NEWS
author wenzelm
Thu Dec 01 22:03:01 2005 +0100 (2005-12-01 ago)
changeset 18324 d1c4b1112e33
parent 18308 f18a54840629
child 18367 c209f4b61b51
permissions -rw-r--r--
unfold_tac: static evaluation of simpset;
     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.prems")
   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 * Input syntax now supports dummy variable binding "%_. b", where the
   131 body does not mention the bound variable.  Note that dummy patterns
   132 implicitly depend on their context of bounds, which makes "{_. _}"
   133 match any set comprehension as expected.  Potential INCOMPATIBILITY --
   134 parse translations need to cope with syntactic constant "_idtdummy" in
   135 the binding position.
   136 
   137 * Removed obsolete syntactic constant "_K" and its associated parse
   138 translation.  INCOMPATIBILITY -- use dummy abstraction instead, for
   139 example "A -> B" => "Pi A (%_. B)".
   140 
   141 
   142 *** HOL ***
   143 
   144 * Alternative iff syntax "A <-> B" for equality on bool (with priority
   145 25 like -->); output depends on the "iff" print_mode, the default is
   146 "A = B" (with priority 50).
   147 
   148 * In the context of the assumption "~(s = t)" the Simplifier rewrites
   149 "t = s" to False (by simproc "neq_simproc").  For backward
   150 compatibility this can be disabled by ML "reset use_neq_simproc".
   151 
   152 * Tactics 'sat' and 'satx' reimplemented, several improvements: goals
   153 no longer need to be stated as "<prems> ==> False", equivalences (i.e.
   154 "=" on type bool) are handled, variable names of the form "lit_<n>"
   155 are no longer reserved, significant speedup.
   156 
   157 
   158 *** ML ***
   159 
   160 * Library: new module Pure/General/rat.ML implementing rational numbers,
   161 replacing the former functions in the Isabelle library.
   162 
   163 * Library: indexed lists - some functions in the Isabelle library
   164 treating lists over 'a as finite mappings from [0...n] to 'a
   165 have been given more convenient names and signatures reminiscent
   166 of similar functions for alists, tables, etc:
   167 
   168   val nth: 'a list -> int -> 'a 
   169   val nth_update: int * 'a -> 'a list -> 'a list
   170   val nth_map: int -> ('a -> 'a) -> 'a list -> 'a list
   171   val fold_index: (int * 'a -> 'b -> 'b) -> 'a list -> 'b -> 'b
   172 
   173 Note that fold_index starts counting at index 0, not 1 like foldln used to.
   174 
   175 * Pure: primitive rule lift_rule now takes goal cterm instead of an
   176 actual goal state (thm).  Use Thm.lift_rule (Thm.cprem_of st i) to
   177 achieve the old behaviour.
   178 
   179 * Pure: the "Goal" constant is now called "prop", supporting a
   180 slightly more general idea of ``protecting'' meta-level rule
   181 statements.
   182 
   183 * Internal goals: structure Goal provides simple interfaces for
   184 init/conclude/finish and tactical prove operations (replacing former
   185 Tactic.prove).  Note that OldGoals.prove_goalw_cterm has long been
   186 obsolete, it is ill-behaved in a local proof context (e.g. with local
   187 fixes/assumes or in a locale context).
   188 
   189 * Simplifier: the simpset of a running simplification process now
   190 contains a proof context (cf. Simplifier.the_context), which is the
   191 very context that the initial simpset has been retrieved from (by
   192 simpset_of/local_simpset_of).  Consequently, all plug-in components
   193 (solver, looper etc.) may depend on arbitrary proof data.
   194 
   195 * Simplifier.inherit_context inherits the proof context (plus the
   196 local bounds) of the current simplification process; any simproc
   197 etc. that calls the Simplifier recursively should do this!  Removed
   198 former Simplifier.inherit_bounds, which is already included here --
   199 INCOMPATIBILITY.  Tools based on low-level rewriting may even have to
   200 specify an explicit context using Simplifier.context/theory_context.
   201 
   202 * Simplifier/Classical Reasoner: more abstract interfaces
   203 change_simpset/claset for modifying the simpset/claset reference of a
   204 theory; raw versions simpset/claset_ref etc. have been discontinued --
   205 INCOMPATIBILITY.
   206 
   207 
   208 
   209 New in Isabelle2005 (October 2005)
   210 ----------------------------------
   211 
   212 *** General ***
   213 
   214 * Theory headers: the new header syntax for Isar theories is
   215 
   216   theory <name>
   217   imports <theory1> ... <theoryN>
   218   uses <file1> ... <fileM>
   219   begin
   220 
   221 where the 'uses' part is optional.  The previous syntax
   222 
   223   theory <name> = <theory1> + ... + <theoryN>:
   224 
   225 will disappear in the next release.  Use isatool fixheaders to convert
   226 existing theory files.  Note that there is no change in ancient
   227 non-Isar theories now, but these will disappear soon.
   228 
   229 * Theory loader: parent theories can now also be referred to via
   230 relative and absolute paths.
   231 
   232 * Command 'find_theorems' searches for a list of criteria instead of a
   233 list of constants. Known criteria are: intro, elim, dest, name:string,
   234 simp:term, and any term. Criteria can be preceded by '-' to select
   235 theorems that do not match. Intro, elim, dest select theorems that
   236 match the current goal, name:s selects theorems whose fully qualified
   237 name contain s, and simp:term selects all simplification rules whose
   238 lhs match term.  Any other term is interpreted as pattern and selects
   239 all theorems matching the pattern. Available in ProofGeneral under
   240 'ProofGeneral -> Find Theorems' or C-c C-f.  Example:
   241 
   242   C-c C-f (100) "(_::nat) + _ + _" intro -name: "HOL."
   243 
   244 prints the last 100 theorems matching the pattern "(_::nat) + _ + _",
   245 matching the current goal as introduction rule and not having "HOL."
   246 in their name (i.e. not being defined in theory HOL).
   247 
   248 * Command 'thms_containing' has been discontinued in favour of
   249 'find_theorems'; INCOMPATIBILITY.
   250 
   251 * Communication with Proof General is now 8bit clean, which means that
   252 Unicode text in UTF-8 encoding may be used within theory texts (both
   253 formal and informal parts).  Cf. option -U of the Isabelle Proof
   254 General interface.  Here are some simple examples (cf. src/HOL/ex):
   255 
   256   http://isabelle.in.tum.de/library/HOL/ex/Hebrew.html
   257   http://isabelle.in.tum.de/library/HOL/ex/Chinese.html
   258 
   259 * Improved efficiency of the Simplifier and, to a lesser degree, the
   260 Classical Reasoner.  Typical big applications run around 2 times
   261 faster.
   262 
   263 
   264 *** Document preparation ***
   265 
   266 * Commands 'display_drafts' and 'print_drafts' perform simple output
   267 of raw sources.  Only those symbols that do not require additional
   268 LaTeX packages (depending on comments in isabellesym.sty) are
   269 displayed properly, everything else is left verbatim.  isatool display
   270 and isatool print are used as front ends (these are subject to the
   271 DVI/PDF_VIEWER and PRINT_COMMAND settings, respectively).
   272 
   273 * Command tags control specific markup of certain regions of text,
   274 notably folding and hiding.  Predefined tags include "theory" (for
   275 theory begin and end), "proof" for proof commands, and "ML" for
   276 commands involving ML code; the additional tags "visible" and
   277 "invisible" are unused by default.  Users may give explicit tag
   278 specifications in the text, e.g. ''by %invisible (auto)''.  The
   279 interpretation of tags is determined by the LaTeX job during document
   280 preparation: see option -V of isatool usedir, or options -n and -t of
   281 isatool document, or even the LaTeX macros \isakeeptag, \isafoldtag,
   282 \isadroptag.
   283 
   284 Several document versions may be produced at the same time via isatool
   285 usedir (the generated index.html will link all of them).  Typical
   286 specifications include ''-V document=theory,proof,ML'' to present
   287 theory/proof/ML parts faithfully, ''-V outline=/proof,/ML'' to fold
   288 proof and ML commands, and ''-V mutilated=-theory,-proof,-ML'' to omit
   289 these parts without any formal replacement text.  The Isabelle site
   290 default settings produce ''document'' and ''outline'' versions as
   291 specified above.
   292 
   293 * Several new antiquotations:
   294 
   295   @{term_type term} prints a term with its type annotated;
   296 
   297   @{typeof term} prints the type of a term;
   298 
   299   @{const const} is the same as @{term const}, but checks that the
   300   argument is a known logical constant;
   301 
   302   @{term_style style term} and @{thm_style style thm} print a term or
   303   theorem applying a "style" to it
   304 
   305   @{ML text}
   306 
   307 Predefined styles are 'lhs' and 'rhs' printing the lhs/rhs of
   308 definitions, equations, inequations etc., 'concl' printing only the
   309 conclusion of a meta-logical statement theorem, and 'prem1' .. 'prem19'
   310 to print the specified premise.  TermStyle.add_style provides an ML
   311 interface for introducing further styles.  See also the "LaTeX Sugar"
   312 document practical applications.  The ML antiquotation prints
   313 type-checked ML expressions verbatim.
   314 
   315 * Markup commands 'chapter', 'section', 'subsection', 'subsubsection',
   316 and 'text' support optional locale specification '(in loc)', which
   317 specifies the default context for interpreting antiquotations.  For
   318 example: 'text (in lattice) {* @{thm inf_assoc}*}'.
   319 
   320 * Option 'locale=NAME' of antiquotations specifies an alternative
   321 context interpreting the subsequent argument.  For example: @{thm
   322 [locale=lattice] inf_assoc}.
   323 
   324 * Proper output of proof terms (@{prf ...} and @{full_prf ...}) within
   325 a proof context.
   326 
   327 * Proper output of antiquotations for theory commands involving a
   328 proof context (such as 'locale' or 'theorem (in loc) ...').
   329 
   330 * Delimiters of outer tokens (string etc.) now produce separate LaTeX
   331 macros (\isachardoublequoteopen, isachardoublequoteclose etc.).
   332 
   333 * isatool usedir: new option -C (default true) controls whether option
   334 -D should include a copy of the original document directory; -C false
   335 prevents unwanted effects such as copying of administrative CVS data.
   336 
   337 
   338 *** Pure ***
   339 
   340 * Considerably improved version of 'constdefs' command.  Now performs
   341 automatic type-inference of declared constants; additional support for
   342 local structure declarations (cf. locales and HOL records), see also
   343 isar-ref manual.  Potential INCOMPATIBILITY: need to observe strictly
   344 sequential dependencies of definitions within a single 'constdefs'
   345 section; moreover, the declared name needs to be an identifier.  If
   346 all fails, consider to fall back on 'consts' and 'defs' separately.
   347 
   348 * Improved indexed syntax and implicit structures.  First of all,
   349 indexed syntax provides a notational device for subscripted
   350 application, using the new syntax \<^bsub>term\<^esub> for arbitrary
   351 expressions.  Secondly, in a local context with structure
   352 declarations, number indexes \<^sub>n or the empty index (default
   353 number 1) refer to a certain fixed variable implicitly; option
   354 show_structs controls printing of implicit structures.  Typical
   355 applications of these concepts involve record types and locales.
   356 
   357 * New command 'no_syntax' removes grammar declarations (and
   358 translations) resulting from the given syntax specification, which is
   359 interpreted in the same manner as for the 'syntax' command.
   360 
   361 * 'Advanced' translation functions (parse_translation etc.) may depend
   362 on the signature of the theory context being presently used for
   363 parsing/printing, see also isar-ref manual.
   364 
   365 * Improved 'oracle' command provides a type-safe interface to turn an
   366 ML expression of type theory -> T -> term into a primitive rule of
   367 type theory -> T -> thm (i.e. the functionality of Thm.invoke_oracle
   368 is already included here); see also FOL/ex/IffExample.thy;
   369 INCOMPATIBILITY.
   370 
   371 * axclass: name space prefix for class "c" is now "c_class" (was "c"
   372 before); "cI" is no longer bound, use "c.intro" instead.
   373 INCOMPATIBILITY.  This change avoids clashes of fact bindings for
   374 axclasses vs. locales.
   375 
   376 * Improved internal renaming of symbolic identifiers -- attach primes
   377 instead of base 26 numbers.
   378 
   379 * New flag show_question_marks controls printing of leading question
   380 marks in schematic variable names.
   381 
   382 * In schematic variable names, *any* symbol following \<^isub> or
   383 \<^isup> is now treated as part of the base name.  For example, the
   384 following works without printing of awkward ".0" indexes:
   385 
   386   lemma "x\<^isub>1 = x\<^isub>2 ==> x\<^isub>2 = x\<^isub>1"
   387     by simp
   388 
   389 * Inner syntax includes (*(*nested*) comments*).
   390 
   391 * Pretty printer now supports unbreakable blocks, specified in mixfix
   392 annotations as "(00...)".
   393 
   394 * Clear separation of logical types and nonterminals, where the latter
   395 may only occur in 'syntax' specifications or type abbreviations.
   396 Before that distinction was only partially implemented via type class
   397 "logic" vs. "{}".  Potential INCOMPATIBILITY in rare cases of improper
   398 use of 'types'/'consts' instead of 'nonterminals'/'syntax'.  Some very
   399 exotic syntax specifications may require further adaption
   400 (e.g. Cube/Cube.thy).
   401 
   402 * Removed obsolete type class "logic", use the top sort {} instead.
   403 Note that non-logical types should be declared as 'nonterminals'
   404 rather than 'types'.  INCOMPATIBILITY for new object-logic
   405 specifications.
   406 
   407 * Attributes 'induct' and 'cases': type or set names may now be
   408 locally fixed variables as well.
   409 
   410 * Simplifier: can now control the depth to which conditional rewriting
   411 is traced via the PG menu Isabelle -> Settings -> Trace Simp Depth
   412 Limit.
   413 
   414 * Simplifier: simplification procedures may now take the current
   415 simpset into account (cf. Simplifier.simproc(_i) / mk_simproc
   416 interface), which is very useful for calling the Simplifier
   417 recursively.  Minor INCOMPATIBILITY: the 'prems' argument of simprocs
   418 is gone -- use prems_of_ss on the simpset instead.  Moreover, the
   419 low-level mk_simproc no longer applies Logic.varify internally, to
   420 allow for use in a context of fixed variables.
   421 
   422 * thin_tac now works even if the assumption being deleted contains !!
   423 or ==>.  More generally, erule now works even if the major premise of
   424 the elimination rule contains !! or ==>.
   425 
   426 * Method 'rules' has been renamed to 'iprover'. INCOMPATIBILITY.
   427 
   428 * Reorganized bootstrapping of the Pure theories; CPure is now derived
   429 from Pure, which contains all common declarations already.  Both
   430 theories are defined via plain Isabelle/Isar .thy files.
   431 INCOMPATIBILITY: elements of CPure (such as the CPure.intro /
   432 CPure.elim / CPure.dest attributes) now appear in the Pure name space;
   433 use isatool fixcpure to adapt your theory and ML sources.
   434 
   435 * New syntax 'name(i-j, i-, i, ...)' for referring to specific
   436 selections of theorems in named facts via index ranges.
   437 
   438 * 'print_theorems': in theory mode, really print the difference
   439 wrt. the last state (works for interactive theory development only),
   440 in proof mode print all local facts (cf. 'print_facts');
   441 
   442 * 'hide': option '(open)' hides only base names.
   443 
   444 * More efficient treatment of intermediate checkpoints in interactive
   445 theory development.
   446 
   447 * Code generator is now invoked via code_module (incremental code
   448 generation) and code_library (modular code generation, ML structures
   449 for each theory).  INCOMPATIBILITY: new keywords 'file' and 'contains'
   450 must be quoted when used as identifiers.
   451 
   452 * New 'value' command for reading, evaluating and printing terms using
   453 the code generator.  INCOMPATIBILITY: command keyword 'value' must be
   454 quoted when used as identifier.
   455 
   456 
   457 *** Locales ***
   458 
   459 * New commands for the interpretation of locale expressions in
   460 theories (1), locales (2) and proof contexts (3).  These generate
   461 proof obligations from the expression specification.  After the
   462 obligations have been discharged, theorems of the expression are added
   463 to the theory, target locale or proof context.  The synopsis of the
   464 commands is a follows:
   465 
   466   (1) interpretation expr inst
   467   (2) interpretation target < expr
   468   (3) interpret expr inst
   469 
   470 Interpretation in theories and proof contexts require a parameter
   471 instantiation of terms from the current context.  This is applied to
   472 specifications and theorems of the interpreted expression.
   473 Interpretation in locales only permits parameter renaming through the
   474 locale expression.  Interpretation is smart in that interpretations
   475 that are active already do not occur in proof obligations, neither are
   476 instantiated theorems stored in duplicate.  Use 'print_interps' to
   477 inspect active interpretations of a particular locale.  For details,
   478 see the Isar Reference manual.  Examples can be found in
   479 HOL/Finite_Set.thy and HOL/Algebra/UnivPoly.thy.
   480 
   481 INCOMPATIBILITY: former 'instantiate' has been withdrawn, use
   482 'interpret' instead.
   483 
   484 * New context element 'constrains' for adding type constraints to
   485 parameters.
   486 
   487 * Context expressions: renaming of parameters with syntax
   488 redeclaration.
   489 
   490 * Locale declaration: 'includes' disallowed.
   491 
   492 * Proper static binding of attribute syntax -- i.e. types / terms /
   493 facts mentioned as arguments are always those of the locale definition
   494 context, independently of the context of later invocations.  Moreover,
   495 locale operations (renaming and type / term instantiation) are applied
   496 to attribute arguments as expected.
   497 
   498 INCOMPATIBILITY of the ML interface: always pass Attrib.src instead of
   499 actual attributes; rare situations may require Attrib.attribute to
   500 embed those attributes into Attrib.src that lack concrete syntax.
   501 Attribute implementations need to cooperate properly with the static
   502 binding mechanism.  Basic parsers Args.XXX_typ/term/prop and
   503 Attrib.XXX_thm etc. already do the right thing without further
   504 intervention.  Only unusual applications -- such as "where" or "of"
   505 (cf. src/Pure/Isar/attrib.ML), which process arguments depending both
   506 on the context and the facts involved -- may have to assign parsed
   507 values to argument tokens explicitly.
   508 
   509 * Changed parameter management in theorem generation for long goal
   510 statements with 'includes'.  INCOMPATIBILITY: produces a different
   511 theorem statement in rare situations.
   512 
   513 * Locale inspection command 'print_locale' omits notes elements.  Use
   514 'print_locale!' to have them included in the output.
   515 
   516 
   517 *** Provers ***
   518 
   519 * Provers/hypsubst.ML: improved version of the subst method, for
   520 single-step rewriting: it now works in bound variable contexts. New is
   521 'subst (asm)', for rewriting an assumption.  INCOMPATIBILITY: may
   522 rewrite a different subterm than the original subst method, which is
   523 still available as 'simplesubst'.
   524 
   525 * Provers/quasi.ML: new transitivity reasoners for transitivity only
   526 and quasi orders.
   527 
   528 * Provers/trancl.ML: new transitivity reasoner for transitive and
   529 reflexive-transitive closure of relations.
   530 
   531 * Provers/blast.ML: new reference depth_limit to make blast's depth
   532 limit (previously hard-coded with a value of 20) user-definable.
   533 
   534 * Provers/simplifier.ML has been moved to Pure, where Simplifier.setup
   535 is peformed already.  Object-logics merely need to finish their
   536 initial simpset configuration as before.  INCOMPATIBILITY.
   537 
   538 
   539 *** HOL ***
   540 
   541 * Symbolic syntax of Hilbert Choice Operator is now as follows:
   542 
   543   syntax (epsilon)
   544     "_Eps" :: "[pttrn, bool] => 'a"    ("(3\<some>_./ _)" [0, 10] 10)
   545 
   546 The symbol \<some> is displayed as the alternative epsilon of LaTeX
   547 and x-symbol; use option '-m epsilon' to get it actually printed.
   548 Moreover, the mathematically important symbolic identifier \<epsilon>
   549 becomes available as variable, constant etc.  INCOMPATIBILITY,
   550 
   551 * "x > y" abbreviates "y < x" and "x >= y" abbreviates "y <= x".
   552 Similarly for all quantifiers: "ALL x > y" etc.  The x-symbol for >=
   553 is \<ge>. New transitivity rules have been added to HOL/Orderings.thy to
   554 support corresponding Isar calculations.
   555 
   556 * "{x:A. P}" abbreviates "{x. x:A & P}", and similarly for "\<in>"
   557 instead of ":".
   558 
   559 * theory SetInterval: changed the syntax for open intervals:
   560 
   561   Old       New
   562   {..n(}    {..<n}
   563   {)n..}    {n<..}
   564   {m..n(}   {m..<n}
   565   {)m..n}   {m<..n}
   566   {)m..n(}  {m<..<n}
   567 
   568 The old syntax is still supported but will disappear in the next
   569 release.  For conversion use the following Emacs search and replace
   570 patterns (these are not perfect but work quite well):
   571 
   572   {)\([^\.]*\)\.\.  ->  {\1<\.\.}
   573   \.\.\([^(}]*\)(}  ->  \.\.<\1}
   574 
   575 * Theory Commutative_Ring (in Library): method comm_ring for proving
   576 equalities in commutative rings; method 'algebra' provides a generic
   577 interface.
