NEWS
author haftmann
Fri Dec 16 09:00:11 2005 +0100 (2005-12-16)
changeset 18418 bf448d999b7e
parent 18399 651438736fa1
child 18422 875451c9d253
permissions -rw-r--r--
re-arranged tuples (theory * 'a) to ('a * theory) in Pure
     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 * Isar: 'def' now admits simultaneous definitions, e.g.:
    65 
    66   def x == "t" and y == "u"
    67 
    68 * Provers/induct: improved internal context management to support
    69 local fixes and defines on-the-fly.  Thus explicit meta-level
    70 connectives !! and ==> are rarely required anymore in inductive goals
    71 (using object-logic connectives for this purpose has been long
    72 obsolete anyway).  The subsequent proof patterns illustrate advanced
    73 techniques of natural induction; general datatypes and inductive sets
    74 work analogously (see also src/HOL/Lambda for realistic examples).
    75 
    76 (1) This is how to ``strengthen'' an inductive goal wrt. certain
    77 parameters:
    78 
    79   lemma
    80     fixes n :: nat and x :: 'a
    81     assumes a: "A n x"
    82     shows "P n x"
    83     using a                     -- {* make induct insert fact a *}
    84   proof (induct n fixing: x)    -- {* generalize goal to "!!x. A n x ==> P n x" *}
    85     case 0
    86     show ?case sorry
    87   next
    88     case (Suc n)
    89     note `!!x. A n x ==> P n x` -- {* induction hypothesis, according to induction rule *}
    90     note `A (Suc n) x`          -- {* induction premise, stemming from fact a *}
    91     show ?case sorry
    92   qed
    93 
    94 (2) This is how to perform induction over ``expressions of a certain
    95 form'', using a locally defined inductive parameter n == "a x"
    96 together with strengthening (the latter is usually required to get
    97 sufficiently flexible induction hypotheses):
    98 
    99   lemma
   100     fixes a :: "'a => nat"
   101     assumes a: "A (a x)"
   102     shows "P (a x)"
   103     using a
   104   proof (induct n == "a x" fixing: x)
   105     ...
   106 
   107 See also HOL/Isar_examples/Puzzle.thy for an application of the this
   108 particular technique.
   109 
   110 (3) This is how to perform existential reasoning ('obtain') by
   111 induction, while avoiding explicit object-logic encodings:
   112 
   113   fix n :: nat
   114   obtain x :: 'a where "P n x" and "Q n x"
   115   proof (induct n fixing: thesis)
   116     case 0
   117     obtain x where "P 0 x" and "Q 0 x" sorry
   118     then show thesis by (rule 0)
   119   next
   120     case (Suc n)
   121     obtain x where "P n x" and "Q n x" by (rule Suc.hyps)
   122     obtain x where "P (Suc n) x" and "Q (Suc n) x" sorry
   123     then show thesis by (rule Suc.prems)
   124   qed
   125 
   126 Here the 'fixing: thesis' specification essentially modifies the scope
   127 of the formal thesis parameter, in order to the get the whole
   128 existence statement through the induction as expected.
   129 
   130 * Provers/induct: support coinduction as well.  See
   131 src/HOL/Library/Coinductive_List.thy for various examples.
   132 
   133 * Input syntax now supports dummy variable binding "%_. b", where the
   134 body does not mention the bound variable.  Note that dummy patterns
   135 implicitly depend on their context of bounds, which makes "{_. _}"
   136 match any set comprehension as expected.  Potential INCOMPATIBILITY --
   137 parse translations need to cope with syntactic constant "_idtdummy" in
   138 the binding position.
   139 
   140 * Removed obsolete syntactic constant "_K" and its associated parse
   141 translation.  INCOMPATIBILITY -- use dummy abstraction instead, for
   142 example "A -> B" => "Pi A (%_. B)".
   143 
   144 
   145 *** HOL ***
   146 
   147 * Alternative iff syntax "A <-> B" for equality on bool (with priority
   148 25 like -->); output depends on the "iff" print_mode, the default is
   149 "A = B" (with priority 50).
   150 
   151 * In the context of the assumption "~(s = t)" the Simplifier rewrites
   152 "t = s" to False (by simproc "neq_simproc").  For backward
   153 compatibility this can be disabled by ML "reset use_neq_simproc".
   154 
   155 * Tactics 'sat' and 'satx' reimplemented, several improvements: goals
   156 no longer need to be stated as "<prems> ==> False", equivalences (i.e.
   157 "=" on type bool) are handled, variable names of the form "lit_<n>"
   158 are no longer reserved, significant speedup.
   159 
   160 * Library: added theory Coinductive_List of potentially infinite lists as
   161 greatest fixed-point.
   162 
   163 
   164 *** ML ***
   165 
   166 * Library: new module Pure/General/rat.ML implementing rational numbers,
   167 replacing the former functions in the Isabelle library.
   168 
   169 * Library: indexed lists - some functions in the Isabelle library
   170 treating lists over 'a as finite mappings from [0...n] to 'a
   171 have been given more convenient names and signatures reminiscent
   172 of similar functions for alists, tables, etc:
   173 
   174   val nth: 'a list -> int -> 'a 
   175   val nth_update: int * 'a -> 'a list -> 'a list
   176   val nth_map: int -> ('a -> 'a) -> 'a list -> 'a list
   177   val fold_index: (int * 'a -> 'b -> 'b) -> 'a list -> 'b -> 'b
   178 
   179 Note that fold_index starts counting at index 0, not 1 like foldln used to.
   180 
   181 * Pure: primitive rule lift_rule now takes goal cterm instead of an
   182 actual goal state (thm).  Use Thm.lift_rule (Thm.cprem_of st i) to
   183 achieve the old behaviour.
   184 
   185 * Pure: the "Goal" constant is now called "prop", supporting a
   186 slightly more general idea of ``protecting'' meta-level rule
   187 statements.
   188 
   189 * Internal goals: structure Goal provides simple interfaces for
   190 init/conclude/finish and tactical prove operations (replacing former
   191 Tactic.prove).  Note that OldGoals.prove_goalw_cterm has long been
   192 obsolete, it is ill-behaved in a local proof context (e.g. with local
   193 fixes/assumes or in a locale context).
   194 
   195 * Simplifier: the simpset of a running simplification process now
   196 contains a proof context (cf. Simplifier.the_context), which is the
   197 very context that the initial simpset has been retrieved from (by
   198 simpset_of/local_simpset_of).  Consequently, all plug-in components
   199 (solver, looper etc.) may depend on arbitrary proof data.
   200 
   201 * Simplifier.inherit_context inherits the proof context (plus the
   202 local bounds) of the current simplification process; any simproc
   203 etc. that calls the Simplifier recursively should do this!  Removed
   204 former Simplifier.inherit_bounds, which is already included here --
   205 INCOMPATIBILITY.  Tools based on low-level rewriting may even have to
   206 specify an explicit context using Simplifier.context/theory_context.
   207 
   208 * Simplifier/Classical Reasoner: more abstract interfaces
   209 change_simpset/claset for modifying the simpset/claset reference of a
   210 theory; raw versions simpset/claset_ref etc. have been discontinued --
   211 INCOMPATIBILITY.
   212 
   213 
   214 
   215 New in Isabelle2005 (October 2005)
   216 ----------------------------------
   217 
   218 *** General ***
   219 
   220 * Theory headers: the new header syntax for Isar theories is
   221 
   222   theory <name>
   223   imports <theory1> ... <theoryN>
   224   uses <file1> ... <fileM>
   225   begin
   226 
   227 where the 'uses' part is optional.  The previous syntax
   228 
   229   theory <name> = <theory1> + ... + <theoryN>:
   230 
   231 will disappear in the next release.  Use isatool fixheaders to convert
   232 existing theory files.  Note that there is no change in ancient
   233 non-Isar theories now, but these will disappear soon.
   234 
   235 * Theory loader: parent theories can now also be referred to via
   236 relative and absolute paths.
   237 
   238 * Command 'find_theorems' searches for a list of criteria instead of a
   239 list of constants. Known criteria are: intro, elim, dest, name:string,
   240 simp:term, and any term. Criteria can be preceded by '-' to select
   241 theorems that do not match. Intro, elim, dest select theorems that
   242 match the current goal, name:s selects theorems whose fully qualified
   243 name contain s, and simp:term selects all simplification rules whose
   244 lhs match term.  Any other term is interpreted as pattern and selects
   245 all theorems matching the pattern. Available in ProofGeneral under
   246 'ProofGeneral -> Find Theorems' or C-c C-f.  Example:
   247 
   248   C-c C-f (100) "(_::nat) + _ + _" intro -name: "HOL."
   249 
   250 prints the last 100 theorems matching the pattern "(_::nat) + _ + _",
   251 matching the current goal as introduction rule and not having "HOL."
   252 in their name (i.e. not being defined in theory HOL).
   253 
   254 * Command 'thms_containing' has been discontinued in favour of
   255 'find_theorems'; INCOMPATIBILITY.
   256 
   257 * Communication with Proof General is now 8bit clean, which means that
   258 Unicode text in UTF-8 encoding may be used within theory texts (both
   259 formal and informal parts).  Cf. option -U of the Isabelle Proof
   260 General interface.  Here are some simple examples (cf. src/HOL/ex):
   261 
   262   http://isabelle.in.tum.de/library/HOL/ex/Hebrew.html
   263   http://isabelle.in.tum.de/library/HOL/ex/Chinese.html
   264 
   265 * Improved efficiency of the Simplifier and, to a lesser degree, the
   266 Classical Reasoner.  Typical big applications run around 2 times
   267 faster.
   268 
   269 
   270 *** Document preparation ***
   271 
   272 * Commands 'display_drafts' and 'print_drafts' perform simple output
   273 of raw sources.  Only those symbols that do not require additional
   274 LaTeX packages (depending on comments in isabellesym.sty) are
   275 displayed properly, everything else is left verbatim.  isatool display
   276 and isatool print are used as front ends (these are subject to the
   277 DVI/PDF_VIEWER and PRINT_COMMAND settings, respectively).
   278 
   279 * Command tags control specific markup of certain regions of text,
   280 notably folding and hiding.  Predefined tags include "theory" (for
   281 theory begin and end), "proof" for proof commands, and "ML" for
   282 commands involving ML code; the additional tags "visible" and
   283 "invisible" are unused by default.  Users may give explicit tag
   284 specifications in the text, e.g. ''by %invisible (auto)''.  The
   285 interpretation of tags is determined by the LaTeX job during document
   286 preparation: see option -V of isatool usedir, or options -n and -t of
   287 isatool document, or even the LaTeX macros \isakeeptag, \isafoldtag,
   288 \isadroptag.
   289 
   290 Several document versions may be produced at the same time via isatool
   291 usedir (the generated index.html will link all of them).  Typical
   292 specifications include ''-V document=theory,proof,ML'' to present
   293 theory/proof/ML parts faithfully, ''-V outline=/proof,/ML'' to fold
   294 proof and ML commands, and ''-V mutilated=-theory,-proof,-ML'' to omit
   295 these parts without any formal replacement text.  The Isabelle site
   296 default settings produce ''document'' and ''outline'' versions as
   297 specified above.
   298 
   299 * Several new antiquotations:
   300 
   301   @{term_type term} prints a term with its type annotated;
   302 
   303   @{typeof term} prints the type of a term;
   304 
   305   @{const const} is the same as @{term const}, but checks that the
   306   argument is a known logical constant;
   307 
   308   @{term_style style term} and @{thm_style style thm} print a term or
   309   theorem applying a "style" to it
   310 
   311   @{ML text}
   312 
   313 Predefined styles are 'lhs' and 'rhs' printing the lhs/rhs of
   314 definitions, equations, inequations etc., 'concl' printing only the
   315 conclusion of a meta-logical statement theorem, and 'prem1' .. 'prem19'
   316 to print the specified premise.  TermStyle.add_style provides an ML
   317 interface for introducing further styles.  See also the "LaTeX Sugar"
   318 document practical applications.  The ML antiquotation prints
   319 type-checked ML expressions verbatim.
   320 
   321 * Markup commands 'chapter', 'section', 'subsection', 'subsubsection',
   322 and 'text' support optional locale specification '(in loc)', which
   323 specifies the default context for interpreting antiquotations.  For
   324 example: 'text (in lattice) {* @{thm inf_assoc}*}'.
   325 
   326 * Option 'locale=NAME' of antiquotations specifies an alternative
   327 context interpreting the subsequent argument.  For example: @{thm
   328 [locale=lattice] inf_assoc}.
   329 
   330 * Proper output of proof terms (@{prf ...} and @{full_prf ...}) within
   331 a proof context.
   332 
   333 * Proper output of antiquotations for theory commands involving a
   334 proof context (such as 'locale' or 'theorem (in loc) ...').
   335 
   336 * Delimiters of outer tokens (string etc.) now produce separate LaTeX
   337 macros (\isachardoublequoteopen, isachardoublequoteclose etc.).
   338 
   339 * isatool usedir: new option -C (default true) controls whether option
   340 -D should include a copy of the original document directory; -C false
   341 prevents unwanted effects such as copying of administrative CVS data.
   342 
   343 
   344 *** Pure ***
   345 
   346 * Considerably improved version of 'constdefs' command.  Now performs
   347 automatic type-inference of declared constants; additional support for
   348 local structure declarations (cf. locales and HOL records), see also
   349 isar-ref manual.  Potential INCOMPATIBILITY: need to observe strictly
   350 sequential dependencies of definitions within a single 'constdefs'
   351 section; moreover, the declared name needs to be an identifier.  If
   352 all fails, consider to fall back on 'consts' and 'defs' separately.
   353 
   354 * Improved indexed syntax and implicit structures.  First of all,
   355 indexed syntax provides a notational device for subscripted
   356 application, using the new syntax \<^bsub>term\<^esub> for arbitrary
   357 expressions.  Secondly, in a local context with structure
   358 declarations, number indexes \<^sub>n or the empty index (default
   359 number 1) refer to a certain fixed variable implicitly; option
   360 show_structs controls printing of implicit structures.  Typical
   361 applications of these concepts involve record types and locales.
   362 
   363 * New command 'no_syntax' removes grammar declarations (and
   364 translations) resulting from the given syntax specification, which is
   365 interpreted in the same manner as for the 'syntax' command.
   366 
   367 * 'Advanced' translation functions (parse_translation etc.) may depend
   368 on the signature of the theory context being presently used for
   369 parsing/printing, see also isar-ref manual.
   370 
   371 * Improved 'oracle' command provides a type-safe interface to turn an
   372 ML expression of type theory -> T -> term into a primitive rule of
   373 type theory -> T -> thm (i.e. the functionality of Thm.invoke_oracle
   374 is already included here); see also FOL/ex/IffExample.thy;
   375 INCOMPATIBILITY.
   376 
   377 * axclass: name space prefix for class "c" is now "c_class" (was "c"
   378 before); "cI" is no longer bound, use "c.intro" instead.
   379 INCOMPATIBILITY.  This change avoids clashes of fact bindings for
   380 axclasses vs. locales.
   381 
   382 * Improved internal renaming of symbolic identifiers -- attach primes
   383 instead of base 26 numbers.
   384 
   385 * New flag show_question_marks controls printing of leading question
   386 marks in schematic variable names.
   387 
   388 * In schematic variable names, *any* symbol following \<^isub> or
   389 \<^isup> is now treated as part of the base name.  For example, the
   390 following works without printing of awkward ".0" indexes:
   391 
   392   lemma "x\<^isub>1 = x\<^isub>2 ==> x\<^isub>2 = x\<^isub>1"
   393     by simp
   394 
   395 * Inner syntax includes (*(*nested*) comments*).
   396 
   397 * Pretty printer now supports unbreakable blocks, specified in mixfix
   398 annotations as "(00...)".
   399 
   400 * Clear separation of logical types and nonterminals, where the latter
   401 may only occur in 'syntax' specifications or type abbreviations.
   402 Before that distinction was only partially implemented via type class
   403 "logic" vs. "{}".  Potential INCOMPATIBILITY in rare cases of improper
   404 use of 'types'/'consts' instead of 'nonterminals'/'syntax'.  Some very
   405 exotic syntax specifications may require further adaption
   406 (e.g. Cube/Cube.thy).
   407 
   408 * Removed obsolete type class "logic", use the top sort {} instead.
   409 Note that non-logical types should be declared as 'nonterminals'
   410 rather than 'types'.  INCOMPATIBILITY for new object-logic
   411 specifications.
   412 
   413 * Attributes 'induct' and 'cases': type or set names may now be
   414 locally fixed variables as well.
   415 
   416 * Simplifier: can now control the depth to which conditional rewriting
   417 is traced via the PG menu Isabelle -> Settings -> Trace Simp Depth
   418 Limit.
   419 
   420 * Simplifier: simplification procedures may now take the current
   421 simpset into account (cf. Simplifier.simproc(_i) / mk_simproc
   422 interface), which is very useful for calling the Simplifier
   423 recursively.  Minor INCOMPATIBILITY: the 'prems' argument of simprocs
   424 is gone -- use prems_of_ss on the simpset instead.  Moreover, the
   425 low-level mk_simproc no longer applies Logic.varify internally, to
   426 allow for use in a context of fixed variables.
   427 
   428 * thin_tac now works even if the assumption being deleted contains !!
   429 or ==>.  More generally, erule now works even if the major premise of
   430 the elimination rule contains !! or ==>.
   431 
   432 * Method 'rules' has been renamed to 'iprover'. INCOMPATIBILITY.
   433 
   434 * Reorganized bootstrapping of the Pure theories; CPure is now derived
   435 from Pure, which contains all common declarations already.  Both
   436 theories are defined via plain Isabelle/Isar .thy files.
   437 INCOMPATIBILITY: elements of CPure (such as the CPure.intro /
   438 CPure.elim / CPure.dest attributes) now appear in the Pure name space;
   439 use isatool fixcpure to adapt your theory and ML sources.
   440 
   441 * New syntax 'name(i-j, i-, i, ...)' for referring to specific
   442 selections of theorems in named facts via index ranges.
   443 
   444 * 'print_theorems': in theory mode, really print the difference
   445 wrt. the last state (works for interactive theory development only),
   446 in proof mode print all local facts (cf. 'print_facts');
   447 
   448 * 'hide': option '(open)' hides only base names.
   449 
   450 * More efficient treatment of intermediate checkpoints in interactive
   451 theory development.
   452 
   453 * Code generator is now invoked via code_module (incremental code
   454 generation) and code_library (modular code generation, ML structures
   455 for each theory).  INCOMPATIBILITY: new keywords 'file' and 'contains'
   456 must be quoted when used as identifiers.
   457 
   458 * New 'value' command for reading, evaluating and printing terms using
   459 the code generator.  INCOMPATIBILITY: command keyword 'value' must be
   460 quoted when used as identifier.
   461 
   462 
   463 *** Locales ***
   464 
   465 * New commands for the interpretation of locale expressions in
   466 theories (1), locales (2) and proof contexts (3).  These generate
   467 proof obligations from the expression specification.  After the
   468 obligations have been discharged, theorems of the expression are added
   469 to the theory, target locale or proof context.  The synopsis of the
   470 commands is a follows:
   471 
   472   (1) interpretation expr inst
   473   (2) interpretation target < expr
   474   (3) interpret expr inst
   475 
   476 Interpretation in theories and proof contexts require a parameter
   477 instantiation of terms from the current context.  This is applied to
   478 specifications and theorems of the interpreted expression.
   479 Interpretation in locales only permits parameter renaming through the
   480 locale expression.  Interpretation is smart in that interpretations
   481 that are active already do not occur in proof obligations, neither are
   482 instantiated theorems stored in duplicate.  Use 'print_interps' to
   483 inspect active interpretations of a particular locale.  For details,
   484 see the Isar Reference manual.  Examples can be found in
   485 HOL/Finite_Set.thy and HOL/Algebra/UnivPoly.thy.
   486 
   487 INCOMPATIBILITY: former 'instantiate' has been withdrawn, use
   488 'interpret' instead.
   489 
   490 * New context element 'constrains' for adding type constraints to
   491 parameters.
   492 
   493 * Context expressions: renaming of parameters with syntax
   494 redeclaration.
   495 
   496 * Locale declaration: 'includes' disallowed.
   497 
   498 * Proper static binding of attribute syntax -- i.e. types / terms /
   499 facts mentioned as arguments are always those of the locale definition
   500 context, independently of the context of later invocations.  Moreover,
   501 locale operations (renaming and type / term instantiation) are applied
   502 to attribute arguments as expected.
   503 
   504 INCOMPATIBILITY of the ML interface: always pass Attrib.src instead of
   505 actual attributes; rare situations may require Attrib.attribute to
   506 embed those attributes into Attrib.src that lack concrete syntax.
   507 Attribute implementations need to cooperate properly with the static
   508 binding mechanism.  Basic parsers Args.XXX_typ/term/prop and
   509 Attrib.XXX_thm etc. already do the right thing without further
   510 intervention.  Only unusual applications -- such as "where" or "of"
   511 (cf. src/Pure/Isar/attrib.ML), which process arguments depending both
   512 on the context and the facts involved -- may have to assign parsed
   513 values to argument tokens explicitly.
   514 
   515 * Changed parameter management in theorem generation for long goal
   516 statements with 'includes'.  INCOMPATIBILITY: produces a different
   517 theorem statement in rare situations.
   518 
   519 * Locale inspection command 'print_locale' omits notes elements.  Use
   520 'print_locale!' to have them included in the output.
   521 
   522 
   523 *** Provers ***
   524 
   525 * Provers/hypsubst.ML: improved version of the subst method, for
   526 single-step rewriting: it now works in bound variable contexts. New is
   527 'subst (asm)', for rewriting an assumption.  INCOMPATIBILITY: may
   528 rewrite a different subterm than the original subst method, which is
   529 still available as 'simplesubst'.
   530 
   531 * Provers/quasi.ML: new transitivity reasoners for transitivity only
   532 and quasi orders.
   533 
   534 * Provers/trancl.ML: new transitivity reasoner for transitive and
   535 reflexive-transitive closure of relations.
   536 
   537 * Provers/blast.ML: new reference depth_limit to make blast's depth
   538 limit (previously hard-coded with a value of 20) user-definable.
