, *fcn*, *fRcn*, *fcRn*
   668   InternalFuns <-- InternalNatFuns, InternalNatFuns2, Internal{C,RC,CR}Funs
   669 
   670 * Hyperreal: Many type-specific theorems have been removed in favor of
   671 theorems specific to various axiomatic type classes (INCOMPATIBILITY):
   672 
   673   add_commute <-- {hypreal,hypnat,hcomplex}_add_commute
   674   add_assoc   <-- {hypreal,hypnat,hcomplex}_add_assocs
   675   OrderedGroup.add_0 <-- {hypreal,hypnat,hcomplex}_add_zero_left
   676   OrderedGroup.add_0_right <-- {hypreal,hcomplex}_add_zero_right
   677   right_minus <-- hypreal_add_minus
   678   left_minus <-- {hypreal,hcomplex}_add_minus_left
   679   mult_commute <-- {hypreal,hypnat,hcomplex}_mult_commute
   680   mult_assoc <-- {hypreal,hypnat,hcomplex}_mult_assoc
   681   mult_1_left <-- {hypreal,hypnat}_mult_1, hcomplex_mult_one_left
   682   mult_1_right <-- hcomplex_mult_one_right
   683   mult_zero_left <-- hcomplex_mult_zero_left
   684   left_distrib <-- {hypreal,hypnat,hcomplex}_add_mult_distrib
   685   right_distrib <-- hypnat_add_mult_distrib2
   686   zero_neq_one <-- {hypreal,hypnat,hcomplex}_zero_not_eq_one
   687   right_inverse <-- hypreal_mult_inverse
   688   left_inverse <-- hypreal_mult_inverse_left, hcomplex_mult_inv_left
   689   order_refl <-- {hypreal,hypnat}_le_refl
   690   order_trans <-- {hypreal,hypnat}_le_trans
   691   order_antisym <-- {hypreal,hypnat}_le_anti_sym
   692   order_less_le <-- {hypreal,hypnat}_less_le
   693   linorder_linear <-- {hypreal,hypnat}_le_linear
   694   add_left_mono <-- {hypreal,hypnat}_add_left_mono
   695   mult_strict_left_mono <-- {hypreal,hypnat}_mult_less_mono2
   696   add_nonneg_nonneg <-- hypreal_le_add_order
   697 
   698 * Hyperreal: Separate theorems having to do with type-specific
   699 versions of constants have been merged into theorems that apply to the
   700 new polymorphic constants (INCOMPATIBILITY):
   701 
   702   STAR_UNIV_set <-- {STAR_real,NatStar_real,STARC_complex}_set
   703   STAR_empty_set <-- {STAR,NatStar,STARC}_empty_set
   704   STAR_Un <-- {STAR,NatStar,STARC}_Un
   705   STAR_Int <-- {STAR,NatStar,STARC}_Int
   706   STAR_Compl <-- {STAR,NatStar,STARC}_Compl
   707   STAR_subset <-- {STAR,NatStar,STARC}_subset
   708   STAR_mem <-- {STAR,NatStar,STARC}_mem
   709   STAR_mem_Compl <-- {STAR,STARC}_mem_Compl
   710   STAR_diff <-- {STAR,STARC}_diff
   711   STAR_star_of_image_subset <-- {STAR_hypreal_of_real, NatStar_hypreal_of_real,
   712     STARC_hcomplex_of_complex}_image_subset
   713   starset_n_Un <-- starset{Nat,C}_n_Un
   714   starset_n_Int <-- starset{Nat,C}_n_Int
   715   starset_n_Compl <-- starset{Nat,C}_n_Compl
   716   starset_n_diff <-- starset{Nat,C}_n_diff
   717   InternalSets_Un <-- Internal{Nat,C}Sets_Un
   718   InternalSets_Int <-- Internal{Nat,C}Sets_Int
   719   InternalSets_Compl <-- Internal{Nat,C}Sets_Compl
   720   InternalSets_diff <-- Internal{Nat,C}Sets_diff
   721   InternalSets_UNIV_diff <-- Internal{Nat,C}Sets_UNIV_diff
   722   InternalSets_starset_n <-- Internal{Nat,C}Sets_starset{Nat,C}_n
   723   starset_starset_n_eq <-- starset{Nat,C}_starset{Nat,C}_n_eq
   724   starset_n_starset <-- starset{Nat,C}_n_starset{Nat,C}
   725   starfun_n_starfun <-- starfun{Nat,Nat2,C,RC,CR}_n_starfun{Nat,Nat2,C,RC,CR}
   726   starfun <-- starfun{Nat,Nat2,C,RC,CR}
   727   starfun_mult <-- starfun{Nat,Nat2,C,RC,CR}_mult
   728   starfun_add <-- starfun{Nat,Nat2,C,RC,CR}_add
   729   starfun_minus <-- starfun{Nat,Nat2,C,RC,CR}_minus
   730   starfun_diff <-- starfun{C,RC,CR}_diff
   731   starfun_o <-- starfun{NatNat2,Nat2,_stafunNat,C,C_starfunRC,_starfunCR}_o
   732   starfun_o2 <-- starfun{NatNat2,_stafunNat,C,C_starfunRC,_starfunCR}_o2
   733   starfun_const_fun <-- starfun{Nat,Nat2,C,RC,CR}_const_fun
   734   starfun_inverse <-- starfun{Nat,C,RC,CR}_inverse
   735   starfun_eq <-- starfun{Nat,Nat2,C,RC,CR}_eq
   736   starfun_eq_iff <-- starfun{C,RC,CR}_eq_iff
   737   starfun_Id <-- starfunC_Id
   738   starfun_approx <-- starfun{Nat,CR}_approx
   739   starfun_capprox <-- starfun{C,RC}_capprox
   740   starfun_abs <-- starfunNat_rabs
   741   starfun_lambda_cancel <-- starfun{C,CR,RC}_lambda_cancel
   742   starfun_lambda_cancel2 <-- starfun{C,CR,RC}_lambda_cancel2
   743   starfun_mult_HFinite_approx <-- starfunCR_mult_HFinite_capprox
   744   starfun_mult_CFinite_capprox <-- starfun{C,RC}_mult_CFinite_capprox
   745   starfun_add_capprox <-- starfun{C,RC}_add_capprox
   746   starfun_add_approx <-- starfunCR_add_approx
   747   starfun_inverse_inverse <-- starfunC_inverse_inverse
   748   starfun_divide <-- starfun{C,CR,RC}_divide
   749   starfun_n <-- starfun{Nat,C}_n
   750   starfun_n_mult <-- starfun{Nat,C}_n_mult
   751   starfun_n_add <-- starfun{Nat,C}_n_add
   752   starfun_n_add_minus <-- starfunNat_n_add_minus
   753   starfun_n_const_fun <-- starfun{Nat,C}_n_const_fun
   754   starfun_n_minus <-- starfun{Nat,C}_n_minus
   755   starfun_n_eq <-- starfun{Nat,C}_n_eq
   756 
   757   star_n_add <-- {hypreal,hypnat,hcomplex}_add
   758   star_n_minus <-- {hypreal,hcomplex}_minus
   759   star_n_diff <-- {hypreal,hcomplex}_diff
   760   star_n_mult <-- {hypreal,hcomplex}_mult
   761   star_n_inverse <-- {hypreal,hcomplex}_inverse
   762   star_n_le <-- {hypreal,hypnat}_le
   763   star_n_less <-- {hypreal,hypnat}_less
   764   star_n_zero_num <-- {hypreal,hypnat,hcomplex}_zero_num
   765   star_n_one_num <-- {hypreal,hypnat,hcomplex}_one_num
   766   star_n_abs <-- hypreal_hrabs
   767   star_n_divide <-- hcomplex_divide
   768 
   769   star_of_add <-- {hypreal_of_real,hypnat_of_nat,hcomplex_of_complex}_add
   770   star_of_minus <-- {hypreal_of_real,hcomplex_of_complex}_minus
   771   star_of_diff <-- hypreal_of_real_diff
   772   star_of_mult <-- {hypreal_of_real,hypnat_of_nat,hcomplex_of_complex}_mult
   773   star_of_one <-- {hypreal_of_real,hcomplex_of_complex}_one
   774   star_of_zero <-- {hypreal_of_real,hypnat_of_nat,hcomplex_of_complex}_zero
   775   star_of_le <-- {hypreal_of_real,hypnat_of_nat}_le_iff
   776   star_of_less <-- {hypreal_of_real,hypnat_of_nat}_less_iff
   777   star_of_eq <-- {hypreal_of_real,hypnat_of_nat,hcomplex_of_complex}_eq_iff
   778   star_of_inverse <-- {hypreal_of_real,hcomplex_of_complex}_inverse
   779   star_of_divide <-- {hypreal_of_real,hcomplex_of_complex}_divide
   780   star_of_of_nat <-- {hypreal_of_real,hcomplex_of_complex}_of_nat
   781   star_of_of_int <-- {hypreal_of_real,hcomplex_of_complex}_of_int
   782   star_of_number_of <-- {hypreal,hcomplex}_number_of
   783   star_of_number_less <-- number_of_less_hypreal_of_real_iff
   784   star_of_number_le <-- number_of_le_hypreal_of_real_iff
   785   star_of_eq_number <-- hypreal_of_real_eq_number_of_iff
   786   star_of_less_number <-- hypreal_of_real_less_number_of_iff
   787   star_of_le_number <-- hypreal_of_real_le_number_of_iff
   788   star_of_power <-- hypreal_of_real_power
   789   star_of_eq_0 <-- hcomplex_of_complex_zero_iff
   790 
   791 * Hyperreal: new method "transfer" that implements the transfer
   792 principle of nonstandard analysis. With a subgoal that mentions
   793 nonstandard types like "'a star", the command "apply transfer"
   794 replaces it with an equivalent one that mentions only standard types.
   795 To be successful, all free variables must have standard types; non-
   796 standard variables must have explicit universal quantifiers.
   797 
   798 * Hyperreal: A theory of Taylor series.
   799 
   800 
   801 *** HOLCF ***
   802 
   803 * Discontinued special version of 'constdefs' (which used to support
   804 continuous functions) in favor of the general Pure one with full
   805 type-inference.
   806 
   807 * New simplification procedure for solving continuity conditions; it
   808 is much faster on terms with many nested lambda abstractions (cubic
   809 instead of exponential time).
   810 
   811 * New syntax for domain package: selector names are now optional.
   812 Parentheses should be omitted unless argument is lazy, for example:
   813 
   814   domain 'a stream = cons "'a" (lazy "'a stream")
   815 
   816 * New command 'fixrec' for defining recursive functions with pattern
   817 matching; defining multiple functions with mutual recursion is also
   818 supported.  Patterns may include the constants cpair, spair, up, sinl,
   819 sinr, or any data constructor defined by the domain package. The given
   820 equations are proven as rewrite rules. See HOLCF/ex/Fixrec_ex.thy for
   821 syntax and examples.
   822 
   823 * New commands 'cpodef' and 'pcpodef' for defining predicate subtypes
   824 of cpo and pcpo types. Syntax is exactly like the 'typedef' command,
   825 but the proof obligation additionally includes an admissibility
   826 requirement. The packages generate instances of class cpo or pcpo,
   827 with continuity and strictness theorems for Rep and Abs.
   828 
   829 * HOLCF: Many theorems have been renamed according to a more standard naming
   830 scheme (INCOMPATIBILITY):
   831 
   832   foo_inject:  "foo$x = foo$y ==> x = y"
   833   foo_eq:      "(foo$x = foo$y) = (x = y)"
   834   foo_less:    "(foo$x << foo$y) = (x << y)"
   835   foo_strict:  "foo$UU = UU"
   836   foo_defined: "... ==> foo$x ~= UU"
   837   foo_defined_iff: "(foo$x = UU) = (x = UU)"
   838 
   839 
   840 *** ZF ***
   841 
   842 * ZF/ex: theories Group and Ring provide examples in abstract algebra,
   843 including the First Isomorphism Theorem (on quotienting by the kernel
   844 of a homomorphism).
   845 
   846 * ZF/Simplifier: install second copy of type solver that actually
   847 makes use of TC rules declared to Isar proof contexts (or locales);
   848 the old version is still required for ML proof scripts.
   849 
   850 
   851 *** Cube ***
   852 
   853 * Converted to Isar theory format; use locales instead of axiomatic
   854 theories.
   855 
   856 
   857 *** ML ***
   858 
   859 * Pure/library.ML no longer defines its own option datatype, but uses
   860 that of the SML basis, which has constructors NONE and SOME instead of
   861 None and Some, as well as exception Option.Option instead of OPTION.
   862 The functions the, if_none, is_some, is_none have been adapted
   863 accordingly, while Option.map replaces apsome.
   864 
   865 * Pure/library.ML: the exception LIST has been given up in favour of
   866 the standard exceptions Empty and Subscript, as well as
   867 Library.UnequalLengths.  Function like Library.hd and Library.tl are
   868 superceded by the standard hd and tl functions etc.
   869 
   870 A number of basic list functions are no longer exported to the ML
   871 toplevel, as they are variants of predefined functions.  The following
   872 suggests how one can translate existing code:
   873 
   874     rev_append xs ys = List.revAppend (xs, ys)
   875     nth_elem (i, xs) = List.nth (xs, i)
   876     last_elem xs = List.last xs
   877     flat xss = List.concat xss
   878     seq fs = List.app fs
   879     partition P xs = List.partition P xs
   880     mapfilter f xs = List.mapPartial f xs
   881 
   882 * Pure/library.ML: several combinators for linear functional
   883 transformations, notably reverse application and composition:
   884 
   885   x |> f                f #> g
   886   (x, y) |-> f          f #-> g
   887 
   888 * Pure/library.ML: introduced/changed precedence of infix operators:
   889 
   890   infix 1 |> |-> ||> ||>> |>> |>>> #> #->;
   891   infix 2 ?;
   892   infix 3 o oo ooo oooo;
   893   infix 4 ~~ upto downto;
   894 
   895 Maybe INCOMPATIBILITY when any of those is used in conjunction with other
   896 infix operators.
   897 
   898 * Pure/library.ML: natural list combinators fold, fold_rev, and
   899 fold_map support linear functional transformations and nesting.  For
   900 example:
   901 
   902   fold f [x1, ..., xN] y =
   903     y |> f x1 |> ... |> f xN
   904 
   905   (fold o fold) f [xs1, ..., xsN] y =
   906     y |> fold f xs1 |> ... |> fold f xsN
   907 
   908   fold f [x1, ..., xN] =
   909     f x1 #> ... #> f xN
   910 
   911   (fold o fold) f [xs1, ..., xsN] =
   912     fold f xs1 #> ... #> fold f xsN
   913 
   914 * Pure/library.ML: the following selectors on type 'a option are
   915 available:
   916 
   917   the:               'a option -> 'a  (*partial*)
   918   these:             'a option -> 'a  where 'a = 'b list
   919   the_default: 'a -> 'a option -> 'a
   920   the_list:          'a option -> 'a list
   921 
   922 * Pure/General: structure AList (cf. Pure/General/alist.ML) provides
   923 basic operations for association lists, following natural argument
   924 order; moreover the explicit equality predicate passed here avoids
   925 potentially expensive polymorphic runtime equality checks.
   926 The old functions may be expressed as follows:
   927 
   928   assoc = uncurry (AList.lookup (op =))
   929   assocs = these oo AList.lookup (op =)
   930   overwrite = uncurry (AList.update (op =)) o swap
   931 
   932 * Pure/General: structure AList (cf. Pure/General/alist.ML) provides
   933 
   934   val make: ('a -> 'b) -> 'a list -> ('a * 'b) list
   935   val find: ('a * 'b -> bool) -> ('c * 'b) list -> 'a -> 'c list
   936 
   937 replacing make_keylist and keyfilter (occassionally used)
   938 Naive rewrites:
   939 
   940   make_keylist = AList.make
   941   keyfilter = AList.find (op =)
   942 
   943 * eq_fst and eq_snd now take explicit equality parameter, thus
   944   avoiding eqtypes. Naive rewrites:
   945 
   946     eq_fst = eq_fst (op =)
   947     eq_snd = eq_snd (op =)
   948 
   949 * Removed deprecated apl and apr (rarely used).
   950   Naive rewrites:
   951 
   952     apl (n, op) =>>= curry op n
   953     apr (op, m) =>>= fn n => op (n, m)
   954 
   955 * Pure/General: structure OrdList (cf. Pure/General/ord_list.ML)
   956 provides a reasonably efficient light-weight implementation of sets as
   957 lists.
   958 
   959 * Pure/General: generic tables (cf. Pure/General/table.ML) provide a
   960 few new operations; existing lookup and update are now curried to
   961 follow natural argument order (for use with fold etc.);
   962 INCOMPATIBILITY, use (uncurry Symtab.lookup) etc. as last resort.
   963 
   964 * Pure/General: output via the Isabelle channels of
   965 writeln/warning/error etc. is now passed through Output.output, with a
   966 hook for arbitrary transformations depending on the print_mode
   967 (cf. Output.add_mode -- the first active mode that provides a output
   968 function wins).  Already formatted output may be embedded into further
   969 text via Output.raw; the result of Pretty.string_of/str_of and derived
   970 functions (string_of_term/cterm/thm etc.) is already marked raw to
   971 accommodate easy composition of diagnostic messages etc.  Programmers
   972 rarely need to care about Output.output or Output.raw at all, with
   973 some notable exceptions: Output.output is required when bypassing the
   974 standard channels (writeln etc.), or in token translations to produce
   975 properly formatted results; Output.raw is required when capturing
   976 already output material that will eventually be presented to the user
   977 a second time.  For the default print mode, both Output.output and
   978 Output.raw have no effect.
   979 
   980 * Pure/General: Output.time_accumulator NAME creates an operator ('a
   981 -> 'b) -> 'a -> 'b to measure runtime and count invocations; the
   982 cumulative results are displayed at the end of a batch session.
   983 
   984 * Pure/General: File.sysify_path and File.quote_sysify path have been
   985 replaced by File.platform_path and File.shell_path (with appropriate
   986 hooks).  This provides a clean interface for unusual systems where the
   987 internal and external process view of file names are different.