   578 
   579 * Theory Finite_Set: changed the syntax for 'setsum', summation over
   580 finite sets: "setsum (%x. e) A", which used to be "\<Sum>x:A. e", is
   581 now either "SUM x:A. e" or "\<Sum>x \<in> A. e". The bound variable can
   582 be a tuple pattern.
   583 
   584 Some new syntax forms are available:
   585 
   586   "\<Sum>x | P. e"      for     "setsum (%x. e) {x. P}"
   587   "\<Sum>x = a..b. e"   for     "setsum (%x. e) {a..b}"
   588   "\<Sum>x = a..<b. e"  for     "setsum (%x. e) {a..<b}"
   589   "\<Sum>x < k. e"      for     "setsum (%x. e) {..<k}"
   590 
   591 The latter form "\<Sum>x < k. e" used to be based on a separate
   592 function "Summation", which has been discontinued.
   593 
   594 * theory Finite_Set: in structured induction proofs, the insert case
   595 is now 'case (insert x F)' instead of the old counterintuitive 'case
   596 (insert F x)'.
   597 
   598 * The 'refute' command has been extended to support a much larger
   599 fragment of HOL, including axiomatic type classes, constdefs and
   600 typedefs, inductive datatypes and recursion.
   601 
   602 * New tactics 'sat' and 'satx' to prove propositional tautologies.
   603 Requires zChaff with proof generation to be installed.  See
   604 HOL/ex/SAT_Examples.thy for examples.
   605 
   606 * Datatype induction via method 'induct' now preserves the name of the
   607 induction variable. For example, when proving P(xs::'a list) by
   608 induction on xs, the induction step is now P(xs) ==> P(a#xs) rather
   609 than P(list) ==> P(a#list) as previously.  Potential INCOMPATIBILITY
   610 in unstructured proof scripts.
   611 
   612 * Reworked implementation of records.  Improved scalability for
   613 records with many fields, avoiding performance problems for type
   614 inference. Records are no longer composed of nested field types, but
   615 of nested extension types. Therefore the record type only grows linear
   616 in the number of extensions and not in the number of fields.  The
   617 top-level (users) view on records is preserved.  Potential
   618 INCOMPATIBILITY only in strange cases, where the theory depends on the
   619 old record representation. The type generated for a record is called
   620 <record_name>_ext_type.
   621 
   622 Flag record_quick_and_dirty_sensitive can be enabled to skip the
   623 proofs triggered by a record definition or a simproc (if
   624 quick_and_dirty is enabled).  Definitions of large records can take
   625 quite long.
   626 
   627 New simproc record_upd_simproc for simplification of multiple record
   628 updates enabled by default.  Moreover, trivial updates are also
   629 removed: r(|x := x r|) = r.  INCOMPATIBILITY: old proofs break
   630 occasionally, since simplification is more powerful by default.
   631 
   632 * typedef: proper support for polymorphic sets, which contain extra
   633 type-variables in the term.
   634 
   635 * Simplifier: automatically reasons about transitivity chains
   636 involving "trancl" (r^+) and "rtrancl" (r^*) by setting up tactics
   637 provided by Provers/trancl.ML as additional solvers.  INCOMPATIBILITY:
   638 old proofs break occasionally as simplification may now solve more
   639 goals than previously.
   640 
   641 * Simplifier: converts x <= y into x = y if assumption y <= x is
   642 present.  Works for all partial orders (class "order"), in particular
   643 numbers and sets.  For linear orders (e.g. numbers) it treats ~ x < y
   644 just like y <= x.
   645 
   646 * Simplifier: new simproc for "let x = a in f x".  If a is a free or
   647 bound variable or a constant then the let is unfolded.  Otherwise
   648 first a is simplified to b, and then f b is simplified to g. If
   649 possible we abstract b from g arriving at "let x = b in h x",
   650 otherwise we unfold the let and arrive at g.  The simproc can be
   651 enabled/disabled by the reference use_let_simproc.  Potential
   652 INCOMPATIBILITY since simplification is more powerful by default.
   653 
   654 * Classical reasoning: the meson method now accepts theorems as arguments.
   655 
   656 * Prover support: pre-release of the Isabelle-ATP linkup, which runs background
   657 jobs to provide advice on the provability of subgoals.
   658 
   659 * Theory OrderedGroup and Ring_and_Field: various additions and
   660 improvements to faciliate calculations involving equalities and
   661 inequalities.
   662 
   663 The following theorems have been eliminated or modified
   664 (INCOMPATIBILITY):
   665 
   666   abs_eq             now named abs_of_nonneg
   667   abs_of_ge_0        now named abs_of_nonneg
   668   abs_minus_eq       now named abs_of_nonpos
   669   imp_abs_id         now named abs_of_nonneg
   670   imp_abs_neg_id     now named abs_of_nonpos
   671   mult_pos           now named mult_pos_pos
   672   mult_pos_le        now named mult_nonneg_nonneg
   673   mult_pos_neg_le    now named mult_nonneg_nonpos
   674   mult_pos_neg2_le   now named mult_nonneg_nonpos2
   675   mult_neg           now named mult_neg_neg
   676   mult_neg_le        now named mult_nonpos_nonpos
   677 
   678 * Theory Parity: added rules for simplifying exponents.
   679 
   680 * Theory List:
   681 
   682 The following theorems have been eliminated or modified
   683 (INCOMPATIBILITY):
   684 
   685   list_all_Nil       now named list_all.simps(1)
   686   list_all_Cons      now named list_all.simps(2)
   687   list_all_conv      now named list_all_iff
   688   set_mem_eq         now named mem_iff
   689 
   690 * Theories SetsAndFunctions and BigO (see HOL/Library) support
   691 asymptotic "big O" calculations.  See the notes in BigO.thy.
   692 
   693 
   694 *** HOL-Complex ***
   695 
   696 * Theory RealDef: better support for embedding natural numbers and
   697 integers in the reals.
   698 
   699 The following theorems have been eliminated or modified
   700 (INCOMPATIBILITY):
   701 
   702   exp_ge_add_one_self  now requires no hypotheses
   703   real_of_int_add      reversed direction of equality (use [symmetric])
   704   real_of_int_minus    reversed direction of equality (use [symmetric])
   705   real_of_int_diff     reversed direction of equality (use [symmetric])
   706   real_of_int_mult     reversed direction of equality (use [symmetric])
   707 
   708 * Theory RComplete: expanded support for floor and ceiling functions.
   709 
   710 * Theory Ln is new, with properties of the natural logarithm
   711 
   712 * Hyperreal: There is a new type constructor "star" for making
   713 nonstandard types.  The old type names are now type synonyms:
   714 
   715   hypreal = real star
   716   hypnat = nat star
   717   hcomplex = complex star
   718 
   719 * Hyperreal: Many groups of similarly-defined constants have been
   720 replaced by polymorphic versions (INCOMPATIBILITY):
   721 
   722   star_of <-- hypreal_of_real, hypnat_of_nat, hcomplex_of_complex
   723 
   724   starset      <-- starsetNat, starsetC
   725   *s*          <-- *sNat*, *sc*
   726   starset_n    <-- starsetNat_n, starsetC_n
   727   *sn*         <-- *sNatn*, *scn*
   728   InternalSets <-- InternalNatSets, InternalCSets
   729 
   730   starfun      <-- starfun{Nat,Nat2,C,RC,CR}
   731   *f*          <-- *fNat*, *fNat2*, *fc*, *fRc*, *fcR*
   732   starfun_n    <-- starfun{Nat,Nat2,C,RC,CR}_n
   733   *fn*         <-- *fNatn*, *fNat2n*, *fcn*, *fRcn*, *fcRn*
   734   InternalFuns <-- InternalNatFuns, InternalNatFuns2, Internal{C,RC,CR}Funs
   735 
   736 * Hyperreal: Many type-specific theorems have been removed in favor of
   737 theorems specific to various axiomatic type classes (INCOMPATIBILITY):
   738 
   739   add_commute <-- {hypreal,hypnat,hcomplex}_add_commute
   740   add_assoc   <-- {hypreal,hypnat,hcomplex}_add_assocs
   741   OrderedGroup.add_0 <-- {hypreal,hypnat,hcomplex}_add_zero_left
   742   OrderedGroup.add_0_right <-- {hypreal,hcomplex}_add_zero_right
   743   right_minus <-- hypreal_add_minus
   744   left_minus <-- {hypreal,hcomplex}_add_minus_left
   745   mult_commute <-- {hypreal,hypnat,hcomplex}_mult_commute
   746   mult_assoc <-- {hypreal,hypnat,hcomplex}_mult_assoc
   747   mult_1_left <-- {hypreal,hypnat}_mult_1, hcomplex_mult_one_left
   748   mult_1_right <-- hcomplex_mult_one_right
   749   mult_zero_left <-- hcomplex_mult_zero_left
   750   left_distrib <-- {hypreal,hypnat,hcomplex}_add_mult_distrib
   751   right_distrib <-- hypnat_add_mult_distrib2
   752   zero_neq_one <-- {hypreal,hypnat,hcomplex}_zero_not_eq_one
   753   right_inverse <-- hypreal_mult_inverse
   754   left_inverse <-- hypreal_mult_inverse_left, hcomplex_mult_inv_left
   755   order_refl <-- {hypreal,hypnat}_le_refl
   756   order_trans <-- {hypreal,hypnat}_le_trans
   757   order_antisym <-- {hypreal,hypnat}_le_anti_sym
   758   order_less_le <-- {hypreal,hypnat}_less_le
   759   linorder_linear <-- {hypreal,hypnat}_le_linear
   760   add_left_mono <-- {hypreal,hypnat}_add_left_mono
   761   mult_strict_left_mono <-- {hypreal,hypnat}_mult_less_mono2
   762   add_nonneg_nonneg <-- hypreal_le_add_order
   763 
   764 * Hyperreal: Separate theorems having to do with type-specific
   765 versions of constants have been merged into theorems that apply to the
   766 new polymorphic constants (INCOMPATIBILITY):
   767 
   768   STAR_UNIV_set <-- {STAR_real,NatStar_real,STARC_complex}_set
   769   STAR_empty_set <-- {STAR,NatStar,STARC}_empty_set
   770   STAR_Un <-- {STAR,NatStar,STARC}_Un
   771   STAR_Int <-- {STAR,NatStar,STARC}_Int
   772   STAR_Compl <-- {STAR,NatStar,STARC}_Compl
   773   STAR_subset <-- {STAR,NatStar,STARC}_subset
   774   STAR_mem <-- {STAR,NatStar,STARC}_mem
   775   STAR_mem_Compl <-- {STAR,STARC}_mem_Compl
   776   STAR_diff <-- {STAR,STARC}_diff
   777   STAR_star_of_image_subset <-- {STAR_hypreal_of_real, NatStar_hypreal_of_real,
   778     STARC_hcomplex_of_complex}_image_subset
   779   starset_n_Un <-- starset{Nat,C}_n_Un
   780   starset_n_Int <-- starset{Nat,C}_n_Int
   781   starset_n_Compl <-- starset{Nat,C}_n_Compl
   782   starset_n_diff <-- starset{Nat,C}_n_diff
   783   InternalSets_Un <-- Internal{Nat,C}Sets_Un
   784   InternalSets_Int <-- Internal{Nat,C}Sets_Int
   785   InternalSets_Compl <-- Internal{Nat,C}Sets_Compl
   786   InternalSets_diff <-- Internal{Nat,C}Sets_diff
   787   InternalSets_UNIV_diff <-- Internal{Nat,C}Sets_UNIV_diff
   788   InternalSets_starset_n <-- Internal{Nat,C}Sets_starset{Nat,C}_n
   789   starset_starset_n_eq <-- starset{Nat,C}_starset{Nat,C}_n_eq
   790   starset_n_starset <-- starset{Nat,C}_n_starset{Nat,C}
   791   starfun_n_starfun <-- starfun{Nat,Nat2,C,RC,CR}_n_starfun{Nat,Nat2,C,RC,CR}
   792   starfun <-- starfun{Nat,Nat2,C,RC,CR}
   793   starfun_mult <-- starfun{Nat,Nat2,C,RC,CR}_mult
   794   starfun_add <-- starfun{Nat,Nat2,C,RC,CR}_add
   795   starfun_minus <-- starfun{Nat,Nat2,C,RC,CR}_minus
   796   starfun_diff <-- starfun{C,RC,CR}_diff
   797   starfun_o <-- starfun{NatNat2,Nat2,_stafunNat,C,C_starfunRC,_starfunCR}_o
   798   starfun_o2 <-- starfun{NatNat2,_stafunNat,C,C_starfunRC,_starfunCR}_o2
   799   starfun_const_fun <-- starfun{Nat,Nat2,C,RC,CR}_const_fun
   800   starfun_inverse <-- starfun{Nat,C,RC,CR}_inverse
   801   starfun_eq <-- starfun{Nat,Nat2,C,RC,CR}_eq
   802   starfun_eq_iff <-- starfun{C,RC,CR}_eq_iff
   803   starfun_Id <-- starfunC_Id
   804   starfun_approx <-- starfun{Nat,CR}_approx
   805   starfun_capprox <-- starfun{C,RC}_capprox
   806   starfun_abs <-- starfunNat_rabs
   807   starfun_lambda_cancel <-- starfun{C,CR,RC}_lambda_cancel
   808   starfun_lambda_cancel2 <-- starfun{C,CR,RC}_lambda_cancel2
   809   starfun_mult_HFinite_approx <-- starfunCR_mult_HFinite_capprox
   810   starfun_mult_CFinite_capprox <-- starfun{C,RC}_mult_CFinite_capprox
   811   starfun_add_capprox <-- starfun{C,RC}_add_capprox
   812   starfun_add_approx <-- starfunCR_add_approx
   813   starfun_inverse_inverse <-- starfunC_inverse_inverse
   814   starfun_divide <-- starfun{C,CR,RC}_divide
   815   starfun_n <-- starfun{Nat,C}_n
   816   starfun_n_mult <-- starfun{Nat,C}_n_mult
   817   starfun_n_add <-- starfun{Nat,C}_n_add
   818   starfun_n_add_minus <-- starfunNat_n_add_minus
   819   starfun_n_const_fun <-- starfun{Nat,C}_n_const_fun
   820   starfun_n_minus <-- starfun{Nat,C}_n_minus
   821   starfun_n_eq <-- starfun{Nat,C}_n_eq
   822 
   823   star_n_add <-- {hypreal,hypnat,hcomplex}_add
   824   star_n_minus <-- {hypreal,hcomplex}_minus
   825   star_n_diff <-- {hypreal,hcomplex}_diff
   826   star_n_mult <-- {hypreal,hcomplex}_mult
   827   star_n_inverse <-- {hypreal,hcomplex}_inverse
   828   star_n_le <-- {hypreal,hypnat}_le
   829   star_n_less <-- {hypreal,hypnat}_less
   830   star_n_zero_num <-- {hypreal,hypnat,hcomplex}_zero_num
   831   star_n_one_num <-- {hypreal,hypnat,hcomplex}_one_num
   832   star_n_abs <-- hypreal_hrabs
   833   star_n_divide <-- hcomplex_divide
   834 
   835   star_of_add <-- {hypreal_of_real,hypnat_of_nat,hcomplex_of_complex}_add
   836   star_of_minus <-- {hypreal_of_real,hcomplex_of_complex}_minus
   837   star_of_diff <-- hypreal_of_real_diff
   838   star_of_mult <-- {hypreal_of_real,hypnat_of_nat,hcomplex_of_complex}_mult
   839   star_of_one <-- {hypreal_of_real,hcomplex_of_complex}_one
   840   star_of_zero <-- {hypreal_of_real,hypnat_of_nat,hcomplex_of_complex}_zero
   841   star_of_le <-- {hypreal_of_real,hypnat_of_nat}_le_iff
   842   star_of_less <-- {hypreal_of_real,hypnat_of_nat}_less_iff
   843   star_of_eq <-- {hypreal_of_real,hypnat_of_nat,hcomplex_of_complex}_eq_iff
   844   star_of_inverse <-- {hypreal_of_real,hcomplex_of_complex}_inverse
   845   star_of_divide <-- {hypreal_of_real,hcomplex_of_complex}_divide
   846   star_of_of_nat <-- {hypreal_of_real,hcomplex_of_complex}_of_nat
   847   star_of_of_int <-- {hypreal_of_real,hcomplex_of_complex}_of_int
   848   star_of_number_of <-- {hypreal,hcomplex}_number_of
   849   star_of_number_less <-- number_of_less_hypreal_of_real_iff
   850   star_of_number_le <-- number_of_le_hypreal_of_real_iff
   851   star_of_eq_number <-- hypreal_of_real_eq_number_of_iff
   852   star_of_less_number <-- hypreal_of_real_less_number_of_iff
   853   star_of_le_number <-- hypreal_of_real_le_number_of_iff
   854   star_of_power <-- hypreal_of_real_power
   855   star_of_eq_0 <-- hcomplex_of_complex_zero_iff
   856 
   857 * Hyperreal: new method "transfer" that implements the transfer
   858 principle of nonstandard analysis. With a subgoal that mentions
   859 nonstandard types like "'a star", the command "apply transfer"
   860 replaces it with an equivalent one that mentions only standard types.
   861 To be successful, all free variables must have standard types; non-
   862 standard variables must have explicit universal quantifiers.
   863 
   864 * Hyperreal: A theory of Taylor series.
   865 
   866 
   867 *** HOLCF ***
   868 
   869 * Discontinued special version of 'constdefs' (which used to support
   870 continuous functions) in favor of the general Pure one with full
   871 type-inference.
   872 
   873 * New simplification procedure for solving continuity conditions; it
   874 is much faster on terms with many nested lambda abstractions (cubic
   875 instead of exponential time).
   876 
   877 * New syntax for domain package: selector names are now optional.
   878 Parentheses should be omitted unless argument is lazy, for example:
   879 
   880   domain 'a stream = cons "'a" (lazy "'a stream")
   881 
   882 * New command 'fixrec' for defining recursive functions with pattern
   883 matching; defining multiple functions with mutual recursion is also
   884 supported.  Patterns may include the constants cpair, spair, up, sinl,
   885 sinr, or any data constructor defined by the domain package. The given
   886 equations are proven as rewrite rules. See HOLCF/ex/Fixrec_ex.thy for
   887 syntax and examples.
   888 
   889 * New commands 'cpodef' and 'pcpodef' for defining predicate subtypes
   890 of cpo and pcpo types. Syntax is exactly like the 'typedef' command,
   891 but the proof obligation additionally includes an admissibility
   892 requirement. The packages generate instances of class cpo or pcpo,
   893 with continuity and strictness theorems for Rep and Abs.
   894 
   895 * HOLCF: Many theorems have been renamed according to a more standard naming
   896 scheme (INCOMPATIBILITY):
   897 
   898   foo_inject:  "foo$x = foo$y ==> x = y"
   899   foo_eq:      "(foo$x = foo$y) = (x = y)"
   900   foo_less:    "(foo$x << foo$y) = (x << y)"
   901   foo_strict:  "foo$UU = UU"
   902   foo_defined: "... ==> foo$x ~= UU"
   903   foo_defined_iff: "(foo$x = UU) = (x = UU)"
   904 
   905 
   906 *** ZF ***
   907 
   908 * ZF/ex: theories Group and Ring provide examples in abstract algebra,
   909 including the First Isomorphism Theorem (on quotienting by the kernel
   910 of a homomorphism).
   911 
   912 * ZF/Simplifier: install second copy of type solver that actually
   913 makes use of TC rules declared to Isar proof contexts (or locales);
   914 the old version is still required for ML proof scripts.
   915 
   916 
   917 *** Cube ***
   918 
   919 * Converted to Isar theory format; use locales instead of axiomatic
   920 theories.
   921 
   922 
   923 *** ML ***
   924 
   925 * Pure/library.ML no longer defines its own option datatype, but uses
   926 that of the SML basis, which has constructors NONE and SOME instead of
   927 None and Some, as well as exception Option.Option instead of OPTION.
   928 The functions the, if_none, is_some, is_none have been adapted
   929 accordingly, while Option.map replaces apsome.
   930 
   931 * Pure/library.ML: the exception LIST has been given up in favour of
   932 the standard exceptions Empty and Subscript, as well as
   933 Library.UnequalLengths.  Function like Library.hd and Library.tl are
   934 superceded by the standard hd and tl functions etc.
   935 
   936 A number of basic list functions are no longer exported to the ML
   937 toplevel, as they are variants of predefined functions.  The following
   938 suggests how one can translate existing code:
   939 
   940     rev_append xs ys = List.revAppend (xs, ys)
   941     nth_elem (i, xs) = List.nth (xs, i)
   942     last_elem xs = List.last xs
   943     flat xss = List.concat xss
   944     seq fs = List.app fs
   945     partition P xs = List.partition P xs
   946     mapfilter f xs = List.mapPartial f xs
   947 
   948 * Pure/library.ML: several combinators for linear functional
   949 transformations, notably reverse application and composition:
   950 
   951   x |> f                f #> g
   952   (x, y) |-> f          f #-> g
   953 
   954 * Pure/library.ML: introduced/changed precedence of infix operators:
   955 
   956   infix 1 |> |-> ||> ||>> |>> |>>> #> #->;
   957   infix 2 ?;
   958   infix 3 o oo ooo oooo;
   959   infix 4 ~~ upto downto;
   960 
   961 Maybe INCOMPATIBILITY when any of those is used in conjunction with other
   962 infix operators.