   539 
   540 * Provers/simplifier.ML has been moved to Pure, where Simplifier.setup
   541 is peformed already.  Object-logics merely need to finish their
   542 initial simpset configuration as before.  INCOMPATIBILITY.
   543 
   544 
   545 *** HOL ***
   546 
   547 * Symbolic syntax of Hilbert Choice Operator is now as follows:
   548 
   549   syntax (epsilon)
   550     "_Eps" :: "[pttrn, bool] => 'a"    ("(3\<some>_./ _)" [0, 10] 10)
   551 
   552 The symbol \<some> is displayed as the alternative epsilon of LaTeX
   553 and x-symbol; use option '-m epsilon' to get it actually printed.
   554 Moreover, the mathematically important symbolic identifier \<epsilon>
   555 becomes available as variable, constant etc.  INCOMPATIBILITY,
   556 
   557 * "x > y" abbreviates "y < x" and "x >= y" abbreviates "y <= x".
   558 Similarly for all quantifiers: "ALL x > y" etc.  The x-symbol for >=
   559 is \<ge>. New transitivity rules have been added to HOL/Orderings.thy to
   560 support corresponding Isar calculations.
   561 
   562 * "{x:A. P}" abbreviates "{x. x:A & P}", and similarly for "\<in>"
   563 instead of ":".
   564 
   565 * theory SetInterval: changed the syntax for open intervals:
   566 
   567   Old       New
   568   {..n(}    {..<n}
   569   {)n..}    {n<..}
   570   {m..n(}   {m..<n}
   571   {)m..n}   {m<..n}
   572   {)m..n(}  {m<..<n}
   573 
   574 The old syntax is still supported but will disappear in the next
   575 release.  For conversion use the following Emacs search and replace
   576 patterns (these are not perfect but work quite well):
   577 
   578   {)\([^\.]*\)\.\.  ->  {\1<\.\.}
   579   \.\.\([^(}]*\)(}  ->  \.\.<\1}
   580 
   581 * Theory Commutative_Ring (in Library): method comm_ring for proving
   582 equalities in commutative rings; method 'algebra' provides a generic
   583 interface.
   584 
   585 * Theory Finite_Set: changed the syntax for 'setsum', summation over
   586 finite sets: "setsum (%x. e) A", which used to be "\<Sum>x:A. e", is
   587 now either "SUM x:A. e" or "\<Sum>x \<in> A. e". The bound variable can
   588 be a tuple pattern.
   589 
   590 Some new syntax forms are available:
   591 
   592   "\<Sum>x | P. e"      for     "setsum (%x. e) {x. P}"
   593   "\<Sum>x = a..b. e"   for     "setsum (%x. e) {a..b}"
   594   "\<Sum>x = a..<b. e"  for     "setsum (%x. e) {a..<b}"
   595   "\<Sum>x < k. e"      for     "setsum (%x. e) {..<k}"
   596 
   597 The latter form "\<Sum>x < k. e" used to be based on a separate
   598 function "Summation", which has been discontinued.
   599 
   600 * theory Finite_Set: in structured induction proofs, the insert case
   601 is now 'case (insert x F)' instead of the old counterintuitive 'case
   602 (insert F x)'.
   603 
   604 * The 'refute' command has been extended to support a much larger
   605 fragment of HOL, including axiomatic type classes, constdefs and
   606 typedefs, inductive datatypes and recursion.
   607 
   608 * New tactics 'sat' and 'satx' to prove propositional tautologies.
   609 Requires zChaff with proof generation to be installed.  See
   610 HOL/ex/SAT_Examples.thy for examples.
   611 
   612 * Datatype induction via method 'induct' now preserves the name of the
   613 induction variable. For example, when proving P(xs::'a list) by
   614 induction on xs, the induction step is now P(xs) ==> P(a#xs) rather
   615 than P(list) ==> P(a#list) as previously.  Potential INCOMPATIBILITY
   616 in unstructured proof scripts.
   617 
   618 * Reworked implementation of records.  Improved scalability for
   619 records with many fields, avoiding performance problems for type
   620 inference. Records are no longer composed of nested field types, but
   621 of nested extension types. Therefore the record type only grows linear
   622 in the number of extensions and not in the number of fields.  The
   623 top-level (users) view on records is preserved.  Potential
   624 INCOMPATIBILITY only in strange cases, where the theory depends on the
   625 old record representation. The type generated for a record is called
   626 <record_name>_ext_type.
   627 
   628 Flag record_quick_and_dirty_sensitive can be enabled to skip the
   629 proofs triggered by a record definition or a simproc (if
   630 quick_and_dirty is enabled).  Definitions of large records can take
   631 quite long.
   632 
   633 New simproc record_upd_simproc for simplification of multiple record
   634 updates enabled by default.  Moreover, trivial updates are also
   635 removed: r(|x := x r|) = r.  INCOMPATIBILITY: old proofs break
   636 occasionally, since simplification is more powerful by default.
   637 
   638 * typedef: proper support for polymorphic sets, which contain extra
   639 type-variables in the term.
   640 
   641 * Simplifier: automatically reasons about transitivity chains
   642 involving "trancl" (r^+) and "rtrancl" (r^*) by setting up tactics
   643 provided by Provers/trancl.ML as additional solvers.  INCOMPATIBILITY:
   644 old proofs break occasionally as simplification may now solve more
   645 goals than previously.
   646 
   647 * Simplifier: converts x <= y into x = y if assumption y <= x is
   648 present.  Works for all partial orders (class "order"), in particular
   649 numbers and sets.  For linear orders (e.g. numbers) it treats ~ x < y
   650 just like y <= x.
   651 
   652 * Simplifier: new simproc for "let x = a in f x".  If a is a free or
   653 bound variable or a constant then the let is unfolded.  Otherwise
   654 first a is simplified to b, and then f b is simplified to g. If
   655 possible we abstract b from g arriving at "let x = b in h x",
   656 otherwise we unfold the let and arrive at g.  The simproc can be
   657 enabled/disabled by the reference use_let_simproc.  Potential
   658 INCOMPATIBILITY since simplification is more powerful by default.
   659 
   660 * Classical reasoning: the meson method now accepts theorems as arguments.
   661 
   662 * Prover support: pre-release of the Isabelle-ATP linkup, which runs background
   663 jobs to provide advice on the provability of subgoals.
   664 
   665 * Theory OrderedGroup and Ring_and_Field: various additions and
   666 improvements to faciliate calculations involving equalities and
   667 inequalities.
   668 
   669 The following theorems have been eliminated or modified
   670 (INCOMPATIBILITY):
   671 
   672   abs_eq             now named abs_of_nonneg
   673   abs_of_ge_0        now named abs_of_nonneg
   674   abs_minus_eq       now named abs_of_nonpos
   675   imp_abs_id         now named abs_of_nonneg
   676   imp_abs_neg_id     now named abs_of_nonpos
   677   mult_pos           now named mult_pos_pos
   678   mult_pos_le        now named mult_nonneg_nonneg
   679   mult_pos_neg_le    now named mult_nonneg_nonpos
   680   mult_pos_neg2_le   now named mult_nonneg_nonpos2
   681   mult_neg           now named mult_neg_neg
   682   mult_neg_le        now named mult_nonpos_nonpos
   683 
   684 * Theory Parity: added rules for simplifying exponents.
   685 
   686 * Theory List:
   687 
   688 The following theorems have been eliminated or modified
   689 (INCOMPATIBILITY):
   690 
   691   list_all_Nil       now named list_all.simps(1)
   692   list_all_Cons      now named list_all.simps(2)
   693   list_all_conv      now named list_all_iff
   694   set_mem_eq         now named mem_iff
   695 
   696 * Theories SetsAndFunctions and BigO (see HOL/Library) support
   697 asymptotic "big O" calculations.  See the notes in BigO.thy.
   698 
   699 
   700 *** HOL-Complex ***
   701 
   702 * Theory RealDef: better support for embedding natural numbers and
   703 integers in the reals.
   704 
   705 The following theorems have been eliminated or modified
   706 (INCOMPATIBILITY):
   707 
   708   exp_ge_add_one_self  now requires no hypotheses
   709   real_of_int_add      reversed direction of equality (use [symmetric])
   710   real_of_int_minus    reversed direction of equality (use [symmetric])
   711   real_of_int_diff     reversed direction of equality (use [symmetric])
   712   real_of_int_mult     reversed direction of equality (use [symmetric])
   713 
   714 * Theory RComplete: expanded support for floor and ceiling functions.
   715 
   716 * Theory Ln is new, with properties of the natural logarithm
   717 
   718 * Hyperreal: There is a new type constructor "star" for making
   719 nonstandard types.  The old type names are now type synonyms:
   720 
   721   hypreal = real star
   722   hypnat = nat star
   723   hcomplex = complex star
   724 
   725 * Hyperreal: Many groups of similarly-defined constants have been
   726 replaced by polymorphic versions (INCOMPATIBILITY):
   727 
   728   star_of <-- hypreal_of_real, hypnat_of_nat, hcomplex_of_complex
   729 
   730   starset      <-- starsetNat, starsetC
   731   *s*          <-- *sNat*, *sc*
   732   starset_n    <-- starsetNat_n, starsetC_n
   733   *sn*         <-- *sNatn*, *scn*
   734   InternalSets <-- InternalNatSets, InternalCSets
   735 
   736   starfun      <-- starfun{Nat,Nat2,C,RC,CR}
   737   *f*          <-- *fNat*, *fNat2*, *fc*, *fRc*, *fcR*
   738   starfun_n    <-- starfun{Nat,Nat2,C,RC,CR}_n
   739   *fn*         <-- *fNatn*, *fNat2n*, *fcn*, *fRcn*, *fcRn*
   740   InternalFuns <-- InternalNatFuns, InternalNatFuns2, Internal{C,RC,CR}Funs
   741 
   742 * Hyperreal: Many type-specific theorems have been removed in favor of
   743 theorems specific to various axiomatic type classes (INCOMPATIBILITY):
   744 
   745   add_commute <-- {hypreal,hypnat,hcomplex}_add_commute
   746   add_assoc   <-- {hypreal,hypnat,hcomplex}_add_assocs
   747   OrderedGroup.add_0 <-- {hypreal,hypnat,hcomplex}_add_zero_left
   748   OrderedGroup.add_0_right <-- {hypreal,hcomplex}_add_zero_right
   749   right_minus <-- hypreal_add_minus
   750   left_minus <-- {hypreal,hcomplex}_add_minus_left
   751   mult_commute <-- {hypreal,hypnat,hcomplex}_mult_commute
   752   mult_assoc <-- {hypreal,hypnat,hcomplex}_mult_assoc
   753   mult_1_left <-- {hypreal,hypnat}_mult_1, hcomplex_mult_one_left
   754   mult_1_right <-- hcomplex_mult_one_right
   755   mult_zero_left <-- hcomplex_mult_zero_left
   756   left_distrib <-- {hypreal,hypnat,hcomplex}_add_mult_distrib
   757   right_distrib <-- hypnat_add_mult_distrib2
   758   zero_neq_one <-- {hypreal,hypnat,hcomplex}_zero_not_eq_one
   759   right_inverse <-- hypreal_mult_inverse
   760   left_inverse <-- hypreal_mult_inverse_left, hcomplex_mult_inv_left
   761   order_refl <-- {hypreal,hypnat}_le_refl
   762   order_trans <-- {hypreal,hypnat}_le_trans
   763   order_antisym <-- {hypreal,hypnat}_le_anti_sym
   764   order_less_le <-- {hypreal,hypnat}_less_le
   765   linorder_linear <-- {hypreal,hypnat}_le_linear
   766   add_left_mono <-- {hypreal,hypnat}_add_left_mono
   767   mult_strict_left_mono <-- {hypreal,hypnat}_mult_less_mono2
   768   add_nonneg_nonneg <-- hypreal_le_add_order
   769 
   770 * Hyperreal: Separate theorems having to do with type-specific
   771 versions of constants have been merged into theorems that apply to the
   772 new polymorphic constants (INCOMPATIBILITY):
   773 
   774   STAR_UNIV_set <-- {STAR_real,NatStar_real,STARC_complex}_set
   775   STAR_empty_set <-- {STAR,NatStar,STARC}_empty_set
   776   STAR_Un <-- {STAR,NatStar,STARC}_Un
   777   STAR_Int <-- {STAR,NatStar,STARC}_Int
   778   STAR_Compl <-- {STAR,NatStar,STARC}_Compl
   779   STAR_subset <-- {STAR,NatStar,STARC}_subset
   780   STAR_mem <-- {STAR,NatStar,STARC}_mem
   781   STAR_mem_Compl <-- {STAR,STARC}_mem_Compl
   782   STAR_diff <-- {STAR,STARC}_diff
   783   STAR_star_of_image_subset <-- {STAR_hypreal_of_real, NatStar_hypreal_of_real,
   784     STARC_hcomplex_of_complex}_image_subset
   785   starset_n_Un <-- starset{Nat,C}_n_Un
   786   starset_n_Int <-- starset{Nat,C}_n_Int
   787   starset_n_Compl <-- starset{Nat,C}_n_Compl
   788   starset_n_diff <-- starset{Nat,C}_n_diff
   789   InternalSets_Un <-- Internal{Nat,C}Sets_Un
   790   InternalSets_Int <-- Internal{Nat,C}Sets_Int
   791   InternalSets_Compl <-- Internal{Nat,C}Sets_Compl
   792   InternalSets_diff <-- Internal{Nat,C}Sets_diff
   793   InternalSets_UNIV_diff <-- Internal{Nat,C}Sets_UNIV_diff
   794   InternalSets_starset_n <-- Internal{Nat,C}Sets_starset{Nat,C}_n
   795   starset_starset_n_eq <-- starset{Nat,C}_starset{Nat,C}_n_eq
   796   starset_n_starset <-- starset{Nat,C}_n_starset{Nat,C}
   797   starfun_n_starfun <-- starfun{Nat,Nat2,C,RC,CR}_n_starfun{Nat,Nat2,C,RC,CR}
   798   starfun <-- starfun{Nat,Nat2,C,RC,CR}
   799   starfun_mult <-- starfun{Nat,Nat2,C,RC,CR}_mult
   800   starfun_add <-- starfun{Nat,Nat2,C,RC,CR}_add
   801   starfun_minus <-- starfun{Nat,Nat2,C,RC,CR}_minus
   802   starfun_diff <-- starfun{C,RC,CR}_diff
   803   starfun_o <-- starfun{NatNat2,Nat2,_stafunNat,C,C_starfunRC,_starfunCR}_o
   804   starfun_o2 <-- starfun{NatNat2,_stafunNat,C,C_starfunRC,_starfunCR}_o2
   805   starfun_const_fun <-- starfun{Nat,Nat2,C,RC,CR}_const_fun
   806   starfun_inverse <-- starfun{Nat,C,RC,CR}_inverse
   807   starfun_eq <-- starfun{Nat,Nat2,C,RC,CR}_eq
   808   starfun_eq_iff <-- starfun{C,RC,CR}_eq_iff
   809   starfun_Id <-- starfunC_Id
   810   starfun_approx <-- starfun{Nat,CR}_approx
   811   starfun_capprox <-- starfun{C,RC}_capprox
   812   starfun_abs <-- starfunNat_rabs
   813   starfun_lambda_cancel <-- starfun{C,CR,RC}_lambda_cancel
   814   starfun_lambda_cancel2 <-- starfun{C,CR,RC}_lambda_cancel2
   815   starfun_mult_HFinite_approx <-- starfunCR_mult_HFinite_capprox
   816   starfun_mult_CFinite_capprox <-- starfun{C,RC}_mult_CFinite_capprox
   817   starfun_add_capprox <-- starfun{C,RC}_add_capprox
   818   starfun_add_approx <-- starfunCR_add_approx
   819   starfun_inverse_inverse <-- starfunC_inverse_inverse
   820   starfun_divide <-- starfun{C,CR,RC}_divide
   821   starfun_n <-- starfun{Nat,C}_n
   822   starfun_n_mult <-- starfun{Nat,C}_n_mult
   823   starfun_n_add <-- starfun{Nat,C}_n_add
   824   starfun_n_add_minus <-- starfunNat_n_add_minus
   825   starfun_n_const_fun <-- starfun{Nat,C}_n_const_fun
   826   starfun_n_minus <-- starfun{Nat,C}_n_minus
   827   starfun_n_eq <-- starfun{Nat,C}_n_eq
   828 
   829   star_n_add <-- {hypreal,hypnat,hcomplex}_add
   830   star_n_minus <-- {hypreal,hcomplex}_minus
   831   star_n_diff <-- {hypreal,hcomplex}_diff
   832   star_n_mult <-- {hypreal,hcomplex}_mult
   833   star_n_inverse <-- {hypreal,hcomplex}_inverse
   834   star_n_le <-- {hypreal,hypnat}_le
   835   star_n_less <-- {hypreal,hypnat}_less
   836   star_n_zero_num <-- {hypreal,hypnat,hcomplex}_zero_num
   837   star_n_one_num <-- {hypreal,hypnat,hcomplex}_one_num
   838   star_n_abs <-- hypreal_hrabs
   839   star_n_divide <-- hcomplex_divide
   840 
   841   star_of_add <-- {hypreal_of_real,hypnat_of_nat,hcomplex_of_complex}_add
   842   star_of_minus <-- {hypreal_of_real,hcomplex_of_complex}_minus
   843   star_of_diff <-- hypreal_of_real_diff
   844   star_of_mult <-- {hypreal_of_real,hypnat_of_nat,hcomplex_of_complex}_mult
   845   star_of_one <-- {hypreal_of_real,hcomplex_of_complex}_one
   846   star_of_zero <-- {hypreal_of_real,hypnat_of_nat,hcomplex_of_complex}_zero
   847   star_of_le <-- {hypreal_of_real,hypnat_of_nat}_le_iff
   848   star_of_less <-- {hypreal_of_real,hypnat_of_nat}_less_iff
   849   star_of_eq <-- {hypreal_of_real,hypnat_of_nat,hcomplex_of_complex}_eq_iff
   850   star_of_inverse <-- {hypreal_of_real,hcomplex_of_complex}_inverse
   851   star_of_divide <-- {hypreal_of_real,hcomplex_of_complex}_divide
   852   star_of_of_nat <-- {hypreal_of_real,hcomplex_of_complex}_of_nat
   853   star_of_of_int <-- {hypreal_of_real,hcomplex_of_complex}_of_int
   854   star_of_number_of <-- {hypreal,hcomplex}_number_of
   855   star_of_number_less <-- number_of_less_hypreal_of_real_iff
   856   star_of_number_le <-- number_of_le_hypreal_of_real_iff
   857   star_of_eq_number <-- hypreal_of_real_eq_number_of_iff
   858   star_of_less_number <-- hypreal_of_real_less_number_of_iff
   859   star_of_le_number <-- hypreal_of_real_le_number_of_iff
   860   star_of_power <-- hypreal_of_real_power
   861   star_of_eq_0 <-- hcomplex_of_complex_zero_iff
   862 
   863 * Hyperreal: new method "transfer" that implements the transfer
   864 principle of nonstandard analysis. With a subgoal that mentions
   865 nonstandard types like "'a star", the command "apply transfer"
   866 replaces it with an equivalent one that mentions only standard types.
   867 To be successful, all free variables must have standard types; non-
   868 standard variables must have explicit universal quantifiers.
   869 
   870 * Hyperreal: A theory of Taylor series.
   871 
   872 
   873 *** HOLCF ***
   874 
   875 * Discontinued special version of 'constdefs' (which used to support
   876 continuous functions) in favor of the general Pure one with full
   877 type-inference.
   878 
   879 * New simplification procedure for solving continuity conditions; it
   880 is much faster on terms with many nested lambda abstractions (cubic
   881 instead of exponential time).
   882 
   883 * New syntax for domain package: selector names are now optional.
   884 Parentheses should be omitted unless argument is lazy, for example:
   885 
   886   domain 'a stream = cons "'a" (lazy "'a stream")
   887 
   888 * New command 'fixrec' for defining recursive functions with pattern
   889 matching; defining multiple functions with mutual recursion is also
   890 supported.  Patterns may include the constants cpair, spair, up, sinl,
   891 sinr, or any data constructor defined by the domain package. The given
   892 equations are proven as rewrite rules. See HOLCF/ex/Fixrec_ex.thy for
   893 syntax and examples.
   894 
   895 * New commands 'cpodef' and 'pcpodef' for defining predicate subtypes
   896 of cpo and pcpo types. Syntax is exactly like the 'typedef' command,
   897 but the proof obligation additionally includes an admissibility
   898 requirement. The packages generate instances of class cpo or pcpo,
   899 with continuity and strictness theorems for Rep and Abs.
   900 
   901 * HOLCF: Many theorems have been renamed according to a more standard naming
   902 scheme (INCOMPATIBILITY):
   903 
   904   foo_inject:  "foo$x = foo$y ==> x = y"
   905   foo_eq:      "(foo$x = foo$y) = (x = y)"
   906   foo_less:    "(foo$x << foo$y) = (x << y)"
   907   foo_strict:  "foo$UU = UU"
   908   foo_defined: "... ==> foo$x ~= UU"
   909   foo_defined_iff: "(foo$x = UU) = (x = UU)"
   910 
   911 
   912 *** ZF ***
   913 
   914 * ZF/ex: theories Group and Ring provide examples in abstract algebra,
   915 including the First Isomorphism Theorem (on quotienting by the kernel
   916 of a homomorphism).
   917 
   918 * ZF/Simplifier: install second copy of type solver that actually
   919 makes use of TC rules declared to Isar proof contexts (or locales);
   920 the old version is still required for ML proof scripts.
   921 
   922 
   923 *** Cube ***
   924 
   925 * Converted to Isar theory format; use locales instead of axiomatic
   926 theories.
   927 
   928 
   929 *** ML ***
   930 
   931 * Pure/library.ML no longer defines its own option datatype, but uses
   932 that of the SML basis, which has constructors NONE and SOME instead of
   933 None and Some, as well as exception Option.Option instead of OPTION.
   934 The functions the, if_none, is_some, is_none have been adapted
   935 accordingly, while Option.map replaces apsome.
   936 
   937 * Pure/library.ML: the exception LIST has been given up in favour of
   938 the standard exceptions Empty and Subscript, as well as
   939 Library.UnequalLengths.  Function like Library.hd and Library.tl are
   940 superceded by the standard hd and tl functions etc.