   988 
   989 * Pure: more efficient orders for basic syntactic entities: added
   990 fast_string_ord, fast_indexname_ord, fast_term_ord; changed sort_ord
   991 and typ_ord to use fast_string_ord and fast_indexname_ord (term_ord is
   992 NOT affected); structures Symtab, Vartab, Typtab, Termtab use the fast
   993 orders now -- potential INCOMPATIBILITY for code that depends on a
   994 particular order for Symtab.keys, Symtab.dest, etc. (consider using
   995 Library.sort_strings on result).
   996 
   997 * Pure/term.ML: combinators fold_atyps, fold_aterms, fold_term_types,
   998 fold_types traverse types/terms from left to right, observing natural
   999 argument order.  Supercedes previous foldl_XXX versions, add_frees,
  1000 add_vars etc. have been adapted as well: INCOMPATIBILITY.
  1001 
  1002 * Pure: name spaces have been refined, with significant changes of the
  1003 internal interfaces -- INCOMPATIBILITY.  Renamed cond_extern(_table)
  1004 to extern(_table).  The plain name entry path is superceded by a
  1005 general 'naming' context, which also includes the 'policy' to produce
  1006 a fully qualified name and external accesses of a fully qualified
  1007 name; NameSpace.extend is superceded by context dependent
  1008 Sign.declare_name.  Several theory and proof context operations modify
  1009 the naming context.  Especially note Theory.restore_naming and
  1010 ProofContext.restore_naming to get back to a sane state; note that
  1011 Theory.add_path is no longer sufficient to recover from
  1012 Theory.absolute_path in particular.
  1013 
  1014 * Pure: new flags short_names (default false) and unique_names
  1015 (default true) for controlling output of qualified names.  If
  1016 short_names is set, names are printed unqualified.  If unique_names is
  1017 reset, the name prefix is reduced to the minimum required to achieve
  1018 the original result when interning again, even if there is an overlap
  1019 with earlier declarations.
  1020 
  1021 * Pure/TheoryDataFun: change of the argument structure; 'prep_ext' is
  1022 now 'extend', and 'merge' gets an additional Pretty.pp argument
  1023 (useful for printing error messages).  INCOMPATIBILITY.
  1024 
  1025 * Pure: major reorganization of the theory context.  Type Sign.sg and
  1026 Theory.theory are now identified, referring to the universal
  1027 Context.theory (see Pure/context.ML).  Actual signature and theory
  1028 content is managed as theory data.  The old code and interfaces were
  1029 spread over many files and structures; the new arrangement introduces
  1030 considerable INCOMPATIBILITY to gain more clarity:
  1031 
  1032   Context -- theory management operations (name, identity, inclusion,
  1033     parents, ancestors, merge, etc.), plus generic theory data;
  1034 
  1035   Sign -- logical signature and syntax operations (declaring consts,
  1036     types, etc.), plus certify/read for common entities;
  1037 
  1038   Theory -- logical theory operations (stating axioms, definitions,
  1039     oracles), plus a copy of logical signature operations (consts,
  1040     types, etc.); also a few basic management operations (Theory.copy,
  1041     Theory.merge, etc.)
  1042 
  1043 The most basic sign_of operations (Theory.sign_of, Thm.sign_of_thm
  1044 etc.) as well as the sign field in Thm.rep_thm etc. have been retained
  1045 for convenience -- they merely return the theory.
  1046 
  1047 * Pure: type Type.tsig is superceded by theory in most interfaces.
  1048 
  1049 * Pure: the Isar proof context type is already defined early in Pure
  1050 as Context.proof (note that ProofContext.context and Proof.context are
  1051 aliases, where the latter is the preferred name).  This enables other
  1052 Isabelle components to refer to that type even before Isar is present.
  1053 
  1054 * Pure/sign/theory: discontinued named name spaces (i.e. classK,
  1055 typeK, constK, axiomK, oracleK), but provide explicit operations for
  1056 any of these kinds.  For example, Sign.intern typeK is now
  1057 Sign.intern_type, Theory.hide_space Sign.typeK is now
  1058 Theory.hide_types.  Also note that former
  1059 Theory.hide_classes/types/consts are now
  1060 Theory.hide_classes_i/types_i/consts_i, while the non '_i' versions
  1061 internalize their arguments!  INCOMPATIBILITY.
  1062 
  1063 * Pure: get_thm interface (of PureThy and ProofContext) expects
  1064 datatype thmref (with constructors Name and NameSelection) instead of
  1065 plain string -- INCOMPATIBILITY;
  1066 
  1067 * Pure: cases produced by proof methods specify options, where NONE
  1068 means to remove case bindings -- INCOMPATIBILITY in
  1069 (RAW_)METHOD_CASES.
  1070 
  1071 * Pure: the following operations retrieve axioms or theorems from a
  1072 theory node or theory hierarchy, respectively:
  1073 
  1074   Theory.axioms_of: theory -> (string * term) list
  1075   Theory.all_axioms_of: theory -> (string * term) list
  1076   PureThy.thms_of: theory -> (string * thm) list
  1077   PureThy.all_thms_of: theory -> (string * thm) list
  1078 
  1079 * Pure: print_tac now outputs the goal through the trace channel.
  1080 
  1081 * Isar toplevel: improved diagnostics, mostly for Poly/ML only.
  1082 Reference Toplevel.debug (default false) controls detailed printing
  1083 and tracing of low-level exceptions; Toplevel.profiling (default 0)
  1084 controls execution profiling -- set to 1 for time and 2 for space
  1085 (both increase the runtime).
  1086 
  1087 * Isar session: The initial use of ROOT.ML is now always timed,
  1088 i.e. the log will show the actual process times, in contrast to the
  1089 elapsed wall-clock time that the outer shell wrapper produces.
  1090 
  1091 * Simplifier: improved handling of bound variables (nameless
  1092 representation, avoid allocating new strings).  Simprocs that invoke
  1093 the Simplifier recursively should use Simplifier.inherit_bounds to
  1094 avoid local name clashes.  Failure to do so produces warnings
  1095 "Simplifier: renamed bound variable ..."; set Simplifier.debug_bounds
  1096 for further details.
  1097 
  1098 * ML functions legacy_bindings and use_legacy_bindings produce ML fact
  1099 bindings for all theorems stored within a given theory; this may help
  1100 in porting non-Isar theories to Isar ones, while keeping ML proof
  1101 scripts for the time being.
  1102 
  1103 * ML operator HTML.with_charset specifies the charset begin used for
  1104 generated HTML files.  For example:
  1105 
  1106   HTML.with_charset "utf-8" use_thy "Hebrew";
  1107   HTML.with_charset "utf-8" use_thy "Chinese";
  1108 
  1109 
  1110 *** System ***
  1111 
  1112 * Allow symlinks to all proper Isabelle executables (Isabelle,
  1113 isabelle, isatool etc.).
  1114 
  1115 * ISABELLE_DOC_FORMAT setting specifies preferred document format (for
  1116 isatool doc, isatool mkdir, display_drafts etc.).
  1117 
  1118 * isatool usedir: option -f allows specification of the ML file to be
  1119 used by Isabelle; default is ROOT.ML.
  1120 
  1121 * New isatool version outputs the version identifier of the Isabelle
  1122 distribution being used.
  1123 
  1124 * HOL: new isatool dimacs2hol converts files in DIMACS CNF format
  1125 (containing Boolean satisfiability problems) into Isabelle/HOL
  1126 theories.
  1127 
  1128 
  1129 
  1130 New in Isabelle2004 (April 2004)
  1131 --------------------------------
  1132 
  1133 *** General ***
  1134 
  1135 * Provers/order.ML:  new efficient reasoner for partial and linear orders.
  1136   Replaces linorder.ML.
  1137 
  1138 * Pure: Greek letters (except small lambda, \<lambda>), as well as Gothic
  1139   (\<aa>...\<zz>\<AA>...\<ZZ>), calligraphic (\<A>...\<Z>), and Euler
  1140   (\<a>...\<z>), are now considered normal letters, and can therefore
  1141   be used anywhere where an ASCII letter (a...zA...Z) has until
  1142   now. COMPATIBILITY: This obviously changes the parsing of some
  1143   terms, especially where a symbol has been used as a binder, say
  1144   '\<Pi>x. ...', which is now a type error since \<Pi>x will be parsed
  1145   as an identifier.  Fix it by inserting a space around former
  1146   symbols.  Call 'isatool fixgreek' to try to fix parsing errors in
  1147   existing theory and ML files.
  1148 
  1149 * Pure: Macintosh and Windows line-breaks are now allowed in theory files.
  1150 
  1151 * Pure: single letter sub/superscripts (\<^isub> and \<^isup>) are now
  1152   allowed in identifiers. Similar to Greek letters \<^isub> is now considered
  1153   a normal (but invisible) letter. For multiple letter subscripts repeat
  1154   \<^isub> like this: x\<^isub>1\<^isub>2.
  1155 
  1156 * Pure: There are now sub-/superscripts that can span more than one
  1157   character. Text between \<^bsub> and \<^esub> is set in subscript in
  1158   ProofGeneral and LaTeX, text between \<^bsup> and \<^esup> in
  1159   superscript. The new control characters are not identifier parts.
  1160 
  1161 * Pure: Control-symbols of the form \<^raw:...> will literally print the
  1162   content of "..." to the latex file instead of \isacntrl... . The "..."
  1163   may consist of any printable characters excluding the end bracket >.
  1164 
  1165 * Pure: Using new Isar command "finalconsts" (or the ML functions
  1166   Theory.add_finals or Theory.add_finals_i) it is now possible to
  1167   declare constants "final", which prevents their being given a definition
  1168   later.  It is useful for constants whose behaviour is fixed axiomatically
  1169   rather than definitionally, such as the meta-logic connectives.
  1170 
  1171 * Pure: 'instance' now handles general arities with general sorts
  1172   (i.e. intersections of classes),
  1173 
  1174 * Presentation: generated HTML now uses a CSS style sheet to make layout
  1175   (somewhat) independent of content. It is copied from lib/html/isabelle.css.
  1176   It can be changed to alter the colors/layout of generated pages.
  1177 
  1178 
  1179 *** Isar ***
  1180 
  1181 * Tactic emulation methods rule_tac, erule_tac, drule_tac, frule_tac,
  1182   cut_tac, subgoal_tac and thin_tac:
  1183   - Now understand static (Isar) contexts.  As a consequence, users of Isar
  1184     locales are no longer forced to write Isar proof scripts.
  1185     For details see Isar Reference Manual, paragraph 4.3.2: Further tactic
  1186     emulations.
  1187   - INCOMPATIBILITY: names of variables to be instantiated may no
  1188     longer be enclosed in quotes.  Instead, precede variable name with `?'.
  1189     This is consistent with the instantiation attribute "where".
  1190 
  1191 * Attributes "where" and "of":
  1192   - Now take type variables of instantiated theorem into account when reading
  1193     the instantiation string.  This fixes a bug that caused instantiated
  1194     theorems to have too special types in some circumstances.
  1195   - "where" permits explicit instantiations of type variables.
  1196 
  1197 * Calculation commands "moreover" and "also" no longer interfere with
  1198   current facts ("this"), admitting arbitrary combinations with "then"
  1199   and derived forms.
  1200 
  1201 * Locales:
  1202   - Goal statements involving the context element "includes" no longer
  1203     generate theorems with internal delta predicates (those ending on
  1204     "_axioms") in the premise.
  1205     Resolve particular premise with <locale>.intro to obtain old form.
  1206   - Fixed bug in type inference ("unify_frozen") that prevented mix of target
  1207     specification and "includes" elements in goal statement.
  1208   - Rule sets <locale>.intro and <locale>.axioms no longer declared as
  1209     [intro?] and [elim?] (respectively) by default.
  1210   - Experimental command for instantiation of locales in proof contexts:
  1211         instantiate <label>[<attrs>]: <loc>
  1212     Instantiates locale <loc> and adds all its theorems to the current context
  1213     taking into account their attributes.  Label and attrs are optional
  1214     modifiers, like in theorem declarations.  If present, names of
  1215     instantiated theorems are qualified with <label>, and the attributes
  1216     <attrs> are applied after any attributes these theorems might have already.
  1217       If the locale has assumptions, a chained fact of the form
  1218     "<loc> t1 ... tn" is expected from which instantiations of the parameters
  1219     are derived.  The command does not support old-style locales declared
  1220     with "locale (open)".
  1221       A few (very simple) examples can be found in FOL/ex/LocaleInst.thy.
  1222 
  1223 * HOL: Tactic emulation methods induct_tac and case_tac understand static
  1224   (Isar) contexts.
  1225 
  1226 
  1227 *** HOL ***
  1228 
  1229 * Proof import: new image HOL4 contains the imported library from
  1230   the HOL4 system with about 2500 theorems. It is imported by
  1231   replaying proof terms produced by HOL4 in Isabelle. The HOL4 image
  1232   can be used like any other Isabelle image.  See
  1233   HOL/Import/HOL/README for more information.
  1234 
  1235 * Simplifier:
  1236   - Much improved handling of linear and partial orders.
  1237     Reasoners for linear and partial orders are set up for type classes
  1238     "linorder" and "order" respectively, and are added to the default simpset
  1239     as solvers.  This means that the simplifier can build transitivity chains
  1240     to solve goals from the assumptions.
  1241   - INCOMPATIBILITY: old proofs break occasionally.  Typically, applications
  1242     of blast or auto after simplification become unnecessary because the goal
  1243     is solved by simplification already.
  1244 
  1245 * Numerics: new theory Ring_and_Field contains over 250 basic numerical laws,
  1246     all proved in axiomatic type classes for semirings, rings and fields.
  1247 
  1248 * Numerics:
  1249   - Numeric types (nat, int, and in HOL-Complex rat, real, complex, etc.) are
  1250     now formalized using the Ring_and_Field theory mentioned above.
  1251   - INCOMPATIBILITY: simplification and arithmetic behaves somewhat differently
  1252     than before, because now they are set up once in a generic manner.
  1253   - INCOMPATIBILITY: many type-specific arithmetic laws have gone.
  1254     Look for the general versions in Ring_and_Field (and Power if they concern
  1255     exponentiation).
  1256 
  1257 * Type "rat" of the rational numbers is now available in HOL-Complex.
  1258 
  1259 * Records:
  1260   - Record types are now by default printed with their type abbreviation
  1261     instead of the list of all field types. This can be configured via
  1262     the reference "print_record_type_abbr".
  1263   - Simproc "record_upd_simproc" for simplification of multiple updates added
  1264     (not enabled by default).
  1265   - Simproc "record_ex_sel_eq_simproc" to simplify EX x. sel r = x resp.
  1266     EX x. x = sel r to True (not enabled by default).
  1267   - Tactic "record_split_simp_tac" to split and simplify records added.
  1268 
  1269 * 'specification' command added, allowing for definition by
  1270   specification.  There is also an 'ax_specification' command that
  1271   introduces the new constants axiomatically.
  1272 
  1273 * arith(_tac) is now able to generate counterexamples for reals as well.
  1274 
  1275 * HOL-Algebra: new locale "ring" for non-commutative rings.
  1276 
  1277 * HOL-ex: InductiveInvariant_examples illustrates advanced recursive function
  1278   definitions, thanks to Sava Krsti\'{c} and John Matthews.
  1279 
  1280 * HOL-Matrix: a first theory for matrices in HOL with an application of
  1281   matrix theory to linear programming.
  1282 
  1283 * Unions and Intersections:
  1284   The latex output syntax of UN and INT has been changed
  1285   from "\Union x \in A. B" to "\Union_{x \in A} B"
  1286   i.e. the index formulae has become a subscript.
  1287   Similarly for "\Union x. B", and for \Inter instead of \Union.
  1288 
  1289 * Unions and Intersections over Intervals:
  1290   There is new short syntax "UN i<=n. A" for "UN i:{0..n}. A". There is
  1291   also an x-symbol version with subscripts "\<Union>\<^bsub>i <= n\<^esub>. A"
  1292   like in normal math, and corresponding versions for < and for intersection.
  1293 
  1294 * HOL/List: Ordering "lexico" is renamed "lenlex" and the standard
  1295   lexicographic dictonary ordering has been added as "lexord".
  1296 
  1297 * ML: the legacy theory structures Int and List have been removed. They had
  1298   conflicted with ML Basis Library structures having the same names.
  1299 
  1300 * 'refute' command added to search for (finite) countermodels.  Only works
  1301   for a fragment of HOL.  The installation of an external SAT solver is
  1302   highly recommended.  See "HOL/Refute.thy" for details.
  1303 
  1304 * 'quickcheck' command: Allows to find counterexamples by evaluating
  1305   formulae under an assignment of free variables to random values.
  1306   In contrast to 'refute', it can deal with inductive datatypes,
  1307   but cannot handle quantifiers. See "HOL/ex/Quickcheck_Examples.thy"
  1308   for examples.
  1309 
  1310 
  1311 *** HOLCF ***
  1312 
  1313 * Streams now come with concatenation and are part of the HOLCF image
  1314 
  1315 
  1316 
  1317 New in Isabelle2003 (May 2003)
  1318 ------------------------------
  1319 
  1320 *** General ***
  1321 
  1322 * Provers/simplifier:
  1323 
  1324   - Completely reimplemented method simp (ML: Asm_full_simp_tac):
  1325     Assumptions are now subject to complete mutual simplification,
  1326     not just from left to right. The simplifier now preserves
  1327     the order of assumptions.
  1328 
  1329     Potential INCOMPATIBILITY:
  1330 
  1331     -- simp sometimes diverges where the old version did
  1332        not, e.g. invoking simp on the goal
  1333 
  1334         [| P (f x); y = x; f x = f y |] ==> Q
  1335 
  1336        now gives rise to the infinite reduction sequence
  1337 
  1338         P(f x) --(f x = f y)--> P(f y) --(y = x)--> P(f x) --(f x = f y)--> ...
  1339 
  1340        Using "simp (asm_lr)" (ML: Asm_lr_simp_tac) instead often solves this
  1341        kind of problem.
  1342 
  1343     -- Tactics combining classical reasoner and simplification (such as auto)
  1344        are also affected by this change, because many of them rely on
  1345        simp. They may sometimes diverge as well or yield a different numbers
  1346        of subgoals. Try to use e.g. force, fastsimp, or safe instead of auto
  1347        in case of problems. Sometimes subsequent calls to the classical
  1348        reasoner will fail because a preceeding call to the simplifier too
  1349        eagerly simplified the goal, e.g. deleted redundant premises.