   963 
   964 * Pure/library.ML: natural list combinators fold, fold_rev, and
   965 fold_map support linear functional transformations and nesting.  For
   966 example:
   967 
   968   fold f [x1, ..., xN] y =
   969     y |> f x1 |> ... |> f xN
   970 
   971   (fold o fold) f [xs1, ..., xsN] y =
   972     y |> fold f xs1 |> ... |> fold f xsN
   973 
   974   fold f [x1, ..., xN] =
   975     f x1 #> ... #> f xN
   976 
   977   (fold o fold) f [xs1, ..., xsN] =
   978     fold f xs1 #> ... #> fold f xsN
   979 
   980 * Pure/library.ML: the following selectors on type 'a option are
   981 available:
   982 
   983   the:               'a option -> 'a  (*partial*)
   984   these:             'a option -> 'a  where 'a = 'b list
   985   the_default: 'a -> 'a option -> 'a
   986   the_list:          'a option -> 'a list
   987 
   988 * Pure/General: structure AList (cf. Pure/General/alist.ML) provides
   989 basic operations for association lists, following natural argument
   990 order; moreover the explicit equality predicate passed here avoids
   991 potentially expensive polymorphic runtime equality checks.
   992 The old functions may be expressed as follows:
   993 
   994   assoc = uncurry (AList.lookup (op =))
   995   assocs = these oo AList.lookup (op =)
   996   overwrite = uncurry (AList.update (op =)) o swap
   997 
   998 * Pure/General: structure AList (cf. Pure/General/alist.ML) provides
   999 
  1000   val make: ('a -> 'b) -> 'a list -> ('a * 'b) list
  1001   val find: ('a * 'b -> bool) -> ('c * 'b) list -> 'a -> 'c list
  1002 
  1003 replacing make_keylist and keyfilter (occassionally used)
  1004 Naive rewrites:
  1005 
  1006   make_keylist = AList.make
  1007   keyfilter = AList.find (op =)
  1008 
  1009 * eq_fst and eq_snd now take explicit equality parameter, thus
  1010   avoiding eqtypes. Naive rewrites:
  1011 
  1012     eq_fst = eq_fst (op =)
  1013     eq_snd = eq_snd (op =)
  1014 
  1015 * Removed deprecated apl and apr (rarely used).
  1016   Naive rewrites:
  1017 
  1018     apl (n, op) =>>= curry op n
  1019     apr (op, m) =>>= fn n => op (n, m)
  1020 
  1021 * Pure/General: structure OrdList (cf. Pure/General/ord_list.ML)
  1022 provides a reasonably efficient light-weight implementation of sets as
  1023 lists.
  1024 
  1025 * Pure/General: generic tables (cf. Pure/General/table.ML) provide a
  1026 few new operations; existing lookup and update are now curried to
  1027 follow natural argument order (for use with fold etc.);
  1028 INCOMPATIBILITY, use (uncurry Symtab.lookup) etc. as last resort.
  1029 
  1030 * Pure/General: output via the Isabelle channels of
  1031 writeln/warning/error etc. is now passed through Output.output, with a
  1032 hook for arbitrary transformations depending on the print_mode
  1033 (cf. Output.add_mode -- the first active mode that provides a output
  1034 function wins).  Already formatted output may be embedded into further
  1035 text via Output.raw; the result of Pretty.string_of/str_of and derived
  1036 functions (string_of_term/cterm/thm etc.) is already marked raw to
  1037 accommodate easy composition of diagnostic messages etc.  Programmers
  1038 rarely need to care about Output.output or Output.raw at all, with
  1039 some notable exceptions: Output.output is required when bypassing the
  1040 standard channels (writeln etc.), or in token translations to produce
  1041 properly formatted results; Output.raw is required when capturing
  1042 already output material that will eventually be presented to the user
  1043 a second time.  For the default print mode, both Output.output and
  1044 Output.raw have no effect.
  1045 
  1046 * Pure/General: Output.time_accumulator NAME creates an operator ('a
  1047 -> 'b) -> 'a -> 'b to measure runtime and count invocations; the
  1048 cumulative results are displayed at the end of a batch session.
  1049 
  1050 * Pure/General: File.sysify_path and File.quote_sysify path have been
  1051 replaced by File.platform_path and File.shell_path (with appropriate
  1052 hooks).  This provides a clean interface for unusual systems where the
  1053 internal and external process view of file names are different.
  1054 
  1055 * Pure: more efficient orders for basic syntactic entities: added
  1056 fast_string_ord, fast_indexname_ord, fast_term_ord; changed sort_ord
  1057 and typ_ord to use fast_string_ord and fast_indexname_ord (term_ord is
  1058 NOT affected); structures Symtab, Vartab, Typtab, Termtab use the fast
  1059 orders now -- potential INCOMPATIBILITY for code that depends on a
  1060 particular order for Symtab.keys, Symtab.dest, etc. (consider using
  1061 Library.sort_strings on result).
  1062 
  1063 * Pure/term.ML: combinators fold_atyps, fold_aterms, fold_term_types,
  1064 fold_types traverse types/terms from left to right, observing natural
  1065 argument order.  Supercedes previous foldl_XXX versions, add_frees,
  1066 add_vars etc. have been adapted as well: INCOMPATIBILITY.
  1067 
  1068 * Pure: name spaces have been refined, with significant changes of the
  1069 internal interfaces -- INCOMPATIBILITY.  Renamed cond_extern(_table)
  1070 to extern(_table).  The plain name entry path is superceded by a
  1071 general 'naming' context, which also includes the 'policy' to produce
  1072 a fully qualified name and external accesses of a fully qualified
  1073 name; NameSpace.extend is superceded by context dependent
  1074 Sign.declare_name.  Several theory and proof context operations modify
  1075 the naming context.  Especially note Theory.restore_naming and
  1076 ProofContext.restore_naming to get back to a sane state; note that
  1077 Theory.add_path is no longer sufficient to recover from
  1078 Theory.absolute_path in particular.
  1079 
  1080 * Pure: new flags short_names (default false) and unique_names
  1081 (default true) for controlling output of qualified names.  If
  1082 short_names is set, names are printed unqualified.  If unique_names is
  1083 reset, the name prefix is reduced to the minimum required to achieve
  1084 the original result when interning again, even if there is an overlap
  1085 with earlier declarations.
  1086 
  1087 * Pure/TheoryDataFun: change of the argument structure; 'prep_ext' is
  1088 now 'extend', and 'merge' gets an additional Pretty.pp argument
  1089 (useful for printing error messages).  INCOMPATIBILITY.
  1090 
  1091 * Pure: major reorganization of the theory context.  Type Sign.sg and
  1092 Theory.theory are now identified, referring to the universal
  1093 Context.theory (see Pure/context.ML).  Actual signature and theory
  1094 content is managed as theory data.  The old code and interfaces were
  1095 spread over many files and structures; the new arrangement introduces
  1096 considerable INCOMPATIBILITY to gain more clarity:
  1097 
  1098   Context -- theory management operations (name, identity, inclusion,
  1099     parents, ancestors, merge, etc.), plus generic theory data;
  1100 
  1101   Sign -- logical signature and syntax operations (declaring consts,
  1102     types, etc.), plus certify/read for common entities;
  1103 
  1104   Theory -- logical theory operations (stating axioms, definitions,
  1105     oracles), plus a copy of logical signature operations (consts,
  1106     types, etc.); also a few basic management operations (Theory.copy,
  1107     Theory.merge, etc.)
  1108 
  1109 The most basic sign_of operations (Theory.sign_of, Thm.sign_of_thm
  1110 etc.) as well as the sign field in Thm.rep_thm etc. have been retained
  1111 for convenience -- they merely return the theory.
  1112 
  1113 * Pure: type Type.tsig is superceded by theory in most interfaces.
  1114 
  1115 * Pure: the Isar proof context type is already defined early in Pure
  1116 as Context.proof (note that ProofContext.context and Proof.context are
  1117 aliases, where the latter is the preferred name).  This enables other
  1118 Isabelle components to refer to that type even before Isar is present.
  1119 
  1120 * Pure/sign/theory: discontinued named name spaces (i.e. classK,
  1121 typeK, constK, axiomK, oracleK), but provide explicit operations for
  1122 any of these kinds.  For example, Sign.intern typeK is now
  1123 Sign.intern_type, Theory.hide_space Sign.typeK is now
  1124 Theory.hide_types.  Also note that former
  1125 Theory.hide_classes/types/consts are now
  1126 Theory.hide_classes_i/types_i/consts_i, while the non '_i' versions
  1127 internalize their arguments!  INCOMPATIBILITY.
  1128 
  1129 * Pure: get_thm interface (of PureThy and ProofContext) expects
  1130 datatype thmref (with constructors Name and NameSelection) instead of
  1131 plain string -- INCOMPATIBILITY;
  1132 
  1133 * Pure: cases produced by proof methods specify options, where NONE
  1134 means to remove case bindings -- INCOMPATIBILITY in
  1135 (RAW_)METHOD_CASES.
  1136 
  1137 * Pure: the following operations retrieve axioms or theorems from a
  1138 theory node or theory hierarchy, respectively:
  1139 
  1140   Theory.axioms_of: theory -> (string * term) list
  1141   Theory.all_axioms_of: theory -> (string * term) list
  1142   PureThy.thms_of: theory -> (string * thm) list
  1143   PureThy.all_thms_of: theory -> (string * thm) list
  1144 
  1145 * Pure: print_tac now outputs the goal through the trace channel.
  1146 
  1147 * Isar toplevel: improved diagnostics, mostly for Poly/ML only.
  1148 Reference Toplevel.debug (default false) controls detailed printing
  1149 and tracing of low-level exceptions; Toplevel.profiling (default 0)
  1150 controls execution profiling -- set to 1 for time and 2 for space
  1151 (both increase the runtime).
  1152 
  1153 * Isar session: The initial use of ROOT.ML is now always timed,
  1154 i.e. the log will show the actual process times, in contrast to the
  1155 elapsed wall-clock time that the outer shell wrapper produces.
  1156 
  1157 * Simplifier: improved handling of bound variables (nameless
  1158 representation, avoid allocating new strings).  Simprocs that invoke
  1159 the Simplifier recursively should use Simplifier.inherit_bounds to
  1160 avoid local name clashes.  Failure to do so produces warnings
  1161 "Simplifier: renamed bound variable ..."; set Simplifier.debug_bounds
  1162 for further details.
  1163 
  1164 * ML functions legacy_bindings and use_legacy_bindings produce ML fact
  1165 bindings for all theorems stored within a given theory; this may help
  1166 in porting non-Isar theories to Isar ones, while keeping ML proof
  1167 scripts for the time being.
  1168 
  1169 * ML operator HTML.with_charset specifies the charset begin used for
  1170 generated HTML files.  For example:
  1171 
  1172   HTML.with_charset "utf-8" use_thy "Hebrew";
  1173   HTML.with_charset "utf-8" use_thy "Chinese";
  1174 
  1175 
  1176 *** System ***
  1177 
  1178 * Allow symlinks to all proper Isabelle executables (Isabelle,
  1179 isabelle, isatool etc.).
  1180 
  1181 * ISABELLE_DOC_FORMAT setting specifies preferred document format (for
  1182 isatool doc, isatool mkdir, display_drafts etc.).
  1183 
  1184 * isatool usedir: option -f allows specification of the ML file to be
  1185 used by Isabelle; default is ROOT.ML.
  1186 
  1187 * New isatool version outputs the version identifier of the Isabelle
  1188 distribution being used.
  1189 
  1190 * HOL: new isatool dimacs2hol converts files in DIMACS CNF format
  1191 (containing Boolean satisfiability problems) into Isabelle/HOL
  1192 theories.
  1193 
  1194 
  1195 
  1196 New in Isabelle2004 (April 2004)
  1197 --------------------------------
  1198 
  1199 *** General ***
  1200 
  1201 * Provers/order.ML:  new efficient reasoner for partial and linear orders.
  1202   Replaces linorder.ML.
  1203 
  1204 * Pure: Greek letters (except small lambda, \<lambda>), as well as Gothic
  1205   (\<aa>...\<zz>\<AA>...\<ZZ>), calligraphic (\<A>...\<Z>), and Euler
  1206   (\<a>...\<z>), are now considered normal letters, and can therefore
  1207   be used anywhere where an ASCII letter (a...zA...Z) has until
  1208   now. COMPATIBILITY: This obviously changes the parsing of some
  1209   terms, especially where a symbol has been used as a binder, say
  1210   '\<Pi>x. ...', which is now a type error since \<Pi>x will be parsed
  1211   as an identifier.  Fix it by inserting a space around former
  1212   symbols.  Call 'isatool fixgreek' to try to fix parsing errors in
  1213   existing theory and ML files.
  1214 
  1215 * Pure: Macintosh and Windows line-breaks are now allowed in theory files.
  1216 
  1217 * Pure: single letter sub/superscripts (\<^isub> and \<^isup>) are now
  1218   allowed in identifiers. Similar to Greek letters \<^isub> is now considered
  1219   a normal (but invisible) letter. For multiple letter subscripts repeat
  1220   \<^isub> like this: x\<^isub>1\<^isub>2.
  1221 
  1222 * Pure: There are now sub-/superscripts that can span more than one
  1223   character. Text between \<^bsub> and \<^esub> is set in subscript in
  1224   ProofGeneral and LaTeX, text between \<^bsup> and \<^esup> in
  1225   superscript. The new control characters are not identifier parts.
  1226 
  1227 * Pure: Control-symbols of the form \<^raw:...> will literally print the
  1228   content of "..." to the latex file instead of \isacntrl... . The "..."
  1229   may consist of any printable characters excluding the end bracket >.
  1230 
  1231 * Pure: Using new Isar command "finalconsts" (or the ML functions
  1232   Theory.add_finals or Theory.add_finals_i) it is now possible to
  1233   declare constants "final", which prevents their being given a definition
  1234   later.  It is useful for constants whose behaviour is fixed axiomatically
  1235   rather than definitionally, such as the meta-logic connectives.
  1236 
  1237 * Pure: 'instance' now handles general arities with general sorts
  1238   (i.e. intersections of classes),
  1239 
  1240 * Presentation: generated HTML now uses a CSS style sheet to make layout
  1241   (somewhat) independent of content. It is copied from lib/html/isabelle.css.
  1242   It can be changed to alter the colors/layout of generated pages.
  1243 
  1244 
  1245 *** Isar ***
  1246 
  1247 * Tactic emulation methods rule_tac, erule_tac, drule_tac, frule_tac,
  1248   cut_tac, subgoal_tac and thin_tac:
  1249   - Now understand static (Isar) contexts.  As a consequence, users of Isar
  1250     locales are no longer forced to write Isar proof scripts.
  1251     For details see Isar Reference Manual, paragraph 4.3.2: Further tactic
  1252     emulations.
  1253   - INCOMPATIBILITY: names of variables to be instantiated may no
  1254     longer be enclosed in quotes.  Instead, precede variable name with `?'.
  1255     This is consistent with the instantiation attribute "where".
  1256 
  1257 * Attributes "where" and "of":
  1258   - Now take type variables of instantiated theorem into account when reading
  1259     the instantiation string.  This fixes a bug that caused instantiated
  1260     theorems to have too special types in some circumstances.
  1261   - "where" permits explicit instantiations of type variables.
  1262 
  1263 * Calculation commands "moreover" and "also" no longer interfere with
  1264   current facts ("this"), admitting arbitrary combinations with "then"
  1265   and derived forms.
  1266 
  1267 * Locales:
  1268   - Goal statements involving the context element "includes" no longer
  1269     generate theorems with internal delta predicates (those ending on
  1270     "_axioms") in the premise.
  1271     Resolve particular premise with <locale>.intro to obtain old form.
  1272   - Fixed bug in type inference ("unify_frozen") that prevented mix of target
  1273     specification and "includes" elements in goal statement.
  1274   - Rule sets <locale>.intro and <locale>.axioms no longer declared as
  1275     [intro?] and [elim?] (respectively) by default.
  1276   - Experimental command for instantiation of locales in proof contexts:
  1277         instantiate <label>[<attrs>]: <loc>
  1278     Instantiates locale <loc> and adds all its theorems to the current context
  1279     taking into account their attributes.  Label and attrs are optional
  1280     modifiers, like in theorem declarations.  If present, names of
  1281     instantiated theorems are qualified with <label>, and the attributes
  1282     <attrs> are applied after any attributes these theorems might have already.
  1283       If the locale has assumptions, a chained fact of the form
  1284     "<loc> t1 ... tn" is expected from which instantiations of the parameters
  1285     are derived.  The command does not support old-style locales declared
  1286     with "locale (open)".
  1287       A few (very simple) examples can be found in FOL/ex/LocaleInst.thy.
  1288 
  1289 * HOL: Tactic emulation methods induct_tac and case_tac understand static
  1290   (Isar) contexts.
  1291 
  1292 
  1293 *** HOL ***
  1294 
  1295 * Proof import: new image HOL4 contains the imported library from
  1296   the HOL4 system with about 2500 theorems. It is imported by
  1297   replaying proof terms produced by HOL4 in Isabelle. The HOL4 image
  1298   can be used like any other Isabelle image.  See
  1299   HOL/Import/HOL/README for more information.
  1300 
  1301 * Simplifier:
  1302   - Much improved handling of linear and partial orders.
  1303     Reasoners for linear and partial orders are set up for type classes
  1304     "linorder" and "order" respectively, and are added to the default simpset
  1305     as solvers.  This means that the simplifier can build transitivity chains
  1306     to solve goals from the assumptions.
  1307   - INCOMPATIBILITY: old proofs break occasionally.  Typically, applications
  1308     of blast or auto after simplification become unnecessary because the goal
  1309     is solved by simplification already.
  1310 
  1311 * Numerics: new theory Ring_and_Field contains over 250 basic numerical laws,
  1312     all proved in axiomatic type classes for semirings, rings and fields.
  1313 
  1314 * Numerics:
  1315   - Numeric types (nat, int, and in HOL-Complex rat, real, complex, etc.) are
  1316     now formalized using the Ring_and_Field theory mentioned above.
  1317   - INCOMPATIBILITY: simplification and arithmetic behaves somewhat differently
  1318     than before, because now they are set up once in a generic manner.
  1319   - INCOMPATIBILITY: many type-specific arithmetic laws have gone.
  1320     Look for the general versions in Ring_and_Field (and Power if they concern
  1321     exponentiation).
  1322 
  1323 * Type "rat" of the rational numbers is now available in HOL-Complex.
  1324 
  1325 * Records:
  1326   - Record types are now by default printed with their type abbreviation
  1327     instead of the list of all field types. This can be configured via
  1328     the reference "print_record_type_abbr".
  1329   - Simproc "record_upd_simproc" for simplification of multiple updates added
  1330     (not enabled by default).
  1331   - Simproc "record_ex_sel_eq_simproc" to simplify EX x. sel r = x resp.
  1332     EX x. x = sel r to True (not enabled by default).
  1333   - Tactic "record_split_simp_tac" to split and simplify records added.
  1334 
  1335 * 'specification' command added, allowing for definition by
  1336   specification.  There is also an 'ax_specification' command that
  1337   introduces the new constants axiomatically.
  1338 
  1339 * arith(_tac) is now able to generate counterexamples for reals as well.
  1340 
  1341 * HOL-Algebra: new locale "ring" for non-commutative rings.
  1342 
  1343 * HOL-ex: InductiveInvariant_examples illustrates advanced recursive function
  1344   definitions, thanks to Sava Krsti\'{c} and John Matthews.
  1345 
  1346 * HOL-Matrix: a first theory for matrices in HOL with an application of
  1347   matrix theory to linear programming.
  1348 
  1349 * Unions and Intersections:
  1350   The latex output syntax of UN and INT has been changed
  1351   from "\Union x \in A. B" to "\Union_{x \in A} B"
  1352   i.e. the index formulae has become a subscript.
  1353   Similarly for "\Union x. B", and for \Inter instead of \Union.
  1354 
  1355 * Unions and Intersections over Intervals:
  1356   There is new short syntax "UN i<=n. A" for "UN i:{0..n}. A". There is
  1357   also an x-symbol version with subscripts "\<Union>\<^bsub>i <= n\<^esub>. A"
  1358   like in normal math, and corresponding versions for < and for intersection.
  1359 
  1360 * HOL/List: Ordering "lexico" is renamed "lenlex" and the standard
  1361   lexicographic dictonary ordering has been added as "lexord".
  1362 
  1363 * ML: the legacy theory structures Int and List have been removed. They had
  1364   conflicted with ML Basis Library structures having the same names.
  1365 
  1366 * 'refute' command added to search for (finite) countermodels.  Only works
  1367   for a fragment of HOL.  The installation of an external SAT solver is
  1368   highly recommended.  See "HOL/Refute.thy" for details.
  1369 
  1370 * 'quickcheck' command: Allows to find counterexamples by evaluating
  1371   formulae under an assignment of free variables to random values.