   941 
   942 A number of basic list functions are no longer exported to the ML
   943 toplevel, as they are variants of predefined functions.  The following
   944 suggests how one can translate existing code:
   945 
   946     rev_append xs ys = List.revAppend (xs, ys)
   947     nth_elem (i, xs) = List.nth (xs, i)
   948     last_elem xs = List.last xs
   949     flat xss = List.concat xss
   950     seq fs = List.app fs
   951     partition P xs = List.partition P xs
   952     mapfilter f xs = List.mapPartial f xs
   953 
   954 * Pure/library.ML: several combinators for linear functional
   955 transformations, notably reverse application and composition:
   956 
   957   x |> f                f #> g
   958   (x, y) |-> f          f #-> g
   959 
   960 * Pure/library.ML: introduced/changed precedence of infix operators:
   961 
   962   infix 1 |> |-> ||> ||>> |>> |>>> #> #->;
   963   infix 2 ?;
   964   infix 3 o oo ooo oooo;
   965   infix 4 ~~ upto downto;
   966 
   967 Maybe INCOMPATIBILITY when any of those is used in conjunction with other
   968 infix operators.
   969 
   970 * Pure/library.ML: natural list combinators fold, fold_rev, and
   971 fold_map support linear functional transformations and nesting.  For
   972 example:
   973 
   974   fold f [x1, ..., xN] y =
   975     y |> f x1 |> ... |> f xN
   976 
   977   (fold o fold) f [xs1, ..., xsN] y =
   978     y |> fold f xs1 |> ... |> fold f xsN
   979 
   980   fold f [x1, ..., xN] =
   981     f x1 #> ... #> f xN
   982 
   983   (fold o fold) f [xs1, ..., xsN] =
   984     fold f xs1 #> ... #> fold f xsN
   985 
   986 * Pure/library.ML: the following selectors on type 'a option are
   987 available:
   988 
   989   the:               'a option -> 'a  (*partial*)
   990   these:             'a option -> 'a  where 'a = 'b list
   991   the_default: 'a -> 'a option -> 'a
   992   the_list:          'a option -> 'a list
   993 
   994 * Pure/General: structure AList (cf. Pure/General/alist.ML) provides
   995 basic operations for association lists, following natural argument
   996 order; moreover the explicit equality predicate passed here avoids
   997 potentially expensive polymorphic runtime equality checks.
   998 The old functions may be expressed as follows:
   999 
  1000   assoc = uncurry (AList.lookup (op =))
  1001   assocs = these oo AList.lookup (op =)
  1002   overwrite = uncurry (AList.update (op =)) o swap
  1003 
  1004 * Pure/General: structure AList (cf. Pure/General/alist.ML) provides
  1005 
  1006   val make: ('a -> 'b) -> 'a list -> ('a * 'b) list
  1007   val find: ('a * 'b -> bool) -> ('c * 'b) list -> 'a -> 'c list
  1008 
  1009 replacing make_keylist and keyfilter (occassionally used)
  1010 Naive rewrites:
  1011 
  1012   make_keylist = AList.make
  1013   keyfilter = AList.find (op =)
  1014 
  1015 * eq_fst and eq_snd now take explicit equality parameter, thus
  1016   avoiding eqtypes. Naive rewrites:
  1017 
  1018     eq_fst = eq_fst (op =)
  1019     eq_snd = eq_snd (op =)
  1020 
  1021 * Removed deprecated apl and apr (rarely used).
  1022   Naive rewrites:
  1023 
  1024     apl (n, op) =>>= curry op n
  1025     apr (op, m) =>>= fn n => op (n, m)
  1026 
  1027 * Pure/General: structure OrdList (cf. Pure/General/ord_list.ML)
  1028 provides a reasonably efficient light-weight implementation of sets as
  1029 lists.
  1030 
  1031 * Pure/General: generic tables (cf. Pure/General/table.ML) provide a
  1032 few new operations; existing lookup and update are now curried to
  1033 follow natural argument order (for use with fold etc.);
  1034 INCOMPATIBILITY, use (uncurry Symtab.lookup) etc. as last resort.
  1035 
  1036 * Pure/General: output via the Isabelle channels of
  1037 writeln/warning/error etc. is now passed through Output.output, with a
  1038 hook for arbitrary transformations depending on the print_mode
  1039 (cf. Output.add_mode -- the first active mode that provides a output
  1040 function wins).  Already formatted output may be embedded into further
  1041 text via Output.raw; the result of Pretty.string_of/str_of and derived
  1042 functions (string_of_term/cterm/thm etc.) is already marked raw to
  1043 accommodate easy composition of diagnostic messages etc.  Programmers
  1044 rarely need to care about Output.output or Output.raw at all, with
  1045 some notable exceptions: Output.output is required when bypassing the
  1046 standard channels (writeln etc.), or in token translations to produce
  1047 properly formatted results; Output.raw is required when capturing
  1048 already output material that will eventually be presented to the user
  1049 a second time.  For the default print mode, both Output.output and
  1050 Output.raw have no effect.
  1051 
  1052 * Pure/General: Output.time_accumulator NAME creates an operator ('a
  1053 -> 'b) -> 'a -> 'b to measure runtime and count invocations; the
  1054 cumulative results are displayed at the end of a batch session.
  1055 
  1056 * Pure/General: File.sysify_path and File.quote_sysify path have been
  1057 replaced by File.platform_path and File.shell_path (with appropriate
  1058 hooks).  This provides a clean interface for unusual systems where the
  1059 internal and external process view of file names are different.
  1060 
  1061 * Pure: more efficient orders for basic syntactic entities: added
  1062 fast_string_ord, fast_indexname_ord, fast_term_ord; changed sort_ord
  1063 and typ_ord to use fast_string_ord and fast_indexname_ord (term_ord is
  1064 NOT affected); structures Symtab, Vartab, Typtab, Termtab use the fast
  1065 orders now -- potential INCOMPATIBILITY for code that depends on a
  1066 particular order for Symtab.keys, Symtab.dest, etc. (consider using
  1067 Library.sort_strings on result).
  1068 
  1069 * Pure/term.ML: combinators fold_atyps, fold_aterms, fold_term_types,
  1070 fold_types traverse types/terms from left to right, observing natural
  1071 argument order.  Supercedes previous foldl_XXX versions, add_frees,
  1072 add_vars etc. have been adapted as well: INCOMPATIBILITY.
  1073 
  1074 * Pure: name spaces have been refined, with significant changes of the
  1075 internal interfaces -- INCOMPATIBILITY.  Renamed cond_extern(_table)
  1076 to extern(_table).  The plain name entry path is superceded by a
  1077 general 'naming' context, which also includes the 'policy' to produce
  1078 a fully qualified name and external accesses of a fully qualified
  1079 name; NameSpace.extend is superceded by context dependent
  1080 Sign.declare_name.  Several theory and proof context operations modify
  1081 the naming context.  Especially note Theory.restore_naming and
  1082 ProofContext.restore_naming to get back to a sane state; note that
  1083 Theory.add_path is no longer sufficient to recover from
  1084 Theory.absolute_path in particular.
  1085 
  1086 * Pure: new flags short_names (default false) and unique_names
  1087 (default true) for controlling output of qualified names.  If
  1088 short_names is set, names are printed unqualified.  If unique_names is
  1089 reset, the name prefix is reduced to the minimum required to achieve
  1090 the original result when interning again, even if there is an overlap
  1091 with earlier declarations.
  1092 
  1093 * Pure/TheoryDataFun: change of the argument structure; 'prep_ext' is
  1094 now 'extend', and 'merge' gets an additional Pretty.pp argument
  1095 (useful for printing error messages).  INCOMPATIBILITY.
  1096 
  1097 * Pure: major reorganization of the theory context.  Type Sign.sg and
  1098 Theory.theory are now identified, referring to the universal
  1099 Context.theory (see Pure/context.ML).  Actual signature and theory
  1100 content is managed as theory data.  The old code and interfaces were
  1101 spread over many files and structures; the new arrangement introduces
  1102 considerable INCOMPATIBILITY to gain more clarity:
  1103 
  1104   Context -- theory management operations (name, identity, inclusion,
  1105     parents, ancestors, merge, etc.), plus generic theory data;
  1106 
  1107   Sign -- logical signature and syntax operations (declaring consts,
  1108     types, etc.), plus certify/read for common entities;
  1109 
  1110   Theory -- logical theory operations (stating axioms, definitions,
  1111     oracles), plus a copy of logical signature operations (consts,
  1112     types, etc.); also a few basic management operations (Theory.copy,
  1113     Theory.merge, etc.)
  1114 
  1115 The most basic sign_of operations (Theory.sign_of, Thm.sign_of_thm
  1116 etc.) as well as the sign field in Thm.rep_thm etc. have been retained
  1117 for convenience -- they merely return the theory.
  1118 
  1119 * Pure: type Type.tsig is superceded by theory in most interfaces.
  1120 
  1121 * Pure: the Isar proof context type is already defined early in Pure
  1122 as Context.proof (note that ProofContext.context and Proof.context are
  1123 aliases, where the latter is the preferred name).  This enables other
  1124 Isabelle components to refer to that type even before Isar is present.
  1125 
  1126 * Pure/sign/theory: discontinued named name spaces (i.e. classK,
  1127 typeK, constK, axiomK, oracleK), but provide explicit operations for
  1128 any of these kinds.  For example, Sign.intern typeK is now
  1129 Sign.intern_type, Theory.hide_space Sign.typeK is now
  1130 Theory.hide_types.  Also note that former
  1131 Theory.hide_classes/types/consts are now
  1132 Theory.hide_classes_i/types_i/consts_i, while the non '_i' versions
  1133 internalize their arguments!  INCOMPATIBILITY.
  1134 
  1135 * Pure: get_thm interface (of PureThy and ProofContext) expects
  1136 datatype thmref (with constructors Name and NameSelection) instead of
  1137 plain string -- INCOMPATIBILITY;
  1138 
  1139 * Pure: cases produced by proof methods specify options, where NONE
  1140 means to remove case bindings -- INCOMPATIBILITY in
  1141 (RAW_)METHOD_CASES.
  1142 
  1143 * Pure: the following operations retrieve axioms or theorems from a
  1144 theory node or theory hierarchy, respectively:
  1145 
  1146   Theory.axioms_of: theory -> (string * term) list
  1147   Theory.all_axioms_of: theory -> (string * term) list
  1148   PureThy.thms_of: theory -> (string * thm) list
  1149   PureThy.all_thms_of: theory -> (string * thm) list
  1150 
  1151 * Pure: print_tac now outputs the goal through the trace channel.
  1152 
  1153 * Isar toplevel: improved diagnostics, mostly for Poly/ML only.
  1154 Reference Toplevel.debug (default false) controls detailed printing
  1155 and tracing of low-level exceptions; Toplevel.profiling (default 0)
  1156 controls execution profiling -- set to 1 for time and 2 for space
  1157 (both increase the runtime).
  1158 
  1159 * Isar session: The initial use of ROOT.ML is now always timed,
  1160 i.e. the log will show the actual process times, in contrast to the
  1161 elapsed wall-clock time that the outer shell wrapper produces.
  1162 
  1163 * Simplifier: improved handling of bound variables (nameless
  1164 representation, avoid allocating new strings).  Simprocs that invoke
  1165 the Simplifier recursively should use Simplifier.inherit_bounds to
  1166 avoid local name clashes.  Failure to do so produces warnings
  1167 "Simplifier: renamed bound variable ..."; set Simplifier.debug_bounds
  1168 for further details.
  1169 
  1170 * ML functions legacy_bindings and use_legacy_bindings produce ML fact
  1171 bindings for all theorems stored within a given theory; this may help
  1172 in porting non-Isar theories to Isar ones, while keeping ML proof
  1173 scripts for the time being.
  1174 
  1175 * ML operator HTML.with_charset specifies the charset begin used for
  1176 generated HTML files.  For example:
  1177 
  1178   HTML.with_charset "utf-8" use_thy "Hebrew";
  1179   HTML.with_charset "utf-8" use_thy "Chinese";
  1180 
  1181 
  1182 *** System ***
  1183 
  1184 * Allow symlinks to all proper Isabelle executables (Isabelle,
  1185 isabelle, isatool etc.).
  1186 
  1187 * ISABELLE_DOC_FORMAT setting specifies preferred document format (for
  1188 isatool doc, isatool mkdir, display_drafts etc.).
  1189 
  1190 * isatool usedir: option -f allows specification of the ML file to be
  1191 used by Isabelle; default is ROOT.ML.
  1192 
  1193 * New isatool version outputs the version identifier of the Isabelle
  1194 distribution being used.
  1195 
  1196 * HOL: new isatool dimacs2hol converts files in DIMACS CNF format
  1197 (containing Boolean satisfiability problems) into Isabelle/HOL
  1198 theories.
  1199 
  1200 
  1201 
  1202 New in Isabelle2004 (April 2004)
  1203 --------------------------------
  1204 
  1205 *** General ***
  1206 
  1207 * Provers/order.ML:  new efficient reasoner for partial and linear orders.
  1208   Replaces linorder.ML.
  1209 
  1210 * Pure: Greek letters (except small lambda, \<lambda>), as well as Gothic
  1211   (\<aa>...\<zz>\<AA>...\<ZZ>), calligraphic (\<A>...\<Z>), and Euler
  1212   (\<a>...\<z>), are now considered normal letters, and can therefore
  1213   be used anywhere where an ASCII letter (a...zA...Z) has until
  1214   now. COMPATIBILITY: This obviously changes the parsing of some
  1215   terms, especially where a symbol has been used as a binder, say
  1216   '\<Pi>x. ...', which is now a type error since \<Pi>x will be parsed
  1217   as an identifier.  Fix it by inserting a space around former
  1218   symbols.  Call 'isatool fixgreek' to try to fix parsing errors in
  1219   existing theory and ML files.
  1220 
  1221 * Pure: Macintosh and Windows line-breaks are now allowed in theory files.
  1222 
  1223 * Pure: single letter sub/superscripts (\<^isub> and \<^isup>) are now
  1224   allowed in identifiers. Similar to Greek letters \<^isub> is now considered
  1225   a normal (but invisible) letter. For multiple letter subscripts repeat
  1226   \<^isub> like this: x\<^isub>1\<^isub>2.
  1227 
  1228 * Pure: There are now sub-/superscripts that can span more than one
  1229   character. Text between \<^bsub> and \<^esub> is set in subscript in
  1230   ProofGeneral and LaTeX, text between \<^bsup> and \<^esup> in
  1231   superscript. The new control characters are not identifier parts.
  1232 
  1233 * Pure: Control-symbols of the form \<^raw:...> will literally print the
  1234   content of "..." to the latex file instead of \isacntrl... . The "..."
  1235   may consist of any printable characters excluding the end bracket >.
  1236 
  1237 * Pure: Using new Isar command "finalconsts" (or the ML functions
  1238   Theory.add_finals or Theory.add_finals_i) it is now possible to
  1239   declare constants "final", which prevents their being given a definition
  1240   later.  It is useful for constants whose behaviour is fixed axiomatically
  1241   rather than definitionally, such as the meta-logic connectives.
  1242 
  1243 * Pure: 'instance' now handles general arities with general sorts
  1244   (i.e. intersections of classes),
  1245 
  1246 * Presentation: generated HTML now uses a CSS style sheet to make layout
  1247   (somewhat) independent of content. It is copied from lib/html/isabelle.css.
  1248   It can be changed to alter the colors/layout of generated pages.
  1249 
  1250 
  1251 *** Isar ***
  1252 
  1253 * Tactic emulation methods rule_tac, erule_tac, drule_tac, frule_tac,
  1254   cut_tac, subgoal_tac and thin_tac:
  1255   - Now understand static (Isar) contexts.  As a consequence, users of Isar
  1256     locales are no longer forced to write Isar proof scripts.
  1257     For details see Isar Reference Manual, paragraph 4.3.2: Further tactic
  1258     emulations.
  1259   - INCOMPATIBILITY: names of variables to be instantiated may no
  1260     longer be enclosed in quotes.  Instead, precede variable name with `?'.
  1261     This is consistent with the instantiation attribute "where".
  1262 
  1263 * Attributes "where" and "of":
  1264   - Now take type variables of instantiated theorem into account when reading
  1265     the instantiation string.  This fixes a bug that caused instantiated
  1266     theorems to have too special types in some circumstances.
  1267   - "where" permits explicit instantiations of type variables.
  1268 
  1269 * Calculation commands "moreover" and "also" no longer interfere with
  1270   current facts ("this"), admitting arbitrary combinations with "then"
  1271   and derived forms.
  1272 
  1273 * Locales:
  1274   - Goal statements involving the context element "includes" no longer
  1275     generate theorems with internal delta predicates (those ending on
  1276     "_axioms") in the premise.
  1277     Resolve particular premise with <locale>.intro to obtain old form.
  1278   - Fixed bug in type inference ("unify_frozen") that prevented mix of target
  1279     specification and "includes" elements in goal statement.
  1280   - Rule sets <locale>.intro and <locale>.axioms no longer declared as
  1281     [intro?] and [elim?] (respectively) by default.
  1282   - Experimental command for instantiation of locales in proof contexts:
  1283         instantiate <label>[<attrs>]: <loc>
  1284     Instantiates locale <loc> and adds all its theorems to the current context
  1285     taking into account their attributes.  Label and attrs are optional
  1286     modifiers, like in theorem declarations.  If present, names of
  1287     instantiated theorems are qualified with <label>, and the attributes
  1288     <attrs> are applied after any attributes these theorems might have already.
  1289       If the locale has assumptions, a chained fact of the form
  1290     "<loc> t1 ... tn" is expected from which instantiations of the parameters
  1291     are derived.  The command does not support old-style locales declared
  1292     with "locale (open)".
  1293       A few (very simple) examples can be found in FOL/ex/LocaleInst.thy.
  1294 
  1295 * HOL: Tactic emulation methods induct_tac and case_tac understand static
  1296   (Isar) contexts.
  1297 
  1298 
  1299 *** HOL ***
  1300 
  1301 * Proof import: new image HOL4 contains the imported library from
  1302   the HOL4 system with about 2500 theorems. It is imported by
  1303   replaying proof terms produced by HOL4 in Isabelle. The HOL4 image
  1304   can be used like any other Isabelle image.  See
  1305   HOL/Import/HOL/README for more information.
  1306 
  1307 * Simplifier:
  1308   - Much improved handling of linear and partial orders.
  1309     Reasoners for linear and partial orders are set up for type classes
  1310     "linorder" and "order" respectively, and are added to the default simpset
  1311     as solvers.  This means that the simplifier can build transitivity chains
  1312     to solve goals from the assumptions.
  1313   - INCOMPATIBILITY: old proofs break occasionally.  Typically, applications
  1314     of blast or auto after simplification become unnecessary because the goal
  1315     is solved by simplification already.
  1316 
  1317 * Numerics: new theory Ring_and_Field contains over 250 basic numerical laws,
  1318     all proved in axiomatic type classes for semirings, rings and fields.
  1319 
  1320 * Numerics:
  1321   - Numeric types (nat, int, and in HOL-Complex rat, real, complex, etc.) are
  1322     now formalized using the Ring_and_Field theory mentioned above.
  1323   - INCOMPATIBILITY: simplification and arithmetic behaves somewhat differently
  1324     than before, because now they are set up once in a generic manner.
  1325   - INCOMPATIBILITY: many type-specific arithmetic laws have gone.
  1326     Look for the general versions in Ring_and_Field (and Power if they concern
  1327     exponentiation).
  1328 
  1329 * Type "rat" of the rational numbers is now available in HOL-Complex.
  1330 
  1331 * Records:
  1332   - Record types are now by default printed with their type abbreviation
  1333     instead of the list of all field types. This can be configured via
  1334     the reference "print_record_type_abbr".
  1335   - Simproc "record_upd_simproc" for simplification of multiple updates added
  1336     (not enabled by default).
  1337   - Simproc "record_ex_sel_eq_simproc" to simplify EX x. sel r = x resp.
  1338     EX x. x = sel r to True (not enabled by default).
  1339   - Tactic "record_split_simp_tac" to split and simplify records added.
  1340 
  1341 * 'specification' command added, allowing for definition by
  1342   specification.  There is also an 'ax_specification' command that
  1343   introduces the new constants axiomatically.
  1344 
  1345 * arith(_tac) is now able to generate counterexamples for reals as well.
  1346 
  1347 * HOL-Algebra: new locale "ring" for non-commutative rings.
  1348 
  1349 * HOL-ex: InductiveInvariant_examples illustrates advanced recursive function
  1350   definitions, thanks to Sava Krsti\'{c} and John Matthews.
  1351 
  1352 * HOL-Matrix: a first theory for matrices in HOL with an application of
  1353   matrix theory to linear programming.
  1354 
  1355 * Unions and Intersections:
  1356   The latex output syntax of UN and INT has been changed
  1357   from "\Union x \in A. B" to "\Union_{x \in A} B"
  1358   i.e. the index formulae has become a subscript.
  1359   Similarly for "\Union x. B", and for \Inter instead of \Union.
  1360 
  1361 * Unions and Intersections over Intervals:
  1362   There is new short syntax "UN i<=n. A" for "UN i:{0..n}. A". There is
  1363   also an x-symbol version with subscripts "\<Union>\<^bsub>i <= n\<^esub>. A"
  1364   like in normal math, and corresponding versions for < and for intersection.
  1365 
  1366 * HOL/List: Ordering "lexico" is renamed "lenlex" and the standard
  1367   lexicographic dictonary ordering has been added as "lexord".
  1368 
  1369 * ML: the legacy theory structures Int and List have been removed. They had
  1370   conflicted with ML Basis Library structures having the same names.
  1371 
  1372 * 'refute' command added to search for (finite) countermodels.  Only works
  1373   for a fragment of HOL.  The installation of an external SAT solver is
  1374   highly recommended.  See "HOL/Refute.thy" for details.
  1375 
  1376 * 'quickcheck' command: Allows to find counterexamples by evaluating
  1377   formulae under an assignment of free variables to random values.
  1378   In contrast to 'refute', it can deal with inductive datatypes,
  1379   but cannot handle quantifiers. See "HOL/ex/Quickcheck_Examples.thy"
  1380   for examples.