  1350 
  1351   - The simplifier trace now shows the names of the applied rewrite rules
  1352 
  1353   - You can limit the number of recursive invocations of the simplifier
  1354     during conditional rewriting (where the simplifie tries to solve the
  1355     conditions before applying the rewrite rule):
  1356     ML "simp_depth_limit := n"
  1357     where n is an integer. Thus you can force termination where previously
  1358     the simplifier would diverge.
  1359 
  1360   - Accepts free variables as head terms in congruence rules.  Useful in Isar.
  1361 
  1362   - No longer aborts on failed congruence proof.  Instead, the
  1363     congruence is ignored.
  1364 
  1365 * Pure: New generic framework for extracting programs from constructive
  1366   proofs. See HOL/Extraction.thy for an example instantiation, as well
  1367   as HOL/Extraction for some case studies.
  1368 
  1369 * Pure: The main goal of the proof state is no longer shown by default, only
  1370 the subgoals. This behaviour is controlled by a new flag.
  1371    PG menu: Isabelle/Isar -> Settings -> Show Main Goal
  1372 (ML: Proof.show_main_goal).
  1373 
  1374 * Pure: You can find all matching introduction rules for subgoal 1, i.e. all
  1375 rules whose conclusion matches subgoal 1:
  1376       PG menu: Isabelle/Isar -> Show me -> matching rules
  1377 The rules are ordered by how closely they match the subgoal.
  1378 In particular, rules that solve a subgoal outright are displayed first
  1379 (or rather last, the way they are printed).
  1380 (ML: ProofGeneral.print_intros())
  1381 
  1382 * Pure: New flag trace_unify_fail causes unification to print
  1383 diagnostic information (PG: in trace buffer) when it fails. This is
  1384 useful for figuring out why single step proofs like rule, erule or
  1385 assumption failed.
  1386 
  1387 * Pure: Locale specifications now produce predicate definitions
  1388 according to the body of text (covering assumptions modulo local
  1389 definitions); predicate "loc_axioms" covers newly introduced text,
  1390 while "loc" is cumulative wrt. all included locale expressions; the
  1391 latter view is presented only on export into the global theory
  1392 context; potential INCOMPATIBILITY, use "(open)" option to fall back
  1393 on the old view without predicates;
  1394 
  1395 * Pure: predefined locales "var" and "struct" are useful for sharing
  1396 parameters (as in CASL, for example); just specify something like
  1397 ``var x + var y + struct M'' as import;
  1398 
  1399 * Pure: improved thms_containing: proper indexing of facts instead of
  1400 raw theorems; check validity of results wrt. current name space;
  1401 include local facts of proof configuration (also covers active
  1402 locales), cover fixed variables in index; may use "_" in term
  1403 specification; an optional limit for the number of printed facts may
  1404 be given (the default is 40);
  1405 
  1406 * Pure: disallow duplicate fact bindings within new-style theory files
  1407 (batch-mode only);
  1408 
  1409 * Provers: improved induct method: assumptions introduced by case
  1410 "foo" are split into "foo.hyps" (from the rule) and "foo.prems" (from
  1411 the goal statement); "foo" still refers to all facts collectively;
  1412 
  1413 * Provers: the function blast.overloaded has been removed: all constants
  1414 are regarded as potentially overloaded, which improves robustness in exchange
  1415 for slight decrease in efficiency;
  1416 
  1417 * Provers/linorder: New generic prover for transitivity reasoning over
  1418 linear orders.  Note: this prover is not efficient!
  1419 
  1420 * Isar: preview of problems to finish 'show' now produce an error
  1421 rather than just a warning (in interactive mode);
  1422 
  1423 
  1424 *** HOL ***
  1425 
  1426 * arith(_tac)
  1427 
  1428  - Produces a counter example if it cannot prove a goal.
  1429    Note that the counter example may be spurious if the goal is not a formula
  1430    of quantifier-free linear arithmetic.
  1431    In ProofGeneral the counter example appears in the trace buffer.
  1432 
  1433  - Knows about div k and mod k where k is a numeral of type nat or int.
  1434 
  1435  - Calls full Presburger arithmetic (by Amine Chaieb) if quantifier-free
  1436    linear arithmetic fails. This takes account of quantifiers and divisibility.
  1437    Presburger arithmetic can also be called explicitly via presburger(_tac).
  1438 
  1439 * simp's arithmetic capabilities have been enhanced a bit: it now
  1440 takes ~= in premises into account (by performing a case split);
  1441 
  1442 * simp reduces "m*(n div m) + n mod m" to n, even if the two summands
  1443 are distributed over a sum of terms;
  1444 
  1445 * New tactic "trans_tac" and method "trans" instantiate
  1446 Provers/linorder.ML for axclasses "order" and "linorder" (predicates
  1447 "<=", "<" and "=").
  1448 
  1449 * function INCOMPATIBILITIES: Pi-sets have been redefined and moved from main
  1450 HOL to Library/FuncSet; constant "Fun.op o" is now called "Fun.comp";
  1451 
  1452 * 'typedef' command has new option "open" to suppress the set
  1453 definition;
  1454 
  1455 * functions Min and Max on finite sets have been introduced (theory
  1456 Finite_Set);
  1457 
  1458 * attribute [symmetric] now works for relations as well; it turns
  1459 (x,y) : R^-1 into (y,x) : R, and vice versa;
  1460 
  1461 * induct over a !!-quantified statement (say !!x1..xn):
  1462   each "case" automatically performs "fix x1 .. xn" with exactly those names.
  1463 
  1464 * Map: `empty' is no longer a constant but a syntactic abbreviation for
  1465 %x. None. Warning: empty_def now refers to the previously hidden definition
  1466 of the empty set.
  1467 
  1468 * Algebra: formalization of classical algebra.  Intended as base for
  1469 any algebraic development in Isabelle.  Currently covers group theory
  1470 (up to Sylow's theorem) and ring theory (Universal Property of
  1471 Univariate Polynomials).  Contributions welcome;
  1472 
  1473 * GroupTheory: deleted, since its material has been moved to Algebra;
  1474 
  1475 * Complex: new directory of the complex numbers with numeric constants,
  1476 nonstandard complex numbers, and some complex analysis, standard and
  1477 nonstandard (Jacques Fleuriot);
  1478 
  1479 * HOL-Complex: new image for analysis, replacing HOL-Real and HOL-Hyperreal;
  1480 
  1481 * Hyperreal: introduced Gauge integration and hyperreal logarithms (Jacques
  1482 Fleuriot);
  1483 
  1484 * Real/HahnBanach: updated and adapted to locales;
  1485 
  1486 * NumberTheory: added Gauss's law of quadratic reciprocity (by Avigad,
  1487 Gray and Kramer);
  1488 
  1489 * UNITY: added the Meier-Sanders theory of progress sets;
  1490 
  1491 * MicroJava: bytecode verifier and lightweight bytecode verifier
  1492 as abstract algorithms, instantiated to the JVM;
  1493 
  1494 * Bali: Java source language formalization. Type system, operational
  1495 semantics, axiomatic semantics. Supported language features:
  1496 classes, interfaces, objects,virtual methods, static methods,
  1497 static/instance fields, arrays, access modifiers, definite
  1498 assignment, exceptions.
  1499 
  1500 
  1501 *** ZF ***
  1502 
  1503 * ZF/Constructible: consistency proof for AC (Gdel's constructible
  1504 universe, etc.);
  1505 
  1506 * Main ZF: virtually all theories converted to new-style format;
  1507 
  1508 
  1509 *** ML ***
  1510 
  1511 * Pure: Tactic.prove provides sane interface for internal proofs;
  1512 omits the infamous "standard" operation, so this is more appropriate
  1513 than prove_goalw_cterm in many situations (e.g. in simprocs);
  1514 
  1515 * Pure: improved error reporting of simprocs;
  1516 
  1517 * Provers: Simplifier.simproc(_i) provides sane interface for setting
  1518 up simprocs;
  1519 
  1520 
  1521 *** Document preparation ***
  1522 
  1523 * uses \par instead of \\ for line breaks in theory text. This may
  1524 shift some page breaks in large documents. To get the old behaviour
  1525 use \renewcommand{\isanewline}{\mbox{}\\\mbox{}} in root.tex.
  1526 
  1527 * minimized dependencies of isabelle.sty and isabellesym.sty on
  1528 other packages
  1529 
  1530 * \<euro> now needs package babel/greek instead of marvosym (which
  1531 broke \Rightarrow)
  1532 
  1533 * normal size for \<zero>...\<nine> (uses \mathbf instead of
  1534 textcomp package)
  1535 
  1536 
  1537 
  1538 New in Isabelle2002 (March 2002)
  1539 --------------------------------
  1540 
  1541 *** Document preparation ***
  1542 
  1543 * greatly simplified document preparation setup, including more
  1544 graceful interpretation of isatool usedir -i/-d/-D options, and more
  1545 instructive isatool mkdir; users should basically be able to get
  1546 started with "isatool mkdir HOL Test && isatool make"; alternatively,
  1547 users may run a separate document processing stage manually like this:
  1548 "isatool usedir -D output HOL Test && isatool document Test/output";
  1549 
  1550 * theory dependency graph may now be incorporated into documents;
  1551 isatool usedir -g true will produce session_graph.eps/.pdf for use
  1552 with \includegraphics of LaTeX;
  1553 
  1554 * proper spacing of consecutive markup elements, especially text
  1555 blocks after section headings;
  1556 
  1557 * support bold style (for single symbols only), input syntax is like
  1558 this: "\<^bold>\<alpha>" or "\<^bold>A";
  1559 
  1560 * \<bullet> is now output as bold \cdot by default, which looks much
  1561 better in printed text;
  1562 
  1563 * added default LaTeX bindings for \<tturnstile> and \<TTurnstile>;
  1564 note that these symbols are currently unavailable in Proof General /
  1565 X-Symbol; new symbols \<zero>, \<one>, ..., \<nine>, and \<euro>;
  1566 
  1567 * isatool latex no longer depends on changed TEXINPUTS, instead
  1568 isatool document copies the Isabelle style files to the target
  1569 location;
  1570 
  1571 
  1572 *** Isar ***
  1573 
  1574 * Pure/Provers: improved proof by cases and induction;
  1575   - 'case' command admits impromptu naming of parameters (such as
  1576     "case (Suc n)");
  1577   - 'induct' method divinates rule instantiation from the inductive
  1578     claim; no longer requires excessive ?P bindings for proper
  1579     instantiation of cases;
  1580   - 'induct' method properly enumerates all possibilities of set/type
  1581     rules; as a consequence facts may be also passed through *type*
  1582     rules without further ado;
  1583   - 'induct' method now derives symbolic cases from the *rulified*
  1584     rule (before it used to rulify cases stemming from the internal
  1585     atomized version); this means that the context of a non-atomic
  1586     statement becomes is included in the hypothesis, avoiding the
  1587     slightly cumbersome show "PROP ?case" form;
  1588   - 'induct' may now use elim-style induction rules without chaining
  1589     facts, using ``missing'' premises from the goal state; this allows
  1590     rules stemming from inductive sets to be applied in unstructured
  1591     scripts, while still benefitting from proper handling of non-atomic
  1592     statements; NB: major inductive premises need to be put first, all
  1593     the rest of the goal is passed through the induction;
  1594   - 'induct' proper support for mutual induction involving non-atomic
  1595     rule statements (uses the new concept of simultaneous goals, see
  1596     below);
  1597   - append all possible rule selections, but only use the first
  1598     success (no backtracking);
  1599   - removed obsolete "(simplified)" and "(stripped)" options of methods;
  1600   - undeclared rule case names default to numbers 1, 2, 3, ...;
  1601   - added 'print_induct_rules' (covered by help item in recent Proof
  1602     General versions);
  1603   - moved induct/cases attributes to Pure, methods to Provers;
  1604   - generic method setup instantiated for FOL and HOL;
  1605 
  1606 * Pure: support multiple simultaneous goal statements, for example
  1607 "have a: A and b: B" (same for 'theorem' etc.); being a pure
  1608 meta-level mechanism, this acts as if several individual goals had
  1609 been stated separately; in particular common proof methods need to be
  1610 repeated in order to cover all claims; note that a single elimination
  1611 step is *not* sufficient to establish the two conjunctions, so this
  1612 fails:
  1613 
  1614   assume "A & B" then have A and B ..   (*".." fails*)
  1615 
  1616 better use "obtain" in situations as above; alternative refer to
  1617 multi-step methods like 'auto', 'simp_all', 'blast+' etc.;
  1618 
  1619 * Pure: proper integration with ``locales''; unlike the original
  1620 version by Florian Kammller, Isar locales package high-level proof
  1621 contexts rather than raw logical ones (e.g. we admit to include
  1622 attributes everywhere); operations on locales include merge and
  1623 rename; support for implicit arguments (``structures''); simultaneous
  1624 type-inference over imports and text; see also HOL/ex/Locales.thy for
  1625 some examples;
  1626 
  1627 * Pure: the following commands have been ``localized'', supporting a
  1628 target locale specification "(in name)": 'lemma', 'theorem',
  1629 'corollary', 'lemmas', 'theorems', 'declare'; the results will be
  1630 stored both within the locale and at the theory level (exported and
  1631 qualified by the locale name);
  1632 
  1633 * Pure: theory goals may now be specified in ``long'' form, with
  1634 ad-hoc contexts consisting of arbitrary locale elements. for example
  1635 ``lemma foo: fixes x assumes "A x" shows "B x"'' (local syntax and
  1636 definitions may be given, too); the result is a meta-level rule with
  1637 the context elements being discharged in the obvious way;
  1638 
  1639 * Pure: new proof command 'using' allows to augment currently used
  1640 facts after a goal statement ('using' is syntactically analogous to
  1641 'apply', but acts on the goal's facts only); this allows chained facts
  1642 to be separated into parts given before and after a claim, as in
  1643 ``from a and b have C using d and e <proof>'';
  1644 
  1645 * Pure: renamed "antecedent" case to "rule_context";
  1646 
  1647 * Pure: new 'judgment' command records explicit information about the
  1648 object-logic embedding (used by several tools internally); no longer
  1649 use hard-wired "Trueprop";
  1650 
  1651 * Pure: added 'corollary' command;
  1652 
  1653 * Pure: fixed 'token_translation' command;
  1654 
  1655 * Pure: removed obsolete 'exported' attribute;
  1656 
  1657 * Pure: dummy pattern "_" in is/let is now automatically lifted over
  1658 bound variables: "ALL x. P x --> Q x" (is "ALL x. _ --> ?C x")
  1659 supersedes more cumbersome ... (is "ALL x. _ x --> ?C x");
  1660 
  1661 * Pure: method 'atomize' presents local goal premises as object-level
  1662 statements (atomic meta-level propositions); setup controlled via
  1663 rewrite rules declarations of 'atomize' attribute; example
  1664 application: 'induct' method with proper rule statements in improper
  1665 proof *scripts*;
  1666 
  1667 * Pure: emulation of instantiation tactics (rule_tac, cut_tac, etc.)
  1668 now consider the syntactic context of assumptions, giving a better
  1669 chance to get type-inference of the arguments right (this is
  1670 especially important for locales);
  1671 
  1672 * Pure: "sorry" no longer requires quick_and_dirty in interactive
  1673 mode;
  1674 
  1675 * Pure/obtain: the formal conclusion "thesis", being marked as
  1676 ``internal'', may no longer be reference directly in the text;
  1677 potential INCOMPATIBILITY, may need to use "?thesis" in rare
  1678 situations;
  1679 
  1680 * Pure: generic 'sym' attribute which declares a rule both as pure
  1681 'elim?' and for the 'symmetric' operation;
  1682 
  1683 * Pure: marginal comments ``--'' may now occur just anywhere in the
  1684 text; the fixed correlation with particular command syntax has been
  1685 discontinued;
  1686 
  1687 * Pure: new method 'rules' is particularly well-suited for proof
  1688 search in intuitionistic logic; a bit slower than 'blast' or 'fast',
  1689 but often produces more compact proof terms with less detours;
  1690 
  1691 * Pure/Provers/classical: simplified integration with pure rule
  1692 attributes and methods; the classical "intro?/elim?/dest?"