  1372   In contrast to 'refute', it can deal with inductive datatypes,
  1373   but cannot handle quantifiers. See "HOL/ex/Quickcheck_Examples.thy"
  1374   for examples.
  1375 
  1376 
  1377 *** HOLCF ***
  1378 
  1379 * Streams now come with concatenation and are part of the HOLCF image
  1380 
  1381 
  1382 
  1383 New in Isabelle2003 (May 2003)
  1384 ------------------------------
  1385 
  1386 *** General ***
  1387 
  1388 * Provers/simplifier:
  1389 
  1390   - Completely reimplemented method simp (ML: Asm_full_simp_tac):
  1391     Assumptions are now subject to complete mutual simplification,
  1392     not just from left to right. The simplifier now preserves
  1393     the order of assumptions.
  1394 
  1395     Potential INCOMPATIBILITY:
  1396 
  1397     -- simp sometimes diverges where the old version did
  1398        not, e.g. invoking simp on the goal
  1399 
  1400         [| P (f x); y = x; f x = f y |] ==> Q
  1401 
  1402        now gives rise to the infinite reduction sequence
  1403 
  1404         P(f x) --(f x = f y)--> P(f y) --(y = x)--> P(f x) --(f x = f y)--> ...
  1405 
  1406        Using "simp (asm_lr)" (ML: Asm_lr_simp_tac) instead often solves this
  1407        kind of problem.
  1408 
  1409     -- Tactics combining classical reasoner and simplification (such as auto)
  1410        are also affected by this change, because many of them rely on
  1411        simp. They may sometimes diverge as well or yield a different numbers
  1412        of subgoals. Try to use e.g. force, fastsimp, or safe instead of auto
  1413        in case of problems. Sometimes subsequent calls to the classical
  1414        reasoner will fail because a preceeding call to the simplifier too
  1415        eagerly simplified the goal, e.g. deleted redundant premises.
  1416 
  1417   - The simplifier trace now shows the names of the applied rewrite rules
  1418 
  1419   - You can limit the number of recursive invocations of the simplifier
  1420     during conditional rewriting (where the simplifie tries to solve the
  1421     conditions before applying the rewrite rule):
  1422     ML "simp_depth_limit := n"
  1423     where n is an integer. Thus you can force termination where previously
  1424     the simplifier would diverge.
  1425 
  1426   - Accepts free variables as head terms in congruence rules.  Useful in Isar.
  1427 
  1428   - No longer aborts on failed congruence proof.  Instead, the
  1429     congruence is ignored.
  1430 
  1431 * Pure: New generic framework for extracting programs from constructive
  1432   proofs. See HOL/Extraction.thy for an example instantiation, as well
  1433   as HOL/Extraction for some case studies.
  1434 
  1435 * Pure: The main goal of the proof state is no longer shown by default, only
  1436 the subgoals. This behaviour is controlled by a new flag.
  1437    PG menu: Isabelle/Isar -> Settings -> Show Main Goal
  1438 (ML: Proof.show_main_goal).
  1439 
  1440 * Pure: You can find all matching introduction rules for subgoal 1, i.e. all
  1441 rules whose conclusion matches subgoal 1:
  1442       PG menu: Isabelle/Isar -> Show me -> matching rules
  1443 The rules are ordered by how closely they match the subgoal.
  1444 In particular, rules that solve a subgoal outright are displayed first
  1445 (or rather last, the way they are printed).
  1446 (ML: ProofGeneral.print_intros())
  1447 
  1448 * Pure: New flag trace_unify_fail causes unification to print
  1449 diagnostic information (PG: in trace buffer) when it fails. This is
  1450 useful for figuring out why single step proofs like rule, erule or
  1451 assumption failed.
  1452 
  1453 * Pure: Locale specifications now produce predicate definitions
  1454 according to the body of text (covering assumptions modulo local
  1455 definitions); predicate "loc_axioms" covers newly introduced text,
  1456 while "loc" is cumulative wrt. all included locale expressions; the
  1457 latter view is presented only on export into the global theory
  1458 context; potential INCOMPATIBILITY, use "(open)" option to fall back
  1459 on the old view without predicates;
  1460 
  1461 * Pure: predefined locales "var" and "struct" are useful for sharing
  1462 parameters (as in CASL, for example); just specify something like
  1463 ``var x + var y + struct M'' as import;
  1464 
  1465 * Pure: improved thms_containing: proper indexing of facts instead of
  1466 raw theorems; check validity of results wrt. current name space;
  1467 include local facts of proof configuration (also covers active
  1468 locales), cover fixed variables in index; may use "_" in term
  1469 specification; an optional limit for the number of printed facts may
  1470 be given (the default is 40);
  1471 
  1472 * Pure: disallow duplicate fact bindings within new-style theory files
  1473 (batch-mode only);
  1474 
  1475 * Provers: improved induct method: assumptions introduced by case
  1476 "foo" are split into "foo.hyps" (from the rule) and "foo.prems" (from
  1477 the goal statement); "foo" still refers to all facts collectively;
  1478 
  1479 * Provers: the function blast.overloaded has been removed: all constants
  1480 are regarded as potentially overloaded, which improves robustness in exchange
  1481 for slight decrease in efficiency;
  1482 
  1483 * Provers/linorder: New generic prover for transitivity reasoning over
  1484 linear orders.  Note: this prover is not efficient!
  1485 
  1486 * Isar: preview of problems to finish 'show' now produce an error
  1487 rather than just a warning (in interactive mode);
  1488 
  1489 
  1490 *** HOL ***
  1491 
  1492 * arith(_tac)
  1493 
  1494  - Produces a counter example if it cannot prove a goal.
  1495    Note that the counter example may be spurious if the goal is not a formula
  1496    of quantifier-free linear arithmetic.
  1497    In ProofGeneral the counter example appears in the trace buffer.
  1498 
  1499  - Knows about div k and mod k where k is a numeral of type nat or int.
  1500 
  1501  - Calls full Presburger arithmetic (by Amine Chaieb) if quantifier-free
  1502    linear arithmetic fails. This takes account of quantifiers and divisibility.
  1503    Presburger arithmetic can also be called explicitly via presburger(_tac).
  1504 
  1505 * simp's arithmetic capabilities have been enhanced a bit: it now
  1506 takes ~= in premises into account (by performing a case split);
  1507 
  1508 * simp reduces "m*(n div m) + n mod m" to n, even if the two summands
  1509 are distributed over a sum of terms;
  1510 
  1511 * New tactic "trans_tac" and method "trans" instantiate
  1512 Provers/linorder.ML for axclasses "order" and "linorder" (predicates
  1513 "<=", "<" and "=").
  1514 
  1515 * function INCOMPATIBILITIES: Pi-sets have been redefined and moved from main
  1516 HOL to Library/FuncSet; constant "Fun.op o" is now called "Fun.comp";
  1517 
  1518 * 'typedef' command has new option "open" to suppress the set
  1519 definition;
  1520 
  1521 * functions Min and Max on finite sets have been introduced (theory
  1522 Finite_Set);
  1523 
  1524 * attribute [symmetric] now works for relations as well; it turns
  1525 (x,y) : R^-1 into (y,x) : R, and vice versa;
  1526 
  1527 * induct over a !!-quantified statement (say !!x1..xn):
  1528   each "case" automatically performs "fix x1 .. xn" with exactly those names.
  1529 
  1530 * Map: `empty' is no longer a constant but a syntactic abbreviation for
  1531 %x. None. Warning: empty_def now refers to the previously hidden definition
  1532 of the empty set.
  1533 
  1534 * Algebra: formalization of classical algebra.  Intended as base for
  1535 any algebraic development in Isabelle.  Currently covers group theory
  1536 (up to Sylow's theorem) and ring theory (Universal Property of
  1537 Univariate Polynomials).  Contributions welcome;
  1538 
  1539 * GroupTheory: deleted, since its material has been moved to Algebra;
  1540 
  1541 * Complex: new directory of the complex numbers with numeric constants,
  1542 nonstandard complex numbers, and some complex analysis, standard and
  1543 nonstandard (Jacques Fleuriot);
  1544 
  1545 * HOL-Complex: new image for analysis, replacing HOL-Real and HOL-Hyperreal;
  1546 
  1547 * Hyperreal: introduced Gauge integration and hyperreal logarithms (Jacques
  1548 Fleuriot);
  1549 
  1550 * Real/HahnBanach: updated and adapted to locales;
  1551 
  1552 * NumberTheory: added Gauss's law of quadratic reciprocity (by Avigad,
  1553 Gray and Kramer);
  1554 
  1555 * UNITY: added the Meier-Sanders theory of progress sets;
  1556 
  1557 * MicroJava: bytecode verifier and lightweight bytecode verifier
  1558 as abstract algorithms, instantiated to the JVM;
  1559 
  1560 * Bali: Java source language formalization. Type system, operational
  1561 semantics, axiomatic semantics. Supported language features:
  1562 classes, interfaces, objects,virtual methods, static methods,
  1563 static/instance fields, arrays, access modifiers, definite
  1564 assignment, exceptions.
  1565 
  1566 
  1567 *** ZF ***
  1568 
  1569 * ZF/Constructible: consistency proof for AC (Gdel's constructible
  1570 universe, etc.);
  1571 
  1572 * Main ZF: virtually all theories converted to new-style format;
  1573 
  1574 
  1575 *** ML ***
  1576 
  1577 * Pure: Tactic.prove provides sane interface for internal proofs;
  1578 omits the infamous "standard" operation, so this is more appropriate
  1579 than prove_goalw_cterm in many situations (e.g. in simprocs);
  1580 
  1581 * Pure: improved error reporting of simprocs;
  1582 
  1583 * Provers: Simplifier.simproc(_i) provides sane interface for setting
  1584 up simprocs;
  1585 
  1586 
  1587 *** Document preparation ***
  1588 
  1589 * uses \par instead of \\ for line breaks in theory text. This may
  1590 shift some page breaks in large documents. To get the old behaviour
  1591 use \renewcommand{\isanewline}{\mbox{}\\\mbox{}} in root.tex.
  1592 
  1593 * minimized dependencies of isabelle.sty and isabellesym.sty on
  1594 other packages
  1595 
  1596 * \<euro> now needs package babel/greek instead of marvosym (which
  1597 broke \Rightarrow)
  1598 
  1599 * normal size for \<zero>...\<nine> (uses \mathbf instead of
  1600 textcomp package)
  1601 
  1602 
  1603 
  1604 New in Isabelle2002 (March 2002)
  1605 --------------------------------
  1606 
  1607 *** Document preparation ***
  1608 
  1609 * greatly simplified document preparation setup, including more
  1610 graceful interpretation of isatool usedir -i/-d/-D options, and more
  1611 instructive isatool mkdir; users should basically be able to get
  1612 started with "isatool mkdir HOL Test && isatool make"; alternatively,
  1613 users may run a separate document processing stage manually like this:
  1614 "isatool usedir -D output HOL Test && isatool document Test/output";
  1615 
  1616 * theory dependency graph may now be incorporated into documents;
  1617 isatool usedir -g true will produce session_graph.eps/.pdf for use
  1618 with \includegraphics of LaTeX;
  1619 
  1620 * proper spacing of consecutive markup elements, especially text
  1621 blocks after section headings;
  1622 
  1623 * support bold style (for single symbols only), input syntax is like
  1624 this: "\<^bold>\<alpha>" or "\<^bold>A";
  1625 
  1626 * \<bullet> is now output as bold \cdot by default, which looks much
  1627 better in printed text;
  1628 
  1629 * added default LaTeX bindings for \<tturnstile> and \<TTurnstile>;
  1630 note that these symbols are currently unavailable in Proof General /
  1631 X-Symbol; new symbols \<zero>, \<one>, ..., \<nine>, and \<euro>;
  1632 
  1633 * isatool latex no longer depends on changed TEXINPUTS, instead
  1634 isatool document copies the Isabelle style files to the target
  1635 location;
  1636 
  1637 
  1638 *** Isar ***
  1639 
  1640 * Pure/Provers: improved proof by cases and induction;
  1641   - 'case' command admits impromptu naming of parameters (such as
  1642     "case (Suc n)");
  1643   - 'induct' method divinates rule instantiation from the inductive
  1644     claim; no longer requires excessive ?P bindings for proper
  1645     instantiation of cases;
  1646   - 'induct' method properly enumerates all possibilities of set/type
  1647     rules; as a consequence facts may be also passed through *type*
  1648     rules without further ado;
  1649   - 'induct' method now derives symbolic cases from the *rulified*
  1650     rule (before it used to rulify cases stemming from the internal
  1651     atomized version); this means that the context of a non-atomic
  1652     statement becomes is included in the hypothesis, avoiding the
  1653     slightly cumbersome show "PROP ?case" form;
  1654   - 'induct' may now use elim-style induction rules without chaining
  1655     facts, using ``missing'' premises from the goal state; this allows
  1656     rules stemming from inductive sets to be applied in unstructured
  1657     scripts, while still benefitting from proper handling of non-atomic
  1658     statements; NB: major inductive premises need to be put first, all
  1659     the rest of the goal is passed through the induction;
  1660   - 'induct' proper support for mutual induction involving non-atomic
  1661     rule statements (uses the new concept of simultaneous goals, see
  1662     below);
  1663   - append all possible rule selections, but only use the first
  1664     success (no backtracking);
  1665   - removed obsolete "(simplified)" and "(stripped)" options of methods;
  1666   - undeclared rule case names default to numbers 1, 2, 3, ...;
  1667   - added 'print_induct_rules' (covered by help item in recent Proof
  1668     General versions);
  1669   - moved induct/cases attributes to Pure, methods to Provers;
  1670   - generic method setup instantiated for FOL and HOL;
  1671 
  1672 * Pure: support multiple simultaneous goal statements, for example
  1673 "have a: A and b: B" (same for 'theorem' etc.); being a pure
  1674 meta-level mechanism, this acts as if several individual goals had
  1675 been stated separately; in particular common proof methods need to be
  1676 repeated in order to cover all claims; note that a single elimination
  1677 step is *not* sufficient to establish the two conjunctions, so this
  1678 fails:
  1679 
  1680   assume "A & B" then have A and B ..   (*".." fails*)
  1681 
  1682 better use "obtain" in situations as above; alternative refer to
  1683 multi-step methods like 'auto', 'simp_all', 'blast+' etc.;
  1684 
  1685 * Pure: proper integration with ``locales''; unlike the original
  1686 version by Florian Kammller, Isar locales package high-level proof
  1687 contexts rather than raw logical ones (e.g. we admit to include
  1688 attributes everywhere); operations on locales include merge and
  1689 rename; support for implicit arguments (``structures''); simultaneous
  1690 type-inference over imports and text; see also HOL/ex/Locales.thy for
  1691 some examples;
  1692 
  1693 * Pure: the following commands have been ``localized'', supporting a
  1694 target locale specification "(in name)": 'lemma', 'theorem',
  1695 'corollary', 'lemmas', 'theorems', 'declare'; the results will be
  1696 stored both within the locale and at the theory level (exported and
  1697 qualified by the locale name);
  1698 
  1699 * Pure: theory goals may now be specified in ``long'' form, with
  1700 ad-hoc contexts consisting of arbitrary locale elements. for example
  1701 ``lemma foo: fixes x assumes "A x" shows "B x"'' (local syntax and
  1702 definitions may be given, too); the result is a meta-level rule with
  1703 the context elements being discharged in the obvious way;
  1704 
  1705 * Pure: new proof command 'using' allows to augment currently used
  1706 facts after a goal statement ('using' is syntactically analogous to
  1707 'apply', but acts on the goal's facts only); this allows chained facts
  1708 to be separated into parts given before and after a claim, as in
  1709 ``from a and b have C using d and e <proof>'';
  1710 
  1711 * Pure: renamed "antecedent" case to "rule_context";
  1712 
  1713 * Pure: new 'judgment' command records explicit information about the
  1714 object-logic embedding (used by several tools internally); no longer
  1715 use hard-wired "Trueprop";
  1716 
  1717 * Pure: added 'corollary' command;
  1718 
  1719 * Pure: fixed 'token_translation' command;
  1720 
  1721 * Pure: removed obsolete 'exported' attribute;
  1722 
  1723 * Pure: dummy pattern "_" in is/let is now automatically lifted over
  1724 bound variables: "ALL x. P x --> Q x" (is "ALL x. _ --> ?C x")
  1725 supersedes more cumbersome ... (is "ALL x. _ x --> ?C x");
  1726 
  1727 * Pure: method 'atomize' presents local goal premises as object-level
  1728 statements (atomic meta-level propositions); setup controlled via
  1729 rewrite rules declarations of 'atomize' attribute; example
  1730 application: 'induct' method with proper rule statements in improper
  1731 proof *scripts*;
  1732 
  1733 * Pure: emulation of instantiation tactics (rule_tac, cut_tac, etc.)
  1734 now consider the syntactic context of assumptions, giving a better
  1735 chance to get type-inference of the arguments right (this is
  1736 especially important for locales);
  1737 
  1738 * Pure: "sorry" no longer requires quick_and_dirty in interactive
  1739 mode;
  1740 
  1741 * Pure/obtain: the formal conclusion "thesis", being marked as
  1742 ``internal'', may no longer be reference directly in the text;
  1743 potential INCOMPATIBILITY, may need to use "?thesis" in rare
  1744 situations;
  1745 
  1746 * Pure: generic 'sym' attribute which declares a rule both as pure
  1747 'elim?' and for the 'symmetric' operation;
  1748 
  1749 * Pure: marginal comments ``--'' may now occur just anywhere in the
  1750 text; the fixed correlation with particular command syntax has been
  1751 discontinued;
  1752 
  1753 * Pure: new method 'rules' is particularly well-suited for proof
  1754 search in intuitionistic logic; a bit slower than 'blast' or 'fast',
  1755 but often produces more compact proof terms with less detours;
  1756 
  1757 * Pure/Provers/classical: simplified integration with pure rule
  1758 attributes and methods; the classical "intro?/elim?/dest?"
  1759 declarations coincide with the pure ones; the "rule" method no longer
  1760 includes classically swapped intros; "intro" and "elim" methods no
  1761 longer pick rules from the context; also got rid of ML declarations
  1762 AddXIs/AddXEs/AddXDs; all of this has some potential for
  1763 INCOMPATIBILITY;
  1764 
  1765 * Provers/classical: attribute 'swapped' produces classical inversions
  1766 of introduction rules;
  1767 
  1768 * Provers/simplifier: 'simplified' attribute may refer to explicit
  1769 rules instead of full simplifier context; 'iff' attribute handles
  1770 conditional rules;
  1771 
  1772 * HOL: 'typedef' now allows alternative names for Rep/Abs morphisms;
  1773 
  1774 * HOL: 'recdef' now fails on unfinished automated proofs, use
  1775 "(permissive)" option to recover old behavior;
  1776 
  1777 * HOL: 'inductive' no longer features separate (collective) attributes
  1778 for 'intros' (was found too confusing);
  1779 
  1780 * HOL: properly declared induction rules less_induct and
  1781 wf_induct_rule;
  1782 
  1783 
  1784 *** HOL ***
  1785 
  1786 * HOL: moved over to sane numeral syntax; the new policy is as
  1787 follows:
  1788 
  1789   - 0 and 1 are polymorphic constants, which are defined on any
  1790   numeric type (nat, int, real etc.);
  1791 
  1792   - 2, 3, 4, ... and -1, -2, -3, ... are polymorphic numerals, based
  1793   binary representation internally;
  1794 
  1795   - type nat has special constructor Suc, and generally prefers Suc 0
  1796   over 1::nat and Suc (Suc 0) over 2::nat;
  1797 
  1798 This change may cause significant problems of INCOMPATIBILITY; here
  1799 are some hints on converting existing sources:
  1800 
  1801   - due to the new "num" token, "-0" and "-1" etc. are now atomic
  1802   entities, so expressions involving "-" (unary or binary minus) need
  1803   to be spaced properly;
  1804 
  1805   - existing occurrences of "1" may need to be constraint "1::nat" or
  1806   even replaced by Suc 0; similar for old "2";
  1807 
  1808   - replace "#nnn" by "nnn", and "#-nnn" by "-nnn";
  1809 
  1810   - remove all special provisions on numerals in proofs;
  1811 
  1812 * HOL: simp rules nat_number expand numerals on nat to Suc/0
  1813 representation (depends on bin_arith_simps in the default context);
  1814 
  1815 * HOL: symbolic syntax for x^2 (numeral 2);
  1816 
  1817 * HOL: the class of all HOL types is now called "type" rather than
  1818 "term"; INCOMPATIBILITY, need to adapt references to this type class
  1819 in axclass/classes, instance/arities, and (usually rare) occurrences
  1820 in typings (of consts etc.); internally the class is called
  1821 "HOL.type", ML programs should refer to HOLogic.typeS;
  1822 
  1823 * HOL/record package improvements:
  1824   - new derived operations "fields" to build a partial record section,
  1825     "extend" to promote a fixed record to a record scheme, and
  1826     "truncate" for the reverse; cf. theorems "xxx.defs", which are *not*
  1827     declared as simp by default;
  1828   - shared operations ("more", "fields", etc.) now need to be always
  1829     qualified) --- potential INCOMPATIBILITY;
  1830   - removed "make_scheme" operations (use "make" with "extend") --
  1831     INCOMPATIBILITY;
  1832   - removed "more" class (simply use "term") -- INCOMPATIBILITY;
  1833   - provides cases/induct rules for use with corresponding Isar
  1834     methods (for concrete records, record schemes, concrete more
  1835     parts, and schematic more parts -- in that order);
  1836   - internal definitions directly based on a light-weight abstract
  1837     theory of product types over typedef rather than datatype;
  1838 
  1839 * HOL: generic code generator for generating executable ML code from
  1840 specifications; specific support for HOL constructs such as inductive
  1841 datatypes and sets, as well as recursive functions; can be invoked
  1842 via 'generate_code' theory section;
  1843 
  1844 * HOL: canonical cases/induct rules for n-tuples (n = 3..7);
  1845 
  1846 * HOL: consolidated and renamed several theories.  In particular:
  1847         Ord.thy has been absorbed into HOL.thy
  1848         String.thy has been absorbed into List.thy
  1849 
  1850 * HOL: concrete setsum syntax "\<Sum>i:A. b" == "setsum (%i. b) A"
  1851 (beware of argument permutation!);
  1852 
  1853 * HOL: linorder_less_split superseded by linorder_cases;
  1854 
  1855 * HOL/List: "nodups" renamed to "distinct";
  1856 
  1857 * HOL: added "The" definite description operator; move Hilbert's "Eps"
  1858 to peripheral theory "Hilbert_Choice"; some INCOMPATIBILITIES:
  1859   - Ex_def has changed, now need to use some_eq_ex
  1860 
  1861 * HOL: made split_all_tac safe; EXISTING PROOFS MAY FAIL OR LOOP, so
  1862 in this (rare) case use:
  1863 
  1864   delSWrapper "split_all_tac"
  1865   addSbefore ("unsafe_split_all_tac", unsafe_split_all_tac)
  1866 
  1867 * HOL: added safe wrapper "split_conv_tac" to claset; EXISTING PROOFS
  1868 MAY FAIL;
  1869 
  1870 * HOL: introduced f^n = f o ... o f; warning: due to the limits of
  1871 Isabelle's type classes, ^ on functions and relations has too general
  1872 a domain, namely ('a * 'b) set and 'a => 'b; this means that it may be
  1873 necessary to attach explicit type constraints;
  1874 
  1875 * HOL/Relation: the prefix name of the infix "O" has been changed from
  1876 "comp" to "rel_comp"; INCOMPATIBILITY: a few theorems have been
  1877 renamed accordingly (eg "compI" -> "rel_compI").