  1381 
  1382 
  1383 *** HOLCF ***
  1384 
  1385 * Streams now come with concatenation and are part of the HOLCF image
  1386 
  1387 
  1388 
  1389 New in Isabelle2003 (May 2003)
  1390 ------------------------------
  1391 
  1392 *** General ***
  1393 
  1394 * Provers/simplifier:
  1395 
  1396   - Completely reimplemented method simp (ML: Asm_full_simp_tac):
  1397     Assumptions are now subject to complete mutual simplification,
  1398     not just from left to right. The simplifier now preserves
  1399     the order of assumptions.
  1400 
  1401     Potential INCOMPATIBILITY:
  1402 
  1403     -- simp sometimes diverges where the old version did
  1404        not, e.g. invoking simp on the goal
  1405 
  1406         [| P (f x); y = x; f x = f y |] ==> Q
  1407 
  1408        now gives rise to the infinite reduction sequence
  1409 
  1410         P(f x) --(f x = f y)--> P(f y) --(y = x)--> P(f x) --(f x = f y)--> ...
  1411 
  1412        Using "simp (asm_lr)" (ML: Asm_lr_simp_tac) instead often solves this
  1413        kind of problem.
  1414 
  1415     -- Tactics combining classical reasoner and simplification (such as auto)
  1416        are also affected by this change, because many of them rely on
  1417        simp. They may sometimes diverge as well or yield a different numbers
  1418        of subgoals. Try to use e.g. force, fastsimp, or safe instead of auto
  1419        in case of problems. Sometimes subsequent calls to the classical
  1420        reasoner will fail because a preceeding call to the simplifier too
  1421        eagerly simplified the goal, e.g. deleted redundant premises.
  1422 
  1423   - The simplifier trace now shows the names of the applied rewrite rules
  1424 
  1425   - You can limit the number of recursive invocations of the simplifier
  1426     during conditional rewriting (where the simplifie tries to solve the
  1427     conditions before applying the rewrite rule):
  1428     ML "simp_depth_limit := n"
  1429     where n is an integer. Thus you can force termination where previously
  1430     the simplifier would diverge.
  1431 
  1432   - Accepts free variables as head terms in congruence rules.  Useful in Isar.
  1433 
  1434   - No longer aborts on failed congruence proof.  Instead, the
  1435     congruence is ignored.
  1436 
  1437 * Pure: New generic framework for extracting programs from constructive
  1438   proofs. See HOL/Extraction.thy for an example instantiation, as well
  1439   as HOL/Extraction for some case studies.
  1440 
  1441 * Pure: The main goal of the proof state is no longer shown by default, only
  1442 the subgoals. This behaviour is controlled by a new flag.
  1443    PG menu: Isabelle/Isar -> Settings -> Show Main Goal
  1444 (ML: Proof.show_main_goal).
  1445 
  1446 * Pure: You can find all matching introduction rules for subgoal 1, i.e. all
  1447 rules whose conclusion matches subgoal 1:
  1448       PG menu: Isabelle/Isar -> Show me -> matching rules
  1449 The rules are ordered by how closely they match the subgoal.
  1450 In particular, rules that solve a subgoal outright are displayed first
  1451 (or rather last, the way they are printed).
  1452 (ML: ProofGeneral.print_intros())
  1453 
  1454 * Pure: New flag trace_unify_fail causes unification to print
  1455 diagnostic information (PG: in trace buffer) when it fails. This is
  1456 useful for figuring out why single step proofs like rule, erule or
  1457 assumption failed.
  1458 
  1459 * Pure: Locale specifications now produce predicate definitions
  1460 according to the body of text (covering assumptions modulo local
  1461 definitions); predicate "loc_axioms" covers newly introduced text,
  1462 while "loc" is cumulative wrt. all included locale expressions; the
  1463 latter view is presented only on export into the global theory
  1464 context; potential INCOMPATIBILITY, use "(open)" option to fall back
  1465 on the old view without predicates;
  1466 
  1467 * Pure: predefined locales "var" and "struct" are useful for sharing
  1468 parameters (as in CASL, for example); just specify something like
  1469 ``var x + var y + struct M'' as import;
  1470 
  1471 * Pure: improved thms_containing: proper indexing of facts instead of
  1472 raw theorems; check validity of results wrt. current name space;
  1473 include local facts of proof configuration (also covers active
  1474 locales), cover fixed variables in index; may use "_" in term
  1475 specification; an optional limit for the number of printed facts may
  1476 be given (the default is 40);
  1477 
  1478 * Pure: disallow duplicate fact bindings within new-style theory files
  1479 (batch-mode only);
  1480 
  1481 * Provers: improved induct method: assumptions introduced by case
  1482 "foo" are split into "foo.hyps" (from the rule) and "foo.prems" (from
  1483 the goal statement); "foo" still refers to all facts collectively;
  1484 
  1485 * Provers: the function blast.overloaded has been removed: all constants
  1486 are regarded as potentially overloaded, which improves robustness in exchange
  1487 for slight decrease in efficiency;
  1488 
  1489 * Provers/linorder: New generic prover for transitivity reasoning over
  1490 linear orders.  Note: this prover is not efficient!
  1491 
  1492 * Isar: preview of problems to finish 'show' now produce an error
  1493 rather than just a warning (in interactive mode);
  1494 
  1495 
  1496 *** HOL ***
  1497 
  1498 * arith(_tac)
  1499 
  1500  - Produces a counter example if it cannot prove a goal.
  1501    Note that the counter example may be spurious if the goal is not a formula
  1502    of quantifier-free linear arithmetic.
  1503    In ProofGeneral the counter example appears in the trace buffer.
  1504 
  1505  - Knows about div k and mod k where k is a numeral of type nat or int.
  1506 
  1507  - Calls full Presburger arithmetic (by Amine Chaieb) if quantifier-free
  1508    linear arithmetic fails. This takes account of quantifiers and divisibility.
  1509    Presburger arithmetic can also be called explicitly via presburger(_tac).
  1510 
  1511 * simp's arithmetic capabilities have been enhanced a bit: it now
  1512 takes ~= in premises into account (by performing a case split);
  1513 
  1514 * simp reduces "m*(n div m) + n mod m" to n, even if the two summands
  1515 are distributed over a sum of terms;
  1516 
  1517 * New tactic "trans_tac" and method "trans" instantiate
  1518 Provers/linorder.ML for axclasses "order" and "linorder" (predicates
  1519 "<=", "<" and "=").
  1520 
  1521 * function INCOMPATIBILITIES: Pi-sets have been redefined and moved from main
  1522 HOL to Library/FuncSet; constant "Fun.op o" is now called "Fun.comp";
  1523 
  1524 * 'typedef' command has new option "open" to suppress the set
  1525 definition;
  1526 
  1527 * functions Min and Max on finite sets have been introduced (theory
  1528 Finite_Set);
  1529 
  1530 * attribute [symmetric] now works for relations as well; it turns
  1531 (x,y) : R^-1 into (y,x) : R, and vice versa;
  1532 
  1533 * induct over a !!-quantified statement (say !!x1..xn):
  1534   each "case" automatically performs "fix x1 .. xn" with exactly those names.
  1535 
  1536 * Map: `empty' is no longer a constant but a syntactic abbreviation for
  1537 %x. None. Warning: empty_def now refers to the previously hidden definition
  1538 of the empty set.
  1539 
  1540 * Algebra: formalization of classical algebra.  Intended as base for
  1541 any algebraic development in Isabelle.  Currently covers group theory
  1542 (up to Sylow's theorem) and ring theory (Universal Property of
  1543 Univariate Polynomials).  Contributions welcome;
  1544 
  1545 * GroupTheory: deleted, since its material has been moved to Algebra;
  1546 
  1547 * Complex: new directory of the complex numbers with numeric constants,
  1548 nonstandard complex numbers, and some complex analysis, standard and
  1549 nonstandard (Jacques Fleuriot);
  1550 
  1551 * HOL-Complex: new image for analysis, replacing HOL-Real and HOL-Hyperreal;
  1552 
  1553 * Hyperreal: introduced Gauge integration and hyperreal logarithms (Jacques
  1554 Fleuriot);
  1555 
  1556 * Real/HahnBanach: updated and adapted to locales;
  1557 
  1558 * NumberTheory: added Gauss's law of quadratic reciprocity (by Avigad,
  1559 Gray and Kramer);
  1560 
  1561 * UNITY: added the Meier-Sanders theory of progress sets;
  1562 
  1563 * MicroJava: bytecode verifier and lightweight bytecode verifier
  1564 as abstract algorithms, instantiated to the JVM;
  1565 
  1566 * Bali: Java source language formalization. Type system, operational
  1567 semantics, axiomatic semantics. Supported language features:
  1568 classes, interfaces, objects,virtual methods, static methods,
  1569 static/instance fields, arrays, access modifiers, definite
  1570 assignment, exceptions.
  1571 
  1572 
  1573 *** ZF ***
  1574 
  1575 * ZF/Constructible: consistency proof for AC (Gdel's constructible
  1576 universe, etc.);
  1577 
  1578 * Main ZF: virtually all theories converted to new-style format;
  1579 
  1580 
  1581 *** ML ***
  1582 
  1583 * Pure: Tactic.prove provides sane interface for internal proofs;
  1584 omits the infamous "standard" operation, so this is more appropriate
  1585 than prove_goalw_cterm in many situations (e.g. in simprocs);
  1586 
  1587 * Pure: improved error reporting of simprocs;
  1588 
  1589 * Provers: Simplifier.simproc(_i) provides sane interface for setting
  1590 up simprocs;
  1591 
  1592 
  1593 *** Document preparation ***
  1594 
  1595 * uses \par instead of \\ for line breaks in theory text. This may
  1596 shift some page breaks in large documents. To get the old behaviour
  1597 use \renewcommand{\isanewline}{\mbox{}\\\mbox{}} in root.tex.
  1598 
  1599 * minimized dependencies of isabelle.sty and isabellesym.sty on
  1600 other packages
  1601 
  1602 * \<euro> now needs package babel/greek instead of marvosym (which
  1603 broke \Rightarrow)
  1604 
  1605 * normal size for \<zero>...\<nine> (uses \mathbf instead of
  1606 textcomp package)
  1607 
  1608 
  1609 
  1610 New in Isabelle2002 (March 2002)
  1611 --------------------------------
  1612 
  1613 *** Document preparation ***
  1614 
  1615 * greatly simplified document preparation setup, including more
  1616 graceful interpretation of isatool usedir -i/-d/-D options, and more
  1617 instructive isatool mkdir; users should basically be able to get
  1618 started with "isatool mkdir HOL Test && isatool make"; alternatively,
  1619 users may run a separate document processing stage manually like this:
  1620 "isatool usedir -D output HOL Test && isatool document Test/output";
  1621 
  1622 * theory dependency graph may now be incorporated into documents;
  1623 isatool usedir -g true will produce session_graph.eps/.pdf for use
  1624 with \includegraphics of LaTeX;
  1625 
  1626 * proper spacing of consecutive markup elements, especially text
  1627 blocks after section headings;
  1628 
  1629 * support bold style (for single symbols only), input syntax is like
  1630 this: "\<^bold>\<alpha>" or "\<^bold>A";
  1631 
  1632 * \<bullet> is now output as bold \cdot by default, which looks much
  1633 better in printed text;
  1634 
  1635 * added default LaTeX bindings for \<tturnstile> and \<TTurnstile>;
  1636 note that these symbols are currently unavailable in Proof General /
  1637 X-Symbol; new symbols \<zero>, \<one>, ..., \<nine>, and \<euro>;
  1638 
  1639 * isatool latex no longer depends on changed TEXINPUTS, instead
  1640 isatool document copies the Isabelle style files to the target
  1641 location;
  1642 
  1643 
  1644 *** Isar ***
  1645 
  1646 * Pure/Provers: improved proof by cases and induction;
  1647   - 'case' command admits impromptu naming of parameters (such as
  1648     "case (Suc n)");
  1649   - 'induct' method divinates rule instantiation from the inductive
  1650     claim; no longer requires excessive ?P bindings for proper
  1651     instantiation of cases;
  1652   - 'induct' method properly enumerates all possibilities of set/type
  1653     rules; as a consequence facts may be also passed through *type*
  1654     rules without further ado;
  1655   - 'induct' method now derives symbolic cases from the *rulified*
  1656     rule (before it used to rulify cases stemming from the internal
  1657     atomized version); this means that the context of a non-atomic
  1658     statement becomes is included in the hypothesis, avoiding the
  1659     slightly cumbersome show "PROP ?case" form;
  1660   - 'induct' may now use elim-style induction rules without chaining
  1661     facts, using ``missing'' premises from the goal state; this allows
  1662     rules stemming from inductive sets to be applied in unstructured
  1663     scripts, while still benefitting from proper handling of non-atomic
  1664     statements; NB: major inductive premises need to be put first, all
  1665     the rest of the goal is passed through the induction;
  1666   - 'induct' proper support for mutual induction involving non-atomic
  1667     rule statements (uses the new concept of simultaneous goals, see
  1668     below);
  1669   - append all possible rule selections, but only use the first
  1670     success (no backtracking);
  1671   - removed obsolete "(simplified)" and "(stripped)" options of methods;
  1672   - undeclared rule case names default to numbers 1, 2, 3, ...;
  1673   - added 'print_induct_rules' (covered by help item in recent Proof
  1674     General versions);
  1675   - moved induct/cases attributes to Pure, methods to Provers;
  1676   - generic method setup instantiated for FOL and HOL;
  1677 
  1678 * Pure: support multiple simultaneous goal statements, for example
  1679 "have a: A and b: B" (same for 'theorem' etc.); being a pure
  1680 meta-level mechanism, this acts as if several individual goals had
  1681 been stated separately; in particular common proof methods need to be
  1682 repeated in order to cover all claims; note that a single elimination
  1683 step is *not* sufficient to establish the two conjunctions, so this
  1684 fails:
  1685 
  1686   assume "A & B" then have A and B ..   (*".." fails*)
  1687 
  1688 better use "obtain" in situations as above; alternative refer to
  1689 multi-step methods like 'auto', 'simp_all', 'blast+' etc.;
  1690 
  1691 * Pure: proper integration with ``locales''; unlike the original
  1692 version by Florian Kammller, Isar locales package high-level proof
  1693 contexts rather than raw logical ones (e.g. we admit to include
  1694 attributes everywhere); operations on locales include merge and
  1695 rename; support for implicit arguments (``structures''); simultaneous
  1696 type-inference over imports and text; see also HOL/ex/Locales.thy for
  1697 some examples;
  1698 
  1699 * Pure: the following commands have been ``localized'', supporting a
  1700 target locale specification "(in name)": 'lemma', 'theorem',
  1701 'corollary', 'lemmas', 'theorems', 'declare'; the results will be
  1702 stored both within the locale and at the theory level (exported and
  1703 qualified by the locale name);
  1704 
  1705 * Pure: theory goals may now be specified in ``long'' form, with
  1706 ad-hoc contexts consisting of arbitrary locale elements. for example
  1707 ``lemma foo: fixes x assumes "A x" shows "B x"'' (local syntax and
  1708 definitions may be given, too); the result is a meta-level rule with
  1709 the context elements being discharged in the obvious way;
  1710 
  1711 * Pure: new proof command 'using' allows to augment currently used
  1712 facts after a goal statement ('using' is syntactically analogous to
  1713 'apply', but acts on the goal's facts only); this allows chained facts
  1714 to be separated into parts given before and after a claim, as in
  1715 ``from a and b have C using d and e <proof>'';
  1716 
  1717 * Pure: renamed "antecedent" case to "rule_context";
  1718 
  1719 * Pure: new 'judgment' command records explicit information about the
  1720 object-logic embedding (used by several tools internally); no longer
  1721 use hard-wired "Trueprop";
  1722 
  1723 * Pure: added 'corollary' command;
  1724 
  1725 * Pure: fixed 'token_translation' command;
  1726 
  1727 * Pure: removed obsolete 'exported' attribute;
  1728 
  1729 * Pure: dummy pattern "_" in is/let is now automatically lifted over
  1730 bound variables: "ALL x. P x --> Q x" (is "ALL x. _ --> ?C x")
  1731 supersedes more cumbersome ... (is "ALL x. _ x --> ?C x");
  1732 
  1733 * Pure: method 'atomize' presents local goal premises as object-level
  1734 statements (atomic meta-level propositions); setup controlled via
  1735 rewrite rules declarations of 'atomize' attribute; example
  1736 application: 'induct' method with proper rule statements in improper
  1737 proof *scripts*;
  1738 
  1739 * Pure: emulation of instantiation tactics (rule_tac, cut_tac, etc.)
  1740 now consider the syntactic context of assumptions, giving a better
  1741 chance to get type-inference of the arguments right (this is
  1742 especially important for locales);
  1743 
  1744 * Pure: "sorry" no longer requires quick_and_dirty in interactive
  1745 mode;
  1746 
  1747 * Pure/obtain: the formal conclusion "thesis", being marked as
  1748 ``internal'', may no longer be reference directly in the text;
  1749 potential INCOMPATIBILITY, may need to use "?thesis" in rare
  1750 situations;
  1751 
  1752 * Pure: generic 'sym' attribute which declares a rule both as pure
  1753 'elim?' and for the 'symmetric' operation;
  1754 
  1755 * Pure: marginal comments ``--'' may now occur just anywhere in the
  1756 text; the fixed correlation with particular command syntax has been
  1757 discontinued;
  1758 
  1759 * Pure: new method 'rules' is particularly well-suited for proof
  1760 search in intuitionistic logic; a bit slower than 'blast' or 'fast',
  1761 but often produces more compact proof terms with less detours;
  1762 
  1763 * Pure/Provers/classical: simplified integration with pure rule
  1764 attributes and methods; the classical "intro?/elim?/dest?"
  1765 declarations coincide with the pure ones; the "rule" method no longer
  1766 includes classically swapped intros; "intro" and "elim" methods no
  1767 longer pick rules from the context; also got rid of ML declarations
  1768 AddXIs/AddXEs/AddXDs; all of this has some potential for
  1769 INCOMPATIBILITY;
  1770 
  1771 * Provers/classical: attribute 'swapped' produces classical inversions
  1772 of introduction rules;
  1773 
  1774 * Provers/simplifier: 'simplified' attribute may refer to explicit
  1775 rules instead of full simplifier context; 'iff' attribute handles
  1776 conditional rules;
  1777 
  1778 * HOL: 'typedef' now allows alternative names for Rep/Abs morphisms;
  1779 
  1780 * HOL: 'recdef' now fails on unfinished automated proofs, use
  1781 "(permissive)" option to recover old behavior;
  1782 
  1783 * HOL: 'inductive' no longer features separate (collective) attributes
  1784 for 'intros' (was found too confusing);
  1785 
  1786 * HOL: properly declared induction rules less_induct and
  1787 wf_induct_rule;
  1788 
  1789 
  1790 *** HOL ***
  1791 
  1792 * HOL: moved over to sane numeral syntax; the new policy is as
  1793 follows:
  1794 
  1795   - 0 and 1 are polymorphic constants, which are defined on any
  1796   numeric type (nat, int, real etc.);
  1797 
  1798   - 2, 3, 4, ... and -1, -2, -3, ... are polymorphic numerals, based
  1799   binary representation internally;
  1800 
  1801   - type nat has special constructor Suc, and generally prefers Suc 0
  1802   over 1::nat and Suc (Suc 0) over 2::nat;
  1803 
  1804 This change may cause significant problems of INCOMPATIBILITY; here
  1805 are some hints on converting existing sources:
  1806 
  1807   - due to the new "num" token, "-0" and "-1" etc. are now atomic
  1808   entities, so expressions involving "-" (unary or binary minus) need
  1809   to be spaced properly;
  1810 
  1811   - existing occurrences of "1" may need to be constraint "1::nat" or
  1812   even replaced by Suc 0; similar for old "2";
  1813 
  1814   - replace "#nnn" by "nnn", and "#-nnn" by "-nnn";
  1815 
  1816   - remove all special provisions on numerals in proofs;
  1817 
  1818 * HOL: simp rules nat_number expand numerals on nat to Suc/0
  1819 representation (depends on bin_arith_simps in the default context);
  1820 
  1821 * HOL: symbolic syntax for x^2 (numeral 2);
  1822 
  1823 * HOL: the class of all HOL types is now called "type" rather than
  1824 "term"; INCOMPATIBILITY, need to adapt references to this type class
  1825 in axclass/classes, instance/arities, and (usually rare) occurrences
  1826 in typings (of consts etc.); internally the class is called
  1827 "HOL.type", ML programs should refer to HOLogic.typeS;
  1828 
  1829 * HOL/record package improvements:
  1830   - new derived operations "fields" to build a partial record section,
  1831     "extend" to promote a fixed record to a record scheme, and
  1832     "truncate" for the reverse; cf. theorems "xxx.defs", which are *not*
  1833     declared as simp by default;
  1834   - shared operations ("more", "fields", etc.) now need to be always
  1835     qualified) --- potential INCOMPATIBILITY;
  1836   - removed "make_scheme" operations (use "make" with "extend") --
  1837     INCOMPATIBILITY;
  1838   - removed "more" class (simply use "term") -- INCOMPATIBILITY;
  1839   - provides cases/induct rules for use with corresponding Isar
  1840     methods (for concrete records, record schemes, concrete more
  1841     parts, and schematic more parts -- in that order);
  1842   - internal definitions directly based on a light-weight abstract
  1843     theory of product types over typedef rather than datatype;
  1844 
  1845 * HOL: generic code generator for generating executable ML code from
  1846 specifications; specific support for HOL constructs such as inductive
  1847 datatypes and sets, as well as recursive functions; can be invoked
  1848 via 'generate_code' theory section;
  1849 
  1850 * HOL: canonical cases/induct rules for n-tuples (n = 3..7);
  1851 
  1852 * HOL: consolidated and renamed several theories.  In particular:
  1853         Ord.thy has been absorbed into HOL.thy
  1854         String.thy has been absorbed into List.thy
  1855 
  1856 * HOL: concrete setsum syntax "\<Sum>i:A. b" == "setsum (%i. b) A"
  1857 (beware of argument permutation!);
  1858 
  1859 * HOL: linorder_less_split superseded by linorder_cases;
  1860 
  1861 * HOL/List: "nodups" renamed to "distinct";
  1862 
  1863 * HOL: added "The" definite description operator; move Hilbert's "Eps"
  1864 to peripheral theory "Hilbert_Choice"; some INCOMPATIBILITIES:
  1865   - Ex_def has changed, now need to use some_eq_ex
  1866 
  1867 * HOL: made split_all_tac safe; EXISTING PROOFS MAY FAIL OR LOOP, so
  1868 in this (rare) case use:
  1869 
  1870   delSWrapper "split_all_tac"
  1871   addSbefore ("unsafe_split_all_tac", unsafe_split_all_tac)
  1872 
  1873 * HOL: added safe wrapper "split_conv_tac" to claset; EXISTING PROOFS
  1874 MAY FAIL;
  1875 
  1876 * HOL: introduced f^n = f o ... o f; warning: due to the limits of
  1877 Isabelle's type classes, ^ on functions and relations has too general
  1878 a domain, namely ('a * 'b) set and 'a => 'b; this means that it may be
  1879 necessary to attach explicit type constraints;
  1880 
  1881 * HOL/Relation: the prefix name of the infix "O" has been changed from
  1882 "comp" to "rel_comp"; INCOMPATIBILITY: a few theorems have been
  1883 renamed accordingly (eg "compI" -> "rel_compI").