  1693 declarations coincide with the pure ones; the "rule" method no longer
  1694 includes classically swapped intros; "intro" and "elim" methods no
  1695 longer pick rules from the context; also got rid of ML declarations
  1696 AddXIs/AddXEs/AddXDs; all of this has some potential for
  1697 INCOMPATIBILITY;
  1698 
  1699 * Provers/classical: attribute 'swapped' produces classical inversions
  1700 of introduction rules;
  1701 
  1702 * Provers/simplifier: 'simplified' attribute may refer to explicit
  1703 rules instead of full simplifier context; 'iff' attribute handles
  1704 conditional rules;
  1705 
  1706 * HOL: 'typedef' now allows alternative names for Rep/Abs morphisms;
  1707 
  1708 * HOL: 'recdef' now fails on unfinished automated proofs, use
  1709 "(permissive)" option to recover old behavior;
  1710 
  1711 * HOL: 'inductive' no longer features separate (collective) attributes
  1712 for 'intros' (was found too confusing);
  1713 
  1714 * HOL: properly declared induction rules less_induct and
  1715 wf_induct_rule;
  1716 
  1717 
  1718 *** HOL ***
  1719 
  1720 * HOL: moved over to sane numeral syntax; the new policy is as
  1721 follows:
  1722 
  1723   - 0 and 1 are polymorphic constants, which are defined on any
  1724   numeric type (nat, int, real etc.);
  1725 
  1726   - 2, 3, 4, ... and -1, -2, -3, ... are polymorphic numerals, based
  1727   binary representation internally;
  1728 
  1729   - type nat has special constructor Suc, and generally prefers Suc 0
  1730   over 1::nat and Suc (Suc 0) over 2::nat;
  1731 
  1732 This change may cause significant problems of INCOMPATIBILITY; here
  1733 are some hints on converting existing sources:
  1734 
  1735   - due to the new "num" token, "-0" and "-1" etc. are now atomic
  1736   entities, so expressions involving "-" (unary or binary minus) need
  1737   to be spaced properly;
  1738 
  1739   - existing occurrences of "1" may need to be constraint "1::nat" or
  1740   even replaced by Suc 0; similar for old "2";
  1741 
  1742   - replace "#nnn" by "nnn", and "#-nnn" by "-nnn";
  1743 
  1744   - remove all special provisions on numerals in proofs;
  1745 
  1746 * HOL: simp rules nat_number expand numerals on nat to Suc/0
  1747 representation (depends on bin_arith_simps in the default context);
  1748 
  1749 * HOL: symbolic syntax for x^2 (numeral 2);
  1750 
  1751 * HOL: the class of all HOL types is now called "type" rather than
  1752 "term"; INCOMPATIBILITY, need to adapt references to this type class
  1753 in axclass/classes, instance/arities, and (usually rare) occurrences
  1754 in typings (of consts etc.); internally the class is called
  1755 "HOL.type", ML programs should refer to HOLogic.typeS;
  1756 
  1757 * HOL/record package improvements:
  1758   - new derived operations "fields" to build a partial record section,
  1759     "extend" to promote a fixed record to a record scheme, and
  1760     "truncate" for the reverse; cf. theorems "xxx.defs", which are *not*
  1761     declared as simp by default;
  1762   - shared operations ("more", "fields", etc.) now need to be always
  1763     qualified) --- potential INCOMPATIBILITY;
  1764   - removed "make_scheme" operations (use "make" with "extend") --
  1765     INCOMPATIBILITY;
  1766   - removed "more" class (simply use "term") -- INCOMPATIBILITY;
  1767   - provides cases/induct rules for use with corresponding Isar
  1768     methods (for concrete records, record schemes, concrete more
  1769     parts, and schematic more parts -- in that order);
  1770   - internal definitions directly based on a light-weight abstract
  1771     theory of product types over typedef rather than datatype;
  1772 
  1773 * HOL: generic code generator for generating executable ML code from
  1774 specifications; specific support for HOL constructs such as inductive
  1775 datatypes and sets, as well as recursive functions; can be invoked
  1776 via 'generate_code' theory section;
  1777 
  1778 * HOL: canonical cases/induct rules for n-tuples (n = 3..7);
  1779 
  1780 * HOL: consolidated and renamed several theories.  In particular:
  1781         Ord.thy has been absorbed into HOL.thy
  1782         String.thy has been absorbed into List.thy
  1783 
  1784 * HOL: concrete setsum syntax "\<Sum>i:A. b" == "setsum (%i. b) A"
  1785 (beware of argument permutation!);
  1786 
  1787 * HOL: linorder_less_split superseded by linorder_cases;
  1788 
  1789 * HOL/List: "nodups" renamed to "distinct";
  1790 
  1791 * HOL: added "The" definite description operator; move Hilbert's "Eps"
  1792 to peripheral theory "Hilbert_Choice"; some INCOMPATIBILITIES:
  1793   - Ex_def has changed, now need to use some_eq_ex
  1794 
  1795 * HOL: made split_all_tac safe; EXISTING PROOFS MAY FAIL OR LOOP, so
  1796 in this (rare) case use:
  1797 
  1798   delSWrapper "split_all_tac"
  1799   addSbefore ("unsafe_split_all_tac", unsafe_split_all_tac)
  1800 
  1801 * HOL: added safe wrapper "split_conv_tac" to claset; EXISTING PROOFS
  1802 MAY FAIL;
  1803 
  1804 * HOL: introduced f^n = f o ... o f; warning: due to the limits of
  1805 Isabelle's type classes, ^ on functions and relations has too general
  1806 a domain, namely ('a * 'b) set and 'a => 'b; this means that it may be
  1807 necessary to attach explicit type constraints;
  1808 
  1809 * HOL/Relation: the prefix name of the infix "O" has been changed from
  1810 "comp" to "rel_comp"; INCOMPATIBILITY: a few theorems have been
  1811 renamed accordingly (eg "compI" -> "rel_compI").
  1812 
  1813 * HOL: syntax translations now work properly with numerals and records
  1814 expressions;
  1815 
  1816 * HOL: bounded abstraction now uses syntax "%" / "\<lambda>" instead
  1817 of "lam" -- INCOMPATIBILITY;
  1818 
  1819 * HOL: got rid of some global declarations (potential INCOMPATIBILITY
  1820 for ML tools): const "()" renamed "Product_Type.Unity", type "unit"
  1821 renamed "Product_Type.unit";
  1822 
  1823 * HOL: renamed rtrancl_into_rtrancl2 to converse_rtrancl_into_rtrancl
  1824 
  1825 * HOL: removed obsolete theorem "optionE" (use "option.exhaust", or
  1826 the "cases" method);
  1827 
  1828 * HOL/GroupTheory: group theory examples including Sylow's theorem (by
  1829 Florian Kammller);
  1830 
  1831 * HOL/IMP: updated and converted to new-style theory format; several
  1832 parts turned into readable document, with proper Isar proof texts and
  1833 some explanations (by Gerwin Klein);
  1834 
  1835 * HOL-Real: added Complex_Numbers (by Gertrud Bauer);
  1836 
  1837 * HOL-Hyperreal is now a logic image;
  1838 
  1839 
  1840 *** HOLCF ***
  1841 
  1842 * Isar: consts/constdefs supports mixfix syntax for continuous
  1843 operations;
  1844 
  1845 * Isar: domain package adapted to new-style theory format, e.g. see
  1846 HOLCF/ex/Dnat.thy;
  1847 
  1848 * theory Lift: proper use of rep_datatype lift instead of ML hacks --
  1849 potential INCOMPATIBILITY; now use plain induct_tac instead of former
  1850 lift.induct_tac, always use UU instead of Undef;
  1851 
  1852 * HOLCF/IMP: updated and converted to new-style theory;
  1853 
  1854 
  1855 *** ZF ***
  1856 
  1857 * Isar: proper integration of logic-specific tools and packages,
  1858 including theory commands '(co)inductive', '(co)datatype',
  1859 'rep_datatype', 'inductive_cases', as well as methods 'ind_cases',
  1860 'induct_tac', 'case_tac', and 'typecheck' (with attribute 'TC');
  1861 
  1862 * theory Main no longer includes AC; for the Axiom of Choice, base
  1863 your theory on Main_ZFC;
  1864 
  1865 * the integer library now covers quotients and remainders, with many
  1866 laws relating division to addition, multiplication, etc.;
  1867 
  1868 * ZF/UNITY: Chandy and Misra's UNITY is now available in ZF, giving a
  1869 typeless version of the formalism;
  1870 
  1871 * ZF/AC, Coind, IMP, Resid: updated and converted to new-style theory
  1872 format;
  1873 
  1874 * ZF/Induct: new directory for examples of inductive definitions,
  1875 including theory Multiset for multiset orderings; converted to
  1876 new-style theory format;
  1877 
  1878 * ZF: many new theorems about lists, ordinals, etc.;
  1879 
  1880 
  1881 *** General ***
  1882 
  1883 * Pure/kernel: meta-level proof terms (by Stefan Berghofer); reference
  1884 variable proof controls level of detail: 0 = no proofs (only oracle
  1885 dependencies), 1 = lemma dependencies, 2 = compact proof terms; see
  1886 also ref manual for further ML interfaces;
  1887 
  1888 * Pure/axclass: removed obsolete ML interface
  1889 goal_subclass/goal_arity;
  1890 
  1891 * Pure/syntax: new token syntax "num" for plain numerals (without "#"
  1892 of "xnum"); potential INCOMPATIBILITY, since -0, -1 etc. are now
  1893 separate tokens, so expressions involving minus need to be spaced
  1894 properly;
  1895 
  1896 * Pure/syntax: support non-oriented infixes, using keyword "infix"
  1897 rather than "infixl" or "infixr";
  1898 
  1899 * Pure/syntax: concrete syntax for dummy type variables admits genuine
  1900 sort constraint specifications in type inference; e.g. "x::_::foo"
  1901 ensures that the type of "x" is of sort "foo" (but not necessarily a
  1902 type variable);
  1903 
  1904 * Pure/syntax: print modes "type_brackets" and "no_type_brackets"
  1905 control output of nested => (types); the default behavior is
  1906 "type_brackets";
  1907 
  1908 * Pure/syntax: builtin parse translation for "_constify" turns valued
  1909 tokens into AST constants;
  1910 
  1911 * Pure/syntax: prefer later declarations of translations and print
  1912 translation functions; potential INCOMPATIBILITY: need to reverse
  1913 multiple declarations for same syntax element constant;
  1914 
  1915 * Pure/show_hyps reset by default (in accordance to existing Isar
  1916 practice);
  1917 
  1918 * Provers/classical: renamed addaltern to addafter, addSaltern to
  1919 addSafter;
  1920 
  1921 * Provers/clasimp: ``iff'' declarations now handle conditional rules
  1922 as well;
  1923 
  1924 * system: tested support for MacOS X; should be able to get Isabelle +
  1925 Proof General to work in a plain Terminal after installing Poly/ML
  1926 (e.g. from the Isabelle distribution area) and GNU bash alone
  1927 (e.g. from http://www.apple.com); full X11, XEmacs and X-Symbol
  1928 support requires further installations, e.g. from
  1929 http://fink.sourceforge.net/);
  1930 
  1931 * system: support Poly/ML 4.1.1 (able to manage larger heaps);
  1932 
  1933 * system: reduced base memory usage by Poly/ML (approx. 20 MB instead
  1934 of 40 MB), cf. ML_OPTIONS;
  1935 
  1936 * system: Proof General keywords specification is now part of the
  1937 Isabelle distribution (see etc/isar-keywords.el);
  1938 
  1939 * system: support for persistent Proof General sessions (refrain from
  1940 outdating all loaded theories on startup); user may create writable
  1941 logic images like this: ``isabelle -q HOL Test'';
  1942 
  1943 * system: smart selection of Isabelle process versus Isabelle
  1944 interface, accommodates case-insensitive file systems (e.g. HFS+); may
  1945 run both "isabelle" and "Isabelle" even if file names are badly
  1946 damaged (executable inspects the case of the first letter of its own
  1947 name); added separate "isabelle-process" and "isabelle-interface";
  1948 
  1949 * system: refrain from any attempt at filtering input streams; no
  1950 longer support ``8bit'' encoding of old isabelle font, instead proper
  1951 iso-latin characters may now be used; the related isatools
  1952 "symbolinput" and "nonascii" have disappeared as well;
  1953 
  1954 * system: removed old "xterm" interface (the print modes "xterm" and
  1955 "xterm_color" are still available for direct use in a suitable
  1956 terminal);
  1957 
  1958 
  1959 
  1960 New in Isabelle99-2 (February 2001)
  1961 -----------------------------------
  1962 
  1963 *** Overview of INCOMPATIBILITIES ***
  1964 
  1965 * HOL: please note that theories in the Library and elsewhere often use the
  1966 new-style (Isar) format; to refer to their theorems in an ML script you must
  1967 bind them to ML identifers by e.g.      val thm_name = thm "thm_name";
  1968 
  1969 * HOL: inductive package no longer splits induction rule aggressively,
  1970 but only as far as specified by the introductions given; the old
  1971 format may be recovered via ML function complete_split_rule or attribute
  1972 'split_rule (complete)';
  1973 
  1974 * HOL: induct renamed to lfp_induct, lfp_Tarski to lfp_unfold,
  1975 gfp_Tarski to gfp_unfold;
  1976 
  1977 * HOL: contrapos, contrapos2 renamed to contrapos_nn, contrapos_pp;
  1978 
  1979 * HOL: infix "dvd" now has priority 50 rather than 70 (because it is a
  1980 relation); infix "^^" has been renamed "``"; infix "``" has been
  1981 renamed "`"; "univalent" has been renamed "single_valued";
  1982 
  1983 * HOL/Real: "rinv" and "hrinv" replaced by overloaded "inverse"
  1984 operation;
  1985 
  1986 * HOLCF: infix "`" has been renamed "$"; the symbol syntax is \<cdot>;
  1987 
  1988 * Isar: 'obtain' no longer declares "that" fact as simp/intro;
  1989 
  1990 * Isar/HOL: method 'induct' now handles non-atomic goals; as a
  1991 consequence, it is no longer monotonic wrt. the local goal context
  1992 (which is now passed through the inductive cases);
  1993 
  1994 * Document preparation: renamed standard symbols \<ll> to \<lless> and
  1995 \<gg> to \<ggreater>;
  1996 
  1997 
  1998 *** Document preparation ***
  1999 
  2000 * \isabellestyle{NAME} selects version of Isabelle output (currently
  2001 available: are "it" for near math-mode best-style output, "sl" for
  2002 slanted text style, and "tt" for plain type-writer; if no
  2003 \isabellestyle command is given, output is according to slanted
  2004 type-writer);
  2005 
  2006 * support sub/super scripts (for single symbols only), input syntax is
  2007 like this: "A\<^sup>*" or "A\<^sup>\<star>";
  2008 
  2009 * some more standard symbols; see Appendix A of the system manual for
  2010 the complete list of symbols defined in isabellesym.sty;
  2011 
  2012 * improved isabelle style files; more abstract symbol implementation
  2013 (should now use \isamath{...} and \isatext{...} in custom symbol
  2014 definitions);
  2015 
  2016 * antiquotation @{goals} and @{subgoals} for output of *dynamic* goals
  2017 state; Note that presentation of goal states does not conform to
  2018 actual human-readable proof documents.  Please do not include goal
  2019 states into document output unless you really know what you are doing!
  2020 
  2021 * proper indentation of antiquoted output with proportional LaTeX
  2022 fonts;
  2023 
  2024 * no_document ML operator temporarily disables LaTeX document
  2025 generation;
  2026 
  2027 * isatool unsymbolize tunes sources for plain ASCII communication;
  2028 
  2029 
  2030 *** Isar ***
  2031 
  2032 * Pure: Isar now suffers initial goal statements to contain unbound
  2033 schematic variables (this does not conform to actual readable proof
  2034 documents, due to unpredictable outcome and non-compositional proof
  2035 checking); users who know what they are doing may use schematic goals
  2036 for Prolog-style synthesis of proven results;
  2037 
  2038 * Pure: assumption method (an implicit finishing) now handles actual
  2039 rules as well;
  2040 
  2041 * Pure: improved 'obtain' --- moved to Pure, insert "that" into
  2042 initial goal, declare "that" only as Pure intro (only for single
  2043 steps); the "that" rule assumption may now be involved in implicit
  2044 finishing, thus ".." becomes a feasible for trivial obtains;
  2045 
  2046 * Pure: default proof step now includes 'intro_classes'; thus trivial
  2047 instance proofs may be performed by "..";
  2048 
  2049 * Pure: ?thesis / ?this / "..." now work for pure meta-level
  2050 statements as well;
  2051 
  2052 * Pure: more robust selection of calculational rules;
  2053 
  2054 * Pure: the builtin notion of 'finished' goal now includes the ==-refl
  2055 rule (as well as the assumption rule);
  2056 
  2057 * Pure: 'thm_deps' command visualizes dependencies of theorems and
  2058 lemmas, using the graph browser tool;
  2059 
  2060 * Pure: predict failure of "show" in interactive mode;
  2061 
  2062 * Pure: 'thms_containing' now takes actual terms as arguments;
  2063 
  2064 * HOL: improved method 'induct' --- now handles non-atomic goals
  2065 (potential INCOMPATIBILITY); tuned error handling;
  2066 
  2067 * HOL: cases and induct rules now provide explicit hints about the
  2068 number of facts to be consumed (0 for "type" and 1 for "set" rules);
  2069 any remaining facts are inserted into the goal verbatim;
  2070 
  2071 * HOL: local contexts (aka cases) may now contain term bindings as
  2072 well; the 'cases' and 'induct' methods new provide a ?case binding for
  2073 the result to be shown in each case;
  2074 
  2075 * HOL: added 'recdef_tc' command;
  2076 
  2077 * isatool convert assists in eliminating legacy ML scripts;
  2078 
  2079 
  2080 *** HOL ***
  2081 
  2082 * HOL/Library: a collection of generic theories to be used together
  2083 with main HOL; the theory loader path already includes this directory
  2084 by default; the following existing theories have been moved here:
  2085 HOL/Induct/Multiset, HOL/Induct/Acc (as Accessible_Part), HOL/While
  2086 (as While_Combinator), HOL/Lex/Prefix (as List_Prefix);