  1878 
  1879 * HOL: syntax translations now work properly with numerals and records
  1880 expressions;
  1881 
  1882 * HOL: bounded abstraction now uses syntax "%" / "\<lambda>" instead
  1883 of "lam" -- INCOMPATIBILITY;
  1884 
  1885 * HOL: got rid of some global declarations (potential INCOMPATIBILITY
  1886 for ML tools): const "()" renamed "Product_Type.Unity", type "unit"
  1887 renamed "Product_Type.unit";
  1888 
  1889 * HOL: renamed rtrancl_into_rtrancl2 to converse_rtrancl_into_rtrancl
  1890 
  1891 * HOL: removed obsolete theorem "optionE" (use "option.exhaust", or
  1892 the "cases" method);
  1893 
  1894 * HOL/GroupTheory: group theory examples including Sylow's theorem (by
  1895 Florian Kammller);
  1896 
  1897 * HOL/IMP: updated and converted to new-style theory format; several
  1898 parts turned into readable document, with proper Isar proof texts and
  1899 some explanations (by Gerwin Klein);
  1900 
  1901 * HOL-Real: added Complex_Numbers (by Gertrud Bauer);
  1902 
  1903 * HOL-Hyperreal is now a logic image;
  1904 
  1905 
  1906 *** HOLCF ***
  1907 
  1908 * Isar: consts/constdefs supports mixfix syntax for continuous
  1909 operations;
  1910 
  1911 * Isar: domain package adapted to new-style theory format, e.g. see
  1912 HOLCF/ex/Dnat.thy;
  1913 
  1914 * theory Lift: proper use of rep_datatype lift instead of ML hacks --
  1915 potential INCOMPATIBILITY; now use plain induct_tac instead of former
  1916 lift.induct_tac, always use UU instead of Undef;
  1917 
  1918 * HOLCF/IMP: updated and converted to new-style theory;
  1919 
  1920 
  1921 *** ZF ***
  1922 
  1923 * Isar: proper integration of logic-specific tools and packages,
  1924 including theory commands '(co)inductive', '(co)datatype',
  1925 'rep_datatype', 'inductive_cases', as well as methods 'ind_cases',
  1926 'induct_tac', 'case_tac', and 'typecheck' (with attribute 'TC');
  1927 
  1928 * theory Main no longer includes AC; for the Axiom of Choice, base
  1929 your theory on Main_ZFC;
  1930 
  1931 * the integer library now covers quotients and remainders, with many
  1932 laws relating division to addition, multiplication, etc.;
  1933 
  1934 * ZF/UNITY: Chandy and Misra's UNITY is now available in ZF, giving a
  1935 typeless version of the formalism;
  1936 
  1937 * ZF/AC, Coind, IMP, Resid: updated and converted to new-style theory
  1938 format;
  1939 
  1940 * ZF/Induct: new directory for examples of inductive definitions,
  1941 including theory Multiset for multiset orderings; converted to
  1942 new-style theory format;
  1943 
  1944 * ZF: many new theorems about lists, ordinals, etc.;
  1945 
  1946 
  1947 *** General ***
  1948 
  1949 * Pure/kernel: meta-level proof terms (by Stefan Berghofer); reference
  1950 variable proof controls level of detail: 0 = no proofs (only oracle
  1951 dependencies), 1 = lemma dependencies, 2 = compact proof terms; see
  1952 also ref manual for further ML interfaces;
  1953 
  1954 * Pure/axclass: removed obsolete ML interface
  1955 goal_subclass/goal_arity;
  1956 
  1957 * Pure/syntax: new token syntax "num" for plain numerals (without "#"
  1958 of "xnum"); potential INCOMPATIBILITY, since -0, -1 etc. are now
  1959 separate tokens, so expressions involving minus need to be spaced
  1960 properly;
  1961 
  1962 * Pure/syntax: support non-oriented infixes, using keyword "infix"
  1963 rather than "infixl" or "infixr";
  1964 
  1965 * Pure/syntax: concrete syntax for dummy type variables admits genuine
  1966 sort constraint specifications in type inference; e.g. "x::_::foo"
  1967 ensures that the type of "x" is of sort "foo" (but not necessarily a
  1968 type variable);
  1969 
  1970 * Pure/syntax: print modes "type_brackets" and "no_type_brackets"
  1971 control output of nested => (types); the default behavior is
  1972 "type_brackets";
  1973 
  1974 * Pure/syntax: builtin parse translation for "_constify" turns valued
  1975 tokens into AST constants;
  1976 
  1977 * Pure/syntax: prefer later declarations of translations and print
  1978 translation functions; potential INCOMPATIBILITY: need to reverse
  1979 multiple declarations for same syntax element constant;
  1980 
  1981 * Pure/show_hyps reset by default (in accordance to existing Isar
  1982 practice);
  1983 
  1984 * Provers/classical: renamed addaltern to addafter, addSaltern to
  1985 addSafter;
  1986 
  1987 * Provers/clasimp: ``iff'' declarations now handle conditional rules
  1988 as well;
  1989 
  1990 * system: tested support for MacOS X; should be able to get Isabelle +
  1991 Proof General to work in a plain Terminal after installing Poly/ML
  1992 (e.g. from the Isabelle distribution area) and GNU bash alone
  1993 (e.g. from http://www.apple.com); full X11, XEmacs and X-Symbol
  1994 support requires further installations, e.g. from
  1995 http://fink.sourceforge.net/);
  1996 
  1997 * system: support Poly/ML 4.1.1 (able to manage larger heaps);
  1998 
  1999 * system: reduced base memory usage by Poly/ML (approx. 20 MB instead
  2000 of 40 MB), cf. ML_OPTIONS;
  2001 
  2002 * system: Proof General keywords specification is now part of the
  2003 Isabelle distribution (see etc/isar-keywords.el);
  2004 
  2005 * system: support for persistent Proof General sessions (refrain from
  2006 outdating all loaded theories on startup); user may create writable
  2007 logic images like this: ``isabelle -q HOL Test'';
  2008 
  2009 * system: smart selection of Isabelle process versus Isabelle
  2010 interface, accommodates case-insensitive file systems (e.g. HFS+); may
  2011 run both "isabelle" and "Isabelle" even if file names are badly
  2012 damaged (executable inspects the case of the first letter of its own
  2013 name); added separate "isabelle-process" and "isabelle-interface";
  2014 
  2015 * system: refrain from any attempt at filtering input streams; no
  2016 longer support ``8bit'' encoding of old isabelle font, instead proper
  2017 iso-latin characters may now be used; the related isatools
  2018 "symbolinput" and "nonascii" have disappeared as well;
  2019 
  2020 * system: removed old "xterm" interface (the print modes "xterm" and
  2021 "xterm_color" are still available for direct use in a suitable
  2022 terminal);
  2023 
  2024 
  2025 
  2026 New in Isabelle99-2 (February 2001)
  2027 -----------------------------------
  2028 
  2029 *** Overview of INCOMPATIBILITIES ***
  2030 
  2031 * HOL: please note that theories in the Library and elsewhere often use the
  2032 new-style (Isar) format; to refer to their theorems in an ML script you must
  2033 bind them to ML identifers by e.g.      val thm_name = thm "thm_name";
  2034 
  2035 * HOL: inductive package no longer splits induction rule aggressively,
  2036 but only as far as specified by the introductions given; the old
  2037 format may be recovered via ML function complete_split_rule or attribute
  2038 'split_rule (complete)';
  2039 
  2040 * HOL: induct renamed to lfp_induct, lfp_Tarski to lfp_unfold,
  2041 gfp_Tarski to gfp_unfold;
  2042 
  2043 * HOL: contrapos, contrapos2 renamed to contrapos_nn, contrapos_pp;
  2044 
  2045 * HOL: infix "dvd" now has priority 50 rather than 70 (because it is a
  2046 relation); infix "^^" has been renamed "``"; infix "``" has been
  2047 renamed "`"; "univalent" has been renamed "single_valued";
  2048 
  2049 * HOL/Real: "rinv" and "hrinv" replaced by overloaded "inverse"
  2050 operation;
  2051 
  2052 * HOLCF: infix "`" has been renamed "$"; the symbol syntax is \<cdot>;
  2053 
  2054 * Isar: 'obtain' no longer declares "that" fact as simp/intro;
  2055 
  2056 * Isar/HOL: method 'induct' now handles non-atomic goals; as a
  2057 consequence, it is no longer monotonic wrt. the local goal context
  2058 (which is now passed through the inductive cases);
  2059 
  2060 * Document preparation: renamed standard symbols \<ll> to \<lless> and
  2061 \<gg> to \<ggreater>;
  2062 
  2063 
  2064 *** Document preparation ***
  2065 
  2066 * \isabellestyle{NAME} selects version of Isabelle output (currently
  2067 available: are "it" for near math-mode best-style output, "sl" for
  2068 slanted text style, and "tt" for plain type-writer; if no
  2069 \isabellestyle command is given, output is according to slanted
  2070 type-writer);
  2071 
  2072 * support sub/super scripts (for single symbols only), input syntax is
  2073 like this: "A\<^sup>*" or "A\<^sup>\<star>";
  2074 
  2075 * some more standard symbols; see Appendix A of the system manual for
  2076 the complete list of symbols defined in isabellesym.sty;
  2077 
  2078 * improved isabelle style files; more abstract symbol implementation
  2079 (should now use \isamath{...} and \isatext{...} in custom symbol
  2080 definitions);
  2081 
  2082 * antiquotation @{goals} and @{subgoals} for output of *dynamic* goals
  2083 state; Note that presentation of goal states does not conform to
  2084 actual human-readable proof documents.  Please do not include goal
  2085 states into document output unless you really know what you are doing!
  2086 
  2087 * proper indentation of antiquoted output with proportional LaTeX
  2088 fonts;
  2089 
  2090 * no_document ML operator temporarily disables LaTeX document
  2091 generation;
  2092 
  2093 * isatool unsymbolize tunes sources for plain ASCII communication;
  2094 
  2095 
  2096 *** Isar ***
  2097 
  2098 * Pure: Isar now suffers initial goal statements to contain unbound
  2099 schematic variables (this does not conform to actual readable proof
  2100 documents, due to unpredictable outcome and non-compositional proof
  2101 checking); users who know what they are doing may use schematic goals
  2102 for Prolog-style synthesis of proven results;
  2103 
  2104 * Pure: assumption method (an implicit finishing) now handles actual
  2105 rules as well;
  2106 
  2107 * Pure: improved 'obtain' --- moved to Pure, insert "that" into
  2108 initial goal, declare "that" only as Pure intro (only for single
  2109 steps); the "that" rule assumption may now be involved in implicit
  2110 finishing, thus ".." becomes a feasible for trivial obtains;
  2111 
  2112 * Pure: default proof step now includes 'intro_classes'; thus trivial
  2113 instance proofs may be performed by "..";
  2114 
  2115 * Pure: ?thesis / ?this / "..." now work for pure meta-level
  2116 statements as well;
  2117 
  2118 * Pure: more robust selection of calculational rules;
  2119 
  2120 * Pure: the builtin notion of 'finished' goal now includes the ==-refl
  2121 rule (as well as the assumption rule);
  2122 
  2123 * Pure: 'thm_deps' command visualizes dependencies of theorems and
  2124 lemmas, using the graph browser tool;
  2125 
  2126 * Pure: predict failure of "show" in interactive mode;
  2127 
  2128 * Pure: 'thms_containing' now takes actual terms as arguments;
  2129 
  2130 * HOL: improved method 'induct' --- now handles non-atomic goals
  2131 (potential INCOMPATIBILITY); tuned error handling;
  2132 
  2133 * HOL: cases and induct rules now provide explicit hints about the
  2134 number of facts to be consumed (0 for "type" and 1 for "set" rules);
  2135 any remaining facts are inserted into the goal verbatim;
  2136 
  2137 * HOL: local contexts (aka cases) may now contain term bindings as
  2138 well; the 'cases' and 'induct' methods new provide a ?case binding for
  2139 the result to be shown in each case;
  2140 
  2141 * HOL: added 'recdef_tc' command;
  2142 
  2143 * isatool convert assists in eliminating legacy ML scripts;
  2144 
  2145 
  2146 *** HOL ***
  2147 
  2148 * HOL/Library: a collection of generic theories to be used together
  2149 with main HOL; the theory loader path already includes this directory
  2150 by default; the following existing theories have been moved here:
  2151 HOL/Induct/Multiset, HOL/Induct/Acc (as Accessible_Part), HOL/While
  2152 (as While_Combinator), HOL/Lex/Prefix (as List_Prefix);
  2153 
  2154 * HOL/Unix: "Some aspects of Unix file-system security", a typical
  2155 modelling and verification task performed in Isabelle/HOL +
  2156 Isabelle/Isar + Isabelle document preparation (by Markus Wenzel).
  2157 
  2158 * HOL/Algebra: special summation operator SUM no longer exists, it has
  2159 been replaced by setsum; infix 'assoc' now has priority 50 (like
  2160 'dvd'); axiom 'one_not_zero' has been moved from axclass 'ring' to
  2161 'domain', this makes the theory consistent with mathematical
  2162 literature;
  2163 
  2164 * HOL basics: added overloaded operations "inverse" and "divide"
  2165 (infix "/"), syntax for generic "abs" operation, generic summation
  2166 operator \<Sum>;
  2167 
  2168 * HOL/typedef: simplified package, provide more useful rules (see also
  2169 HOL/subset.thy);
  2170 
  2171 * HOL/datatype: induction rule for arbitrarily branching datatypes is
  2172 now expressed as a proper nested rule (old-style tactic scripts may
  2173 require atomize_strip_tac to cope with non-atomic premises);
  2174 
  2175 * HOL: renamed theory "Prod" to "Product_Type", renamed "split" rule
  2176 to "split_conv" (old name still available for compatibility);
  2177 
  2178 * HOL: improved concrete syntax for strings (e.g. allows translation
  2179 rules with string literals);
  2180 
  2181 * HOL-Real-Hyperreal: this extends HOL-Real with the hyperreals
  2182  and Fleuriot's mechanization of analysis, including the transcendental
  2183  functions for the reals;
  2184 
  2185 * HOL/Real, HOL/Hyperreal: improved arithmetic simplification;
  2186 
  2187 
  2188 *** CTT ***
  2189 
  2190 * CTT: x-symbol support for Pi, Sigma, -->, : (membership); note that
  2191 "lam" is displayed as TWO lambda-symbols
  2192 
  2193 * CTT: theory Main now available, containing everything (that is, Bool
  2194 and Arith);
  2195 
  2196 
  2197 *** General ***
  2198 
  2199 * Pure: the Simplifier has been implemented properly as a derived rule
  2200 outside of the actual kernel (at last!); the overall performance
  2201 penalty in practical applications is about 50%, while reliability of
  2202 the Isabelle inference kernel has been greatly improved;
  2203 
  2204 * print modes "brackets" and "no_brackets" control output of nested =>
  2205 (types) and ==> (props); the default behaviour is "brackets";
  2206 
  2207 * Provers: fast_tac (and friends) now handle actual object-logic rules
  2208 as assumptions as well;
  2209 
  2210 * system: support Poly/ML 4.0;
  2211 
  2212 * system: isatool install handles KDE version 1 or 2;
  2213 
  2214 
  2215 
  2216 New in Isabelle99-1 (October 2000)
  2217 ----------------------------------
  2218 
  2219 *** Overview of INCOMPATIBILITIES ***
  2220 
  2221 * HOL: simplification of natural numbers is much changed; to partly
  2222 recover the old behaviour (e.g. to prevent n+n rewriting to #2*n)
  2223 issue the following ML commands:
  2224 
  2225   Delsimprocs Nat_Numeral_Simprocs.cancel_numerals;
  2226   Delsimprocs [Nat_Numeral_Simprocs.combine_numerals];
  2227 
  2228 * HOL: simplification no longer dives into case-expressions; this is
  2229 controlled by "t.weak_case_cong" for each datatype t;
  2230 
  2231 * HOL: nat_less_induct renamed to less_induct;
  2232 
  2233 * HOL: systematic renaming of the SOME (Eps) rules, may use isatool
  2234 fixsome to patch .thy and .ML sources automatically;
  2235 
  2236   select_equality  -> some_equality
  2237   select_eq_Ex     -> some_eq_ex
  2238   selectI2EX       -> someI2_ex
  2239   selectI2         -> someI2
  2240   selectI          -> someI
  2241   select1_equality -> some1_equality
  2242   Eps_sym_eq       -> some_sym_eq_trivial
  2243   Eps_eq           -> some_eq_trivial
  2244 
  2245 * HOL: exhaust_tac on datatypes superceded by new generic case_tac;
  2246 
  2247 * HOL: removed obsolete theorem binding expand_if (refer to split_if
  2248 instead);
  2249 
  2250 * HOL: the recursion equations generated by 'recdef' are now called
  2251 f.simps instead of f.rules;
  2252 
  2253 * HOL: qed_spec_mp now also handles bounded ALL as well;
  2254 
  2255 * HOL: 0 is now overloaded, so the type constraint ":: nat" may
  2256 sometimes be needed;
  2257 
  2258 * HOL: the constant for "f``x" is now "image" rather than "op ``";
  2259 
  2260 * HOL: the constant for "f-``x" is now "vimage" rather than "op -``";
  2261 
  2262 * HOL: the disjoint sum is now "<+>" instead of "Plus"; the cartesian
  2263 product is now "<*>" instead of "Times"; the lexicographic product is
  2264 now "<*lex*>" instead of "**";
  2265 
  2266 * HOL: theory Sexp is now in HOL/Induct examples (it used to be part
  2267 of main HOL, but was unused); better use HOL's datatype package;
  2268 
  2269 * HOL: removed "symbols" syntax for constant "override" of theory Map;
  2270 the old syntax may be recovered as follows:
  2271 
  2272   syntax (symbols)
  2273     override  :: "('a ~=> 'b) => ('a ~=> 'b) => ('a ~=> 'b)"
  2274       (infixl "\\<oplus>" 100)
  2275 
  2276 * HOL/Real: "rabs" replaced by overloaded "abs" function;
  2277 
  2278 * HOL/ML: even fewer consts are declared as global (see theories Ord,
  2279 Lfp, Gfp, WF); this only affects ML packages that refer to const names
  2280 internally;
  2281 
  2282 * HOL and ZF: syntax for quotienting wrt an equivalence relation
  2283 changed from A/r to A//r;
  2284 
  2285 * ZF: new treatment of arithmetic (nat & int) may break some old
  2286 proofs;
  2287 
  2288 * Isar: renamed some attributes (RS -> THEN, simplify -> simplified,
  2289 rulify -> rule_format, elimify -> elim_format, ...);
  2290 
  2291 * Isar/Provers: intro/elim/dest attributes changed; renamed
  2292 intro/intro!/intro!! flags to intro!/intro/intro? (in most cases, one
  2293 should have to change intro!! to intro? only); replaced "delrule" by
  2294 "rule del";
  2295 
  2296 * Isar/HOL: renamed "intrs" to "intros" in inductive definitions;
  2297 
  2298 * Provers: strengthened force_tac by using new first_best_tac;
  2299 
  2300 * LaTeX document preparation: several changes of isabelle.sty (see
  2301 lib/texinputs);
  2302 
  2303 
  2304 *** Document preparation ***
  2305 
  2306 * formal comments (text blocks etc.) in new-style theories may now
  2307 contain antiquotations of thm/prop/term/typ/text to be presented
  2308 according to latex print mode; concrete syntax is like this:
  2309 @{term[show_types] "f(x) = a + x"};
  2310 
  2311 * isatool mkdir provides easy setup of Isabelle session directories,
  2312 including proper document sources;
  2313 
  2314 * generated LaTeX sources are now deleted after successful run
  2315 (isatool document -c); may retain a copy somewhere else via -D option
  2316 of isatool usedir;
  2317 
  2318 * isatool usedir -D now lets isatool latex -o sty update the Isabelle
  2319 style files, achieving self-contained LaTeX sources and simplifying
  2320 LaTeX debugging;
  2321 
  2322 * old-style theories now produce (crude) LaTeX output as well;
  2323 
  2324 * browser info session directories are now self-contained (may be put
  2325 on WWW server seperately); improved graphs of nested sessions; removed
  2326 graph for 'all sessions';
  2327 
  2328 * several improvements in isabelle style files; \isabellestyle{it}
  2329 produces fake math mode output; \isamarkupheader is now \section by
  2330 default; see lib/texinputs/isabelle.sty etc.;
  2331 
  2332 
  2333 *** Isar ***
  2334 
  2335 * Isar/Pure: local results and corresponding term bindings are now
  2336 subject to Hindley-Milner polymorphism (similar to ML); this
  2337 accommodates incremental type-inference very nicely;
  2338 
  2339 * Isar/Pure: new derived language element 'obtain' supports
  2340 generalized existence reasoning;
  2341 
  2342 * Isar/Pure: new calculational elements 'moreover' and 'ultimately'
  2343 support accumulation of results, without applying any rules yet;
  2344 useful to collect intermediate results without explicit name
  2345 references, and for use with transitivity rules with more than 2
  2346 premises;
  2347 
  2348 * Isar/Pure: scalable support for case-analysis type proofs: new
  2349 'case' language element refers to local contexts symbolically, as
  2350 produced by certain proof methods; internally, case names are attached
  2351 to theorems as "tags";
  2352 
  2353 * Isar/Pure: theory command 'hide' removes declarations from
  2354 class/type/const name spaces;
  2355 
  2356 * Isar/Pure: theory command 'defs' supports option "(overloaded)" to
  2357 indicate potential overloading;
  2358 
  2359 * Isar/Pure: changed syntax of local blocks from {{ }} to { };
  2360 
  2361 * Isar/Pure: syntax of sorts made 'inner', i.e. have to write
  2362 "{a,b,c}" instead of {a,b,c};
  2363 
  2364 * Isar/Pure now provides its own version of intro/elim/dest
  2365 attributes; useful for building new logics, but beware of confusion
  2366 with the version in Provers/classical;
  2367 
  2368 * Isar/Pure: the local context of (non-atomic) goals is provided via
  2369 case name 'antecedent';
  2370 
  2371 * Isar/Pure: removed obsolete 'transfer' attribute (transfer of thms
  2372 to the current context is now done automatically);
  2373 
  2374 * Isar/Pure: theory command 'method_setup' provides a simple interface
  2375 for definining proof methods in ML;
  2376 
  2377 * Isar/Provers: intro/elim/dest attributes changed; renamed
  2378 intro/intro!/intro!! flags to intro!/intro/intro? (INCOMPATIBILITY, in
  2379 most cases, one should have to change intro!! to intro? only);
  2380 replaced "delrule" by "rule del";
  2381 
  2382 * Isar/Provers: new 'hypsubst' method, plain 'subst' method and
  2383 'symmetric' attribute (the latter supercedes [RS sym]);
  2384 
  2385 * Isar/Provers: splitter support (via 'split' attribute and 'simp'
  2386 method modifier); 'simp' method: 'only:' modifier removes loopers as
  2387 well (including splits);
  2388 
  2389 * Isar/Provers: Simplifier and Classical methods now support all kind
  2390 of modifiers used in the past, including 'cong', 'iff', etc.