  1884 
  1885 * HOL: syntax translations now work properly with numerals and records
  1886 expressions;
  1887 
  1888 * HOL: bounded abstraction now uses syntax "%" / "\<lambda>" instead
  1889 of "lam" -- INCOMPATIBILITY;
  1890 
  1891 * HOL: got rid of some global declarations (potential INCOMPATIBILITY
  1892 for ML tools): const "()" renamed "Product_Type.Unity", type "unit"
  1893 renamed "Product_Type.unit";
  1894 
  1895 * HOL: renamed rtrancl_into_rtrancl2 to converse_rtrancl_into_rtrancl
  1896 
  1897 * HOL: removed obsolete theorem "optionE" (use "option.exhaust", or
  1898 the "cases" method);
  1899 
  1900 * HOL/GroupTheory: group theory examples including Sylow's theorem (by
  1901 Florian Kammller);
  1902 
  1903 * HOL/IMP: updated and converted to new-style theory format; several
  1904 parts turned into readable document, with proper Isar proof texts and
  1905 some explanations (by Gerwin Klein);
  1906 
  1907 * HOL-Real: added Complex_Numbers (by Gertrud Bauer);
  1908 
  1909 * HOL-Hyperreal is now a logic image;
  1910 
  1911 
  1912 *** HOLCF ***
  1913 
  1914 * Isar: consts/constdefs supports mixfix syntax for continuous
  1915 operations;
  1916 
  1917 * Isar: domain package adapted to new-style theory format, e.g. see
  1918 HOLCF/ex/Dnat.thy;
  1919 
  1920 * theory Lift: proper use of rep_datatype lift instead of ML hacks --
  1921 potential INCOMPATIBILITY; now use plain induct_tac instead of former
  1922 lift.induct_tac, always use UU instead of Undef;
  1923 
  1924 * HOLCF/IMP: updated and converted to new-style theory;
  1925 
  1926 
  1927 *** ZF ***
  1928 
  1929 * Isar: proper integration of logic-specific tools and packages,
  1930 including theory commands '(co)inductive', '(co)datatype',
  1931 'rep_datatype', 'inductive_cases', as well as methods 'ind_cases',
  1932 'induct_tac', 'case_tac', and 'typecheck' (with attribute 'TC');
  1933 
  1934 * theory Main no longer includes AC; for the Axiom of Choice, base
  1935 your theory on Main_ZFC;
  1936 
  1937 * the integer library now covers quotients and remainders, with many
  1938 laws relating division to addition, multiplication, etc.;
  1939 
  1940 * ZF/UNITY: Chandy and Misra's UNITY is now available in ZF, giving a
  1941 typeless version of the formalism;
  1942 
  1943 * ZF/AC, Coind, IMP, Resid: updated and converted to new-style theory
  1944 format;
  1945 
  1946 * ZF/Induct: new directory for examples of inductive definitions,
  1947 including theory Multiset for multiset orderings; converted to
  1948 new-style theory format;
  1949 
  1950 * ZF: many new theorems about lists, ordinals, etc.;
  1951 
  1952 
  1953 *** General ***
  1954 
  1955 * Pure/kernel: meta-level proof terms (by Stefan Berghofer); reference
  1956 variable proof controls level of detail: 0 = no proofs (only oracle
  1957 dependencies), 1 = lemma dependencies, 2 = compact proof terms; see
  1958 also ref manual for further ML interfaces;
  1959 
  1960 * Pure/axclass: removed obsolete ML interface
  1961 goal_subclass/goal_arity;
  1962 
  1963 * Pure/syntax: new token syntax "num" for plain numerals (without "#"
  1964 of "xnum"); potential INCOMPATIBILITY, since -0, -1 etc. are now
  1965 separate tokens, so expressions involving minus need to be spaced
  1966 properly;
  1967 
  1968 * Pure/syntax: support non-oriented infixes, using keyword "infix"
  1969 rather than "infixl" or "infixr";
  1970 
  1971 * Pure/syntax: concrete syntax for dummy type variables admits genuine
  1972 sort constraint specifications in type inference; e.g. "x::_::foo"
  1973 ensures that the type of "x" is of sort "foo" (but not necessarily a
  1974 type variable);
  1975 
  1976 * Pure/syntax: print modes "type_brackets" and "no_type_brackets"
  1977 control output of nested => (types); the default behavior is
  1978 "type_brackets";
  1979 
  1980 * Pure/syntax: builtin parse translation for "_constify" turns valued
  1981 tokens into AST constants;
  1982 
  1983 * Pure/syntax: prefer later declarations of translations and print
  1984 translation functions; potential INCOMPATIBILITY: need to reverse
  1985 multiple declarations for same syntax element constant;
  1986 
  1987 * Pure/show_hyps reset by default (in accordance to existing Isar
  1988 practice);
  1989 
  1990 * Provers/classical: renamed addaltern to addafter, addSaltern to
  1991 addSafter;
  1992 
  1993 * Provers/clasimp: ``iff'' declarations now handle conditional rules
  1994 as well;
  1995 
  1996 * system: tested support for MacOS X; should be able to get Isabelle +
  1997 Proof General to work in a plain Terminal after installing Poly/ML
  1998 (e.g. from the Isabelle distribution area) and GNU bash alone
  1999 (e.g. from http://www.apple.com); full X11, XEmacs and X-Symbol
  2000 support requires further installations, e.g. from
  2001 http://fink.sourceforge.net/);
  2002 
  2003 * system: support Poly/ML 4.1.1 (able to manage larger heaps);
  2004 
  2005 * system: reduced base memory usage by Poly/ML (approx. 20 MB instead
  2006 of 40 MB), cf. ML_OPTIONS;
  2007 
  2008 * system: Proof General keywords specification is now part of the
  2009 Isabelle distribution (see etc/isar-keywords.el);
  2010 
  2011 * system: support for persistent Proof General sessions (refrain from
  2012 outdating all loaded theories on startup); user may create writable
  2013 logic images like this: ``isabelle -q HOL Test'';
  2014 
  2015 * system: smart selection of Isabelle process versus Isabelle
  2016 interface, accommodates case-insensitive file systems (e.g. HFS+); may
  2017 run both "isabelle" and "Isabelle" even if file names are badly
  2018 damaged (executable inspects the case of the first letter of its own
  2019 name); added separate "isabelle-process" and "isabelle-interface";
  2020 
  2021 * system: refrain from any attempt at filtering input streams; no
  2022 longer support ``8bit'' encoding of old isabelle font, instead proper
  2023 iso-latin characters may now be used; the related isatools
  2024 "symbolinput" and "nonascii" have disappeared as well;
  2025 
  2026 * system: removed old "xterm" interface (the print modes "xterm" and
  2027 "xterm_color" are still available for direct use in a suitable
  2028 terminal);
  2029 
  2030 
  2031 
  2032 New in Isabelle99-2 (February 2001)
  2033 -----------------------------------
  2034 
  2035 *** Overview of INCOMPATIBILITIES ***
  2036 
  2037 * HOL: please note that theories in the Library and elsewhere often use the
  2038 new-style (Isar) format; to refer to their theorems in an ML script you must
  2039 bind them to ML identifers by e.g.      val thm_name = thm "thm_name";
  2040 
  2041 * HOL: inductive package no longer splits induction rule aggressively,
  2042 but only as far as specified by the introductions given; the old
  2043 format may be recovered via ML function complete_split_rule or attribute
  2044 'split_rule (complete)';
  2045 
  2046 * HOL: induct renamed to lfp_induct, lfp_Tarski to lfp_unfold,
  2047 gfp_Tarski to gfp_unfold;
  2048 
  2049 * HOL: contrapos, contrapos2 renamed to contrapos_nn, contrapos_pp;
  2050 
  2051 * HOL: infix "dvd" now has priority 50 rather than 70 (because it is a
  2052 relation); infix "^^" has been renamed "``"; infix "``" has been
  2053 renamed "`"; "univalent" has been renamed "single_valued";
  2054 
  2055 * HOL/Real: "rinv" and "hrinv" replaced by overloaded "inverse"
  2056 operation;
  2057 
  2058 * HOLCF: infix "`" has been renamed "$"; the symbol syntax is \<cdot>;
  2059 
  2060 * Isar: 'obtain' no longer declares "that" fact as simp/intro;
  2061 
  2062 * Isar/HOL: method 'induct' now handles non-atomic goals; as a
  2063 consequence, it is no longer monotonic wrt. the local goal context
  2064 (which is now passed through the inductive cases);
  2065 
  2066 * Document preparation: renamed standard symbols \<ll> to \<lless> and
  2067 \<gg> to \<ggreater>;
  2068 
  2069 
  2070 *** Document preparation ***
  2071 
  2072 * \isabellestyle{NAME} selects version of Isabelle output (currently
  2073 available: are "it" for near math-mode best-style output, "sl" for
  2074 slanted text style, and "tt" for plain type-writer; if no
  2075 \isabellestyle command is given, output is according to slanted
  2076 type-writer);
  2077 
  2078 * support sub/super scripts (for single symbols only), input syntax is
  2079 like this: "A\<^sup>*" or "A\<^sup>\<star>";
  2080 
  2081 * some more standard symbols; see Appendix A of the system manual for
  2082 the complete list of symbols defined in isabellesym.sty;
  2083 
  2084 * improved isabelle style files; more abstract symbol implementation
  2085 (should now use \isamath{...} and \isatext{...} in custom symbol
  2086 definitions);
  2087 
  2088 * antiquotation @{goals} and @{subgoals} for output of *dynamic* goals
  2089 state; Note that presentation of goal states does not conform to
  2090 actual human-readable proof documents.  Please do not include goal
  2091 states into document output unless you really know what you are doing!
  2092 
  2093 * proper indentation of antiquoted output with proportional LaTeX
  2094 fonts;
  2095 
  2096 * no_document ML operator temporarily disables LaTeX document
  2097 generation;
  2098 
  2099 * isatool unsymbolize tunes sources for plain ASCII communication;
  2100 
  2101 
  2102 *** Isar ***
  2103 
  2104 * Pure: Isar now suffers initial goal statements to contain unbound
  2105 schematic variables (this does not conform to actual readable proof
  2106 documents, due to unpredictable outcome and non-compositional proof
  2107 checking); users who know what they are doing may use schematic goals
  2108 for Prolog-style synthesis of proven results;
  2109 
  2110 * Pure: assumption method (an implicit finishing) now handles actual
  2111 rules as well;
  2112 
  2113 * Pure: improved 'obtain' --- moved to Pure, insert "that" into
  2114 initial goal, declare "that" only as Pure intro (only for single
  2115 steps); the "that" rule assumption may now be involved in implicit
  2116 finishing, thus ".." becomes a feasible for trivial obtains;
  2117 
  2118 * Pure: default proof step now includes 'intro_classes'; thus trivial
  2119 instance proofs may be performed by "..";
  2120 
  2121 * Pure: ?thesis / ?this / "..." now work for pure meta-level
  2122 statements as well;
  2123 
  2124 * Pure: more robust selection of calculational rules;
  2125 
  2126 * Pure: the builtin notion of 'finished' goal now includes the ==-refl
  2127 rule (as well as the assumption rule);
  2128 
  2129 * Pure: 'thm_deps' command visualizes dependencies of theorems and
  2130 lemmas, using the graph browser tool;
  2131 
  2132 * Pure: predict failure of "show" in interactive mode;
  2133 
  2134 * Pure: 'thms_containing' now takes actual terms as arguments;
  2135 
  2136 * HOL: improved method 'induct' --- now handles non-atomic goals
  2137 (potential INCOMPATIBILITY); tuned error handling;
  2138 
  2139 * HOL: cases and induct rules now provide explicit hints about the
  2140 number of facts to be consumed (0 for "type" and 1 for "set" rules);
  2141 any remaining facts are inserted into the goal verbatim;
  2142 
  2143 * HOL: local contexts (aka cases) may now contain term bindings as
  2144 well; the 'cases' and 'induct' methods new provide a ?case binding for
  2145 the result to be shown in each case;
  2146 
  2147 * HOL: added 'recdef_tc' command;
  2148 
  2149 * isatool convert assists in eliminating legacy ML scripts;
  2150 
  2151 
  2152 *** HOL ***
  2153 
  2154 * HOL/Library: a collection of generic theories to be used together
  2155 with main HOL; the theory loader path already includes this directory
  2156 by default; the following existing theories have been moved here:
  2157 HOL/Induct/Multiset, HOL/Induct/Acc (as Accessible_Part), HOL/While
  2158 (as While_Combinator), HOL/Lex/Prefix (as List_Prefix);
  2159 
  2160 * HOL/Unix: "Some aspects of Unix file-system security", a typical
  2161 modelling and verification task performed in Isabelle/HOL +
  2162 Isabelle/Isar + Isabelle document preparation (by Markus Wenzel).
  2163 
  2164 * HOL/Algebra: special summation operator SUM no longer exists, it has
  2165 been replaced by setsum; infix 'assoc' now has priority 50 (like
  2166 'dvd'); axiom 'one_not_zero' has been moved from axclass 'ring' to
  2167 'domain', this makes the theory consistent with mathematical
  2168 literature;
  2169 
  2170 * HOL basics: added overloaded operations "inverse" and "divide"
  2171 (infix "/"), syntax for generic "abs" operation, generic summation
  2172 operator \<Sum>;
  2173 
  2174 * HOL/typedef: simplified package, provide more useful rules (see also
  2175 HOL/subset.thy);
  2176 
  2177 * HOL/datatype: induction rule for arbitrarily branching datatypes is
  2178 now expressed as a proper nested rule (old-style tactic scripts may
  2179 require atomize_strip_tac to cope with non-atomic premises);
  2180 
  2181 * HOL: renamed theory "Prod" to "Product_Type", renamed "split" rule
  2182 to "split_conv" (old name still available for compatibility);
  2183 
  2184 * HOL: improved concrete syntax for strings (e.g. allows translation
  2185 rules with string literals);
  2186 
  2187 * HOL-Real-Hyperreal: this extends HOL-Real with the hyperreals
  2188  and Fleuriot's mechanization of analysis, including the transcendental
  2189  functions for the reals;
  2190 
  2191 * HOL/Real, HOL/Hyperreal: improved arithmetic simplification;
  2192 
  2193 
  2194 *** CTT ***
  2195 
  2196 * CTT: x-symbol support for Pi, Sigma, -->, : (membership); note that
  2197 "lam" is displayed as TWO lambda-symbols
  2198 
  2199 * CTT: theory Main now available, containing everything (that is, Bool
  2200 and Arith);
  2201 
  2202 
  2203 *** General ***
  2204 
  2205 * Pure: the Simplifier has been implemented properly as a derived rule
  2206 outside of the actual kernel (at last!); the overall performance
  2207 penalty in practical applications is about 50%, while reliability of
  2208 the Isabelle inference kernel has been greatly improved;
  2209 
  2210 * print modes "brackets" and "no_brackets" control output of nested =>
  2211 (types) and ==> (props); the default behaviour is "brackets";
  2212 
  2213 * Provers: fast_tac (and friends) now handle actual object-logic rules
  2214 as assumptions as well;
  2215 
  2216 * system: support Poly/ML 4.0;
  2217 
  2218 * system: isatool install handles KDE version 1 or 2;
  2219 
  2220 
  2221 
  2222 New in Isabelle99-1 (October 2000)
  2223 ----------------------------------
  2224 
  2225 *** Overview of INCOMPATIBILITIES ***
  2226 
  2227 * HOL: simplification of natural numbers is much changed; to partly
  2228 recover the old behaviour (e.g. to prevent n+n rewriting to #2*n)
  2229 issue the following ML commands:
  2230 
  2231   Delsimprocs Nat_Numeral_Simprocs.cancel_numerals;
  2232   Delsimprocs [Nat_Numeral_Simprocs.combine_numerals];
  2233 
  2234 * HOL: simplification no longer dives into case-expressions; this is
  2235 controlled by "t.weak_case_cong" for each datatype t;
  2236 
  2237 * HOL: nat_less_induct renamed to less_induct;
  2238 
  2239 * HOL: systematic renaming of the SOME (Eps) rules, may use isatool
  2240 fixsome to patch .thy and .ML sources automatically;
  2241 
  2242   select_equality  -> some_equality
  2243   select_eq_Ex     -> some_eq_ex
  2244   selectI2EX       -> someI2_ex
  2245   selectI2         -> someI2
  2246   selectI          -> someI
  2247   select1_equality -> some1_equality
  2248   Eps_sym_eq       -> some_sym_eq_trivial
  2249   Eps_eq           -> some_eq_trivial
  2250 
  2251 * HOL: exhaust_tac on datatypes superceded by new generic case_tac;
  2252 
  2253 * HOL: removed obsolete theorem binding expand_if (refer to split_if
  2254 instead);
  2255 
  2256 * HOL: the recursion equations generated by 'recdef' are now called
  2257 f.simps instead of f.rules;
  2258 
  2259 * HOL: qed_spec_mp now also handles bounded ALL as well;
  2260 
  2261 * HOL: 0 is now overloaded, so the type constraint ":: nat" may
  2262 sometimes be needed;
  2263 
  2264 * HOL: the constant for "f``x" is now "image" rather than "op ``";
  2265 
  2266 * HOL: the constant for "f-``x" is now "vimage" rather than "op -``";
  2267 
  2268 * HOL: the disjoint sum is now "<+>" instead of "Plus"; the cartesian
  2269 product is now "<*>" instead of "Times"; the lexicographic product is
  2270 now "<*lex*>" instead of "**";
  2271 
  2272 * HOL: theory Sexp is now in HOL/Induct examples (it used to be part
  2273 of main HOL, but was unused); better use HOL's datatype package;
  2274 
  2275 * HOL: removed "symbols" syntax for constant "override" of theory Map;
  2276 the old syntax may be recovered as follows:
  2277 
  2278   syntax (symbols)
  2279     override  :: "('a ~=> 'b) => ('a ~=> 'b) => ('a ~=> 'b)"
  2280       (infixl "\\<oplus>" 100)
  2281 
  2282 * HOL/Real: "rabs" replaced by overloaded "abs" function;
  2283 
  2284 * HOL/ML: even fewer consts are declared as global (see theories Ord,
  2285 Lfp, Gfp, WF); this only affects ML packages that refer to const names
  2286 internally;
  2287 
  2288 * HOL and ZF: syntax for quotienting wrt an equivalence relation
  2289 changed from A/r to A//r;
  2290 
  2291 * ZF: new treatment of arithmetic (nat & int) may break some old
  2292 proofs;
  2293 
  2294 * Isar: renamed some attributes (RS -> THEN, simplify -> simplified,
  2295 rulify -> rule_format, elimify -> elim_format, ...);
  2296 
  2297 * Isar/Provers: intro/elim/dest attributes changed; renamed
  2298 intro/intro!/intro!! flags to intro!/intro/intro? (in most cases, one
  2299 should have to change intro!! to intro? only); replaced "delrule" by
  2300 "rule del";
  2301 
  2302 * Isar/HOL: renamed "intrs" to "intros" in inductive definitions;
  2303 
  2304 * Provers: strengthened force_tac by using new first_best_tac;
  2305 
  2306 * LaTeX document preparation: several changes of isabelle.sty (see
  2307 lib/texinputs);
  2308 
  2309 
  2310 *** Document preparation ***
  2311 
  2312 * formal comments (text blocks etc.) in new-style theories may now
  2313 contain antiquotations of thm/prop/term/typ/text to be presented
  2314 according to latex print mode; concrete syntax is like this:
  2315 @{term[show_types] "f(x) = a + x"};
  2316 
  2317 * isatool mkdir provides easy setup of Isabelle session directories,
  2318 including proper document sources;
  2319 
  2320 * generated LaTeX sources are now deleted after successful run
  2321 (isatool document -c); may retain a copy somewhere else via -D option
  2322 of isatool usedir;
  2323 
  2324 * isatool usedir -D now lets isatool latex -o sty update the Isabelle
  2325 style files, achieving self-contained LaTeX sources and simplifying
  2326 LaTeX debugging;
  2327 
  2328 * old-style theories now produce (crude) LaTeX output as well;
  2329 
  2330 * browser info session directories are now self-contained (may be put
  2331 on WWW server seperately); improved graphs of nested sessions; removed
  2332 graph for 'all sessions';
  2333 
  2334 * several improvements in isabelle style files; \isabellestyle{it}
  2335 produces fake math mode output; \isamarkupheader is now \section by
  2336 default; see lib/texinputs/isabelle.sty etc.;
  2337 
  2338 
  2339 *** Isar ***
  2340 
  2341 * Isar/Pure: local results and corresponding term bindings are now
  2342 subject to Hindley-Milner polymorphism (similar to ML); this
  2343 accommodates incremental type-inference very nicely;
  2344 
  2345 * Isar/Pure: new derived language element 'obtain' supports
  2346 generalized existence reasoning;
  2347 
  2348 * Isar/Pure: new calculational elements 'moreover' and 'ultimately'
  2349 support accumulation of results, without applying any rules yet;
  2350 useful to collect intermediate results without explicit name
  2351 references, and for use with transitivity rules with more than 2
  2352 premises;
  2353 
  2354 * Isar/Pure: scalable support for case-analysis type proofs: new
  2355 'case' language element refers to local contexts symbolically, as
  2356 produced by certain proof methods; internally, case names are attached
  2357 to theorems as "tags";
  2358 
  2359 * Isar/Pure: theory command 'hide' removes declarations from
  2360 class/type/const name spaces;
  2361 
  2362 * Isar/Pure: theory command 'defs' supports option "(overloaded)" to
  2363 indicate potential overloading;
  2364 
  2365 * Isar/Pure: changed syntax of local blocks from {{ }} to { };
  2366 
  2367 * Isar/Pure: syntax of sorts made 'inner', i.e. have to write
  2368 "{a,b,c}" instead of {a,b,c};
  2369 
  2370 * Isar/Pure now provides its own version of intro/elim/dest
  2371 attributes; useful for building new logics, but beware of confusion
  2372 with the version in Provers/classical;
  2373 
  2374 * Isar/Pure: the local context of (non-atomic) goals is provided via
  2375 case name 'antecedent';
  2376 
  2377 * Isar/Pure: removed obsolete 'transfer' attribute (transfer of thms
  2378 to the current context is now done automatically);
  2379 
  2380 * Isar/Pure: theory command 'method_setup' provides a simple interface
  2381 for definining proof methods in ML;
  2382 
  2383 * Isar/Provers: intro/elim/dest attributes changed; renamed
  2384 intro/intro!/intro!! flags to intro!/intro/intro? (INCOMPATIBILITY, in
  2385 most cases, one should have to change intro!! to intro? only);
  2386 replaced "delrule" by "rule del";
  2387 
  2388 * Isar/Provers: new 'hypsubst' method, plain 'subst' method and
  2389 'symmetric' attribute (the latter supercedes [RS sym]);
  2390 
  2391 * Isar/Provers: splitter support (via 'split' attribute and 'simp'
  2392 method modifier); 'simp' method: 'only:' modifier removes loopers as
  2393 well (including splits);
  2394 
  2395 * Isar/Provers: Simplifier and Classical methods now support all kind
  2396 of modifiers used in the past, including 'cong', 'iff', etc.