  2087 
  2088 * HOL/Unix: "Some aspects of Unix file-system security", a typical
  2089 modelling and verification task performed in Isabelle/HOL +
  2090 Isabelle/Isar + Isabelle document preparation (by Markus Wenzel).
  2091 
  2092 * HOL/Algebra: special summation operator SUM no longer exists, it has
  2093 been replaced by setsum; infix 'assoc' now has priority 50 (like
  2094 'dvd'); axiom 'one_not_zero' has been moved from axclass 'ring' to
  2095 'domain', this makes the theory consistent with mathematical
  2096 literature;
  2097 
  2098 * HOL basics: added overloaded operations "inverse" and "divide"
  2099 (infix "/"), syntax for generic "abs" operation, generic summation
  2100 operator \<Sum>;
  2101 
  2102 * HOL/typedef: simplified package, provide more useful rules (see also
  2103 HOL/subset.thy);
  2104 
  2105 * HOL/datatype: induction rule for arbitrarily branching datatypes is
  2106 now expressed as a proper nested rule (old-style tactic scripts may
  2107 require atomize_strip_tac to cope with non-atomic premises);
  2108 
  2109 * HOL: renamed theory "Prod" to "Product_Type", renamed "split" rule
  2110 to "split_conv" (old name still available for compatibility);
  2111 
  2112 * HOL: improved concrete syntax for strings (e.g. allows translation
  2113 rules with string literals);
  2114 
  2115 * HOL-Real-Hyperreal: this extends HOL-Real with the hyperreals
  2116  and Fleuriot's mechanization of analysis, including the transcendental
  2117  functions for the reals;
  2118 
  2119 * HOL/Real, HOL/Hyperreal: improved arithmetic simplification;
  2120 
  2121 
  2122 *** CTT ***
  2123 
  2124 * CTT: x-symbol support for Pi, Sigma, -->, : (membership); note that
  2125 "lam" is displayed as TWO lambda-symbols
  2126 
  2127 * CTT: theory Main now available, containing everything (that is, Bool
  2128 and Arith);
  2129 
  2130 
  2131 *** General ***
  2132 
  2133 * Pure: the Simplifier has been implemented properly as a derived rule
  2134 outside of the actual kernel (at last!); the overall performance
  2135 penalty in practical applications is about 50%, while reliability of
  2136 the Isabelle inference kernel has been greatly improved;
  2137 
  2138 * print modes "brackets" and "no_brackets" control output of nested =>
  2139 (types) and ==> (props); the default behaviour is "brackets";
  2140 
  2141 * Provers: fast_tac (and friends) now handle actual object-logic rules
  2142 as assumptions as well;
  2143 
  2144 * system: support Poly/ML 4.0;
  2145 
  2146 * system: isatool install handles KDE version 1 or 2;
  2147 
  2148 
  2149 
  2150 New in Isabelle99-1 (October 2000)
  2151 ----------------------------------
  2152 
  2153 *** Overview of INCOMPATIBILITIES ***
  2154 
  2155 * HOL: simplification of natural numbers is much changed; to partly
  2156 recover the old behaviour (e.g. to prevent n+n rewriting to #2*n)
  2157 issue the following ML commands:
  2158 
  2159   Delsimprocs Nat_Numeral_Simprocs.cancel_numerals;
  2160   Delsimprocs [Nat_Numeral_Simprocs.combine_numerals];
  2161 
  2162 * HOL: simplification no longer dives into case-expressions; this is
  2163 controlled by "t.weak_case_cong" for each datatype t;
  2164 
  2165 * HOL: nat_less_induct renamed to less_induct;
  2166 
  2167 * HOL: systematic renaming of the SOME (Eps) rules, may use isatool
  2168 fixsome to patch .thy and .ML sources automatically;
  2169 
  2170   select_equality  -> some_equality
  2171   select_eq_Ex     -> some_eq_ex
  2172   selectI2EX       -> someI2_ex
  2173   selectI2         -> someI2
  2174   selectI          -> someI
  2175   select1_equality -> some1_equality
  2176   Eps_sym_eq       -> some_sym_eq_trivial
  2177   Eps_eq           -> some_eq_trivial
  2178 
  2179 * HOL: exhaust_tac on datatypes superceded by new generic case_tac;
  2180 
  2181 * HOL: removed obsolete theorem binding expand_if (refer to split_if
  2182 instead);
  2183 
  2184 * HOL: the recursion equations generated by 'recdef' are now called
  2185 f.simps instead of f.rules;
  2186 
  2187 * HOL: qed_spec_mp now also handles bounded ALL as well;
  2188 
  2189 * HOL: 0 is now overloaded, so the type constraint ":: nat" may
  2190 sometimes be needed;
  2191 
  2192 * HOL: the constant for "f``x" is now "image" rather than "op ``";
  2193 
  2194 * HOL: the constant for "f-``x" is now "vimage" rather than "op -``";
  2195 
  2196 * HOL: the disjoint sum is now "<+>" instead of "Plus"; the cartesian
  2197 product is now "<*>" instead of "Times"; the lexicographic product is
  2198 now "<*lex*>" instead of "**";
  2199 
  2200 * HOL: theory Sexp is now in HOL/Induct examples (it used to be part
  2201 of main HOL, but was unused); better use HOL's datatype package;
  2202 
  2203 * HOL: removed "symbols" syntax for constant "override" of theory Map;
  2204 the old syntax may be recovered as follows:
  2205 
  2206   syntax (symbols)
  2207     override  :: "('a ~=> 'b) => ('a ~=> 'b) => ('a ~=> 'b)"
  2208       (infixl "\\<oplus>" 100)
  2209 
  2210 * HOL/Real: "rabs" replaced by overloaded "abs" function;
  2211 
  2212 * HOL/ML: even fewer consts are declared as global (see theories Ord,
  2213 Lfp, Gfp, WF); this only affects ML packages that refer to const names
  2214 internally;
  2215 
  2216 * HOL and ZF: syntax for quotienting wrt an equivalence relation
  2217 changed from A/r to A//r;
  2218 
  2219 * ZF: new treatment of arithmetic (nat & int) may break some old
  2220 proofs;
  2221 
  2222 * Isar: renamed some attributes (RS -> THEN, simplify -> simplified,
  2223 rulify -> rule_format, elimify -> elim_format, ...);
  2224 
  2225 * Isar/Provers: intro/elim/dest attributes changed; renamed
  2226 intro/intro!/intro!! flags to intro!/intro/intro? (in most cases, one
  2227 should have to change intro!! to intro? only); replaced "delrule" by
  2228 "rule del";
  2229 
  2230 * Isar/HOL: renamed "intrs" to "intros" in inductive definitions;
  2231 
  2232 * Provers: strengthened force_tac by using new first_best_tac;
  2233 
  2234 * LaTeX document preparation: several changes of isabelle.sty (see
  2235 lib/texinputs);
  2236 
  2237 
  2238 *** Document preparation ***
  2239 
  2240 * formal comments (text blocks etc.) in new-style theories may now
  2241 contain antiquotations of thm/prop/term/typ/text to be presented
  2242 according to latex print mode; concrete syntax is like this:
  2243 @{term[show_types] "f(x) = a + x"};
  2244 
  2245 * isatool mkdir provides easy setup of Isabelle session directories,
  2246 including proper document sources;
  2247 
  2248 * generated LaTeX sources are now deleted after successful run
  2249 (isatool document -c); may retain a copy somewhere else via -D option
  2250 of isatool usedir;
  2251 
  2252 * isatool usedir -D now lets isatool latex -o sty update the Isabelle
  2253 style files, achieving self-contained LaTeX sources and simplifying
  2254 LaTeX debugging;
  2255 
  2256 * old-style theories now produce (crude) LaTeX output as well;
  2257 
  2258 * browser info session directories are now self-contained (may be put
  2259 on WWW server seperately); improved graphs of nested sessions; removed
  2260 graph for 'all sessions';
  2261 
  2262 * several improvements in isabelle style files; \isabellestyle{it}
  2263 produces fake math mode output; \isamarkupheader is now \section by
  2264 default; see lib/texinputs/isabelle.sty etc.;
  2265 
  2266 
  2267 *** Isar ***
  2268 
  2269 * Isar/Pure: local results and corresponding term bindings are now
  2270 subject to Hindley-Milner polymorphism (similar to ML); this
  2271 accommodates incremental type-inference very nicely;
  2272 
  2273 * Isar/Pure: new derived language element 'obtain' supports
  2274 generalized existence reasoning;
  2275 
  2276 * Isar/Pure: new calculational elements 'moreover' and 'ultimately'
  2277 support accumulation of results, without applying any rules yet;
  2278 useful to collect intermediate results without explicit name
  2279 references, and for use with transitivity rules with more than 2
  2280 premises;
  2281 
  2282 * Isar/Pure: scalable support for case-analysis type proofs: new
  2283 'case' language element refers to local contexts symbolically, as
  2284 produced by certain proof methods; internally, case names are attached
  2285 to theorems as "tags";
  2286 
  2287 * Isar/Pure: theory command 'hide' removes declarations from
  2288 class/type/const name spaces;
  2289 
  2290 * Isar/Pure: theory command 'defs' supports option "(overloaded)" to
  2291 indicate potential overloading;
  2292 
  2293 * Isar/Pure: changed syntax of local blocks from {{ }} to { };
  2294 
  2295 * Isar/Pure: syntax of sorts made 'inner', i.e. have to write
  2296 "{a,b,c}" instead of {a,b,c};
  2297 
  2298 * Isar/Pure now provides its own version of intro/elim/dest
  2299 attributes; useful for building new logics, but beware of confusion
  2300 with the version in Provers/classical;
  2301 
  2302 * Isar/Pure: the local context of (non-atomic) goals is provided via
  2303 case name 'antecedent';
  2304 
  2305 * Isar/Pure: removed obsolete 'transfer' attribute (transfer of thms
  2306 to the current context is now done automatically);
  2307 
  2308 * Isar/Pure: theory command 'method_setup' provides a simple interface
  2309 for definining proof methods in ML;
  2310 
  2311 * Isar/Provers: intro/elim/dest attributes changed; renamed
  2312 intro/intro!/intro!! flags to intro!/intro/intro? (INCOMPATIBILITY, in
  2313 most cases, one should have to change intro!! to intro? only);
  2314 replaced "delrule" by "rule del";
  2315 
  2316 * Isar/Provers: new 'hypsubst' method, plain 'subst' method and
  2317 'symmetric' attribute (the latter supercedes [RS sym]);
  2318 
  2319 * Isar/Provers: splitter support (via 'split' attribute and 'simp'
  2320 method modifier); 'simp' method: 'only:' modifier removes loopers as
  2321 well (including splits);
  2322 
  2323 * Isar/Provers: Simplifier and Classical methods now support all kind
  2324 of modifiers used in the past, including 'cong', 'iff', etc.
  2325 
  2326 * Isar/Provers: added 'fastsimp' and 'clarsimp' methods (combination
  2327 of Simplifier and Classical reasoner);
  2328 
  2329 * Isar/HOL: new proof method 'cases' and improved version of 'induct'
  2330 now support named cases; major packages (inductive, datatype, primrec,
  2331 recdef) support case names and properly name parameters;
  2332 
  2333 * Isar/HOL: new transitivity rules for substitution in inequalities --
  2334 monotonicity conditions are extracted to be proven at end of
  2335 calculations;
  2336 
  2337 * Isar/HOL: removed 'case_split' thm binding, should use 'cases' proof
  2338 method anyway;
  2339 
  2340 * Isar/HOL: removed old expand_if = split_if; theorems if_splits =
  2341 split_if split_if_asm; datatype package provides theorems foo.splits =
  2342 foo.split foo.split_asm for each datatype;
  2343 
  2344 * Isar/HOL: tuned inductive package, rename "intrs" to "intros"
  2345 (potential INCOMPATIBILITY), emulation of mk_cases feature for proof
  2346 scripts: new 'inductive_cases' command and 'ind_cases' method; (Note:
  2347 use "(cases (simplified))" method in proper proof texts);
  2348 
  2349 * Isar/HOL: added global 'arith_split' attribute for 'arith' method;
  2350 
  2351 * Isar: names of theorems etc. may be natural numbers as well;
  2352 
  2353 * Isar: 'pr' command: optional arguments for goals_limit and
  2354 ProofContext.prems_limit; no longer prints theory contexts, but only
  2355 proof states;
  2356 
  2357 * Isar: diagnostic commands 'pr', 'thm', 'prop', 'term', 'typ' admit
  2358 additional print modes to be specified; e.g. "pr(latex)" will print
  2359 proof state according to the Isabelle LaTeX style;
  2360 
  2361 * Isar: improved support for emulating tactic scripts, including proof
  2362 methods 'rule_tac' etc., 'cut_tac', 'thin_tac', 'subgoal_tac',
  2363 'rename_tac', 'rotate_tac', 'tactic', and 'case_tac' / 'induct_tac'
  2364 (for HOL datatypes);
  2365 
  2366 * Isar: simplified (more robust) goal selection of proof methods: 1st
  2367 goal, all goals, or explicit goal specifier (tactic emulation); thus
  2368 'proof method scripts' have to be in depth-first order;
  2369 
  2370 * Isar: tuned 'let' syntax: replaced 'as' keyword by 'and';
  2371 
  2372 * Isar: removed 'help' command, which hasn't been too helpful anyway;
  2373 should instead use individual commands for printing items
  2374 (print_commands, print_methods etc.);
  2375 
  2376 * Isar: added 'nothing' --- the empty list of theorems;
  2377 
  2378 
  2379 *** HOL ***
  2380 
  2381 * HOL/MicroJava: formalization of a fragment of Java, together with a
  2382 corresponding virtual machine and a specification of its bytecode
  2383 verifier and a lightweight bytecode verifier, including proofs of
  2384 type-safety; by Gerwin Klein, Tobias Nipkow, David von Oheimb, and
  2385 Cornelia Pusch (see also the homepage of project Bali at
  2386 http://isabelle.in.tum.de/Bali/);
  2387 
  2388 * HOL/Algebra: new theory of rings and univariate polynomials, by
  2389 Clemens Ballarin;
  2390 
  2391 * HOL/NumberTheory: fundamental Theorem of Arithmetic, Chinese
  2392 Remainder Theorem, Fermat/Euler Theorem, Wilson's Theorem, by Thomas M
  2393 Rasmussen;
  2394 
  2395 * HOL/Lattice: fundamental concepts of lattice theory and order
  2396 structures, including duals, properties of bounds versus algebraic
  2397 laws, lattice operations versus set-theoretic ones, the Knaster-Tarski
  2398 Theorem for complete lattices etc.; may also serve as a demonstration
  2399 for abstract algebraic reasoning using axiomatic type classes, and
  2400 mathematics-style proof in Isabelle/Isar; by Markus Wenzel;
  2401 
  2402 * HOL/Prolog: a (bare-bones) implementation of Lambda-Prolog, by David
  2403 von Oheimb;
  2404 
  2405 * HOL/IMPP: extension of IMP with local variables and mutually
  2406 recursive procedures, by David von Oheimb;
  2407 
  2408 * HOL/Lambda: converted into new-style theory and document;
  2409 
  2410 * HOL/ex/Multiquote: example of multiple nested quotations and
  2411 anti-quotations -- basically a generalized version of de-Bruijn
  2412 representation; very useful in avoiding lifting of operations;
  2413 
  2414 * HOL/record: added general record equality rule to simpset; fixed
  2415 select-update simplification procedure to handle extended records as
  2416 well; admit "r" as field name;
  2417 
  2418 * HOL: 0 is now overloaded over the new sort "zero", allowing its use with
  2419 other numeric types and also as the identity of groups, rings, etc.;
  2420 
  2421 * HOL: new axclass plus_ac0 for addition with the AC-laws and 0 as identity.
  2422 Types nat and int belong to this axclass;
  2423 
  2424 * HOL: greatly improved simplification involving numerals of type nat, int, real:
  2425    (i + #8 + j) = Suc k simplifies to  #7 + (i + j) = k
  2426    i*j + k + j*#3*i     simplifies to  #4*(i*j) + k
  2427   two terms #m*u and #n*u are replaced by #(m+n)*u
  2428     (where #m, #n and u can implicitly be 1; this is simproc combine_numerals)
  2429   and the term/formula #m*u+x ~~ #n*u+y simplifies simplifies to #(m-n)+x ~~ y
  2430     or x ~~ #(n-m)+y, where ~~ is one of = < <= or - (simproc cancel_numerals);
  2431 
  2432 * HOL: meson_tac is available (previously in ex/meson.ML); it is a
  2433 powerful prover for predicate logic but knows nothing of clasets; see
  2434 ex/mesontest.ML and ex/mesontest2.ML for example applications;
  2435 
  2436 * HOL: new version of "case_tac" subsumes both boolean case split and
  2437 "exhaust_tac" on datatypes; INCOMPATIBILITY: exhaust_tac no longer
  2438 exists, may define val exhaust_tac = case_tac for ad-hoc portability;
  2439 
  2440 * HOL: simplification no longer dives into case-expressions: only the
  2441 selector expression is simplified, but not the remaining arms; to
  2442 enable full simplification of case-expressions for datatype t, you may
  2443 remove t.weak_case_cong from the simpset, either globally (Delcongs
  2444 [thm"t.weak_case_cong"];) or locally (delcongs [...]).
  2445 
  2446 * HOL/recdef: the recursion equations generated by 'recdef' for
  2447 function 'f' are now called f.simps instead of f.rules; if all
  2448 termination conditions are proved automatically, these simplification
  2449 rules are added to the simpset, as in primrec; rules may be named
  2450 individually as well, resulting in a separate list of theorems for
  2451 each equation;
  2452 
  2453 * HOL/While is a new theory that provides a while-combinator. It
  2454 permits the definition of tail-recursive functions without the
  2455 provision of a termination measure. The latter is necessary once the
  2456 invariant proof rule for while is applied.
  2457 
  2458 * HOL: new (overloaded) notation for the set of elements below/above
  2459 some element: {..u}, {..u(}, {l..}, {)l..}. See theory SetInterval.
  2460 
  2461 * HOL: theorems impI, allI, ballI bound as "strip";
  2462 
  2463 * HOL: new tactic induct_thm_tac: thm -> string -> int -> tactic
  2464 induct_tac th "x1 ... xn" expects th to have a conclusion of the form
  2465 P v1 ... vn and abbreviates res_inst_tac [("v1","x1"),...,("vn","xn")] th;
  2466 
  2467 * HOL/Real: "rabs" replaced by overloaded "abs" function;
  2468 
  2469 * HOL: theory Sexp now in HOL/Induct examples (it used to be part of
  2470 main HOL, but was unused);
  2471 
  2472 * HOL: fewer consts declared as global (e.g. have to refer to
  2473 "Lfp.lfp" instead of "lfp" internally; affects ML packages only);
  2474 
  2475 * HOL: tuned AST representation of nested pairs, avoiding bogus output
  2476 in case of overlap with user translations (e.g. judgements over
  2477 tuples); (note that the underlying logical represenation is still
  2478 bogus);
  2479 
  2480 
  2481 *** ZF ***
  2482 
  2483 * ZF: simplification automatically cancels common terms in arithmetic
  2484 expressions over nat and int;
  2485 
  2486 * ZF: new treatment of nat to minimize type-checking: all operators
  2487 coerce their operands to a natural number using the function natify,
  2488 making the algebraic laws unconditional;
  2489 
  2490 * ZF: as above, for int: operators coerce their operands to an integer
  2491 using the function intify;
  2492 
  2493 * ZF: the integer library now contains many of the usual laws for the
  2494 orderings, including $<=, and monotonicity laws for $+ and $*;
  2495 
  2496 * ZF: new example ZF/ex/NatSum to demonstrate integer arithmetic
  2497 simplification;
  2498 
  2499 * FOL and ZF: AddIffs now available, giving theorems of the form P<->Q
  2500 to the simplifier and classical reasoner simultaneously;
  2501 
  2502 
  2503 *** General ***
  2504 
  2505 * Provers: blast_tac now handles actual object-logic rules as
  2506 assumptions; note that auto_tac uses blast_tac internally as well;
  2507 
  2508 * Provers: new functions rulify/rulify_no_asm: thm -> thm for turning
  2509 outer -->/All/Ball into ==>/!!; qed_spec_mp now uses rulify_no_asm;
  2510 
  2511 * Provers: delrules now handles destruct rules as well (no longer need
  2512 explicit make_elim);
  2513 
  2514 * Provers: Blast_tac now warns of and ignores "weak elimination rules" e.g.