  2391 
  2392 * Isar/Provers: added 'fastsimp' and 'clarsimp' methods (combination
  2393 of Simplifier and Classical reasoner);
  2394 
  2395 * Isar/HOL: new proof method 'cases' and improved version of 'induct'
  2396 now support named cases; major packages (inductive, datatype, primrec,
  2397 recdef) support case names and properly name parameters;
  2398 
  2399 * Isar/HOL: new transitivity rules for substitution in inequalities --
  2400 monotonicity conditions are extracted to be proven at end of
  2401 calculations;
  2402 
  2403 * Isar/HOL: removed 'case_split' thm binding, should use 'cases' proof
  2404 method anyway;
  2405 
  2406 * Isar/HOL: removed old expand_if = split_if; theorems if_splits =
  2407 split_if split_if_asm; datatype package provides theorems foo.splits =
  2408 foo.split foo.split_asm for each datatype;
  2409 
  2410 * Isar/HOL: tuned inductive package, rename "intrs" to "intros"
  2411 (potential INCOMPATIBILITY), emulation of mk_cases feature for proof
  2412 scripts: new 'inductive_cases' command and 'ind_cases' method; (Note:
  2413 use "(cases (simplified))" method in proper proof texts);
  2414 
  2415 * Isar/HOL: added global 'arith_split' attribute for 'arith' method;
  2416 
  2417 * Isar: names of theorems etc. may be natural numbers as well;
  2418 
  2419 * Isar: 'pr' command: optional arguments for goals_limit and
  2420 ProofContext.prems_limit; no longer prints theory contexts, but only
  2421 proof states;
  2422 
  2423 * Isar: diagnostic commands 'pr', 'thm', 'prop', 'term', 'typ' admit
  2424 additional print modes to be specified; e.g. "pr(latex)" will print
  2425 proof state according to the Isabelle LaTeX style;
  2426 
  2427 * Isar: improved support for emulating tactic scripts, including proof
  2428 methods 'rule_tac' etc., 'cut_tac', 'thin_tac', 'subgoal_tac',
  2429 'rename_tac', 'rotate_tac', 'tactic', and 'case_tac' / 'induct_tac'
  2430 (for HOL datatypes);
  2431 
  2432 * Isar: simplified (more robust) goal selection of proof methods: 1st
  2433 goal, all goals, or explicit goal specifier (tactic emulation); thus
  2434 'proof method scripts' have to be in depth-first order;
  2435 
  2436 * Isar: tuned 'let' syntax: replaced 'as' keyword by 'and';
  2437 
  2438 * Isar: removed 'help' command, which hasn't been too helpful anyway;
  2439 should instead use individual commands for printing items
  2440 (print_commands, print_methods etc.);
  2441 
  2442 * Isar: added 'nothing' --- the empty list of theorems;
  2443 
  2444 
  2445 *** HOL ***
  2446 
  2447 * HOL/MicroJava: formalization of a fragment of Java, together with a
  2448 corresponding virtual machine and a specification of its bytecode
  2449 verifier and a lightweight bytecode verifier, including proofs of
  2450 type-safety; by Gerwin Klein, Tobias Nipkow, David von Oheimb, and
  2451 Cornelia Pusch (see also the homepage of project Bali at
  2452 http://isabelle.in.tum.de/Bali/);
  2453 
  2454 * HOL/Algebra: new theory of rings and univariate polynomials, by
  2455 Clemens Ballarin;
  2456 
  2457 * HOL/NumberTheory: fundamental Theorem of Arithmetic, Chinese
  2458 Remainder Theorem, Fermat/Euler Theorem, Wilson's Theorem, by Thomas M
  2459 Rasmussen;
  2460 
  2461 * HOL/Lattice: fundamental concepts of lattice theory and order
  2462 structures, including duals, properties of bounds versus algebraic
  2463 laws, lattice operations versus set-theoretic ones, the Knaster-Tarski
  2464 Theorem for complete lattices etc.; may also serve as a demonstration
  2465 for abstract algebraic reasoning using axiomatic type classes, and
  2466 mathematics-style proof in Isabelle/Isar; by Markus Wenzel;
  2467 
  2468 * HOL/Prolog: a (bare-bones) implementation of Lambda-Prolog, by David
  2469 von Oheimb;
  2470 
  2471 * HOL/IMPP: extension of IMP with local variables and mutually
  2472 recursive procedures, by David von Oheimb;
  2473 
  2474 * HOL/Lambda: converted into new-style theory and document;
  2475 
  2476 * HOL/ex/Multiquote: example of multiple nested quotations and
  2477 anti-quotations -- basically a generalized version of de-Bruijn
  2478 representation; very useful in avoiding lifting of operations;
  2479 
  2480 * HOL/record: added general record equality rule to simpset; fixed
  2481 select-update simplification procedure to handle extended records as
  2482 well; admit "r" as field name;
  2483 
  2484 * HOL: 0 is now overloaded over the new sort "zero", allowing its use with
  2485 other numeric types and also as the identity of groups, rings, etc.;
  2486 
  2487 * HOL: new axclass plus_ac0 for addition with the AC-laws and 0 as identity.
  2488 Types nat and int belong to this axclass;
  2489 
  2490 * HOL: greatly improved simplification involving numerals of type nat, int, real:
  2491    (i + #8 + j) = Suc k simplifies to  #7 + (i + j) = k
  2492    i*j + k + j*#3*i     simplifies to  #4*(i*j) + k
  2493   two terms #m*u and #n*u are replaced by #(m+n)*u
  2494     (where #m, #n and u can implicitly be 1; this is simproc combine_numerals)
  2495   and the term/formula #m*u+x ~~ #n*u+y simplifies simplifies to #(m-n)+x ~~ y
  2496     or x ~~ #(n-m)+y, where ~~ is one of = < <= or - (simproc cancel_numerals);
  2497 
  2498 * HOL: meson_tac is available (previously in ex/meson.ML); it is a
  2499 powerful prover for predicate logic but knows nothing of clasets; see
  2500 ex/mesontest.ML and ex/mesontest2.ML for example applications;
  2501 
  2502 * HOL: new version of "case_tac" subsumes both boolean case split and
  2503 "exhaust_tac" on datatypes; INCOMPATIBILITY: exhaust_tac no longer
  2504 exists, may define val exhaust_tac = case_tac for ad-hoc portability;
  2505 
  2506 * HOL: simplification no longer dives into case-expressions: only the
  2507 selector expression is simplified, but not the remaining arms; to
  2508 enable full simplification of case-expressions for datatype t, you may
  2509 remove t.weak_case_cong from the simpset, either globally (Delcongs
  2510 [thm"t.weak_case_cong"];) or locally (delcongs [...]).
  2511 
  2512 * HOL/recdef: the recursion equations generated by 'recdef' for
  2513 function 'f' are now called f.simps instead of f.rules; if all
  2514 termination conditions are proved automatically, these simplification
  2515 rules are added to the simpset, as in primrec; rules may be named
  2516 individually as well, resulting in a separate list of theorems for
  2517 each equation;
  2518 
  2519 * HOL/While is a new theory that provides a while-combinator. It
  2520 permits the definition of tail-recursive functions without the
  2521 provision of a termination measure. The latter is necessary once the
  2522 invariant proof rule for while is applied.
  2523 
  2524 * HOL: new (overloaded) notation for the set of elements below/above
  2525 some element: {..u}, {..u(}, {l..}, {)l..}. See theory SetInterval.
  2526 
  2527 * HOL: theorems impI, allI, ballI bound as "strip";
  2528 
  2529 * HOL: new tactic induct_thm_tac: thm -> string -> int -> tactic
  2530 induct_tac th "x1 ... xn" expects th to have a conclusion of the form
  2531 P v1 ... vn and abbreviates res_inst_tac [("v1","x1"),...,("vn","xn")] th;
  2532 
  2533 * HOL/Real: "rabs" replaced by overloaded "abs" function;
  2534 
  2535 * HOL: theory Sexp now in HOL/Induct examples (it used to be part of
  2536 main HOL, but was unused);
  2537 
  2538 * HOL: fewer consts declared as global (e.g. have to refer to
  2539 "Lfp.lfp" instead of "lfp" internally; affects ML packages only);
  2540 
  2541 * HOL: tuned AST representation of nested pairs, avoiding bogus output
  2542 in case of overlap with user translations (e.g. judgements over
  2543 tuples); (note that the underlying logical represenation is still
  2544 bogus);
  2545 
  2546 
  2547 *** ZF ***
  2548 
  2549 * ZF: simplification automatically cancels common terms in arithmetic
  2550 expressions over nat and int;
  2551 
  2552 * ZF: new treatment of nat to minimize type-checking: all operators
  2553 coerce their operands to a natural number using the function natify,
  2554 making the algebraic laws unconditional;
  2555 
  2556 * ZF: as above, for int: operators coerce their operands to an integer
  2557 using the function intify;
  2558 
  2559 * ZF: the integer library now contains many of the usual laws for the
  2560 orderings, including $<=, and monotonicity laws for $+ and $*;
  2561 
  2562 * ZF: new example ZF/ex/NatSum to demonstrate integer arithmetic
  2563 simplification;
  2564 
  2565 * FOL and ZF: AddIffs now available, giving theorems of the form P<->Q
  2566 to the simplifier and classical reasoner simultaneously;
  2567 
  2568 
  2569 *** General ***
  2570 
  2571 * Provers: blast_tac now handles actual object-logic rules as
  2572 assumptions; note that auto_tac uses blast_tac internally as well;
  2573 
  2574 * Provers: new functions rulify/rulify_no_asm: thm -> thm for turning
  2575 outer -->/All/Ball into ==>/!!; qed_spec_mp now uses rulify_no_asm;
  2576 
  2577 * Provers: delrules now handles destruct rules as well (no longer need
  2578 explicit make_elim);
  2579 
  2580 * Provers: Blast_tac now warns of and ignores "weak elimination rules" e.g.
  2581   [| inj ?f;          ?f ?x = ?f ?y; ?x = ?y ==> ?W |] ==> ?W
  2582 use instead the strong form,
  2583   [| inj ?f; ~ ?W ==> ?f ?x = ?f ?y; ?x = ?y ==> ?W |] ==> ?W
  2584 in HOL, FOL and ZF the function cla_make_elim will create such rules
  2585 from destruct-rules;
  2586 
  2587 * Provers: Simplifier.easy_setup provides a fast path to basic
  2588 Simplifier setup for new object-logics;
  2589 
  2590 * Pure: AST translation rules no longer require constant head on LHS;
  2591 
  2592 * Pure: improved name spaces: ambiguous output is qualified; support
  2593 for hiding of names;
  2594 
  2595 * system: smart setup of canonical ML_HOME, ISABELLE_INTERFACE, and
  2596 XSYMBOL_HOME; no longer need to do manual configuration in most
  2597 situations;
  2598 
  2599 * system: compression of ML heaps images may now be controlled via -c
  2600 option of isabelle and isatool usedir (currently only observed by
  2601 Poly/ML);
  2602 
  2603 * system: isatool installfonts may handle X-Symbol fonts as well (very
  2604 useful for remote X11);
  2605 
  2606 * system: provide TAGS file for Isabelle sources;
  2607 
  2608 * ML: infix 'OF' is a version of 'MRS' with more appropriate argument
  2609 order;
  2610 
  2611 * ML: renamed flags Syntax.trace_norm_ast to Syntax.trace_ast; global
  2612 timing flag supersedes proof_timing and Toplevel.trace;
  2613 
  2614 * ML: new combinators |>> and |>>> for incremental transformations
  2615 with secondary results (e.g. certain theory extensions):
  2616 
  2617 * ML: PureThy.add_defs gets additional argument to indicate potential
  2618 overloading (usually false);
  2619 
  2620 * ML: PureThy.add_thms/add_axioms/add_defs now return theorems as
  2621 results;
  2622 
  2623 
  2624 
  2625 New in Isabelle99 (October 1999)
  2626 --------------------------------
  2627 
  2628 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  2629 
  2630 * HOL: The THEN and ELSE parts of conditional expressions (if P then x else y)
  2631 are no longer simplified.  (This allows the simplifier to unfold recursive
  2632 functional programs.)  To restore the old behaviour, declare
  2633 
  2634     Delcongs [if_weak_cong];
  2635 
  2636 * HOL: Removed the obsolete syntax "Compl A"; use -A for set
  2637 complement;
  2638 
  2639 * HOL: the predicate "inj" is now defined by translation to "inj_on";
  2640 
  2641 * HOL/datatype: mutual_induct_tac no longer exists --
  2642   use induct_tac "x_1 ... x_n" instead of mutual_induct_tac ["x_1", ..., "x_n"]
  2643 
  2644 * HOL/typedef: fixed type inference for representing set; type
  2645 arguments now have to occur explicitly on the rhs as type constraints;
  2646 
  2647 * ZF: The con_defs part of an inductive definition may no longer refer
  2648 to constants declared in the same theory;
  2649 
  2650 * HOL, ZF: the function mk_cases, generated by the inductive
  2651 definition package, has lost an argument.  To simplify its result, it
  2652 uses the default simpset instead of a supplied list of theorems.
  2653 
  2654 * HOL/List: the constructors of type list are now Nil and Cons;
  2655 
  2656 * Simplifier: the type of the infix ML functions
  2657         setSSolver addSSolver setSolver addSolver
  2658 is now  simpset * solver -> simpset  where `solver' is a new abstract type
  2659 for packaging solvers. A solver is created via
  2660         mk_solver: string -> (thm list -> int -> tactic) -> solver
  2661 where the string argument is only a comment.
  2662 
  2663 
  2664 *** Proof tools ***
  2665 
  2666 * Provers/Arith/fast_lin_arith.ML contains a functor for creating a
  2667 decision procedure for linear arithmetic. Currently it is used for
  2668 types `nat', `int', and `real' in HOL (see below); it can, should and
  2669 will be instantiated for other types and logics as well.
  2670 
  2671 * The simplifier now accepts rewrite rules with flexible heads, eg
  2672      hom ?f ==> ?f(?x+?y) = ?f ?x + ?f ?y
  2673   They are applied like any rule with a non-pattern lhs, i.e. by first-order
  2674   matching.
  2675 
  2676 
  2677 *** General ***
  2678 
  2679 * New Isabelle/Isar subsystem provides an alternative to traditional
  2680 tactical theorem proving; together with the ProofGeneral/isar user
  2681 interface it offers an interactive environment for developing human
  2682 readable proof documents (Isar == Intelligible semi-automated
  2683 reasoning); for further information see isatool doc isar-ref,
  2684 src/HOL/Isar_examples and http://isabelle.in.tum.de/Isar/
  2685 
  2686 * improved and simplified presentation of theories: better HTML markup
  2687 (including colors), graph views in several sizes; isatool usedir now
  2688 provides a proper interface for user theories (via -P option); actual
  2689 document preparation based on (PDF)LaTeX is available as well (for
  2690 new-style theories only); see isatool doc system for more information;
  2691 
  2692 * native support for Proof General, both for classic Isabelle and
  2693 Isabelle/Isar;
  2694 
  2695 * ML function thm_deps visualizes dependencies of theorems and lemmas,
  2696 using the graph browser tool;
  2697 
  2698 * Isabelle manuals now also available as PDF;
  2699 
  2700 * theory loader rewritten from scratch (may not be fully
  2701 bug-compatible); old loadpath variable has been replaced by show_path,
  2702 add_path, del_path, reset_path functions; new operations such as
  2703 update_thy, touch_thy, remove_thy, use/update_thy_only (see also
  2704 isatool doc ref);
  2705 
  2706 * improved isatool install: option -k creates KDE application icon,
  2707 option -p DIR installs standalone binaries;
  2708 
  2709 * added ML_PLATFORM setting (useful for cross-platform installations);
  2710 more robust handling of platform specific ML images for SML/NJ;
  2711 
  2712 * the settings environment is now statically scoped, i.e. it is never
  2713 created again in sub-processes invoked from isabelle, isatool, or
  2714 Isabelle;
  2715 
  2716 * path element specification '~~' refers to '$ISABELLE_HOME';
  2717 
  2718 * in locales, the "assumes" and "defines" parts may be omitted if
  2719 empty;
  2720 
  2721 * new print_mode "xsymbols" for extended symbol support (e.g. genuine
  2722 long arrows);
  2723 
  2724 * new print_mode "HTML";
  2725 
  2726 * new flag show_tags controls display of tags of theorems (which are
  2727 basically just comments that may be attached by some tools);
  2728 
  2729 * Isamode 2.6 requires patch to accomodate change of Isabelle font
  2730 mode and goal output format:
  2731 
  2732 diff -r Isamode-2.6/elisp/isa-load.el Isamode/elisp/isa-load.el
  2733 244c244
  2734 <       (list (isa-getenv "ISABELLE") "-msymbols" logic-name)
  2735 ---
  2736 >       (list (isa-getenv "ISABELLE") "-misabelle_font" "-msymbols" logic-name)
  2737 diff -r Isabelle-2.6/elisp/isa-proofstate.el Isamode/elisp/isa-proofstate.el
  2738 181c181
  2739 < (defconst proofstate-proofstart-regexp "^Level [0-9]+$"
  2740 ---
  2741 > (defconst proofstate-proofstart-regexp "^Level [0-9]+"
  2742 
  2743 * function bind_thms stores lists of theorems (cf. bind_thm);
  2744 
  2745 * new shorthand tactics ftac, eatac, datac, fatac;
  2746 
  2747 * qed (and friends) now accept "" as result name; in that case the
  2748 theorem is not stored, but proper checks and presentation of the
  2749 result still apply;
  2750 
  2751 * theorem database now also indexes constants "Trueprop", "all",
  2752 "==>", "=="; thus thms_containing, findI etc. may retrieve more rules;
  2753 
  2754 
  2755 *** HOL ***
  2756 
  2757 ** HOL arithmetic **
  2758 
  2759 * There are now decision procedures for linear arithmetic over nat and
  2760 int:
  2761 
  2762 1. arith_tac copes with arbitrary formulae involving `=', `<', `<=',
  2763 `+', `-', `Suc', `min', `max' and numerical constants; other subterms
  2764 are treated as atomic; subformulae not involving type `nat' or `int'
  2765 are ignored; quantified subformulae are ignored unless they are
  2766 positive universal or negative existential. The tactic has to be
  2767 invoked by hand and can be a little bit slow. In particular, the
  2768 running time is exponential in the number of occurrences of `min' and
  2769 `max', and `-' on `nat'.