  2397 
  2398 * Isar/Provers: added 'fastsimp' and 'clarsimp' methods (combination
  2399 of Simplifier and Classical reasoner);
  2400 
  2401 * Isar/HOL: new proof method 'cases' and improved version of 'induct'
  2402 now support named cases; major packages (inductive, datatype, primrec,
  2403 recdef) support case names and properly name parameters;
  2404 
  2405 * Isar/HOL: new transitivity rules for substitution in inequalities --
  2406 monotonicity conditions are extracted to be proven at end of
  2407 calculations;
  2408 
  2409 * Isar/HOL: removed 'case_split' thm binding, should use 'cases' proof
  2410 method anyway;
  2411 
  2412 * Isar/HOL: removed old expand_if = split_if; theorems if_splits =
  2413 split_if split_if_asm; datatype package provides theorems foo.splits =
  2414 foo.split foo.split_asm for each datatype;
  2415 
  2416 * Isar/HOL: tuned inductive package, rename "intrs" to "intros"
  2417 (potential INCOMPATIBILITY), emulation of mk_cases feature for proof
  2418 scripts: new 'inductive_cases' command and 'ind_cases' method; (Note:
  2419 use "(cases (simplified))" method in proper proof texts);
  2420 
  2421 * Isar/HOL: added global 'arith_split' attribute for 'arith' method;
  2422 
  2423 * Isar: names of theorems etc. may be natural numbers as well;
  2424 
  2425 * Isar: 'pr' command: optional arguments for goals_limit and
  2426 ProofContext.prems_limit; no longer prints theory contexts, but only
  2427 proof states;
  2428 
  2429 * Isar: diagnostic commands 'pr', 'thm', 'prop', 'term', 'typ' admit
  2430 additional print modes to be specified; e.g. "pr(latex)" will print
  2431 proof state according to the Isabelle LaTeX style;
  2432 
  2433 * Isar: improved support for emulating tactic scripts, including proof
  2434 methods 'rule_tac' etc., 'cut_tac', 'thin_tac', 'subgoal_tac',
  2435 'rename_tac', 'rotate_tac', 'tactic', and 'case_tac' / 'induct_tac'
  2436 (for HOL datatypes);
  2437 
  2438 * Isar: simplified (more robust) goal selection of proof methods: 1st
  2439 goal, all goals, or explicit goal specifier (tactic emulation); thus
  2440 'proof method scripts' have to be in depth-first order;
  2441 
  2442 * Isar: tuned 'let' syntax: replaced 'as' keyword by 'and';
  2443 
  2444 * Isar: removed 'help' command, which hasn't been too helpful anyway;
  2445 should instead use individual commands for printing items
  2446 (print_commands, print_methods etc.);
  2447 
  2448 * Isar: added 'nothing' --- the empty list of theorems;
  2449 
  2450 
  2451 *** HOL ***
  2452 
  2453 * HOL/MicroJava: formalization of a fragment of Java, together with a
  2454 corresponding virtual machine and a specification of its bytecode
  2455 verifier and a lightweight bytecode verifier, including proofs of
  2456 type-safety; by Gerwin Klein, Tobias Nipkow, David von Oheimb, and
  2457 Cornelia Pusch (see also the homepage of project Bali at
  2458 http://isabelle.in.tum.de/Bali/);
  2459 
  2460 * HOL/Algebra: new theory of rings and univariate polynomials, by
  2461 Clemens Ballarin;
  2462 
  2463 * HOL/NumberTheory: fundamental Theorem of Arithmetic, Chinese
  2464 Remainder Theorem, Fermat/Euler Theorem, Wilson's Theorem, by Thomas M
  2465 Rasmussen;
  2466 
  2467 * HOL/Lattice: fundamental concepts of lattice theory and order
  2468 structures, including duals, properties of bounds versus algebraic
  2469 laws, lattice operations versus set-theoretic ones, the Knaster-Tarski
  2470 Theorem for complete lattices etc.; may also serve as a demonstration
  2471 for abstract algebraic reasoning using axiomatic type classes, and
  2472 mathematics-style proof in Isabelle/Isar; by Markus Wenzel;
  2473 
  2474 * HOL/Prolog: a (bare-bones) implementation of Lambda-Prolog, by David
  2475 von Oheimb;
  2476 
  2477 * HOL/IMPP: extension of IMP with local variables and mutually
  2478 recursive procedures, by David von Oheimb;
  2479 
  2480 * HOL/Lambda: converted into new-style theory and document;
  2481 
  2482 * HOL/ex/Multiquote: example of multiple nested quotations and
  2483 anti-quotations -- basically a generalized version of de-Bruijn
  2484 representation; very useful in avoiding lifting of operations;
  2485 
  2486 * HOL/record: added general record equality rule to simpset; fixed
  2487 select-update simplification procedure to handle extended records as
  2488 well; admit "r" as field name;
  2489 
  2490 * HOL: 0 is now overloaded over the new sort "zero", allowing its use with
  2491 other numeric types and also as the identity of groups, rings, etc.;
  2492 
  2493 * HOL: new axclass plus_ac0 for addition with the AC-laws and 0 as identity.
  2494 Types nat and int belong to this axclass;
  2495 
  2496 * HOL: greatly improved simplification involving numerals of type nat, int, real:
  2497    (i + #8 + j) = Suc k simplifies to  #7 + (i + j) = k
  2498    i*j + k + j*#3*i     simplifies to  #4*(i*j) + k
  2499   two terms #m*u and #n*u are replaced by #(m+n)*u
  2500     (where #m, #n and u can implicitly be 1; this is simproc combine_numerals)
  2501   and the term/formula #m*u+x ~~ #n*u+y simplifies simplifies to #(m-n)+x ~~ y
  2502     or x ~~ #(n-m)+y, where ~~ is one of = < <= or - (simproc cancel_numerals);
  2503 
  2504 * HOL: meson_tac is available (previously in ex/meson.ML); it is a
  2505 powerful prover for predicate logic but knows nothing of clasets; see
  2506 ex/mesontest.ML and ex/mesontest2.ML for example applications;
  2507 
  2508 * HOL: new version of "case_tac" subsumes both boolean case split and
  2509 "exhaust_tac" on datatypes; INCOMPATIBILITY: exhaust_tac no longer
  2510 exists, may define val exhaust_tac = case_tac for ad-hoc portability;
  2511 
  2512 * HOL: simplification no longer dives into case-expressions: only the
  2513 selector expression is simplified, but not the remaining arms; to
  2514 enable full simplification of case-expressions for datatype t, you may
  2515 remove t.weak_case_cong from the simpset, either globally (Delcongs
  2516 [thm"t.weak_case_cong"];) or locally (delcongs [...]).
  2517 
  2518 * HOL/recdef: the recursion equations generated by 'recdef' for
  2519 function 'f' are now called f.simps instead of f.rules; if all
  2520 termination conditions are proved automatically, these simplification
  2521 rules are added to the simpset, as in primrec; rules may be named
  2522 individually as well, resulting in a separate list of theorems for
  2523 each equation;
  2524 
  2525 * HOL/While is a new theory that provides a while-combinator. It
  2526 permits the definition of tail-recursive functions without the
  2527 provision of a termination measure. The latter is necessary once the
  2528 invariant proof rule for while is applied.
  2529 
  2530 * HOL: new (overloaded) notation for the set of elements below/above
  2531 some element: {..u}, {..u(}, {l..}, {)l..}. See theory SetInterval.
  2532 
  2533 * HOL: theorems impI, allI, ballI bound as "strip";
  2534 
  2535 * HOL: new tactic induct_thm_tac: thm -> string -> int -> tactic
  2536 induct_tac th "x1 ... xn" expects th to have a conclusion of the form
  2537 P v1 ... vn and abbreviates res_inst_tac [("v1","x1"),...,("vn","xn")] th;
  2538 
  2539 * HOL/Real: "rabs" replaced by overloaded "abs" function;
  2540 
  2541 * HOL: theory Sexp now in HOL/Induct examples (it used to be part of
  2542 main HOL, but was unused);
  2543 
  2544 * HOL: fewer consts declared as global (e.g. have to refer to
  2545 "Lfp.lfp" instead of "lfp" internally; affects ML packages only);
  2546 
  2547 * HOL: tuned AST representation of nested pairs, avoiding bogus output
  2548 in case of overlap with user translations (e.g. judgements over
  2549 tuples); (note that the underlying logical represenation is still
  2550 bogus);
  2551 
  2552 
  2553 *** ZF ***
  2554 
  2555 * ZF: simplification automatically cancels common terms in arithmetic
  2556 expressions over nat and int;
  2557 
  2558 * ZF: new treatment of nat to minimize type-checking: all operators
  2559 coerce their operands to a natural number using the function natify,
  2560 making the algebraic laws unconditional;
  2561 
  2562 * ZF: as above, for int: operators coerce their operands to an integer
  2563 using the function intify;
  2564 
  2565 * ZF: the integer library now contains many of the usual laws for the
  2566 orderings, including $<=, and monotonicity laws for $+ and $*;
  2567 
  2568 * ZF: new example ZF/ex/NatSum to demonstrate integer arithmetic
  2569 simplification;
  2570 
  2571 * FOL and ZF: AddIffs now available, giving theorems of the form P<->Q
  2572 to the simplifier and classical reasoner simultaneously;
  2573 
  2574 
  2575 *** General ***
  2576 
  2577 * Provers: blast_tac now handles actual object-logic rules as
  2578 assumptions; note that auto_tac uses blast_tac internally as well;
  2579 
  2580 * Provers: new functions rulify/rulify_no_asm: thm -> thm for turning
  2581 outer -->/All/Ball into ==>/!!; qed_spec_mp now uses rulify_no_asm;
  2582 
  2583 * Provers: delrules now handles destruct rules as well (no longer need
  2584 explicit make_elim);
  2585 
  2586 * Provers: Blast_tac now warns of and ignores "weak elimination rules" e.g.
  2587   [| inj ?f;          ?f ?x = ?f ?y; ?x = ?y ==> ?W |] ==> ?W
  2588 use instead the strong form,
  2589   [| inj ?f; ~ ?W ==> ?f ?x = ?f ?y; ?x = ?y ==> ?W |] ==> ?W
  2590 in HOL, FOL and ZF the function cla_make_elim will create such rules
  2591 from destruct-rules;
  2592 
  2593 * Provers: Simplifier.easy_setup provides a fast path to basic
  2594 Simplifier setup for new object-logics;
  2595 
  2596 * Pure: AST translation rules no longer require constant head on LHS;
  2597 
  2598 * Pure: improved name spaces: ambiguous output is qualified; support
  2599 for hiding of names;
  2600 
  2601 * system: smart setup of canonical ML_HOME, ISABELLE_INTERFACE, and
  2602 XSYMBOL_HOME; no longer need to do manual configuration in most
  2603 situations;
  2604 
  2605 * system: compression of ML heaps images may now be controlled via -c
  2606 option of isabelle and isatool usedir (currently only observed by
  2607 Poly/ML);
  2608 
  2609 * system: isatool installfonts may handle X-Symbol fonts as well (very
  2610 useful for remote X11);
  2611 
  2612 * system: provide TAGS file for Isabelle sources;
  2613 
  2614 * ML: infix 'OF' is a version of 'MRS' with more appropriate argument
  2615 order;
  2616 
  2617 * ML: renamed flags Syntax.trace_norm_ast to Syntax.trace_ast; global
  2618 timing flag supersedes proof_timing and Toplevel.trace;
  2619 
  2620 * ML: new combinators |>> and |>>> for incremental transformations
  2621 with secondary results (e.g. certain theory extensions):
  2622 
  2623 * ML: PureThy.add_defs gets additional argument to indicate potential
  2624 overloading (usually false);
  2625 
  2626 * ML: PureThy.add_thms/add_axioms/add_defs now return theorems as
  2627 results;
  2628 
  2629 
  2630 
  2631 New in Isabelle99 (October 1999)
  2632 --------------------------------
  2633 
  2634 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  2635 
  2636 * HOL: The THEN and ELSE parts of conditional expressions (if P then x else y)
  2637 are no longer simplified.  (This allows the simplifier to unfold recursive
  2638 functional programs.)  To restore the old behaviour, declare
  2639 
  2640     Delcongs [if_weak_cong];
  2641 
  2642 * HOL: Removed the obsolete syntax "Compl A"; use -A for set
  2643 complement;
  2644 
  2645 * HOL: the predicate "inj" is now defined by translation to "inj_on";
  2646 
  2647 * HOL/datatype: mutual_induct_tac no longer exists --
  2648   use induct_tac "x_1 ... x_n" instead of mutual_induct_tac ["x_1", ..., "x_n"]
  2649 
  2650 * HOL/typedef: fixed type inference for representing set; type
  2651 arguments now have to occur explicitly on the rhs as type constraints;
  2652 
  2653 * ZF: The con_defs part of an inductive definition may no longer refer
  2654 to constants declared in the same theory;
  2655 
  2656 * HOL, ZF: the function mk_cases, generated by the inductive
  2657 definition package, has lost an argument.  To simplify its result, it
  2658 uses the default simpset instead of a supplied list of theorems.
  2659 
  2660 * HOL/List: the constructors of type list are now Nil and Cons;
  2661 
  2662 * Simplifier: the type of the infix ML functions
  2663         setSSolver addSSolver setSolver addSolver
  2664 is now  simpset * solver -> simpset  where `solver' is a new abstract type
  2665 for packaging solvers. A solver is created via
  2666         mk_solver: string -> (thm list -> int -> tactic) -> solver
  2667 where the string argument is only a comment.
  2668 
  2669 
  2670 *** Proof tools ***
  2671 
  2672 * Provers/Arith/fast_lin_arith.ML contains a functor for creating a
  2673 decision procedure for linear arithmetic. Currently it is used for
  2674 types `nat', `int', and `real' in HOL (see below); it can, should and
  2675 will be instantiated for other types and logics as well.
  2676 
  2677 * The simplifier now accepts rewrite rules with flexible heads, eg
  2678      hom ?f ==> ?f(?x+?y) = ?f ?x + ?f ?y
  2679   They are applied like any rule with a non-pattern lhs, i.e. by first-order
  2680   matching.
  2681 
  2682 
  2683 *** General ***
  2684 
  2685 * New Isabelle/Isar subsystem provides an alternative to traditional
  2686 tactical theorem proving; together with the ProofGeneral/isar user
  2687 interface it offers an interactive environment for developing human
  2688 readable proof documents (Isar == Intelligible semi-automated
  2689 reasoning); for further information see isatool doc isar-ref,
  2690 src/HOL/Isar_examples and http://isabelle.in.tum.de/Isar/
  2691 
  2692 * improved and simplified presentation of theories: better HTML markup
  2693 (including colors), graph views in several sizes; isatool usedir now
  2694 provides a proper interface for user theories (via -P option); actual
  2695 document preparation based on (PDF)LaTeX is available as well (for
  2696 new-style theories only); see isatool doc system for more information;
  2697 
  2698 * native support for Proof General, both for classic Isabelle and
  2699 Isabelle/Isar;
  2700 
  2701 * ML function thm_deps visualizes dependencies of theorems and lemmas,
  2702 using the graph browser tool;
  2703 
  2704 * Isabelle manuals now also available as PDF;
  2705 
  2706 * theory loader rewritten from scratch (may not be fully
  2707 bug-compatible); old loadpath variable has been replaced by show_path,
  2708 add_path, del_path, reset_path functions; new operations such as
  2709 update_thy, touch_thy, remove_thy, use/update_thy_only (see also
  2710 isatool doc ref);
  2711 
  2712 * improved isatool install: option -k creates KDE application icon,
  2713 option -p DIR installs standalone binaries;
  2714 
  2715 * added ML_PLATFORM setting (useful for cross-platform installations);
  2716 more robust handling of platform specific ML images for SML/NJ;
  2717 
  2718 * the settings environment is now statically scoped, i.e. it is never
  2719 created again in sub-processes invoked from isabelle, isatool, or
  2720 Isabelle;
  2721 
  2722 * path element specification '~~' refers to '$ISABELLE_HOME';
  2723 
  2724 * in locales, the "assumes" and "defines" parts may be omitted if
  2725 empty;
  2726 
  2727 * new print_mode "xsymbols" for extended symbol support (e.g. genuine
  2728 long arrows);
  2729 
  2730 * new print_mode "HTML";
  2731 
  2732 * new flag show_tags controls display of tags of theorems (which are
  2733 basically just comments that may be attached by some tools);
  2734 
  2735 * Isamode 2.6 requires patch to accomodate change of Isabelle font
  2736 mode and goal output format:
  2737 
  2738 diff -r Isamode-2.6/elisp/isa-load.el Isamode/elisp/isa-load.el
  2739 244c244
  2740 <       (list (isa-getenv "ISABELLE") "-msymbols" logic-name)
  2741 ---
  2742 >       (list (isa-getenv "ISABELLE") "-misabelle_font" "-msymbols" logic-name)
  2743 diff -r Isabelle-2.6/elisp/isa-proofstate.el Isamode/elisp/isa-proofstate.el
  2744 181c181
  2745 < (defconst proofstate-proofstart-regexp "^Level [0-9]+$"
  2746 ---
  2747 > (defconst proofstate-proofstart-regexp "^Level [0-9]+"
  2748 
  2749 * function bind_thms stores lists of theorems (cf. bind_thm);
  2750 
  2751 * new shorthand tactics ftac, eatac, datac, fatac;
  2752 
  2753 * qed (and friends) now accept "" as result name; in that case the
  2754 theorem is not stored, but proper checks and presentation of the
  2755 result still apply;
  2756 
  2757 * theorem database now also indexes constants "Trueprop", "all",
  2758 "==>", "=="; thus thms_containing, findI etc. may retrieve more rules;
  2759 
  2760 
  2761 *** HOL ***
  2762 
  2763 ** HOL arithmetic **
  2764 
  2765 * There are now decision procedures for linear arithmetic over nat and
  2766 int:
  2767 
  2768 1. arith_tac copes with arbitrary formulae involving `=', `<', `<=',
  2769 `+', `-', `Suc', `min', `max' and numerical constants; other subterms
  2770 are treated as atomic; subformulae not involving type `nat' or `int'
  2771 are ignored; quantified subformulae are ignored unless they are
  2772 positive universal or negative existential. The tactic has to be
  2773 invoked by hand and can be a little bit slow. In particular, the
  2774 running time is exponential in the number of occurrences of `min' and
  2775 `max', and `-' on `nat'.
  2776 
  2777 2. fast_arith_tac is a cut-down version of arith_tac: it only takes
  2778 (negated) (in)equalities among the premises and the conclusion into
  2779 account (i.e. no compound formulae) and does not know about `min' and
  2780 `max', and `-' on `nat'. It is fast and is used automatically by the
  2781 simplifier.
  2782 
  2783 NB: At the moment, these decision procedures do not cope with mixed
  2784 nat/int formulae where the two parts interact, such as `m < n ==>
  2785 int(m) < int(n)'.