  2515   [| inj ?f;          ?f ?x = ?f ?y; ?x = ?y ==> ?W |] ==> ?W
  2516 use instead the strong form,
  2517   [| inj ?f; ~ ?W ==> ?f ?x = ?f ?y; ?x = ?y ==> ?W |] ==> ?W
  2518 in HOL, FOL and ZF the function cla_make_elim will create such rules
  2519 from destruct-rules;
  2520 
  2521 * Provers: Simplifier.easy_setup provides a fast path to basic
  2522 Simplifier setup for new object-logics;
  2523 
  2524 * Pure: AST translation rules no longer require constant head on LHS;
  2525 
  2526 * Pure: improved name spaces: ambiguous output is qualified; support
  2527 for hiding of names;
  2528 
  2529 * system: smart setup of canonical ML_HOME, ISABELLE_INTERFACE, and
  2530 XSYMBOL_HOME; no longer need to do manual configuration in most
  2531 situations;
  2532 
  2533 * system: compression of ML heaps images may now be controlled via -c
  2534 option of isabelle and isatool usedir (currently only observed by
  2535 Poly/ML);
  2536 
  2537 * system: isatool installfonts may handle X-Symbol fonts as well (very
  2538 useful for remote X11);
  2539 
  2540 * system: provide TAGS file for Isabelle sources;
  2541 
  2542 * ML: infix 'OF' is a version of 'MRS' with more appropriate argument
  2543 order;
  2544 
  2545 * ML: renamed flags Syntax.trace_norm_ast to Syntax.trace_ast; global
  2546 timing flag supersedes proof_timing and Toplevel.trace;
  2547 
  2548 * ML: new combinators |>> and |>>> for incremental transformations
  2549 with secondary results (e.g. certain theory extensions):
  2550 
  2551 * ML: PureThy.add_defs gets additional argument to indicate potential
  2552 overloading (usually false);
  2553 
  2554 * ML: PureThy.add_thms/add_axioms/add_defs now return theorems as
  2555 results;
  2556 
  2557 
  2558 
  2559 New in Isabelle99 (October 1999)
  2560 --------------------------------
  2561 
  2562 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  2563 
  2564 * HOL: The THEN and ELSE parts of conditional expressions (if P then x else y)
  2565 are no longer simplified.  (This allows the simplifier to unfold recursive
  2566 functional programs.)  To restore the old behaviour, declare
  2567 
  2568     Delcongs [if_weak_cong];
  2569 
  2570 * HOL: Removed the obsolete syntax "Compl A"; use -A for set
  2571 complement;
  2572 
  2573 * HOL: the predicate "inj" is now defined by translation to "inj_on";
  2574 
  2575 * HOL/datatype: mutual_induct_tac no longer exists --
  2576   use induct_tac "x_1 ... x_n" instead of mutual_induct_tac ["x_1", ..., "x_n"]
  2577 
  2578 * HOL/typedef: fixed type inference for representing set; type
  2579 arguments now have to occur explicitly on the rhs as type constraints;
  2580 
  2581 * ZF: The con_defs part of an inductive definition may no longer refer
  2582 to constants declared in the same theory;
  2583 
  2584 * HOL, ZF: the function mk_cases, generated by the inductive
  2585 definition package, has lost an argument.  To simplify its result, it
  2586 uses the default simpset instead of a supplied list of theorems.
  2587 
  2588 * HOL/List: the constructors of type list are now Nil and Cons;
  2589 
  2590 * Simplifier: the type of the infix ML functions
  2591         setSSolver addSSolver setSolver addSolver
  2592 is now  simpset * solver -> simpset  where `solver' is a new abstract type
  2593 for packaging solvers. A solver is created via
  2594         mk_solver: string -> (thm list -> int -> tactic) -> solver
  2595 where the string argument is only a comment.
  2596 
  2597 
  2598 *** Proof tools ***
  2599 
  2600 * Provers/Arith/fast_lin_arith.ML contains a functor for creating a
  2601 decision procedure for linear arithmetic. Currently it is used for
  2602 types `nat', `int', and `real' in HOL (see below); it can, should and
  2603 will be instantiated for other types and logics as well.
  2604 
  2605 * The simplifier now accepts rewrite rules with flexible heads, eg
  2606      hom ?f ==> ?f(?x+?y) = ?f ?x + ?f ?y
  2607   They are applied like any rule with a non-pattern lhs, i.e. by first-order
  2608   matching.
  2609 
  2610 
  2611 *** General ***
  2612 
  2613 * New Isabelle/Isar subsystem provides an alternative to traditional
  2614 tactical theorem proving; together with the ProofGeneral/isar user
  2615 interface it offers an interactive environment for developing human
  2616 readable proof documents (Isar == Intelligible semi-automated
  2617 reasoning); for further information see isatool doc isar-ref,
  2618 src/HOL/Isar_examples and http://isabelle.in.tum.de/Isar/
  2619 
  2620 * improved and simplified presentation of theories: better HTML markup
  2621 (including colors), graph views in several sizes; isatool usedir now
  2622 provides a proper interface for user theories (via -P option); actual
  2623 document preparation based on (PDF)LaTeX is available as well (for
  2624 new-style theories only); see isatool doc system for more information;
  2625 
  2626 * native support for Proof General, both for classic Isabelle and
  2627 Isabelle/Isar;
  2628 
  2629 * ML function thm_deps visualizes dependencies of theorems and lemmas,
  2630 using the graph browser tool;
  2631 
  2632 * Isabelle manuals now also available as PDF;
  2633 
  2634 * theory loader rewritten from scratch (may not be fully
  2635 bug-compatible); old loadpath variable has been replaced by show_path,
  2636 add_path, del_path, reset_path functions; new operations such as
  2637 update_thy, touch_thy, remove_thy, use/update_thy_only (see also
  2638 isatool doc ref);
  2639 
  2640 * improved isatool install: option -k creates KDE application icon,
  2641 option -p DIR installs standalone binaries;
  2642 
  2643 * added ML_PLATFORM setting (useful for cross-platform installations);
  2644 more robust handling of platform specific ML images for SML/NJ;
  2645 
  2646 * the settings environment is now statically scoped, i.e. it is never
  2647 created again in sub-processes invoked from isabelle, isatool, or
  2648 Isabelle;
  2649 
  2650 * path element specification '~~' refers to '$ISABELLE_HOME';
  2651 
  2652 * in locales, the "assumes" and "defines" parts may be omitted if
  2653 empty;
  2654 
  2655 * new print_mode "xsymbols" for extended symbol support (e.g. genuine
  2656 long arrows);
  2657 
  2658 * new print_mode "HTML";
  2659 
  2660 * new flag show_tags controls display of tags of theorems (which are
  2661 basically just comments that may be attached by some tools);
  2662 
  2663 * Isamode 2.6 requires patch to accomodate change of Isabelle font
  2664 mode and goal output format:
  2665 
  2666 diff -r Isamode-2.6/elisp/isa-load.el Isamode/elisp/isa-load.el
  2667 244c244
  2668 <       (list (isa-getenv "ISABELLE") "-msymbols" logic-name)
  2669 ---
  2670 >       (list (isa-getenv "ISABELLE") "-misabelle_font" "-msymbols" logic-name)
  2671 diff -r Isabelle-2.6/elisp/isa-proofstate.el Isamode/elisp/isa-proofstate.el
  2672 181c181
  2673 < (defconst proofstate-proofstart-regexp "^Level [0-9]+$"
  2674 ---
  2675 > (defconst proofstate-proofstart-regexp "^Level [0-9]+"
  2676 
  2677 * function bind_thms stores lists of theorems (cf. bind_thm);
  2678 
  2679 * new shorthand tactics ftac, eatac, datac, fatac;
  2680 
  2681 * qed (and friends) now accept "" as result name; in that case the
  2682 theorem is not stored, but proper checks and presentation of the
  2683 result still apply;
  2684 
  2685 * theorem database now also indexes constants "Trueprop", "all",
  2686 "==>", "=="; thus thms_containing, findI etc. may retrieve more rules;
  2687 
  2688 
  2689 *** HOL ***
  2690 
  2691 ** HOL arithmetic **
  2692 
  2693 * There are now decision procedures for linear arithmetic over nat and
  2694 int:
  2695 
  2696 1. arith_tac copes with arbitrary formulae involving `=', `<', `<=',
  2697 `+', `-', `Suc', `min', `max' and numerical constants; other subterms
  2698 are treated as atomic; subformulae not involving type `nat' or `int'
  2699 are ignored; quantified subformulae are ignored unless they are
  2700 positive universal or negative existential. The tactic has to be
  2701 invoked by hand and can be a little bit slow. In particular, the
  2702 running time is exponential in the number of occurrences of `min' and
  2703 `max', and `-' on `nat'.
  2704 
  2705 2. fast_arith_tac is a cut-down version of arith_tac: it only takes
  2706 (negated) (in)equalities among the premises and the conclusion into
  2707 account (i.e. no compound formulae) and does not know about `min' and
  2708 `max', and `-' on `nat'. It is fast and is used automatically by the
  2709 simplifier.
  2710 
  2711 NB: At the moment, these decision procedures do not cope with mixed
  2712 nat/int formulae where the two parts interact, such as `m < n ==>
  2713 int(m) < int(n)'.
  2714 
  2715 * HOL/Numeral provides a generic theory of numerals (encoded
  2716 efficiently as bit strings); setup for types nat/int/real is in place;
  2717 INCOMPATIBILITY: since numeral syntax is now polymorphic, rather than
  2718 int, existing theories and proof scripts may require a few additional
  2719 type constraints;
  2720 
  2721 * integer division and remainder can now be performed on constant
  2722 arguments;
  2723 
  2724 * many properties of integer multiplication, division and remainder
  2725 are now available;
  2726 
  2727 * An interface to the Stanford Validity Checker (SVC) is available through the
  2728 tactic svc_tac.  Propositional tautologies and theorems of linear arithmetic
  2729 are proved automatically.  SVC must be installed separately, and its results
  2730 must be TAKEN ON TRUST (Isabelle does not check the proofs, but tags any
  2731 invocation of the underlying oracle).  For SVC see
  2732   http://verify.stanford.edu/SVC
  2733 
  2734 * IsaMakefile: the HOL-Real target now builds an actual image;
  2735 
  2736 
  2737 ** HOL misc **
  2738 
  2739 * HOL/Real/HahnBanach: the Hahn-Banach theorem for real vector spaces
  2740 (in Isabelle/Isar) -- by Gertrud Bauer;
  2741 
  2742 * HOL/BCV: generic model of bytecode verification, i.e. data-flow
  2743 analysis for assembly languages with subtypes;
  2744 
  2745 * HOL/TLA (Lamport's Temporal Logic of Actions): major reorganization
  2746 -- avoids syntactic ambiguities and treats state, transition, and
  2747 temporal levels more uniformly; introduces INCOMPATIBILITIES due to
  2748 changed syntax and (many) tactics;
  2749 
  2750 * HOL/inductive: Now also handles more general introduction rules such
  2751   as "ALL y. (y, x) : r --> y : acc r ==> x : acc r"; monotonicity
  2752   theorems are now maintained within the theory (maintained via the
  2753   "mono" attribute);
  2754 
  2755 * HOL/datatype: Now also handles arbitrarily branching datatypes
  2756   (using function types) such as
  2757 
  2758   datatype 'a tree = Atom 'a | Branch "nat => 'a tree"
  2759 
  2760 * HOL/record: record_simproc (part of the default simpset) takes care
  2761 of selectors applied to updated records; record_split_tac is no longer
  2762 part of the default claset; update_defs may now be removed from the
  2763 simpset in many cases; COMPATIBILITY: old behavior achieved by
  2764 
  2765   claset_ref () := claset() addSWrapper record_split_wrapper;
  2766   Delsimprocs [record_simproc]
  2767 
  2768 * HOL/typedef: fixed type inference for representing set; type
  2769 arguments now have to occur explicitly on the rhs as type constraints;
  2770 
  2771 * HOL/recdef (TFL): 'congs' syntax now expects comma separated list of theorem
  2772 names rather than an ML expression;
  2773 
  2774 * HOL/defer_recdef (TFL): like recdef but the well-founded relation can be
  2775 supplied later.  Program schemes can be defined, such as
  2776     "While B C s = (if B s then While B C (C s) else s)"
  2777 where the well-founded relation can be chosen after B and C have been given.
  2778 
  2779 * HOL/List: the constructors of type list are now Nil and Cons;
  2780 INCOMPATIBILITY: while [] and infix # syntax is still there, of
  2781 course, ML tools referring to List.list.op # etc. have to be adapted;
  2782 
  2783 * HOL_quantifiers flag superseded by "HOL" print mode, which is
  2784 disabled by default; run isabelle with option -m HOL to get back to
  2785 the original Gordon/HOL-style output;
  2786 
  2787 * HOL/Ord.thy: new bounded quantifier syntax (input only): ALL x<y. P,
  2788 ALL x<=y. P, EX x<y. P, EX x<=y. P;
  2789 
  2790 * HOL basic syntax simplified (more orthogonal): all variants of
  2791 All/Ex now support plain / symbolic / HOL notation; plain syntax for
  2792 Eps operator is provided as well: "SOME x. P[x]";
  2793 
  2794 * HOL/Sum.thy: sum_case has been moved to HOL/Datatype;
  2795 
  2796 * HOL/Univ.thy: infix syntax <*>, <+>, <**>, <+> eliminated and made
  2797 thus available for user theories;
  2798 
  2799 * HOLCF/IOA/Sequents: renamed 'Cons' to 'Consq' to avoid clash with
  2800 HOL/List; hardly an INCOMPATIBILITY since '>>' syntax is used all the
  2801 time;
  2802 
  2803 * HOL: new tactic smp_tac: int -> int -> tactic, which applies spec
  2804 several times and then mp;
  2805 
  2806 
  2807 *** LK ***
  2808 
  2809 * the notation <<...>> is now available as a notation for sequences of
  2810 formulas;
  2811 
  2812 * the simplifier is now installed
  2813 
  2814 * the axiom system has been generalized (thanks to Soren Heilmann)
  2815 
  2816 * the classical reasoner now has a default rule database
  2817 
  2818 
  2819 *** ZF ***
  2820 
  2821 * new primrec section allows primitive recursive functions to be given
  2822 directly (as in HOL) over datatypes and the natural numbers;
  2823 
  2824 * new tactics induct_tac and exhaust_tac for induction (or case
  2825 analysis) over datatypes and the natural numbers;
  2826 
  2827 * the datatype declaration of type T now defines the recursor T_rec;
  2828 
  2829 * simplification automatically does freeness reasoning for datatype
  2830 constructors;
  2831 
  2832 * automatic type-inference, with AddTCs command to insert new
  2833 type-checking rules;
  2834 
  2835 * datatype introduction rules are now added as Safe Introduction rules
  2836 to the claset;
  2837 
  2838 * the syntax "if P then x else y" is now available in addition to
  2839 if(P,x,y);
  2840 
  2841 
  2842 *** Internal programming interfaces ***
  2843 
  2844 * tuned simplifier trace output; new flag debug_simp;
  2845 
  2846 * structures Vartab / Termtab (instances of TableFun) offer efficient
  2847 tables indexed by indexname_ord / term_ord (compatible with aconv);
  2848 
  2849 * AxClass.axclass_tac lost the theory argument;
  2850 
  2851 * tuned current_goals_markers semantics: begin / end goal avoids
  2852 printing empty lines;
  2853 
  2854 * removed prs and prs_fn hook, which was broken because it did not
  2855 include \n in its semantics, forcing writeln to add one
  2856 uncoditionally; replaced prs_fn by writeln_fn; consider std_output:
  2857 string -> unit if you really want to output text without newline;
  2858 
  2859 * Symbol.output subject to print mode; INCOMPATIBILITY: defaults to
  2860 plain output, interface builders may have to enable 'isabelle_font'
  2861 mode to get Isabelle font glyphs as before;
  2862 
  2863 * refined token_translation interface; INCOMPATIBILITY: output length
  2864 now of type real instead of int;
  2865 
  2866 * theory loader actions may be traced via new ThyInfo.add_hook
  2867 interface (see src/Pure/Thy/thy_info.ML); example application: keep
  2868 your own database of information attached to *whole* theories -- as
  2869 opposed to intra-theory data slots offered via TheoryDataFun;
  2870 
  2871 * proper handling of dangling sort hypotheses (at last!);
  2872 Thm.strip_shyps and Drule.strip_shyps_warning take care of removing
  2873 extra sort hypotheses that can be witnessed from the type signature;
  2874 the force_strip_shyps flag is gone, any remaining shyps are simply
  2875 left in the theorem (with a warning issued by strip_shyps_warning);
  2876 
  2877 
  2878 
  2879 New in Isabelle98-1 (October 1998)
  2880 ----------------------------------
  2881 
  2882 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  2883 
  2884 * several changes of automated proof tools;
  2885 
  2886 * HOL: major changes to the inductive and datatype packages, including
  2887 some minor incompatibilities of theory syntax;
  2888 
  2889 * HOL: renamed r^-1 to 'converse' from 'inverse'; 'inj_onto' is now
  2890 called `inj_on';
  2891 
  2892 * HOL: removed duplicate thms in Arith:
  2893   less_imp_add_less  should be replaced by  trans_less_add1
  2894   le_imp_add_le      should be replaced by  trans_le_add1
  2895 
  2896 * HOL: unary minus is now overloaded (new type constraints may be
  2897 required);
  2898 
  2899 * HOL and ZF: unary minus for integers is now #- instead of #~.  In
  2900 ZF, expressions such as n#-1 must be changed to n#- 1, since #-1 is
  2901 now taken as an integer constant.
  2902 
  2903 * Pure: ML function 'theory_of' renamed to 'theory';
  2904 
  2905 
  2906 *** Proof tools ***
  2907 
  2908 * Simplifier:
  2909   1. Asm_full_simp_tac is now more aggressive.
  2910      1. It will sometimes reorient premises if that increases their power to
  2911         simplify.
  2912      2. It does no longer proceed strictly from left to right but may also
  2913         rotate premises to achieve further simplification.
  2914      For compatibility reasons there is now Asm_lr_simp_tac which is like the
  2915      old Asm_full_simp_tac in that it does not rotate premises.
  2916   2. The simplifier now knows a little bit about nat-arithmetic.