  2770 
  2771 2. fast_arith_tac is a cut-down version of arith_tac: it only takes
  2772 (negated) (in)equalities among the premises and the conclusion into
  2773 account (i.e. no compound formulae) and does not know about `min' and
  2774 `max', and `-' on `nat'. It is fast and is used automatically by the
  2775 simplifier.
  2776 
  2777 NB: At the moment, these decision procedures do not cope with mixed
  2778 nat/int formulae where the two parts interact, such as `m < n ==>
  2779 int(m) < int(n)'.
  2780 
  2781 * HOL/Numeral provides a generic theory of numerals (encoded
  2782 efficiently as bit strings); setup for types nat/int/real is in place;
  2783 INCOMPATIBILITY: since numeral syntax is now polymorphic, rather than
  2784 int, existing theories and proof scripts may require a few additional
  2785 type constraints;
  2786 
  2787 * integer division and remainder can now be performed on constant
  2788 arguments;
  2789 
  2790 * many properties of integer multiplication, division and remainder
  2791 are now available;
  2792 
  2793 * An interface to the Stanford Validity Checker (SVC) is available through the
  2794 tactic svc_tac.  Propositional tautologies and theorems of linear arithmetic
  2795 are proved automatically.  SVC must be installed separately, and its results
  2796 must be TAKEN ON TRUST (Isabelle does not check the proofs, but tags any
  2797 invocation of the underlying oracle).  For SVC see
  2798   http://verify.stanford.edu/SVC
  2799 
  2800 * IsaMakefile: the HOL-Real target now builds an actual image;
  2801 
  2802 
  2803 ** HOL misc **
  2804 
  2805 * HOL/Real/HahnBanach: the Hahn-Banach theorem for real vector spaces
  2806 (in Isabelle/Isar) -- by Gertrud Bauer;
  2807 
  2808 * HOL/BCV: generic model of bytecode verification, i.e. data-flow
  2809 analysis for assembly languages with subtypes;
  2810 
  2811 * HOL/TLA (Lamport's Temporal Logic of Actions): major reorganization
  2812 -- avoids syntactic ambiguities and treats state, transition, and
  2813 temporal levels more uniformly; introduces INCOMPATIBILITIES due to
  2814 changed syntax and (many) tactics;
  2815 
  2816 * HOL/inductive: Now also handles more general introduction rules such
  2817   as "ALL y. (y, x) : r --> y : acc r ==> x : acc r"; monotonicity
  2818   theorems are now maintained within the theory (maintained via the
  2819   "mono" attribute);
  2820 
  2821 * HOL/datatype: Now also handles arbitrarily branching datatypes
  2822   (using function types) such as
  2823 
  2824   datatype 'a tree = Atom 'a | Branch "nat => 'a tree"
  2825 
  2826 * HOL/record: record_simproc (part of the default simpset) takes care
  2827 of selectors applied to updated records; record_split_tac is no longer
  2828 part of the default claset; update_defs may now be removed from the
  2829 simpset in many cases; COMPATIBILITY: old behavior achieved by
  2830 
  2831   claset_ref () := claset() addSWrapper record_split_wrapper;
  2832   Delsimprocs [record_simproc]
  2833 
  2834 * HOL/typedef: fixed type inference for representing set; type
  2835 arguments now have to occur explicitly on the rhs as type constraints;
  2836 
  2837 * HOL/recdef (TFL): 'congs' syntax now expects comma separated list of theorem
  2838 names rather than an ML expression;
  2839 
  2840 * HOL/defer_recdef (TFL): like recdef but the well-founded relation can be
  2841 supplied later.  Program schemes can be defined, such as
  2842     "While B C s = (if B s then While B C (C s) else s)"
  2843 where the well-founded relation can be chosen after B and C have been given.
  2844 
  2845 * HOL/List: the constructors of type list are now Nil and Cons;
  2846 INCOMPATIBILITY: while [] and infix # syntax is still there, of
  2847 course, ML tools referring to List.list.op # etc. have to be adapted;
  2848 
  2849 * HOL_quantifiers flag superseded by "HOL" print mode, which is
  2850 disabled by default; run isabelle with option -m HOL to get back to
  2851 the original Gordon/HOL-style output;
  2852 
  2853 * HOL/Ord.thy: new bounded quantifier syntax (input only): ALL x<y. P,
  2854 ALL x<=y. P, EX x<y. P, EX x<=y. P;
  2855 
  2856 * HOL basic syntax simplified (more orthogonal): all variants of
  2857 All/Ex now support plain / symbolic / HOL notation; plain syntax for
  2858 Eps operator is provided as well: "SOME x. P[x]";
  2859 
  2860 * HOL/Sum.thy: sum_case has been moved to HOL/Datatype;
  2861 
  2862 * HOL/Univ.thy: infix syntax <*>, <+>, <**>, <+> eliminated and made
  2863 thus available for user theories;
  2864 
  2865 * HOLCF/IOA/Sequents: renamed 'Cons' to 'Consq' to avoid clash with
  2866 HOL/List; hardly an INCOMPATIBILITY since '>>' syntax is used all the
  2867 time;
  2868 
  2869 * HOL: new tactic smp_tac: int -> int -> tactic, which applies spec
  2870 several times and then mp;
  2871 
  2872 
  2873 *** LK ***
  2874 
  2875 * the notation <<...>> is now available as a notation for sequences of
  2876 formulas;
  2877 
  2878 * the simplifier is now installed
  2879 
  2880 * the axiom system has been generalized (thanks to Soren Heilmann)
  2881 
  2882 * the classical reasoner now has a default rule database
  2883 
  2884 
  2885 *** ZF ***
  2886 
  2887 * new primrec section allows primitive recursive functions to be given
  2888 directly (as in HOL) over datatypes and the natural numbers;
  2889 
  2890 * new tactics induct_tac and exhaust_tac for induction (or case
  2891 analysis) over datatypes and the natural numbers;
  2892 
  2893 * the datatype declaration of type T now defines the recursor T_rec;
  2894 
  2895 * simplification automatically does freeness reasoning for datatype
  2896 constructors;
  2897 
  2898 * automatic type-inference, with AddTCs command to insert new
  2899 type-checking rules;
  2900 
  2901 * datatype introduction rules are now added as Safe Introduction rules
  2902 to the claset;
  2903 
  2904 * the syntax "if P then x else y" is now available in addition to
  2905 if(P,x,y);
  2906 
  2907 
  2908 *** Internal programming interfaces ***
  2909 
  2910 * tuned simplifier trace output; new flag debug_simp;
  2911 
  2912 * structures Vartab / Termtab (instances of TableFun) offer efficient
  2913 tables indexed by indexname_ord / term_ord (compatible with aconv);
  2914 
  2915 * AxClass.axclass_tac lost the theory argument;
  2916 
  2917 * tuned current_goals_markers semantics: begin / end goal avoids
  2918 printing empty lines;
  2919 
  2920 * removed prs and prs_fn hook, which was broken because it did not
  2921 include \n in its semantics, forcing writeln to add one
  2922 uncoditionally; replaced prs_fn by writeln_fn; consider std_output:
  2923 string -> unit if you really want to output text without newline;
  2924 
  2925 * Symbol.output subject to print mode; INCOMPATIBILITY: defaults to
  2926 plain output, interface builders may have to enable 'isabelle_font'
  2927 mode to get Isabelle font glyphs as before;
  2928 
  2929 * refined token_translation interface; INCOMPATIBILITY: output length
  2930 now of type real instead of int;
  2931 
  2932 * theory loader actions may be traced via new ThyInfo.add_hook
  2933 interface (see src/Pure/Thy/thy_info.ML); example application: keep
  2934 your own database of information attached to *whole* theories -- as
  2935 opposed to intra-theory data slots offered via TheoryDataFun;
  2936 
  2937 * proper handling of dangling sort hypotheses (at last!);
  2938 Thm.strip_shyps and Drule.strip_shyps_warning take care of removing
  2939 extra sort hypotheses that can be witnessed from the type signature;
  2940 the force_strip_shyps flag is gone, any remaining shyps are simply
  2941 left in the theorem (with a warning issued by strip_shyps_warning);
  2942 
  2943 
  2944 
  2945 New in Isabelle98-1 (October 1998)
  2946 ----------------------------------
  2947 
  2948 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  2949 
  2950 * several changes of automated proof tools;
  2951 
  2952 * HOL: major changes to the inductive and datatype packages, including
  2953 some minor incompatibilities of theory syntax;
  2954 
  2955 * HOL: renamed r^-1 to 'converse' from 'inverse'; 'inj_onto' is now
  2956 called `inj_on';
  2957 
  2958 * HOL: removed duplicate thms in Arith:
  2959   less_imp_add_less  should be replaced by  trans_less_add1
  2960   le_imp_add_le      should be replaced by  trans_le_add1
  2961 
  2962 * HOL: unary minus is now overloaded (new type constraints may be
  2963 required);
  2964 
  2965 * HOL and ZF: unary minus for integers is now #- instead of #~.  In
  2966 ZF, expressions such as n#-1 must be changed to n#- 1, since #-1 is
  2967 now taken as an integer constant.
  2968 
  2969 * Pure: ML function 'theory_of' renamed to 'theory';
  2970 
  2971 
  2972 *** Proof tools ***
  2973 
  2974 * Simplifier:
  2975   1. Asm_full_simp_tac is now more aggressive.
  2976      1. It will sometimes reorient premises if that increases their power to
  2977         simplify.
  2978      2. It does no longer proceed strictly from left to right but may also
  2979         rotate premises to achieve further simplification.
  2980      For compatibility reasons there is now Asm_lr_simp_tac which is like the
  2981      old Asm_full_simp_tac in that it does not rotate premises.
  2982   2. The simplifier now knows a little bit about nat-arithmetic.
  2983 
  2984 * Classical reasoner: wrapper mechanism for the classical reasoner now
  2985 allows for selected deletion of wrappers, by introduction of names for
  2986 wrapper functionals.  This implies that addbefore, addSbefore,
  2987 addaltern, and addSaltern now take a pair (name, tactic) as argument,
  2988 and that adding two tactics with the same name overwrites the first
  2989 one (emitting a warning).
  2990   type wrapper = (int -> tactic) -> (int -> tactic)
  2991   setWrapper, setSWrapper, compWrapper and compSWrapper are replaced by
  2992   addWrapper, addSWrapper: claset * (string * wrapper) -> claset
  2993   delWrapper, delSWrapper: claset *  string            -> claset
  2994   getWrapper is renamed to appWrappers, getSWrapper to appSWrappers;
  2995 
  2996 * Classical reasoner: addbefore/addSbefore now have APPEND/ORELSE
  2997 semantics; addbefore now affects only the unsafe part of step_tac
  2998 etc.; this affects addss/auto_tac/force_tac, so EXISTING PROOFS MAY
  2999 FAIL, but proofs should be fixable easily, e.g. by replacing Auto_tac
  3000 by Force_tac;
  3001 
  3002 * Classical reasoner: setwrapper to setWrapper and compwrapper to
  3003 compWrapper; added safe wrapper (and access functions for it);
  3004 
  3005 * HOL/split_all_tac is now much faster and fails if there is nothing
  3006 to split.  Some EXISTING PROOFS MAY REQUIRE ADAPTION because the order
  3007 and the names of the automatically generated variables have changed.
  3008 split_all_tac has moved within claset() from unsafe wrappers to safe
  3009 wrappers, which means that !!-bound variables are split much more
  3010 aggressively, and safe_tac and clarify_tac now split such variables.
  3011 If this splitting is not appropriate, use delSWrapper "split_all_tac".
  3012 Note: the same holds for record_split_tac, which does the job of
  3013 split_all_tac for record fields.
  3014 
  3015 * HOL/Simplifier: Rewrite rules for case distinctions can now be added
  3016 permanently to the default simpset using Addsplits just like
  3017 Addsimps. They can be removed via Delsplits just like
  3018 Delsimps. Lower-case versions are also available.
  3019 
  3020 * HOL/Simplifier: The rule split_if is now part of the default
  3021 simpset. This means that the simplifier will eliminate all occurrences
  3022 of if-then-else in the conclusion of a goal. To prevent this, you can
  3023 either remove split_if completely from the default simpset by
  3024 `Delsplits [split_if]' or remove it in a specific call of the
  3025 simplifier using `... delsplits [split_if]'.  You can also add/delete
  3026 other case splitting rules to/from the default simpset: every datatype
  3027 generates suitable rules `split_t_case' and `split_t_case_asm' (where
  3028 t is the name of the datatype).
  3029 
  3030 * Classical reasoner / Simplifier combination: new force_tac (and
  3031 derivatives Force_tac, force) combines rewriting and classical
  3032 reasoning (and whatever other tools) similarly to auto_tac, but is
  3033 aimed to solve the given subgoal completely.
  3034 
  3035 
  3036 *** General ***
  3037 
  3038 * new top-level commands `Goal' and `Goalw' that improve upon `goal'
  3039 and `goalw': the theory is no longer needed as an explicit argument -
  3040 the current theory context is used; assumptions are no longer returned
  3041 at the ML-level unless one of them starts with ==> or !!; it is
  3042 recommended to convert to these new commands using isatool fixgoal
  3043 (backup your sources first!);
  3044 
  3045 * new top-level commands 'thm' and 'thms' for retrieving theorems from
  3046 the current theory context, and 'theory' to lookup stored theories;
  3047 
  3048 * new theory section 'locale' for declaring constants, assumptions and
  3049 definitions that have local scope;
  3050 
  3051 * new theory section 'nonterminals' for purely syntactic types;
  3052 
  3053 * new theory section 'setup' for generic ML setup functions
  3054 (e.g. package initialization);
  3055 
  3056 * the distribution now includes Isabelle icons: see
  3057 lib/logo/isabelle-{small,tiny}.xpm;
  3058 
  3059 * isatool install - install binaries with absolute references to
  3060 ISABELLE_HOME/bin;
  3061 
  3062 * isatool logo -- create instances of the Isabelle logo (as EPS);
  3063 
  3064 * print mode 'emacs' reserved for Isamode;
  3065 
  3066 * support multiple print (ast) translations per constant name;
  3067 
  3068 * theorems involving oracles are now printed with a suffixed [!];
  3069 
  3070 
  3071 *** HOL ***
  3072 
  3073 * there is now a tutorial on Isabelle/HOL (do 'isatool doc tutorial');
  3074 
  3075 * HOL/inductive package reorganized and improved: now supports mutual
  3076 definitions such as
  3077 
  3078   inductive EVEN ODD
  3079     intrs
  3080       null "0 : EVEN"
  3081       oddI "n : EVEN ==> Suc n : ODD"
  3082       evenI "n : ODD ==> Suc n : EVEN"
  3083 
  3084 new theorem list "elims" contains an elimination rule for each of the
  3085 recursive sets; inductive definitions now handle disjunctive premises
  3086 correctly (also ZF);
  3087 
  3088 INCOMPATIBILITIES: requires Inductive as an ancestor; component
  3089 "mutual_induct" no longer exists - the induction rule is always
  3090 contained in "induct";
  3091 
  3092 
  3093 * HOL/datatype package re-implemented and greatly improved: now
  3094 supports mutually recursive datatypes such as
  3095 
  3096   datatype
  3097     'a aexp = IF_THEN_ELSE ('a bexp) ('a aexp) ('a aexp)
  3098             | SUM ('a aexp) ('a aexp)
  3099             | DIFF ('a aexp) ('a aexp)
  3100             | NUM 'a
  3101   and
  3102     'a bexp = LESS ('a aexp) ('a aexp)
  3103             | AND ('a bexp) ('a bexp)
  3104             | OR ('a bexp) ('a bexp)
  3105 
  3106 as well as indirectly recursive datatypes such as
  3107 
  3108   datatype
  3109     ('a, 'b) term = Var 'a
  3110                   | App 'b ((('a, 'b) term) list)
  3111 
  3112 The new tactic  mutual_induct_tac [<var_1>, ..., <var_n>] i  performs
  3113 induction on mutually / indirectly recursive datatypes.
  3114 
  3115 Primrec equations are now stored in theory and can be accessed via
  3116 <function_name>.simps.
  3117 
  3118 INCOMPATIBILITIES:
  3119 
  3120   - Theories using datatypes must now have theory Datatype as an
  3121     ancestor.
  3122   - The specific <typename>.induct_tac no longer exists - use the
  3123     generic induct_tac instead.
  3124   - natE has been renamed to nat.exhaust - use exhaust_tac
  3125     instead of res_inst_tac ... natE. Note that the variable
  3126     names in nat.exhaust differ from the names in natE, this
  3127     may cause some "fragile" proofs to fail.
  3128   - The theorems split_<typename>_case and split_<typename>_case_asm
  3129     have been renamed to <typename>.split and <typename>.split_asm.
  3130   - Since default sorts of type variables are now handled correctly,
  3131     some datatype definitions may have to be annotated with explicit
  3132     sort constraints.
  3133   - Primrec definitions no longer require function name and type
  3134     of recursive argument.
  3135 
  3136 Consider using isatool fixdatatype to adapt your theories and proof
  3137 scripts to the new package (backup your sources first!).
  3138 
  3139 
  3140 * HOL/record package: considerably improved implementation; now
  3141 includes concrete syntax for record types, terms, updates; theorems
  3142 for surjective pairing and splitting !!-bound record variables; proof
  3143 support is as follows:
  3144 
  3145   1) standard conversions (selectors or updates applied to record
  3146 constructor terms) are part of the standard simpset;
  3147 
  3148   2) inject equations of the form ((x, y) = (x', y')) == x=x' & y=y' are
  3149 made part of standard simpset and claset via addIffs;
  3150 
  3151   3) a tactic for record field splitting (record_split_tac) is part of
  3152 the standard claset (addSWrapper);
  3153 
  3154 To get a better idea about these rules you may retrieve them via
  3155 something like 'thms "foo.simps"' or 'thms "foo.iffs"', where "foo" is
  3156 the name of your record type.
  3157 
  3158 The split tactic 3) conceptually simplifies by the following rule:
  3159 
  3160   "(!!x. PROP ?P x) == (!!a b. PROP ?P (a, b))"
  3161 
  3162 Thus any record variable that is bound by meta-all will automatically
  3163 blow up into some record constructor term, consequently the
  3164 simplifications of 1), 2) apply.  Thus force_tac, auto_tac etc. shall
  3165 solve record problems automatically.
  3166 
  3167 
  3168 * reorganized the main HOL image: HOL/Integ and String loaded by
  3169 default; theory Main includes everything;
  3170 
  3171 * automatic simplification of integer sums and comparisons, using cancellation;
  3172 
  3173 * added option_map_eq_Some and not_Some_eq to the default simpset and claset;
  3174 
  3175 * added disj_not1 = "(~P | Q) = (P --> Q)" to the default simpset;
  3176 
  3177 * many new identities for unions, intersections, set difference, etc.;
  3178 
  3179 * expand_if, expand_split, expand_sum_case and expand_nat_case are now
  3180 called split_if, split_split, split_sum_case and split_nat_case (to go
  3181 with add/delsplits);
  3182 
  3183 * HOL/Prod introduces simplification procedure unit_eq_proc rewriting
  3184 (?x::unit) = (); this is made part of the default simpset, which COULD
  3185 MAKE EXISTING PROOFS FAIL under rare circumstances (consider
  3186 'Delsimprocs [unit_eq_proc];' as last resort); also note that
  3187 unit_abs_eta_conv is added in order to counter the effect of
  3188 unit_eq_proc on (%u::unit. f u), replacing it by f rather than by
  3189 %u.f();
  3190 
  3191 * HOL/Fun INCOMPATIBILITY: `inj_onto' is now called `inj_on' (which
  3192 makes more sense);
  3193 
  3194 * HOL/Set INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
  3195   It and 'sym RS equals0D' are now in the default  claset, giving automatic
  3196   disjointness reasoning but breaking a few old proofs.