  2786 
  2787 * HOL/Numeral provides a generic theory of numerals (encoded
  2788 efficiently as bit strings); setup for types nat/int/real is in place;
  2789 INCOMPATIBILITY: since numeral syntax is now polymorphic, rather than
  2790 int, existing theories and proof scripts may require a few additional
  2791 type constraints;
  2792 
  2793 * integer division and remainder can now be performed on constant
  2794 arguments;
  2795 
  2796 * many properties of integer multiplication, division and remainder
  2797 are now available;
  2798 
  2799 * An interface to the Stanford Validity Checker (SVC) is available through the
  2800 tactic svc_tac.  Propositional tautologies and theorems of linear arithmetic
  2801 are proved automatically.  SVC must be installed separately, and its results
  2802 must be TAKEN ON TRUST (Isabelle does not check the proofs, but tags any
  2803 invocation of the underlying oracle).  For SVC see
  2804   http://verify.stanford.edu/SVC
  2805 
  2806 * IsaMakefile: the HOL-Real target now builds an actual image;
  2807 
  2808 
  2809 ** HOL misc **
  2810 
  2811 * HOL/Real/HahnBanach: the Hahn-Banach theorem for real vector spaces
  2812 (in Isabelle/Isar) -- by Gertrud Bauer;
  2813 
  2814 * HOL/BCV: generic model of bytecode verification, i.e. data-flow
  2815 analysis for assembly languages with subtypes;
  2816 
  2817 * HOL/TLA (Lamport's Temporal Logic of Actions): major reorganization
  2818 -- avoids syntactic ambiguities and treats state, transition, and
  2819 temporal levels more uniformly; introduces INCOMPATIBILITIES due to
  2820 changed syntax and (many) tactics;
  2821 
  2822 * HOL/inductive: Now also handles more general introduction rules such
  2823   as "ALL y. (y, x) : r --> y : acc r ==> x : acc r"; monotonicity
  2824   theorems are now maintained within the theory (maintained via the
  2825   "mono" attribute);
  2826 
  2827 * HOL/datatype: Now also handles arbitrarily branching datatypes
  2828   (using function types) such as
  2829 
  2830   datatype 'a tree = Atom 'a | Branch "nat => 'a tree"
  2831 
  2832 * HOL/record: record_simproc (part of the default simpset) takes care
  2833 of selectors applied to updated records; record_split_tac is no longer
  2834 part of the default claset; update_defs may now be removed from the
  2835 simpset in many cases; COMPATIBILITY: old behavior achieved by
  2836 
  2837   claset_ref () := claset() addSWrapper record_split_wrapper;
  2838   Delsimprocs [record_simproc]
  2839 
  2840 * HOL/typedef: fixed type inference for representing set; type
  2841 arguments now have to occur explicitly on the rhs as type constraints;
  2842 
  2843 * HOL/recdef (TFL): 'congs' syntax now expects comma separated list of theorem
  2844 names rather than an ML expression;
  2845 
  2846 * HOL/defer_recdef (TFL): like recdef but the well-founded relation can be
  2847 supplied later.  Program schemes can be defined, such as
  2848     "While B C s = (if B s then While B C (C s) else s)"
  2849 where the well-founded relation can be chosen after B and C have been given.
  2850 
  2851 * HOL/List: the constructors of type list are now Nil and Cons;
  2852 INCOMPATIBILITY: while [] and infix # syntax is still there, of
  2853 course, ML tools referring to List.list.op # etc. have to be adapted;
  2854 
  2855 * HOL_quantifiers flag superseded by "HOL" print mode, which is
  2856 disabled by default; run isabelle with option -m HOL to get back to
  2857 the original Gordon/HOL-style output;
  2858 
  2859 * HOL/Ord.thy: new bounded quantifier syntax (input only): ALL x<y. P,
  2860 ALL x<=y. P, EX x<y. P, EX x<=y. P;
  2861 
  2862 * HOL basic syntax simplified (more orthogonal): all variants of
  2863 All/Ex now support plain / symbolic / HOL notation; plain syntax for
  2864 Eps operator is provided as well: "SOME x. P[x]";
  2865 
  2866 * HOL/Sum.thy: sum_case has been moved to HOL/Datatype;
  2867 
  2868 * HOL/Univ.thy: infix syntax <*>, <+>, <**>, <+> eliminated and made
  2869 thus available for user theories;
  2870 
  2871 * HOLCF/IOA/Sequents: renamed 'Cons' to 'Consq' to avoid clash with
  2872 HOL/List; hardly an INCOMPATIBILITY since '>>' syntax is used all the
  2873 time;
  2874 
  2875 * HOL: new tactic smp_tac: int -> int -> tactic, which applies spec
  2876 several times and then mp;
  2877 
  2878 
  2879 *** LK ***
  2880 
  2881 * the notation <<...>> is now available as a notation for sequences of
  2882 formulas;
  2883 
  2884 * the simplifier is now installed
  2885 
  2886 * the axiom system has been generalized (thanks to Soren Heilmann)
  2887 
  2888 * the classical reasoner now has a default rule database
  2889 
  2890 
  2891 *** ZF ***
  2892 
  2893 * new primrec section allows primitive recursive functions to be given
  2894 directly (as in HOL) over datatypes and the natural numbers;
  2895 
  2896 * new tactics induct_tac and exhaust_tac for induction (or case
  2897 analysis) over datatypes and the natural numbers;
  2898 
  2899 * the datatype declaration of type T now defines the recursor T_rec;
  2900 
  2901 * simplification automatically does freeness reasoning for datatype
  2902 constructors;
  2903 
  2904 * automatic type-inference, with AddTCs command to insert new
  2905 type-checking rules;
  2906 
  2907 * datatype introduction rules are now added as Safe Introduction rules
  2908 to the claset;
  2909 
  2910 * the syntax "if P then x else y" is now available in addition to
  2911 if(P,x,y);
  2912 
  2913 
  2914 *** Internal programming interfaces ***
  2915 
  2916 * tuned simplifier trace output; new flag debug_simp;
  2917 
  2918 * structures Vartab / Termtab (instances of TableFun) offer efficient
  2919 tables indexed by indexname_ord / term_ord (compatible with aconv);
  2920 
  2921 * AxClass.axclass_tac lost the theory argument;
  2922 
  2923 * tuned current_goals_markers semantics: begin / end goal avoids
  2924 printing empty lines;
  2925 
  2926 * removed prs and prs_fn hook, which was broken because it did not
  2927 include \n in its semantics, forcing writeln to add one
  2928 uncoditionally; replaced prs_fn by writeln_fn; consider std_output:
  2929 string -> unit if you really want to output text without newline;
  2930 
  2931 * Symbol.output subject to print mode; INCOMPATIBILITY: defaults to
  2932 plain output, interface builders may have to enable 'isabelle_font'
  2933 mode to get Isabelle font glyphs as before;
  2934 
  2935 * refined token_translation interface; INCOMPATIBILITY: output length
  2936 now of type real instead of int;
  2937 
  2938 * theory loader actions may be traced via new ThyInfo.add_hook
  2939 interface (see src/Pure/Thy/thy_info.ML); example application: keep
  2940 your own database of information attached to *whole* theories -- as
  2941 opposed to intra-theory data slots offered via TheoryDataFun;
  2942 
  2943 * proper handling of dangling sort hypotheses (at last!);
  2944 Thm.strip_shyps and Drule.strip_shyps_warning take care of removing
  2945 extra sort hypotheses that can be witnessed from the type signature;
  2946 the force_strip_shyps flag is gone, any remaining shyps are simply
  2947 left in the theorem (with a warning issued by strip_shyps_warning);
  2948 
  2949 
  2950 
  2951 New in Isabelle98-1 (October 1998)
  2952 ----------------------------------
  2953 
  2954 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  2955 
  2956 * several changes of automated proof tools;
  2957 
  2958 * HOL: major changes to the inductive and datatype packages, including
  2959 some minor incompatibilities of theory syntax;
  2960 
  2961 * HOL: renamed r^-1 to 'converse' from 'inverse'; 'inj_onto' is now
  2962 called `inj_on';
  2963 
  2964 * HOL: removed duplicate thms in Arith:
  2965   less_imp_add_less  should be replaced by  trans_less_add1
  2966   le_imp_add_le      should be replaced by  trans_le_add1
  2967 
  2968 * HOL: unary minus is now overloaded (new type constraints may be
  2969 required);
  2970 
  2971 * HOL and ZF: unary minus for integers is now #- instead of #~.  In
  2972 ZF, expressions such as n#-1 must be changed to n#- 1, since #-1 is
  2973 now taken as an integer constant.
  2974 
  2975 * Pure: ML function 'theory_of' renamed to 'theory';
  2976 
  2977 
  2978 *** Proof tools ***
  2979 
  2980 * Simplifier:
  2981   1. Asm_full_simp_tac is now more aggressive.
  2982      1. It will sometimes reorient premises if that increases their power to
  2983         simplify.
  2984      2. It does no longer proceed strictly from left to right but may also
  2985         rotate premises to achieve further simplification.
  2986      For compatibility reasons there is now Asm_lr_simp_tac which is like the
  2987      old Asm_full_simp_tac in that it does not rotate premises.
  2988   2. The simplifier now knows a little bit about nat-arithmetic.
  2989 
  2990 * Classical reasoner: wrapper mechanism for the classical reasoner now
  2991 allows for selected deletion of wrappers, by introduction of names for
  2992 wrapper functionals.  This implies that addbefore, addSbefore,
  2993 addaltern, and addSaltern now take a pair (name, tactic) as argument,
  2994 and that adding two tactics with the same name overwrites the first
  2995 one (emitting a warning).
  2996   type wrapper = (int -> tactic) -> (int -> tactic)
  2997   setWrapper, setSWrapper, compWrapper and compSWrapper are replaced by
  2998   addWrapper, addSWrapper: claset * (string * wrapper) -> claset
  2999   delWrapper, delSWrapper: claset *  string            -> claset
  3000   getWrapper is renamed to appWrappers, getSWrapper to appSWrappers;
  3001 
  3002 * Classical reasoner: addbefore/addSbefore now have APPEND/ORELSE
  3003 semantics; addbefore now affects only the unsafe part of step_tac
  3004 etc.; this affects addss/auto_tac/force_tac, so EXISTING PROOFS MAY
  3005 FAIL, but proofs should be fixable easily, e.g. by replacing Auto_tac
  3006 by Force_tac;
  3007 
  3008 * Classical reasoner: setwrapper to setWrapper and compwrapper to
  3009 compWrapper; added safe wrapper (and access functions for it);
  3010 
  3011 * HOL/split_all_tac is now much faster and fails if there is nothing
  3012 to split.  Some EXISTING PROOFS MAY REQUIRE ADAPTION because the order
  3013 and the names of the automatically generated variables have changed.
  3014 split_all_tac has moved within claset() from unsafe wrappers to safe
  3015 wrappers, which means that !!-bound variables are split much more
  3016 aggressively, and safe_tac and clarify_tac now split such variables.
  3017 If this splitting is not appropriate, use delSWrapper "split_all_tac".
  3018 Note: the same holds for record_split_tac, which does the job of
  3019 split_all_tac for record fields.
  3020 
  3021 * HOL/Simplifier: Rewrite rules for case distinctions can now be added
  3022 permanently to the default simpset using Addsplits just like
  3023 Addsimps. They can be removed via Delsplits just like
  3024 Delsimps. Lower-case versions are also available.
  3025 
  3026 * HOL/Simplifier: The rule split_if is now part of the default
  3027 simpset. This means that the simplifier will eliminate all occurrences
  3028 of if-then-else in the conclusion of a goal. To prevent this, you can
  3029 either remove split_if completely from the default simpset by
  3030 `Delsplits [split_if]' or remove it in a specific call of the
  3031 simplifier using `... delsplits [split_if]'.  You can also add/delete
  3032 other case splitting rules to/from the default simpset: every datatype
  3033 generates suitable rules `split_t_case' and `split_t_case_asm' (where
  3034 t is the name of the datatype).
  3035 
  3036 * Classical reasoner / Simplifier combination: new force_tac (and
  3037 derivatives Force_tac, force) combines rewriting and classical
  3038 reasoning (and whatever other tools) similarly to auto_tac, but is
  3039 aimed to solve the given subgoal completely.
  3040 
  3041 
  3042 *** General ***
  3043 
  3044 * new top-level commands `Goal' and `Goalw' that improve upon `goal'
  3045 and `goalw': the theory is no longer needed as an explicit argument -
  3046 the current theory context is used; assumptions are no longer returned
  3047 at the ML-level unless one of them starts with ==> or !!; it is
  3048 recommended to convert to these new commands using isatool fixgoal
  3049 (backup your sources first!);
  3050 
  3051 * new top-level commands 'thm' and 'thms' for retrieving theorems from
  3052 the current theory context, and 'theory' to lookup stored theories;
  3053 
  3054 * new theory section 'locale' for declaring constants, assumptions and
  3055 definitions that have local scope;
  3056 
  3057 * new theory section 'nonterminals' for purely syntactic types;
  3058 
  3059 * new theory section 'setup' for generic ML setup functions
  3060 (e.g. package initialization);
  3061 
  3062 * the distribution now includes Isabelle icons: see
  3063 lib/logo/isabelle-{small,tiny}.xpm;
  3064 
  3065 * isatool install - install binaries with absolute references to
  3066 ISABELLE_HOME/bin;
  3067 
  3068 * isatool logo -- create instances of the Isabelle logo (as EPS);
  3069 
  3070 * print mode 'emacs' reserved for Isamode;
  3071 
  3072 * support multiple print (ast) translations per constant name;
  3073 
  3074 * theorems involving oracles are now printed with a suffixed [!];
  3075 
  3076 
  3077 *** HOL ***
  3078 
  3079 * there is now a tutorial on Isabelle/HOL (do 'isatool doc tutorial');
  3080 
  3081 * HOL/inductive package reorganized and improved: now supports mutual
  3082 definitions such as
  3083 
  3084   inductive EVEN ODD
  3085     intrs
  3086       null "0 : EVEN"
  3087       oddI "n : EVEN ==> Suc n : ODD"
  3088       evenI "n : ODD ==> Suc n : EVEN"
  3089 
  3090 new theorem list "elims" contains an elimination rule for each of the
  3091 recursive sets; inductive definitions now handle disjunctive premises
  3092 correctly (also ZF);
  3093 
  3094 INCOMPATIBILITIES: requires Inductive as an ancestor; component
  3095 "mutual_induct" no longer exists - the induction rule is always
  3096 contained in "induct";
  3097 
  3098 
  3099 * HOL/datatype package re-implemented and greatly improved: now
  3100 supports mutually recursive datatypes such as
  3101 
  3102   datatype
  3103     'a aexp = IF_THEN_ELSE ('a bexp) ('a aexp) ('a aexp)
  3104             | SUM ('a aexp) ('a aexp)
  3105             | DIFF ('a aexp) ('a aexp)
  3106             | NUM 'a
  3107   and
  3108     'a bexp = LESS ('a aexp) ('a aexp)
  3109             | AND ('a bexp) ('a bexp)
  3110             | OR ('a bexp) ('a bexp)
  3111 
  3112 as well as indirectly recursive datatypes such as
  3113 
  3114   datatype
  3115     ('a, 'b) term = Var 'a
  3116                   | App 'b ((('a, 'b) term) list)
  3117 
  3118 The new tactic  mutual_induct_tac [<var_1>, ..., <var_n>] i  performs
  3119 induction on mutually / indirectly recursive datatypes.
  3120 
  3121 Primrec equations are now stored in theory and can be accessed via
  3122 <function_name>.simps.
  3123 
  3124 INCOMPATIBILITIES:
  3125 
  3126   - Theories using datatypes must now have theory Datatype as an
  3127     ancestor.
  3128   - The specific <typename>.induct_tac no longer exists - use the
  3129     generic induct_tac instead.
  3130   - natE has been renamed to nat.exhaust - use exhaust_tac
  3131     instead of res_inst_tac ... natE. Note that the variable
  3132     names in nat.exhaust differ from the names in natE, this
  3133     may cause some "fragile" proofs to fail.
  3134   - The theorems split_<typename>_case and split_<typename>_case_asm
  3135     have been renamed to <typename>.split and <typename>.split_asm.
  3136   - Since default sorts of type variables are now handled correctly,
  3137     some datatype definitions may have to be annotated with explicit
  3138     sort constraints.
  3139   - Primrec definitions no longer require function name and type
  3140     of recursive argument.
  3141 
  3142 Consider using isatool fixdatatype to adapt your theories and proof
  3143 scripts to the new package (backup your sources first!).
  3144 
  3145 
  3146 * HOL/record package: considerably improved implementation; now
  3147 includes concrete syntax for record types, terms, updates; theorems
  3148 for surjective pairing and splitting !!-bound record variables; proof
  3149 support is as follows:
  3150 
  3151   1) standard conversions (selectors or updates applied to record
  3152 constructor terms) are part of the standard simpset;
  3153 
  3154   2) inject equations of the form ((x, y) = (x', y')) == x=x' & y=y' are
  3155 made part of standard simpset and claset via addIffs;
  3156 
  3157   3) a tactic for record field splitting (record_split_tac) is part of
  3158 the standard claset (addSWrapper);
  3159 
  3160 To get a better idea about these rules you may retrieve them via
  3161 something like 'thms "foo.simps"' or 'thms "foo.iffs"', where "foo" is
  3162 the name of your record type.
  3163 
  3164 The split tactic 3) conceptually simplifies by the following rule:
  3165 
  3166   "(!!x. PROP ?P x) == (!!a b. PROP ?P (a, b))"
  3167 
  3168 Thus any record variable that is bound by meta-all will automatically
  3169 blow up into some record constructor term, consequently the
  3170 simplifications of 1), 2) apply.  Thus force_tac, auto_tac etc. shall
  3171 solve record problems automatically.
  3172 
  3173 
  3174 * reorganized the main HOL image: HOL/Integ and String loaded by
  3175 default; theory Main includes everything;
  3176 
  3177 * automatic simplification of integer sums and comparisons, using cancellation;
  3178 
  3179 * added option_map_eq_Some and not_Some_eq to the default simpset and claset;
  3180 
  3181 * added disj_not1 = "(~P | Q) = (P --> Q)" to the default simpset;
  3182 
  3183 * many new identities for unions, intersections, set difference, etc.;
  3184 
  3185 * expand_if, expand_split, expand_sum_case and expand_nat_case are now
  3186 called split_if, split_split, split_sum_case and split_nat_case (to go
  3187 with add/delsplits);
  3188 
  3189 * HOL/Prod introduces simplification procedure unit_eq_proc rewriting
  3190 (?x::unit) = (); this is made part of the default simpset, which COULD
  3191 MAKE EXISTING PROOFS FAIL under rare circumstances (consider
  3192 'Delsimprocs [unit_eq_proc];' as last resort); also note that
  3193 unit_abs_eta_conv is added in order to counter the effect of
  3194 unit_eq_proc on (%u::unit. f u), replacing it by f rather than by
  3195 %u.f();
  3196 
  3197 * HOL/Fun INCOMPATIBILITY: `inj_onto' is now called `inj_on' (which
  3198 makes more sense);
  3199 
  3200 * HOL/Set INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
  3201   It and 'sym RS equals0D' are now in the default  claset, giving automatic
  3202   disjointness reasoning but breaking a few old proofs.
  3203 
  3204 * HOL/Relation INCOMPATIBILITY: renamed the relational operator r^-1
  3205 to 'converse' from 'inverse' (for compatibility with ZF and some
  3206 literature);
  3207 
  3208 * HOL/recdef can now declare non-recursive functions, with {} supplied as
  3209 the well-founded relation;
  3210 
  3211 * HOL/Set INCOMPATIBILITY: the complement of set A is now written -A instead of
  3212     Compl A.  The "Compl" syntax remains available as input syntax for this
  3213     release ONLY.
  3214 
  3215 * HOL/Update: new theory of function updates:
  3216     f(a:=b) == %x. if x=a then b else f x
  3217 may also be iterated as in f(a:=b,c:=d,...);
  3218 
  3219 * HOL/Vimage: new theory for inverse image of a function, syntax f-``B;
  3220 
  3221 * HOL/List:
  3222   - new function list_update written xs[i:=v] that updates the i-th
  3223     list position. May also be iterated as in xs[i:=a,j:=b,...].
  3224   - new function `upt' written [i..j(] which generates the list
  3225     [i,i+1,...,j-1], i.e. the upper bound is excluded. To include the upper
  3226     bound write [i..j], which is a shorthand for [i..j+1(].
  3227   - new lexicographic orderings and corresponding wellfoundedness theorems.
  3228 
  3229 * HOL/Arith:
  3230   - removed 'pred' (predecessor) function;
  3231   - generalized some theorems about n-1;
  3232   - many new laws about "div" and "mod";
  3233   - new laws about greatest common divisors (see theory ex/Primes);
  3234 
  3235 * HOL/Relation: renamed the relational operator r^-1 "converse"
  3236 instead of "inverse";
  3237 
  3238 * HOL/Induct/Multiset: a theory of multisets, including the wellfoundedness
  3239   of the multiset ordering;
  3240 
  3241 * directory HOL/Real: a construction of the reals using Dedekind cuts
  3242   (not included by default);
  3243 
  3244 * directory HOL/UNITY: Chandy and Misra's UNITY formalism;
  3245 
  3246 * directory HOL/Hoare: a new version of Hoare logic which permits many-sorted
  3247   programs, i.e. different program variables may have different types.
  3248 
  3249 * calling (stac rew i) now fails if "rew" has no effect on the goal
  3250   [previously, this check worked only if the rewrite rule was unconditional]
  3251   Now rew can involve either definitions or equalities (either == or =).
  3252 
  3253 
  3254 *** ZF ***
  3255 
  3256 * theory Main includes everything; INCOMPATIBILITY: theory ZF.thy contains
  3257   only the theorems proved on ZF.ML;
  3258 
  3259 * ZF INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
  3260   It and 'sym RS equals0D' are now in the default  claset, giving automatic
  3261   disjointness reasoning but breaking a few old proofs.
  3262 
  3263 * ZF/Update: new theory of function updates
  3264     with default rewrite rule  f(x:=y) ` z = if(z=x, y, f`z)
  3265   may also be iterated as in f(a:=b,c:=d,...);
  3266 
  3267 * in  let x=t in u(x), neither t nor u(x) has to be an FOL term.