  2917 
  2918 * Classical reasoner: wrapper mechanism for the classical reasoner now
  2919 allows for selected deletion of wrappers, by introduction of names for
  2920 wrapper functionals.  This implies that addbefore, addSbefore,
  2921 addaltern, and addSaltern now take a pair (name, tactic) as argument,
  2922 and that adding two tactics with the same name overwrites the first
  2923 one (emitting a warning).
  2924   type wrapper = (int -> tactic) -> (int -> tactic)
  2925   setWrapper, setSWrapper, compWrapper and compSWrapper are replaced by
  2926   addWrapper, addSWrapper: claset * (string * wrapper) -> claset
  2927   delWrapper, delSWrapper: claset *  string            -> claset
  2928   getWrapper is renamed to appWrappers, getSWrapper to appSWrappers;
  2929 
  2930 * Classical reasoner: addbefore/addSbefore now have APPEND/ORELSE
  2931 semantics; addbefore now affects only the unsafe part of step_tac
  2932 etc.; this affects addss/auto_tac/force_tac, so EXISTING PROOFS MAY
  2933 FAIL, but proofs should be fixable easily, e.g. by replacing Auto_tac
  2934 by Force_tac;
  2935 
  2936 * Classical reasoner: setwrapper to setWrapper and compwrapper to
  2937 compWrapper; added safe wrapper (and access functions for it);
  2938 
  2939 * HOL/split_all_tac is now much faster and fails if there is nothing
  2940 to split.  Some EXISTING PROOFS MAY REQUIRE ADAPTION because the order
  2941 and the names of the automatically generated variables have changed.
  2942 split_all_tac has moved within claset() from unsafe wrappers to safe
  2943 wrappers, which means that !!-bound variables are split much more
  2944 aggressively, and safe_tac and clarify_tac now split such variables.
  2945 If this splitting is not appropriate, use delSWrapper "split_all_tac".
  2946 Note: the same holds for record_split_tac, which does the job of
  2947 split_all_tac for record fields.
  2948 
  2949 * HOL/Simplifier: Rewrite rules for case distinctions can now be added
  2950 permanently to the default simpset using Addsplits just like
  2951 Addsimps. They can be removed via Delsplits just like
  2952 Delsimps. Lower-case versions are also available.
  2953 
  2954 * HOL/Simplifier: The rule split_if is now part of the default
  2955 simpset. This means that the simplifier will eliminate all occurrences
  2956 of if-then-else in the conclusion of a goal. To prevent this, you can
  2957 either remove split_if completely from the default simpset by
  2958 `Delsplits [split_if]' or remove it in a specific call of the
  2959 simplifier using `... delsplits [split_if]'.  You can also add/delete
  2960 other case splitting rules to/from the default simpset: every datatype
  2961 generates suitable rules `split_t_case' and `split_t_case_asm' (where
  2962 t is the name of the datatype).
  2963 
  2964 * Classical reasoner / Simplifier combination: new force_tac (and
  2965 derivatives Force_tac, force) combines rewriting and classical
  2966 reasoning (and whatever other tools) similarly to auto_tac, but is
  2967 aimed to solve the given subgoal completely.
  2968 
  2969 
  2970 *** General ***
  2971 
  2972 * new top-level commands `Goal' and `Goalw' that improve upon `goal'
  2973 and `goalw': the theory is no longer needed as an explicit argument -
  2974 the current theory context is used; assumptions are no longer returned
  2975 at the ML-level unless one of them starts with ==> or !!; it is
  2976 recommended to convert to these new commands using isatool fixgoal
  2977 (backup your sources first!);
  2978 
  2979 * new top-level commands 'thm' and 'thms' for retrieving theorems from
  2980 the current theory context, and 'theory' to lookup stored theories;
  2981 
  2982 * new theory section 'locale' for declaring constants, assumptions and
  2983 definitions that have local scope;
  2984 
  2985 * new theory section 'nonterminals' for purely syntactic types;
  2986 
  2987 * new theory section 'setup' for generic ML setup functions
  2988 (e.g. package initialization);
  2989 
  2990 * the distribution now includes Isabelle icons: see
  2991 lib/logo/isabelle-{small,tiny}.xpm;
  2992 
  2993 * isatool install - install binaries with absolute references to
  2994 ISABELLE_HOME/bin;
  2995 
  2996 * isatool logo -- create instances of the Isabelle logo (as EPS);
  2997 
  2998 * print mode 'emacs' reserved for Isamode;
  2999 
  3000 * support multiple print (ast) translations per constant name;
  3001 
  3002 * theorems involving oracles are now printed with a suffixed [!];
  3003 
  3004 
  3005 *** HOL ***
  3006 
  3007 * there is now a tutorial on Isabelle/HOL (do 'isatool doc tutorial');
  3008 
  3009 * HOL/inductive package reorganized and improved: now supports mutual
  3010 definitions such as
  3011 
  3012   inductive EVEN ODD
  3013     intrs
  3014       null "0 : EVEN"
  3015       oddI "n : EVEN ==> Suc n : ODD"
  3016       evenI "n : ODD ==> Suc n : EVEN"
  3017 
  3018 new theorem list "elims" contains an elimination rule for each of the
  3019 recursive sets; inductive definitions now handle disjunctive premises
  3020 correctly (also ZF);
  3021 
  3022 INCOMPATIBILITIES: requires Inductive as an ancestor; component
  3023 "mutual_induct" no longer exists - the induction rule is always
  3024 contained in "induct";
  3025 
  3026 
  3027 * HOL/datatype package re-implemented and greatly improved: now
  3028 supports mutually recursive datatypes such as
  3029 
  3030   datatype
  3031     'a aexp = IF_THEN_ELSE ('a bexp) ('a aexp) ('a aexp)
  3032             | SUM ('a aexp) ('a aexp)
  3033             | DIFF ('a aexp) ('a aexp)
  3034             | NUM 'a
  3035   and
  3036     'a bexp = LESS ('a aexp) ('a aexp)
  3037             | AND ('a bexp) ('a bexp)
  3038             | OR ('a bexp) ('a bexp)
  3039 
  3040 as well as indirectly recursive datatypes such as
  3041 
  3042   datatype
  3043     ('a, 'b) term = Var 'a
  3044                   | App 'b ((('a, 'b) term) list)
  3045 
  3046 The new tactic  mutual_induct_tac [<var_1>, ..., <var_n>] i  performs
  3047 induction on mutually / indirectly recursive datatypes.
  3048 
  3049 Primrec equations are now stored in theory and can be accessed via
  3050 <function_name>.simps.
  3051 
  3052 INCOMPATIBILITIES:
  3053 
  3054   - Theories using datatypes must now have theory Datatype as an
  3055     ancestor.
  3056   - The specific <typename>.induct_tac no longer exists - use the
  3057     generic induct_tac instead.
  3058   - natE has been renamed to nat.exhaust - use exhaust_tac
  3059     instead of res_inst_tac ... natE. Note that the variable
  3060     names in nat.exhaust differ from the names in natE, this
  3061     may cause some "fragile" proofs to fail.
  3062   - The theorems split_<typename>_case and split_<typename>_case_asm
  3063     have been renamed to <typename>.split and <typename>.split_asm.
  3064   - Since default sorts of type variables are now handled correctly,
  3065     some datatype definitions may have to be annotated with explicit
  3066     sort constraints.
  3067   - Primrec definitions no longer require function name and type
  3068     of recursive argument.
  3069 
  3070 Consider using isatool fixdatatype to adapt your theories and proof
  3071 scripts to the new package (backup your sources first!).
  3072 
  3073 
  3074 * HOL/record package: considerably improved implementation; now
  3075 includes concrete syntax for record types, terms, updates; theorems
  3076 for surjective pairing and splitting !!-bound record variables; proof
  3077 support is as follows:
  3078 
  3079   1) standard conversions (selectors or updates applied to record
  3080 constructor terms) are part of the standard simpset;
  3081 
  3082   2) inject equations of the form ((x, y) = (x', y')) == x=x' & y=y' are
  3083 made part of standard simpset and claset via addIffs;
  3084 
  3085   3) a tactic for record field splitting (record_split_tac) is part of
  3086 the standard claset (addSWrapper);
  3087 
  3088 To get a better idea about these rules you may retrieve them via
  3089 something like 'thms "foo.simps"' or 'thms "foo.iffs"', where "foo" is
  3090 the name of your record type.
  3091 
  3092 The split tactic 3) conceptually simplifies by the following rule:
  3093 
  3094   "(!!x. PROP ?P x) == (!!a b. PROP ?P (a, b))"
  3095 
  3096 Thus any record variable that is bound by meta-all will automatically
  3097 blow up into some record constructor term, consequently the
  3098 simplifications of 1), 2) apply.  Thus force_tac, auto_tac etc. shall
  3099 solve record problems automatically.
  3100 
  3101 
  3102 * reorganized the main HOL image: HOL/Integ and String loaded by
  3103 default; theory Main includes everything;
  3104 
  3105 * automatic simplification of integer sums and comparisons, using cancellation;
  3106 
  3107 * added option_map_eq_Some and not_Some_eq to the default simpset and claset;
  3108 
  3109 * added disj_not1 = "(~P | Q) = (P --> Q)" to the default simpset;
  3110 
  3111 * many new identities for unions, intersections, set difference, etc.;
  3112 
  3113 * expand_if, expand_split, expand_sum_case and expand_nat_case are now
  3114 called split_if, split_split, split_sum_case and split_nat_case (to go
  3115 with add/delsplits);
  3116 
  3117 * HOL/Prod introduces simplification procedure unit_eq_proc rewriting
  3118 (?x::unit) = (); this is made part of the default simpset, which COULD
  3119 MAKE EXISTING PROOFS FAIL under rare circumstances (consider
  3120 'Delsimprocs [unit_eq_proc];' as last resort); also note that
  3121 unit_abs_eta_conv is added in order to counter the effect of
  3122 unit_eq_proc on (%u::unit. f u), replacing it by f rather than by
  3123 %u.f();
  3124 
  3125 * HOL/Fun INCOMPATIBILITY: `inj_onto' is now called `inj_on' (which
  3126 makes more sense);
  3127 
  3128 * HOL/Set INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
  3129   It and 'sym RS equals0D' are now in the default  claset, giving automatic
  3130   disjointness reasoning but breaking a few old proofs.
  3131 
  3132 * HOL/Relation INCOMPATIBILITY: renamed the relational operator r^-1
  3133 to 'converse' from 'inverse' (for compatibility with ZF and some
  3134 literature);
  3135 
  3136 * HOL/recdef can now declare non-recursive functions, with {} supplied as
  3137 the well-founded relation;
  3138 
  3139 * HOL/Set INCOMPATIBILITY: the complement of set A is now written -A instead of
  3140     Compl A.  The "Compl" syntax remains available as input syntax for this
  3141     release ONLY.
  3142 
  3143 * HOL/Update: new theory of function updates:
  3144     f(a:=b) == %x. if x=a then b else f x
  3145 may also be iterated as in f(a:=b,c:=d,...);
  3146 
  3147 * HOL/Vimage: new theory for inverse image of a function, syntax f-``B;
  3148 
  3149 * HOL/List:
  3150   - new function list_update written xs[i:=v] that updates the i-th
  3151     list position. May also be iterated as in xs[i:=a,j:=b,...].
  3152   - new function `upt' written [i..j(] which generates the list
  3153     [i,i+1,...,j-1], i.e. the upper bound is excluded. To include the upper
  3154     bound write [i..j], which is a shorthand for [i..j+1(].
  3155   - new lexicographic orderings and corresponding wellfoundedness theorems.
  3156 
  3157 * HOL/Arith:
  3158   - removed 'pred' (predecessor) function;
  3159   - generalized some theorems about n-1;
  3160   - many new laws about "div" and "mod";
  3161   - new laws about greatest common divisors (see theory ex/Primes);
  3162 
  3163 * HOL/Relation: renamed the relational operator r^-1 "converse"
  3164 instead of "inverse";
  3165 
  3166 * HOL/Induct/Multiset: a theory of multisets, including the wellfoundedness
  3167   of the multiset ordering;
  3168 
  3169 * directory HOL/Real: a construction of the reals using Dedekind cuts
  3170   (not included by default);
  3171 
  3172 * directory HOL/UNITY: Chandy and Misra's UNITY formalism;
  3173 
  3174 * directory HOL/Hoare: a new version of Hoare logic which permits many-sorted
  3175   programs, i.e. different program variables may have different types.
  3176 
  3177 * calling (stac rew i) now fails if "rew" has no effect on the goal
  3178   [previously, this check worked only if the rewrite rule was unconditional]
  3179   Now rew can involve either definitions or equalities (either == or =).
  3180 
  3181 
  3182 *** ZF ***
  3183 
  3184 * theory Main includes everything; INCOMPATIBILITY: theory ZF.thy contains
  3185   only the theorems proved on ZF.ML;
  3186 
  3187 * ZF INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
  3188   It and 'sym RS equals0D' are now in the default  claset, giving automatic
  3189   disjointness reasoning but breaking a few old proofs.
  3190 
  3191 * ZF/Update: new theory of function updates
  3192     with default rewrite rule  f(x:=y) ` z = if(z=x, y, f`z)
  3193   may also be iterated as in f(a:=b,c:=d,...);
  3194 
  3195 * in  let x=t in u(x), neither t nor u(x) has to be an FOL term.
  3196 
  3197 * calling (stac rew i) now fails if "rew" has no effect on the goal
  3198   [previously, this check worked only if the rewrite rule was unconditional]
  3199   Now rew can involve either definitions or equalities (either == or =).
  3200 
  3201 * case_tac provided for compatibility with HOL
  3202     (like the old excluded_middle_tac, but with subgoals swapped)
  3203 
  3204 
  3205 *** Internal programming interfaces ***
  3206 
  3207 * Pure: several new basic modules made available for general use, see
  3208 also src/Pure/README;
  3209 
  3210 * improved the theory data mechanism to support encapsulation (data
  3211 kind name replaced by private Object.kind, acting as authorization
  3212 key); new type-safe user interface via functor TheoryDataFun; generic
  3213 print_data function becomes basically useless;
  3214 
  3215 * removed global_names compatibility flag -- all theory declarations
  3216 are qualified by default;
  3217 
  3218 * module Pure/Syntax now offers quote / antiquote translation
  3219 functions (useful for Hoare logic etc. with implicit dependencies);
  3220 see HOL/ex/Antiquote for an example use;
  3221 
  3222 * Simplifier now offers conversions (asm_)(full_)rewrite: simpset ->
  3223 cterm -> thm;
  3224 
  3225 * new tactical CHANGED_GOAL for checking that a tactic modifies a
  3226 subgoal;
  3227 
  3228 * Display.print_goals function moved to Locale.print_goals;
  3229 
  3230 * standard print function for goals supports current_goals_markers
  3231 variable for marking begin of proof, end of proof, start of goal; the
  3232 default is ("", "", ""); setting current_goals_markers := ("<proof>",
  3233 "</proof>", "<goal>") causes SGML like tagged proof state printing,
  3234 for example;
  3235 
  3236 
  3237 
  3238 New in Isabelle98 (January 1998)
  3239 --------------------------------
  3240 
  3241 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  3242 
  3243 * changed lexical syntax of terms / types: dots made part of long
  3244 identifiers, e.g. "%x.x" no longer possible, should be "%x. x";
  3245 
  3246 * simpset (and claset) reference variable replaced by functions
  3247 simpset / simpset_ref;
  3248 
  3249 * no longer supports theory aliases (via merge) and non-trivial
  3250 implicit merge of thms' signatures;
  3251 
  3252 * most internal names of constants changed due to qualified names;
  3253 
  3254 * changed Pure/Sequence interface (see Pure/seq.ML);
  3255 
  3256 
  3257 *** General Changes ***
  3258 
  3259 * hierachically structured name spaces (for consts, types, axms, thms
  3260 etc.); new lexical class 'longid' (e.g. Foo.bar.x) may render much of
  3261 old input syntactically incorrect (e.g. "%x.x"); COMPATIBILITY:
  3262 isatool fixdots ensures space after dots (e.g. "%x. x"); set
  3263 long_names for fully qualified output names; NOTE: ML programs
  3264 (special tactics, packages etc.) referring to internal names may have
  3265 to be adapted to cope with fully qualified names; in case of severe
  3266 backward campatibility problems try setting 'global_names' at compile
  3267 time to have enrything declared within a flat name space; one may also
  3268 fine tune name declarations in theories via the 'global' and 'local'
  3269 section;
  3270 
  3271 * reimplemented the implicit simpset and claset using the new anytype
  3272 data filed in signatures; references simpset:simpset ref etc. are
  3273 replaced by functions simpset:unit->simpset and
  3274 simpset_ref:unit->simpset ref; COMPATIBILITY: use isatool fixclasimp
  3275 to patch your ML files accordingly;
  3276 
  3277 * HTML output now includes theory graph data for display with Java
  3278 applet or isatool browser; data generated automatically via isatool
  3279 usedir (see -i option, ISABELLE_USEDIR_OPTIONS);
  3280 
  3281 * defs may now be conditional; improved rewrite_goals_tac to handle
  3282 conditional equations;
  3283 
  3284 * defs now admits additional type arguments, using TYPE('a) syntax;
  3285 
  3286 * theory aliases via merge (e.g. M=A+B+C) no longer supported, always
  3287 creates a new theory node; implicit merge of thms' signatures is
  3288 restricted to 'trivial' ones; COMPATIBILITY: one may have to use
  3289 transfer:theory->thm->thm in (rare) cases;
  3290 
  3291 * improved handling of draft signatures / theories; draft thms (and
  3292 ctyps, cterms) are automatically promoted to real ones;
  3293 
  3294 * slightly changed interfaces for oracles: admit many per theory, named
  3295 (e.g. oracle foo = mlfun), additional name argument for invoke_oracle;
  3296 
  3297 * print_goals: optional output of const types (set show_consts and
  3298 show_types);
  3299 
  3300 * improved output of warnings (###) and errors (***);
  3301 
  3302 * subgoal_tac displays a warning if the new subgoal has type variables;
  3303 
  3304 * removed old README and Makefiles;
  3305 
  3306 * replaced print_goals_ref hook by print_current_goals_fn and result_error_fn;
  3307 
  3308 * removed obsolete init_pps and init_database;
  3309 
  3310 * deleted the obsolete tactical STATE, which was declared by
  3311     fun STATE tacfun st = tacfun st st;
  3312 
  3313 * cd and use now support path variables, e.g. $ISABELLE_HOME, or ~
  3314 (which abbreviates $HOME);
  3315 
  3316 * changed Pure/Sequence interface (see Pure/seq.ML); COMPATIBILITY:
  3317 use isatool fixseq to adapt your ML programs (this works for fully
  3318 qualified references to the Sequence structure only!);
  3319 
  3320 * use_thy no longer requires writable current directory; it always
  3321 reloads .ML *and* .thy file, if either one is out of date;
  3322 
  3323 
  3324 *** Classical Reasoner ***
  3325 
  3326 * Clarify_tac, clarify_tac, clarify_step_tac, Clarify_step_tac: new
  3327 tactics that use classical reasoning to simplify a subgoal without
  3328 splitting it into several subgoals;
  3329 
  3330 * Safe_tac: like safe_tac but uses the default claset;
  3331 
  3332 
  3333 *** Simplifier ***
  3334 
  3335 * added simplification meta rules:
  3336     (asm_)(full_)simplify: simpset -> thm -> thm;
  3337 
  3338 * simplifier.ML no longer part of Pure -- has to be loaded by object
  3339 logics (again);
  3340 
  3341 * added prems argument to simplification procedures;
  3342 
  3343 * HOL, FOL, ZF: added infix function `addsplits':
  3344   instead of `<simpset> setloop (split_tac <thms>)'
  3345   you can simply write `<simpset> addsplits <thms>'
  3346 
  3347 
  3348 *** Syntax ***
  3349 
  3350 * TYPE('a) syntax for type reflection terms;
  3351 
  3352 * no longer handles consts with name "" -- declare as 'syntax' instead;
  3353 
  3354 * pretty printer: changed order of mixfix annotation preference (again!);
  3355 
  3356 * Pure: fixed idt/idts vs. pttrn/pttrns syntactic categories;
  3357 
  3358 
  3359 *** HOL ***
  3360 
  3361 * HOL: there is a new splitter `split_asm_tac' that can be used e.g.
  3362   with `addloop' of the simplifier to faciliate case splitting in premises.
  3363 
  3364 * HOL/TLA: Stephan Merz's formalization of Lamport's Temporal Logic of Actions;
  3365 
  3366 * HOL/Auth: new protocol proofs including some for the Internet
  3367   protocol TLS;
  3368 
  3369 * HOL/Map: new theory of `maps' a la VDM;
  3370 
  3371 * HOL/simplifier: simplification procedures nat_cancel_sums for
  3372 cancelling out common nat summands from =, <, <= (in)equalities, or
  3373 differences; simplification procedures nat_cancel_factor for
  3374 cancelling common factor from =, <, <= (in)equalities over natural
  3375 sums; nat_cancel contains both kinds of procedures, it is installed by
  3376 default in Arith.thy -- this COULD MAKE EXISTING PROOFS FAIL;
  3377 
  3378 * HOL/simplifier: terms of the form
  3379   `? x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x)'  (or t=x)
  3380   are rewritten to
  3381   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t)',
  3382   and those of the form
  3383   `! x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x) --> R(x)'  (or t=x)
  3384   are rewritten to
  3385   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t) --> R(t)',
  3386 
  3387 * HOL/datatype
  3388   Each datatype `t' now comes with a theorem `split_t_case' of the form
  3389 
  3390   P(t_case f1 ... fn x) =
  3391      ( (!y1 ... ym1. x = C1 y1 ... ym1 --> P(f1 y1 ... ym1)) &
  3392         ...
  3393        (!y1 ... ymn. x = Cn y1 ... ymn --> P(f1 y1 ... ymn))
  3394      )
  3395 
  3396   and a theorem `split_t_case_asm' of the form
  3397 
  3398   P(t_case f1 ... fn x) =
  3399     ~( (? y1 ... ym1. x = C1 y1 ... ym1 & ~P(f1 y1 ... ym1)) |
  3400         ...
  3401        (? y1 ... ymn. x = Cn y1 ... ymn & ~P(f1 y1 ... ymn))
  3402      )
  3403   which can be added to a simpset via `addsplits'. The existing theorems
  3404   expand_list_case and expand_option_case have been renamed to
  3405   split_list_case and split_option_case.
  3406 
  3407 * HOL/Arithmetic:
  3408   - `pred n' is automatically converted to `n-1'.
  3409     Users are strongly encouraged not to use `pred' any longer,
  3410     because it will disappear altogether at some point.
  3411   - Users are strongly encouraged to write "0 < n" rather than
  3412     "n ~= 0". Theorems and proof tools have been modified towards this
  3413     `standard'.
  3414 
  3415 * HOL/Lists:
  3416   the function "set_of_list" has been renamed "set" (and its theorems too);
  3417   the function "nth" now takes its arguments in the reverse order and
  3418   has acquired the infix notation "!" as in "xs!n".
  3419 
  3420 * HOL/Set: UNIV is now a constant and is no longer translated to Compl{};
  3421 
  3422 * HOL/Set: The operator (UN x.B x) now abbreviates (UN x:UNIV. B x) and its
  3423   specialist theorems (like UN1_I) are gone.  Similarly for (INT x.B x);
  3424 
  3425 * HOL/record: extensible records with schematic structural subtyping
  3426 (single inheritance); EXPERIMENTAL version demonstrating the encoding,
  3427 still lacks various theorems and concrete record syntax;
  3428 
  3429 
  3430 *** HOLCF ***
  3431 
  3432 * removed "axioms" and "generated by" sections;
  3433 
  3434 * replaced "ops" section by extended "consts" section, which is capable of
  3435   handling the continuous function space "->" directly;
  3436 
  3437 * domain package:
  3438   . proves theorems immediately and stores them in the theory,
  3439   . creates hierachical name space,
  3440   . now uses normal mixfix annotations (instead of cinfix...),
  3441   . minor changes to some names and values (for consistency),
  3442   . e.g. cases -> casedist, dists_eq -> dist_eqs, [take_lemma] -> take_lemmas,
  3443   . separator between mutual domain defs: changed "," to "and",
  3444   . improved handling of sort constraints;  now they have to
  3445     appear on the left-hand side of the equations only;
  3446 
  3447 * fixed LAM <x,y,zs>.b syntax;
  3448 
  3449 * added extended adm_tac to simplifier in HOLCF -- can now discharge
  3450 adm (%x. P (t x)), where P is chainfinite and t continuous;
  3451 
  3452 
  3453 *** FOL and ZF ***
  3454 
  3455 * FOL: there is a new splitter `split_asm_tac' that can be used e.g.
  3456   with `addloop' of the simplifier to faciliate case splitting in premises.
  3457 
  3458 * qed_spec_mp, qed_goal_spec_mp, qed_goalw_spec_mp are available, as
  3459 in HOL, they strip ALL and --> from proved theorems;
  3460 
  3461 
  3462 
  3463 New in Isabelle94-8 (May 1997)
  3464 ------------------------------
  3465 
  3466 *** General Changes ***
  3467 
  3468 * new utilities to build / run / maintain Isabelle etc. (in parts
  3469 still somewhat experimental); old Makefiles etc. still functional;
  3470 
  3471 * new 'Isabelle System Manual';
  3472 
  3473 * INSTALL text, together with ./configure and ./build scripts;
  3474 
  3475 * reimplemented type inference for greater efficiency, better error
  3476 messages and clean internal interface;
  3477 
  3478 * prlim command for dealing with lots of subgoals (an easier way of
  3479 setting goals_limit);
  3480 
  3481 
  3482 *** Syntax ***
  3483 
  3484 * supports alternative (named) syntax tables (parser and pretty
  3485 printer); internal interface is provided by add_modesyntax(_i);
  3486 
  3487 * Pure, FOL, ZF, HOL, HOLCF now support symbolic input and output; to
  3488 be used in conjunction with the Isabelle symbol font; uses the
  3489 "symbols" syntax table;
  3490 
  3491 * added token_translation interface (may translate name tokens in
  3492 arbitrary ways, dependent on their type (free, bound, tfree, ...) and
  3493 the current print_mode); IMPORTANT: user print translation functions
  3494 are responsible for marking newly introduced bounds
  3495 (Syntax.mark_boundT);
  3496 
  3497 * token translations for modes "xterm" and "xterm_color" that display
  3498 names in bold, underline etc. or colors (which requires a color
  3499 version of xterm);
  3500 
  3501 * infixes may now be declared with names independent of their syntax;
  3502 
  3503 * added typed_print_translation (like print_translation, but may
  3504 access type of constant);
  3505 
  3506 
  3507 *** Classical Reasoner ***
  3508 
  3509 Blast_tac: a new tactic!  It is often more powerful than fast_tac, but has
  3510 some limitations.  Blast_tac...
  3511   + ignores addss, addbefore, addafter; this restriction is intrinsic
  3512   + ignores elimination rules that don't have the correct format
  3513         (the conclusion MUST be a formula variable)
  3514   + ignores types, which can make HOL proofs fail
  3515   + rules must not require higher-order unification, e.g. apply_type in ZF
  3516     [message "Function Var's argument not a bound variable" relates to this]
  3517   + its proof strategy is more general but can actually be slower
  3518 
  3519 * substitution with equality assumptions no longer permutes other
  3520 assumptions;
  3521 
  3522 * minor changes in semantics of addafter (now called addaltern); renamed
  3523 setwrapper to setWrapper and compwrapper to compWrapper; added safe wrapper
  3524 (and access functions for it);
  3525 
  3526 * improved combination of classical reasoner and simplifier:
  3527   + functions for handling clasimpsets
  3528   + improvement of addss: now the simplifier is called _after_ the
  3529     safe steps.
  3530   + safe variant of addss called addSss: uses safe simplifications
  3531     _during_ the safe steps. It is more complete as it allows multiple
  3532     instantiations of unknowns (e.g. with slow_tac).
  3533 
  3534 *** Simplifier ***
  3535 
  3536 * added interface for simplification procedures (functions that
  3537 produce *proven* rewrite rules on the fly, depending on current
  3538 redex);
  3539 
  3540 * ordering on terms as parameter (used for ordered rewriting);
  3541 
  3542 * new functions delcongs, deleqcongs, and Delcongs. richer rep_ss;
  3543 
  3544 * the solver is now split into a safe and an unsafe part.
  3545 This should be invisible for the normal user, except that the
  3546 functions setsolver and addsolver have been renamed to setSolver and
  3547 addSolver; added safe_asm_full_simp_tac;
  3548 
  3549 
  3550 *** HOL ***
  3551 
  3552 * a generic induction tactic `induct_tac' which works for all datatypes and
  3553 also for type `nat';
  3554 
  3555 * a generic case distinction tactic `exhaust_tac' which works for all
  3556 datatypes and also for type `nat';
  3557 
  3558 * each datatype comes with a function `size';
  3559 
  3560 * patterns in case expressions allow tuple patterns as arguments to
  3561 constructors, for example `case x of [] => ... | (x,y,z)#ps => ...';
  3562 
  3563 * primrec now also works with type nat;
  3564 
  3565 * recdef: a new declaration form, allows general recursive functions to be
  3566 defined in theory files.  See HOL/ex/Fib, HOL/ex/Primes, HOL/Subst/Unify.
  3567 
  3568 * the constant for negation has been renamed from "not" to "Not" to
  3569 harmonize with FOL, ZF, LK, etc.;
  3570 
  3571 * HOL/ex/LFilter theory of a corecursive "filter" functional for
  3572 infinite lists;
  3573 
  3574 * HOL/Modelcheck demonstrates invocation of model checker oracle;
  3575 
  3576 * HOL/ex/Ring.thy declares cring_simp, which solves equational
  3577 problems in commutative rings, using axiomatic type classes for + and *;
  3578 
  3579 * more examples in HOL/MiniML and HOL/Auth;
  3580 
  3581 * more default rewrite rules for quantifiers, union/intersection;
  3582 
  3583 * a new constant `arbitrary == @x.False';
  3584 
  3585 * HOLCF/IOA replaces old HOL/IOA;
  3586 
  3587 * HOLCF changes: derived all rules and arities
  3588   + axiomatic type classes instead of classes
  3589   + typedef instead of faking type definitions
  3590   + eliminated the internal constants less_fun, less_cfun, UU_fun, UU_cfun etc.
  3591   + new axclasses cpo, chfin, flat with flat < chfin < pcpo < cpo < po
  3592   + eliminated the types void, one, tr
  3593   + use unit lift and bool lift (with translations) instead of one and tr
  3594   + eliminated blift from Lift3.thy (use Def instead of blift)
  3595   all eliminated rules are derived as theorems --> no visible changes ;
  3596 
  3597 
  3598 *** ZF ***
  3599 
  3600 * ZF now has Fast_tac, Simp_tac and Auto_tac.  Union_iff is a now a default
  3601 rewrite rule; this may affect some proofs.  eq_cs is gone but can be put back
  3602 as ZF_cs addSIs [equalityI];
  3603 
  3604 
  3605 
  3606 New in Isabelle94-7 (November 96)
  3607 ---------------------------------
  3608 
  3609 * allowing negative levels (as offsets) in prlev and choplev;
  3610 
  3611 * super-linear speedup for large simplifications;
  3612 
  3613 * FOL, ZF and HOL now use miniscoping: rewriting pushes
  3614 quantifications in as far as possible (COULD MAKE EXISTING PROOFS
  3615 FAIL); can suppress it using the command Delsimps (ex_simps @
  3616 all_simps); De Morgan laws are also now included, by default;
  3617 
  3618 * improved printing of ==>  :  ~:
  3619 
  3620 * new object-logic "Sequents" adds linear logic, while replacing LK
  3621 and Modal (thanks to Sara Kalvala);
  3622 
  3623 * HOL/Auth: correctness proofs for authentication protocols;
  3624 
  3625 * HOL: new auto_tac combines rewriting and classical reasoning (many
  3626 examples on HOL/Auth);
  3627 
  3628 * HOL: new command AddIffs for declaring theorems of the form P=Q to
  3629 the rewriter and classical reasoner simultaneously;
  3630 
  3631 * function uresult no longer returns theorems in "standard" format;
  3632 regain previous version by: val uresult = standard o uresult;
  3633 
  3634 
  3635 
  3636 New in Isabelle94-6
  3637 -------------------
  3638 
  3639 * oracles -- these establish an interface between Isabelle and trusted
  3640 external reasoners, which may deliver results as theorems;
  3641 
  3642 * proof objects (in particular record all uses of oracles);
  3643 
  3644 * Simp_tac, Fast_tac, etc. that refer to implicit simpset / claset;
  3645 
  3646 * "constdefs" section in theory files;
  3647 
  3648 * "primrec" section (HOL) no longer requires names;
  3649 
  3650 * internal type "tactic" now simply "thm -> thm Sequence.seq";
  3651 
  3652 
  3653 
  3654 New in Isabelle94-5
  3655 -------------------
  3656 
  3657 * reduced space requirements;
  3658 
  3659 * automatic HTML generation from theories;
  3660 
  3661 * theory files no longer require "..." (quotes) around most types;
  3662 
  3663 * new examples, including two proofs of the Church-Rosser theorem;
  3664 
  3665 * non-curried (1994) version of HOL is no longer distributed;
  3666 
  3667 
  3668 
  3669 New in Isabelle94-4
  3670 -------------------
  3671 
  3672 * greatly reduced space requirements;
  3673 
  3674 * theory files (.thy) no longer require \...\ escapes at line breaks;
  3675 
  3676 * searchable theorem database (see the section "Retrieving theorems" on
  3677 page 8 of the Reference Manual);
  3678 
  3679 * new examples, including Grabczewski's monumental case study of the
  3680 Axiom of Choice;
  3681 
  3682 * The previous version of HOL renamed to Old_HOL;
  3683 
  3684 * The new version of HOL (previously called CHOL) uses a curried syntax
  3685 for functions.  Application looks like f a b instead of f(a,b);
  3686 
  3687 * Mutually recursive inductive definitions finally work in HOL;
  3688 
  3689 * In ZF, pattern-matching on tuples is now available in all abstractions and
  3690 translates to the operator "split";
  3691 
  3692 
  3693 
  3694 New in Isabelle94-3
  3695 -------------------
  3696 
  3697 * new infix operator, addss, allowing the classical reasoner to
  3698 perform simplification at each step of its search.  Example:
  3699         fast_tac (cs addss ss)
  3700 
  3701 * a new logic, CHOL, the same as HOL, but with a curried syntax
  3702 for functions.  Application looks like f a b instead of f(a,b).  Also pairs
  3703 look like (a,b) instead of <a,b>;
  3704 
  3705 * PLEASE NOTE: CHOL will eventually replace HOL!
  3706 
  3707 * In CHOL, pattern-matching on tuples is now available in all abstractions.
  3708 It translates to the operator "split".  A new theory of integers is available;
  3709 
  3710 * In ZF, integer numerals now denote two's-complement binary integers.
  3711 Arithmetic operations can be performed by rewriting.  See ZF/ex/Bin.ML;
  3712 
  3713 * Many new examples: I/O automata, Church-Rosser theorem, equivalents
  3714 of the Axiom of Choice;
  3715 
  3716 
  3717 
  3718 New in Isabelle94-2
  3719 -------------------
  3720 
  3721 * Significantly faster resolution;
  3722 
  3723 * the different sections in a .thy file can now be mixed and repeated
  3724 freely;
  3725 
  3726 * Database of theorems for FOL, HOL and ZF.  New
  3727 commands including qed, qed_goal and bind_thm store theorems in the database.
  3728 
  3729 * Simple database queries: return a named theorem (get_thm) or all theorems of
  3730 a given theory (thms_of), or find out what theory a theorem was proved in
  3731 (theory_of_thm);
  3732 
  3733 * Bugs fixed in the inductive definition and datatype packages;
  3734 
  3735 * The classical reasoner provides deepen_tac and depth_tac, making FOL_dup_cs
  3736 and HOL_dup_cs obsolete;
  3737 
  3738 * Syntactic ambiguities caused by the new treatment of syntax in Isabelle94-1
  3739 have been removed;
  3740 
  3741 * Simpler definition of function space in ZF;
  3742 
  3743 * new results about cardinal and ordinal arithmetic in ZF;
  3744 
  3745 * 'subtype' facility in HOL for introducing new types as subsets of existing
  3746 types;
  3747 
  3748 
  3749 $Id$