  3268 
  3269 * calling (stac rew i) now fails if "rew" has no effect on the goal
  3270   [previously, this check worked only if the rewrite rule was unconditional]
  3271   Now rew can involve either definitions or equalities (either == or =).
  3272 
  3273 * case_tac provided for compatibility with HOL
  3274     (like the old excluded_middle_tac, but with subgoals swapped)
  3275 
  3276 
  3277 *** Internal programming interfaces ***
  3278 
  3279 * Pure: several new basic modules made available for general use, see
  3280 also src/Pure/README;
  3281 
  3282 * improved the theory data mechanism to support encapsulation (data
  3283 kind name replaced by private Object.kind, acting as authorization
  3284 key); new type-safe user interface via functor TheoryDataFun; generic
  3285 print_data function becomes basically useless;
  3286 
  3287 * removed global_names compatibility flag -- all theory declarations
  3288 are qualified by default;
  3289 
  3290 * module Pure/Syntax now offers quote / antiquote translation
  3291 functions (useful for Hoare logic etc. with implicit dependencies);
  3292 see HOL/ex/Antiquote for an example use;
  3293 
  3294 * Simplifier now offers conversions (asm_)(full_)rewrite: simpset ->
  3295 cterm -> thm;
  3296 
  3297 * new tactical CHANGED_GOAL for checking that a tactic modifies a
  3298 subgoal;
  3299 
  3300 * Display.print_goals function moved to Locale.print_goals;
  3301 
  3302 * standard print function for goals supports current_goals_markers
  3303 variable for marking begin of proof, end of proof, start of goal; the
  3304 default is ("", "", ""); setting current_goals_markers := ("<proof>",
  3305 "</proof>", "<goal>") causes SGML like tagged proof state printing,
  3306 for example;
  3307 
  3308 
  3309 
  3310 New in Isabelle98 (January 1998)
  3311 --------------------------------
  3312 
  3313 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  3314 
  3315 * changed lexical syntax of terms / types: dots made part of long
  3316 identifiers, e.g. "%x.x" no longer possible, should be "%x. x";
  3317 
  3318 * simpset (and claset) reference variable replaced by functions
  3319 simpset / simpset_ref;
  3320 
  3321 * no longer supports theory aliases (via merge) and non-trivial
  3322 implicit merge of thms' signatures;
  3323 
  3324 * most internal names of constants changed due to qualified names;
  3325 
  3326 * changed Pure/Sequence interface (see Pure/seq.ML);
  3327 
  3328 
  3329 *** General Changes ***
  3330 
  3331 * hierachically structured name spaces (for consts, types, axms, thms
  3332 etc.); new lexical class 'longid' (e.g. Foo.bar.x) may render much of
  3333 old input syntactically incorrect (e.g. "%x.x"); COMPATIBILITY:
  3334 isatool fixdots ensures space after dots (e.g. "%x. x"); set
  3335 long_names for fully qualified output names; NOTE: ML programs
  3336 (special tactics, packages etc.) referring to internal names may have
  3337 to be adapted to cope with fully qualified names; in case of severe
  3338 backward campatibility problems try setting 'global_names' at compile
  3339 time to have enrything declared within a flat name space; one may also
  3340 fine tune name declarations in theories via the 'global' and 'local'
  3341 section;
  3342 
  3343 * reimplemented the implicit simpset and claset using the new anytype
  3344 data filed in signatures; references simpset:simpset ref etc. are
  3345 replaced by functions simpset:unit->simpset and
  3346 simpset_ref:unit->simpset ref; COMPATIBILITY: use isatool fixclasimp
  3347 to patch your ML files accordingly;
  3348 
  3349 * HTML output now includes theory graph data for display with Java
  3350 applet or isatool browser; data generated automatically via isatool
  3351 usedir (see -i option, ISABELLE_USEDIR_OPTIONS);
  3352 
  3353 * defs may now be conditional; improved rewrite_goals_tac to handle
  3354 conditional equations;
  3355 
  3356 * defs now admits additional type arguments, using TYPE('a) syntax;
  3357 
  3358 * theory aliases via merge (e.g. M=A+B+C) no longer supported, always
  3359 creates a new theory node; implicit merge of thms' signatures is
  3360 restricted to 'trivial' ones; COMPATIBILITY: one may have to use
  3361 transfer:theory->thm->thm in (rare) cases;
  3362 
  3363 * improved handling of draft signatures / theories; draft thms (and
  3364 ctyps, cterms) are automatically promoted to real ones;
  3365 
  3366 * slightly changed interfaces for oracles: admit many per theory, named
  3367 (e.g. oracle foo = mlfun), additional name argument for invoke_oracle;
  3368 
  3369 * print_goals: optional output of const types (set show_consts and
  3370 show_types);
  3371 
  3372 * improved output of warnings (###) and errors (***);
  3373 
  3374 * subgoal_tac displays a warning if the new subgoal has type variables;
  3375 
  3376 * removed old README and Makefiles;
  3377 
  3378 * replaced print_goals_ref hook by print_current_goals_fn and result_error_fn;
  3379 
  3380 * removed obsolete init_pps and init_database;
  3381 
  3382 * deleted the obsolete tactical STATE, which was declared by
  3383     fun STATE tacfun st = tacfun st st;
  3384 
  3385 * cd and use now support path variables, e.g. $ISABELLE_HOME, or ~
  3386 (which abbreviates $HOME);
  3387 
  3388 * changed Pure/Sequence interface (see Pure/seq.ML); COMPATIBILITY:
  3389 use isatool fixseq to adapt your ML programs (this works for fully
  3390 qualified references to the Sequence structure only!);
  3391 
  3392 * use_thy no longer requires writable current directory; it always
  3393 reloads .ML *and* .thy file, if either one is out of date;
  3394 
  3395 
  3396 *** Classical Reasoner ***
  3397 
  3398 * Clarify_tac, clarify_tac, clarify_step_tac, Clarify_step_tac: new
  3399 tactics that use classical reasoning to simplify a subgoal without
  3400 splitting it into several subgoals;
  3401 
  3402 * Safe_tac: like safe_tac but uses the default claset;
  3403 
  3404 
  3405 *** Simplifier ***
  3406 
  3407 * added simplification meta rules:
  3408     (asm_)(full_)simplify: simpset -> thm -> thm;
  3409 
  3410 * simplifier.ML no longer part of Pure -- has to be loaded by object
  3411 logics (again);
  3412 
  3413 * added prems argument to simplification procedures;
  3414 
  3415 * HOL, FOL, ZF: added infix function `addsplits':
  3416   instead of `<simpset> setloop (split_tac <thms>)'
  3417   you can simply write `<simpset> addsplits <thms>'
  3418 
  3419 
  3420 *** Syntax ***
  3421 
  3422 * TYPE('a) syntax for type reflection terms;
  3423 
  3424 * no longer handles consts with name "" -- declare as 'syntax' instead;
  3425 
  3426 * pretty printer: changed order of mixfix annotation preference (again!);
  3427 
  3428 * Pure: fixed idt/idts vs. pttrn/pttrns syntactic categories;
  3429 
  3430 
  3431 *** HOL ***
  3432 
  3433 * HOL: there is a new splitter `split_asm_tac' that can be used e.g.
  3434   with `addloop' of the simplifier to faciliate case splitting in premises.
  3435 
  3436 * HOL/TLA: Stephan Merz's formalization of Lamport's Temporal Logic of Actions;
  3437 
  3438 * HOL/Auth: new protocol proofs including some for the Internet
  3439   protocol TLS;
  3440 
  3441 * HOL/Map: new theory of `maps' a la VDM;
  3442 
  3443 * HOL/simplifier: simplification procedures nat_cancel_sums for
  3444 cancelling out common nat summands from =, <, <= (in)equalities, or
  3445 differences; simplification procedures nat_cancel_factor for
  3446 cancelling common factor from =, <, <= (in)equalities over natural
  3447 sums; nat_cancel contains both kinds of procedures, it is installed by
  3448 default in Arith.thy -- this COULD MAKE EXISTING PROOFS FAIL;
  3449 
  3450 * HOL/simplifier: terms of the form
  3451   `? x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x)'  (or t=x)
  3452   are rewritten to
  3453   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t)',
  3454   and those of the form
  3455   `! x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x) --> R(x)'  (or t=x)
  3456   are rewritten to
  3457   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t) --> R(t)',
  3458 
  3459 * HOL/datatype
  3460   Each datatype `t' now comes with a theorem `split_t_case' of the form
  3461 
  3462   P(t_case f1 ... fn x) =
  3463      ( (!y1 ... ym1. x = C1 y1 ... ym1 --> P(f1 y1 ... ym1)) &
  3464         ...
  3465        (!y1 ... ymn. x = Cn y1 ... ymn --> P(f1 y1 ... ymn))
  3466      )
  3467 
  3468   and a theorem `split_t_case_asm' of the form
  3469 
  3470   P(t_case f1 ... fn x) =
  3471     ~( (? y1 ... ym1. x = C1 y1 ... ym1 & ~P(f1 y1 ... ym1)) |
  3472         ...
  3473        (? y1 ... ymn. x = Cn y1 ... ymn & ~P(f1 y1 ... ymn))
  3474      )
  3475   which can be added to a simpset via `addsplits'. The existing theorems
  3476   expand_list_case and expand_option_case have been renamed to
  3477   split_list_case and split_option_case.
  3478 
  3479 * HOL/Arithmetic:
  3480   - `pred n' is automatically converted to `n-1'.
  3481     Users are strongly encouraged not to use `pred' any longer,
  3482     because it will disappear altogether at some point.
  3483   - Users are strongly encouraged to write "0 < n" rather than
  3484     "n ~= 0". Theorems and proof tools have been modified towards this
  3485     `standard'.
  3486 
  3487 * HOL/Lists:
  3488   the function "set_of_list" has been renamed "set" (and its theorems too);
  3489   the function "nth" now takes its arguments in the reverse order and
  3490   has acquired the infix notation "!" as in "xs!n".
  3491 
  3492 * HOL/Set: UNIV is now a constant and is no longer translated to Compl{};
  3493 
  3494 * HOL/Set: The operator (UN x.B x) now abbreviates (UN x:UNIV. B x) and its
  3495   specialist theorems (like UN1_I) are gone.  Similarly for (INT x.B x);
  3496 
  3497 * HOL/record: extensible records with schematic structural subtyping
  3498 (single inheritance); EXPERIMENTAL version demonstrating the encoding,
  3499 still lacks various theorems and concrete record syntax;
  3500 
  3501 
  3502 *** HOLCF ***
  3503 
  3504 * removed "axioms" and "generated by" sections;
  3505 
  3506 * replaced "ops" section by extended "consts" section, which is capable of
  3507   handling the continuous function space "->" directly;
  3508 
  3509 * domain package:
  3510   . proves theorems immediately and stores them in the theory,
  3511   . creates hierachical name space,
  3512   . now uses normal mixfix annotations (instead of cinfix...),
  3513   . minor changes to some names and values (for consistency),
  3514   . e.g. cases -> casedist, dists_eq -> dist_eqs, [take_lemma] -> take_lemmas,
  3515   . separator between mutual domain defs: changed "," to "and",
  3516   . improved handling of sort constraints;  now they have to
  3517     appear on the left-hand side of the equations only;
  3518 
  3519 * fixed LAM <x,y,zs>.b syntax;
  3520 
  3521 * added extended adm_tac to simplifier in HOLCF -- can now discharge
  3522 adm (%x. P (t x)), where P is chainfinite and t continuous;
  3523 
  3524 
  3525 *** FOL and ZF ***
  3526 
  3527 * FOL: there is a new splitter `split_asm_tac' that can be used e.g.
  3528   with `addloop' of the simplifier to faciliate case splitting in premises.
  3529 
  3530 * qed_spec_mp, qed_goal_spec_mp, qed_goalw_spec_mp are available, as
  3531 in HOL, they strip ALL and --> from proved theorems;
  3532 
  3533 
  3534 
  3535 New in Isabelle94-8 (May 1997)
  3536 ------------------------------
  3537 
  3538 *** General Changes ***
  3539 
  3540 * new utilities to build / run / maintain Isabelle etc. (in parts
  3541 still somewhat experimental); old Makefiles etc. still functional;
  3542 
  3543 * new 'Isabelle System Manual';
  3544 
  3545 * INSTALL text, together with ./configure and ./build scripts;
  3546 
  3547 * reimplemented type inference for greater efficiency, better error
  3548 messages and clean internal interface;
  3549 
  3550 * prlim command for dealing with lots of subgoals (an easier way of
  3551 setting goals_limit);
  3552 
  3553 
  3554 *** Syntax ***
  3555 
  3556 * supports alternative (named) syntax tables (parser and pretty
  3557 printer); internal interface is provided by add_modesyntax(_i);
  3558 
  3559 * Pure, FOL, ZF, HOL, HOLCF now support symbolic input and output; to
  3560 be used in conjunction with the Isabelle symbol font; uses the
  3561 "symbols" syntax table;
  3562 
  3563 * added token_translation interface (may translate name tokens in
  3564 arbitrary ways, dependent on their type (free, bound, tfree, ...) and
  3565 the current print_mode); IMPORTANT: user print translation functions
  3566 are responsible for marking newly introduced bounds
  3567 (Syntax.mark_boundT);
  3568 
  3569 * token translations for modes "xterm" and "xterm_color" that display
  3570 names in bold, underline etc. or colors (which requires a color
  3571 version of xterm);
  3572 
  3573 * infixes may now be declared with names independent of their syntax;
  3574 
  3575 * added typed_print_translation (like print_translation, but may
  3576 access type of constant);
  3577 
  3578 
  3579 *** Classical Reasoner ***
  3580 
  3581 Blast_tac: a new tactic!  It is often more powerful than fast_tac, but has
  3582 some limitations.  Blast_tac...
  3583   + ignores addss, addbefore, addafter; this restriction is intrinsic
  3584   + ignores elimination rules that don't have the correct format
  3585         (the conclusion MUST be a formula variable)
  3586   + ignores types, which can make HOL proofs fail
  3587   + rules must not require higher-order unification, e.g. apply_type in ZF
  3588     [message "Function Var's argument not a bound variable" relates to this]
  3589   + its proof strategy is more general but can actually be slower
  3590 
  3591 * substitution with equality assumptions no longer permutes other
  3592 assumptions;
  3593 
  3594 * minor changes in semantics of addafter (now called addaltern); renamed
  3595 setwrapper to setWrapper and compwrapper to compWrapper; added safe wrapper
  3596 (and access functions for it);
  3597 
  3598 * improved combination of classical reasoner and simplifier:
  3599   + functions for handling clasimpsets
  3600   + improvement of addss: now the simplifier is called _after_ the
  3601     safe steps.
  3602   + safe variant of addss called addSss: uses safe simplifications
  3603     _during_ the safe steps. It is more complete as it allows multiple
  3604     instantiations of unknowns (e.g. with slow_tac).
  3605 
  3606 *** Simplifier ***
  3607 
  3608 * added interface for simplification procedures (functions that
  3609 produce *proven* rewrite rules on the fly, depending on current
  3610 redex);
  3611 
  3612 * ordering on terms as parameter (used for ordered rewriting);
  3613 
  3614 * new functions delcongs, deleqcongs, and Delcongs. richer rep_ss;
  3615 
  3616 * the solver is now split into a safe and an unsafe part.
  3617 This should be invisible for the normal user, except that the
  3618 functions setsolver and addsolver have been renamed to setSolver and
  3619 addSolver; added safe_asm_full_simp_tac;
  3620 
  3621 
  3622 *** HOL ***
  3623 
  3624 * a generic induction tactic `induct_tac' which works for all datatypes and
  3625 also for type `nat';
  3626 
  3627 * a generic case distinction tactic `exhaust_tac' which works for all
  3628 datatypes and also for type `nat';
  3629 
  3630 * each datatype comes with a function `size';
  3631 
  3632 * patterns in case expressions allow tuple patterns as arguments to
  3633 constructors, for example `case x of [] => ... | (x,y,z)#ps => ...';
  3634 
  3635 * primrec now also works with type nat;
  3636 
  3637 * recdef: a new declaration form, allows general recursive functions to be
  3638 defined in theory files.  See HOL/ex/Fib, HOL/ex/Primes, HOL/Subst/Unify.
  3639 
  3640 * the constant for negation has been renamed from "not" to "Not" to
  3641 harmonize with FOL, ZF, LK, etc.;
  3642 
  3643 * HOL/ex/LFilter theory of a corecursive "filter" functional for
  3644 infinite lists;
  3645 
  3646 * HOL/Modelcheck demonstrates invocation of model checker oracle;
  3647 
  3648 * HOL/ex/Ring.thy declares cring_simp, which solves equational
  3649 problems in commutative rings, using axiomatic type classes for + and *;
  3650 
  3651 * more examples in HOL/MiniML and HOL/Auth;
  3652 
  3653 * more default rewrite rules for quantifiers, union/intersection;
  3654 
  3655 * a new constant `arbitrary == @x.False';
  3656 
  3657 * HOLCF/IOA replaces old HOL/IOA;
  3658 
  3659 * HOLCF changes: derived all rules and arities
  3660   + axiomatic type classes instead of classes
  3661   + typedef instead of faking type definitions
  3662   + eliminated the internal constants less_fun, less_cfun, UU_fun, UU_cfun etc.
  3663   + new axclasses cpo, chfin, flat with flat < chfin < pcpo < cpo < po
  3664   + eliminated the types void, one, tr
  3665   + use unit lift and bool lift (with translations) instead of one and tr
  3666   + eliminated blift from Lift3.thy (use Def instead of blift)
  3667   all eliminated rules are derived as theorems --> no visible changes ;
  3668 
  3669 
  3670 *** ZF ***
  3671 
  3672 * ZF now has Fast_tac, Simp_tac and Auto_tac.  Union_iff is a now a default
  3673 rewrite rule; this may affect some proofs.  eq_cs is gone but can be put back
  3674 as ZF_cs addSIs [equalityI];
  3675 
  3676 
  3677 
  3678 New in Isabelle94-7 (November 96)
  3679 ---------------------------------
  3680 
  3681 * allowing negative levels (as offsets) in prlev and choplev;
  3682 
  3683 * super-linear speedup for large simplifications;
  3684 
  3685 * FOL, ZF and HOL now use miniscoping: rewriting pushes
  3686 quantifications in as far as possible (COULD MAKE EXISTING PROOFS
  3687 FAIL); can suppress it using the command Delsimps (ex_simps @
  3688 all_simps); De Morgan laws are also now included, by default;
  3689 
  3690 * improved printing of ==>  :  ~:
  3691 
  3692 * new object-logic "Sequents" adds linear logic, while replacing LK
  3693 and Modal (thanks to Sara Kalvala);
  3694 
  3695 * HOL/Auth: correctness proofs for authentication protocols;
  3696 
  3697 * HOL: new auto_tac combines rewriting and classical reasoning (many
  3698 examples on HOL/Auth);
  3699 
  3700 * HOL: new command AddIffs for declaring theorems of the form P=Q to
  3701 the rewriter and classical reasoner simultaneously;
  3702 
  3703 * function uresult no longer returns theorems in "standard" format;
  3704 regain previous version by: val uresult = standard o uresult;
  3705 
  3706 
  3707 
  3708 New in Isabelle94-6
  3709 -------------------
  3710 
  3711 * oracles -- these establish an interface between Isabelle and trusted
  3712 external reasoners, which may deliver results as theorems;
  3713 
  3714 * proof objects (in particular record all uses of oracles);
  3715 
  3716 * Simp_tac, Fast_tac, etc. that refer to implicit simpset / claset;
  3717 
  3718 * "constdefs" section in theory files;
  3719 
  3720 * "primrec" section (HOL) no longer requires names;
  3721 
  3722 * internal type "tactic" now simply "thm -> thm Sequence.seq";
  3723 
  3724 
  3725 
  3726 New in Isabelle94-5
  3727 -------------------
  3728 
  3729 * reduced space requirements;
  3730 
  3731 * automatic HTML generation from theories;
  3732 
  3733 * theory files no longer require "..." (quotes) around most types;
  3734 
  3735 * new examples, including two proofs of the Church-Rosser theorem;
  3736 
  3737 * non-curried (1994) version of HOL is no longer distributed;
  3738 
  3739 
  3740 
  3741 New in Isabelle94-4
  3742 -------------------
  3743 
  3744 * greatly reduced space requirements;
  3745 
  3746 * theory files (.thy) no longer require \...\ escapes at line breaks;
  3747 
  3748 * searchable theorem database (see the section "Retrieving theorems" on
  3749 page 8 of the Reference Manual);
  3750 
  3751 * new examples, including Grabczewski's monumental case study of the
  3752 Axiom of Choice;
  3753 
  3754 * The previous version of HOL renamed to Old_HOL;
  3755 
  3756 * The new version of HOL (previously called CHOL) uses a curried syntax
  3757 for functions.  Application looks like f a b instead of f(a,b);
  3758 
  3759 * Mutually recursive inductive definitions finally work in HOL;
  3760 
  3761 * In ZF, pattern-matching on tuples is now available in all abstractions and
  3762 translates to the operator "split";
  3763 
  3764 
  3765 
  3766 New in Isabelle94-3
  3767 -------------------
  3768 
  3769 * new infix operator, addss, allowing the classical reasoner to
  3770 perform simplification at each step of its search.  Example:
  3771         fast_tac (cs addss ss)
  3772 
  3773 * a new logic, CHOL, the same as HOL, but with a curried syntax
  3774 for functions.  Application looks like f a b instead of f(a,b).  Also pairs
  3775 look like (a,b) instead of <a,b>;
  3776 
  3777 * PLEASE NOTE: CHOL will eventually replace HOL!
  3778 
  3779 * In CHOL, pattern-matching on tuples is now available in all abstractions.
  3780 It translates to the operator "split".  A new theory of integers is available;
  3781 
  3782 * In ZF, integer numerals now denote two's-complement binary integers.
  3783 Arithmetic operations can be performed by rewriting.  See ZF/ex/Bin.ML;
  3784 
  3785 * Many new examples: I/O automata, Church-Rosser theorem, equivalents
  3786 of the Axiom of Choice;
  3787 
  3788 
  3789 
  3790 New in Isabelle94-2
  3791 -------------------
  3792 
  3793 * Significantly faster resolution;
  3794 
  3795 * the different sections in a .thy file can now be mixed and repeated
  3796 freely;
  3797 
  3798 * Database of theorems for FOL, HOL and ZF.  New
  3799 commands including qed, qed_goal and bind_thm store theorems in the database.
  3800 
  3801 * Simple database queries: return a named theorem (get_thm) or all theorems of
  3802 a given theory (thms_of), or find out what theory a theorem was proved in
  3803 (theory_of_thm);
  3804 
  3805 * Bugs fixed in the inductive definition and datatype packages;
  3806 
  3807 * The classical reasoner provides deepen_tac and depth_tac, making FOL_dup_cs
  3808 and HOL_dup_cs obsolete;
  3809 
  3810 * Syntactic ambiguities caused by the new treatment of syntax in Isabelle94-1
  3811 have been removed;
  3812 
  3813 * Simpler definition of function space in ZF;
  3814 
  3815 * new results about cardinal and ordinal arithmetic in ZF;
  3816 
  3817 * 'subtype' facility in HOL for introducing new types as subsets of existing
  3818 types;
  3819 
  3820 
  3821 $Id$