  3197 
  3198 * HOL/Relation INCOMPATIBILITY: renamed the relational operator r^-1
  3199 to 'converse' from 'inverse' (for compatibility with ZF and some
  3200 literature);
  3201 
  3202 * HOL/recdef can now declare non-recursive functions, with {} supplied as
  3203 the well-founded relation;
  3204 
  3205 * HOL/Set INCOMPATIBILITY: the complement of set A is now written -A instead of
  3206     Compl A.  The "Compl" syntax remains available as input syntax for this
  3207     release ONLY.
  3208 
  3209 * HOL/Update: new theory of function updates:
  3210     f(a:=b) == %x. if x=a then b else f x
  3211 may also be iterated as in f(a:=b,c:=d,...);
  3212 
  3213 * HOL/Vimage: new theory for inverse image of a function, syntax f-``B;
  3214 
  3215 * HOL/List:
  3216   - new function list_update written xs[i:=v] that updates the i-th
  3217     list position. May also be iterated as in xs[i:=a,j:=b,...].
  3218   - new function `upt' written [i..j(] which generates the list
  3219     [i,i+1,...,j-1], i.e. the upper bound is excluded. To include the upper
  3220     bound write [i..j], which is a shorthand for [i..j+1(].
  3221   - new lexicographic orderings and corresponding wellfoundedness theorems.
  3222 
  3223 * HOL/Arith:
  3224   - removed 'pred' (predecessor) function;
  3225   - generalized some theorems about n-1;
  3226   - many new laws about "div" and "mod";
  3227   - new laws about greatest common divisors (see theory ex/Primes);
  3228 
  3229 * HOL/Relation: renamed the relational operator r^-1 "converse"
  3230 instead of "inverse";
  3231 
  3232 * HOL/Induct/Multiset: a theory of multisets, including the wellfoundedness
  3233   of the multiset ordering;
  3234 
  3235 * directory HOL/Real: a construction of the reals using Dedekind cuts
  3236   (not included by default);
  3237 
  3238 * directory HOL/UNITY: Chandy and Misra's UNITY formalism;
  3239 
  3240 * directory HOL/Hoare: a new version of Hoare logic which permits many-sorted
  3241   programs, i.e. different program variables may have different types.
  3242 
  3243 * calling (stac rew i) now fails if "rew" has no effect on the goal
  3244   [previously, this check worked only if the rewrite rule was unconditional]
  3245   Now rew can involve either definitions or equalities (either == or =).
  3246 
  3247 
  3248 *** ZF ***
  3249 
  3250 * theory Main includes everything; INCOMPATIBILITY: theory ZF.thy contains
  3251   only the theorems proved on ZF.ML;
  3252 
  3253 * ZF INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
  3254   It and 'sym RS equals0D' are now in the default  claset, giving automatic
  3255   disjointness reasoning but breaking a few old proofs.
  3256 
  3257 * ZF/Update: new theory of function updates
  3258     with default rewrite rule  f(x:=y) ` z = if(z=x, y, f`z)
  3259   may also be iterated as in f(a:=b,c:=d,...);
  3260 
  3261 * in  let x=t in u(x), neither t nor u(x) has to be an FOL term.
  3262 
  3263 * calling (stac rew i) now fails if "rew" has no effect on the goal
  3264   [previously, this check worked only if the rewrite rule was unconditional]
  3265   Now rew can involve either definitions or equalities (either == or =).
  3266 
  3267 * case_tac provided for compatibility with HOL
  3268     (like the old excluded_middle_tac, but with subgoals swapped)
  3269 
  3270 
  3271 *** Internal programming interfaces ***
  3272 
  3273 * Pure: several new basic modules made available for general use, see
  3274 also src/Pure/README;
  3275 
  3276 * improved the theory data mechanism to support encapsulation (data
  3277 kind name replaced by private Object.kind, acting as authorization
  3278 key); new type-safe user interface via functor TheoryDataFun; generic
  3279 print_data function becomes basically useless;
  3280 
  3281 * removed global_names compatibility flag -- all theory declarations
  3282 are qualified by default;
  3283 
  3284 * module Pure/Syntax now offers quote / antiquote translation
  3285 functions (useful for Hoare logic etc. with implicit dependencies);
  3286 see HOL/ex/Antiquote for an example use;
  3287 
  3288 * Simplifier now offers conversions (asm_)(full_)rewrite: simpset ->
  3289 cterm -> thm;
  3290 
  3291 * new tactical CHANGED_GOAL for checking that a tactic modifies a
  3292 subgoal;
  3293 
  3294 * Display.print_goals function moved to Locale.print_goals;
  3295 
  3296 * standard print function for goals supports current_goals_markers
  3297 variable for marking begin of proof, end of proof, start of goal; the
  3298 default is ("", "", ""); setting current_goals_markers := ("<proof>",
  3299 "</proof>", "<goal>") causes SGML like tagged proof state printing,
  3300 for example;
  3301 
  3302 
  3303 
  3304 New in Isabelle98 (January 1998)
  3305 --------------------------------
  3306 
  3307 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  3308 
  3309 * changed lexical syntax of terms / types: dots made part of long
  3310 identifiers, e.g. "%x.x" no longer possible, should be "%x. x";
  3311 
  3312 * simpset (and claset) reference variable replaced by functions
  3313 simpset / simpset_ref;
  3314 
  3315 * no longer supports theory aliases (via merge) and non-trivial
  3316 implicit merge of thms' signatures;
  3317 
  3318 * most internal names of constants changed due to qualified names;
  3319 
  3320 * changed Pure/Sequence interface (see Pure/seq.ML);
  3321 
  3322 
  3323 *** General Changes ***
  3324 
  3325 * hierachically structured name spaces (for consts, types, axms, thms
  3326 etc.); new lexical class 'longid' (e.g. Foo.bar.x) may render much of
  3327 old input syntactically incorrect (e.g. "%x.x"); COMPATIBILITY:
  3328 isatool fixdots ensures space after dots (e.g. "%x. x"); set
  3329 long_names for fully qualified output names; NOTE: ML programs
  3330 (special tactics, packages etc.) referring to internal names may have
  3331 to be adapted to cope with fully qualified names; in case of severe
  3332 backward campatibility problems try setting 'global_names' at compile
  3333 time to have enrything declared within a flat name space; one may also
  3334 fine tune name declarations in theories via the 'global' and 'local'
  3335 section;
  3336 
  3337 * reimplemented the implicit simpset and claset using the new anytype
  3338 data filed in signatures; references simpset:simpset ref etc. are
  3339 replaced by functions simpset:unit->simpset and
  3340 simpset_ref:unit->simpset ref; COMPATIBILITY: use isatool fixclasimp
  3341 to patch your ML files accordingly;
  3342 
  3343 * HTML output now includes theory graph data for display with Java
  3344 applet or isatool browser; data generated automatically via isatool
  3345 usedir (see -i option, ISABELLE_USEDIR_OPTIONS);
  3346 
  3347 * defs may now be conditional; improved rewrite_goals_tac to handle
  3348 conditional equations;
  3349 
  3350 * defs now admits additional type arguments, using TYPE('a) syntax;
  3351 
  3352 * theory aliases via merge (e.g. M=A+B+C) no longer supported, always
  3353 creates a new theory node; implicit merge of thms' signatures is
  3354 restricted to 'trivial' ones; COMPATIBILITY: one may have to use
  3355 transfer:theory->thm->thm in (rare) cases;
  3356 
  3357 * improved handling of draft signatures / theories; draft thms (and
  3358 ctyps, cterms) are automatically promoted to real ones;
  3359 
  3360 * slightly changed interfaces for oracles: admit many per theory, named
  3361 (e.g. oracle foo = mlfun), additional name argument for invoke_oracle;
  3362 
  3363 * print_goals: optional output of const types (set show_consts and
  3364 show_types);
  3365 
  3366 * improved output of warnings (###) and errors (***);
  3367 
  3368 * subgoal_tac displays a warning if the new subgoal has type variables;
  3369 
  3370 * removed old README and Makefiles;
  3371 
  3372 * replaced print_goals_ref hook by print_current_goals_fn and result_error_fn;
  3373 
  3374 * removed obsolete init_pps and init_database;
  3375 
  3376 * deleted the obsolete tactical STATE, which was declared by
  3377     fun STATE tacfun st = tacfun st st;
  3378 
  3379 * cd and use now support path variables, e.g. $ISABELLE_HOME, or ~
  3380 (which abbreviates $HOME);
  3381 
  3382 * changed Pure/Sequence interface (see Pure/seq.ML); COMPATIBILITY:
  3383 use isatool fixseq to adapt your ML programs (this works for fully
  3384 qualified references to the Sequence structure only!);
  3385 
  3386 * use_thy no longer requires writable current directory; it always
  3387 reloads .ML *and* .thy file, if either one is out of date;
  3388 
  3389 
  3390 *** Classical Reasoner ***
  3391 
  3392 * Clarify_tac, clarify_tac, clarify_step_tac, Clarify_step_tac: new
  3393 tactics that use classical reasoning to simplify a subgoal without
  3394 splitting it into several subgoals;
  3395 
  3396 * Safe_tac: like safe_tac but uses the default claset;
  3397 
  3398 
  3399 *** Simplifier ***
  3400 
  3401 * added simplification meta rules:
  3402     (asm_)(full_)simplify: simpset -> thm -> thm;
  3403 
  3404 * simplifier.ML no longer part of Pure -- has to be loaded by object
  3405 logics (again);
  3406 
  3407 * added prems argument to simplification procedures;
  3408 
  3409 * HOL, FOL, ZF: added infix function `addsplits':
  3410   instead of `<simpset> setloop (split_tac <thms>)'
  3411   you can simply write `<simpset> addsplits <thms>'
  3412 
  3413 
  3414 *** Syntax ***
  3415 
  3416 * TYPE('a) syntax for type reflection terms;
  3417 
  3418 * no longer handles consts with name "" -- declare as 'syntax' instead;
  3419 
  3420 * pretty printer: changed order of mixfix annotation preference (again!);
  3421 
  3422 * Pure: fixed idt/idts vs. pttrn/pttrns syntactic categories;
  3423 
  3424 
  3425 *** HOL ***
  3426 
  3427 * HOL: there is a new splitter `split_asm_tac' that can be used e.g.
  3428   with `addloop' of the simplifier to faciliate case splitting in premises.
  3429 
  3430 * HOL/TLA: Stephan Merz's formalization of Lamport's Temporal Logic of Actions;
  3431 
  3432 * HOL/Auth: new protocol proofs including some for the Internet
  3433   protocol TLS;
  3434 
  3435 * HOL/Map: new theory of `maps' a la VDM;
  3436 
  3437 * HOL/simplifier: simplification procedures nat_cancel_sums for
  3438 cancelling out common nat summands from =, <, <= (in)equalities, or
  3439 differences; simplification procedures nat_cancel_factor for
  3440 cancelling common factor from =, <, <= (in)equalities over natural
  3441 sums; nat_cancel contains both kinds of procedures, it is installed by
  3442 default in Arith.thy -- this COULD MAKE EXISTING PROOFS FAIL;
  3443 
  3444 * HOL/simplifier: terms of the form
  3445   `? x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x)'  (or t=x)
  3446   are rewritten to
  3447   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t)',
  3448   and those of the form
  3449   `! x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x) --> R(x)'  (or t=x)
  3450   are rewritten to
  3451   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t) --> R(t)',
  3452 
  3453 * HOL/datatype
  3454   Each datatype `t' now comes with a theorem `split_t_case' of the form
  3455 
  3456   P(t_case f1 ... fn x) =
  3457      ( (!y1 ... ym1. x = C1 y1 ... ym1 --> P(f1 y1 ... ym1)) &
  3458         ...
  3459        (!y1 ... ymn. x = Cn y1 ... ymn --> P(f1 y1 ... ymn))
  3460      )
  3461 
  3462   and a theorem `split_t_case_asm' of the form
  3463 
  3464   P(t_case f1 ... fn x) =
  3465     ~( (? y1 ... ym1. x = C1 y1 ... ym1 & ~P(f1 y1 ... ym1)) |
  3466         ...
  3467        (? y1 ... ymn. x = Cn y1 ... ymn & ~P(f1 y1 ... ymn))
  3468      )
  3469   which can be added to a simpset via `addsplits'. The existing theorems
  3470   expand_list_case and expand_option_case have been renamed to
  3471   split_list_case and split_option_case.
  3472 
  3473 * HOL/Arithmetic:
  3474   - `pred n' is automatically converted to `n-1'.
  3475     Users are strongly encouraged not to use `pred' any longer,
  3476     because it will disappear altogether at some point.
  3477   - Users are strongly encouraged to write "0 < n" rather than
  3478     "n ~= 0". Theorems and proof tools have been modified towards this
  3479     `standard'.
  3480 
  3481 * HOL/Lists:
  3482   the function "set_of_list" has been renamed "set" (and its theorems too);
  3483   the function "nth" now takes its arguments in the reverse order and
  3484   has acquired the infix notation "!" as in "xs!n".
  3485 
  3486 * HOL/Set: UNIV is now a constant and is no longer translated to Compl{};
  3487 
  3488 * HOL/Set: The operator (UN x.B x) now abbreviates (UN x:UNIV. B x) and its
  3489   specialist theorems (like UN1_I) are gone.  Similarly for (INT x.B x);
  3490 
  3491 * HOL/record: extensible records with schematic structural subtyping
  3492 (single inheritance); EXPERIMENTAL version demonstrating the encoding,
  3493 still lacks various theorems and concrete record syntax;
  3494 
  3495 
  3496 *** HOLCF ***
  3497 
  3498 * removed "axioms" and "generated by" sections;
  3499 
  3500 * replaced "ops" section by extended "consts" section, which is capable of
  3501   handling the continuous function space "->" directly;
  3502 
  3503 * domain package:
  3504   . proves theorems immediately and stores them in the theory,
  3505   . creates hierachical name space,
  3506   . now uses normal mixfix annotations (instead of cinfix...),
  3507   . minor changes to some names and values (for consistency),
  3508   . e.g. cases -> casedist, dists_eq -> dist_eqs, [take_lemma] -> take_lemmas,
  3509   . separator between mutual domain defs: changed "," to "and",
  3510   . improved handling of sort constraints;  now they have to
  3511     appear on the left-hand side of the equations only;
  3512 
  3513 * fixed LAM <x,y,zs>.b syntax;
  3514 
  3515 * added extended adm_tac to simplifier in HOLCF -- can now discharge
  3516 adm (%x. P (t x)), where P is chainfinite and t continuous;
  3517 
  3518 
  3519 *** FOL and ZF ***
  3520 
  3521 * FOL: there is a new splitter `split_asm_tac' that can be used e.g.
  3522   with `addloop' of the simplifier to faciliate case splitting in premises.
  3523 
  3524 * qed_spec_mp, qed_goal_spec_mp, qed_goalw_spec_mp are available, as
  3525 in HOL, they strip ALL and --> from proved theorems;
  3526 
  3527 
  3528 
  3529 New in Isabelle94-8 (May 1997)
  3530 ------------------------------
  3531 
  3532 *** General Changes ***
  3533 
  3534 * new utilities to build / run / maintain Isabelle etc. (in parts
  3535 still somewhat experimental); old Makefiles etc. still functional;
  3536 
  3537 * new 'Isabelle System Manual';
  3538 
  3539 * INSTALL text, together with ./configure and ./build scripts;
  3540 
  3541 * reimplemented type inference for greater efficiency, better error
  3542 messages and clean internal interface;
  3543 
  3544 * prlim command for dealing with lots of subgoals (an easier way of
  3545 setting goals_limit);
  3546 
  3547 
  3548 *** Syntax ***
  3549 
  3550 * supports alternative (named) syntax tables (parser and pretty
  3551 printer); internal interface is provided by add_modesyntax(_i);
  3552 
  3553 * Pure, FOL, ZF, HOL, HOLCF now support symbolic input and output; to
  3554 be used in conjunction with the Isabelle symbol font; uses the
  3555 "symbols" syntax table;
  3556 
  3557 * added token_translation interface (may translate name tokens in
  3558 arbitrary ways, dependent on their type (free, bound, tfree, ...) and
  3559 the current print_mode); IMPORTANT: user print translation functions
  3560 are responsible for marking newly introduced bounds
  3561 (Syntax.mark_boundT);
  3562 
  3563 * token translations for modes "xterm" and "xterm_color" that display
  3564 names in bold, underline etc. or colors (which requires a color
  3565 version of xterm);
  3566 
  3567 * infixes may now be declared with names independent of their syntax;
  3568 
  3569 * added typed_print_translation (like print_translation, but may
  3570 access type of constant);
  3571 
  3572 
  3573 *** Classical Reasoner ***
  3574 
  3575 Blast_tac: a new tactic!  It is often more powerful than fast_tac, but has
  3576 some limitations.  Blast_tac...
  3577   + ignores addss, addbefore, addafter; this restriction is intrinsic
  3578   + ignores elimination rules that don't have the correct format
  3579         (the conclusion MUST be a formula variable)
  3580   + ignores types, which can make HOL proofs fail
  3581   + rules must not require higher-order unification, e.g. apply_type in ZF
  3582     [message "Function Var's argument not a bound variable" relates to this]
  3583   + its proof strategy is more general but can actually be slower
  3584 
  3585 * substitution with equality assumptions no longer permutes other
  3586 assumptions;
  3587 
  3588 * minor changes in semantics of addafter (now called addaltern); renamed
  3589 setwrapper to setWrapper and compwrapper to compWrapper; added safe wrapper
  3590 (and access functions for it);
  3591 
  3592 * improved combination of classical reasoner and simplifier:
  3593   + functions for handling clasimpsets
  3594   + improvement of addss: now the simplifier is called _after_ the
  3595     safe steps.
  3596   + safe variant of addss called addSss: uses safe simplifications
  3597     _during_ the safe steps. It is more complete as it allows multiple
  3598     instantiations of unknowns (e.g. with slow_tac).
  3599 
  3600 *** Simplifier ***
  3601 
  3602 * added interface for simplification procedures (functions that
  3603 produce *proven* rewrite rules on the fly, depending on current
  3604 redex);
  3605 
  3606 * ordering on terms as parameter (used for ordered rewriting);
  3607 
  3608 * new functions delcongs, deleqcongs, and Delcongs. richer rep_ss;
  3609 
  3610 * the solver is now split into a safe and an unsafe part.
  3611 This should be invisible for the normal user, except that the
  3612 functions setsolver and addsolver have been renamed to setSolver and
  3613 addSolver; added safe_asm_full_simp_tac;
  3614 
  3615 
  3616 *** HOL ***
  3617 
  3618 * a generic induction tactic `induct_tac' which works for all datatypes and
  3619 also for type `nat';
  3620 
  3621 * a generic case distinction tactic `exhaust_tac' which works for all
  3622 datatypes and also for type `nat';
  3623 
  3624 * each datatype comes with a function `size';
  3625 
  3626 * patterns in case expressions allow tuple patterns as arguments to
  3627 constructors, for example `case x of [] => ... | (x,y,z)#ps => ...';
  3628 
  3629 * primrec now also works with type nat;
  3630 
  3631 * recdef: a new declaration form, allows general recursive functions to be
  3632 defined in theory files.  See HOL/ex/Fib, HOL/ex/Primes, HOL/Subst/Unify.
  3633 
  3634 * the constant for negation has been renamed from "not" to "Not" to
  3635 harmonize with FOL, ZF, LK, etc.;
  3636 
  3637 * HOL/ex/LFilter theory of a corecursive "filter" functional for
  3638 infinite lists;
  3639 
  3640 * HOL/Modelcheck demonstrates invocation of model checker oracle;
  3641 
  3642 * HOL/ex/Ring.thy declares cring_simp, which solves equational
  3643 problems in commutative rings, using axiomatic type classes for + and *;
  3644 
  3645 * more examples in HOL/MiniML and HOL/Auth;
  3646 
  3647 * more default rewrite rules for quantifiers, union/intersection;
  3648 
  3649 * a new constant `arbitrary == @x.False';
  3650 
  3651 * HOLCF/IOA replaces old HOL/IOA;
  3652 
  3653 * HOLCF changes: derived all rules and arities
  3654   + axiomatic type classes instead of classes
  3655   + typedef instead of faking type definitions
  3656   + eliminated the internal constants less_fun, less_cfun, UU_fun, UU_cfun etc.
  3657   + new axclasses cpo, chfin, flat with flat < chfin < pcpo < cpo < po
  3658   + eliminated the types void, one, tr
  3659   + use unit lift and bool lift (with translations) instead of one and tr
  3660   + eliminated blift from Lift3.thy (use Def instead of blift)
  3661   all eliminated rules are derived as theorems --> no visible changes ;
  3662 
  3663 
  3664 *** ZF ***
  3665 
  3666 * ZF now has Fast_tac, Simp_tac and Auto_tac.  Union_iff is a now a default
  3667 rewrite rule; this may affect some proofs.  eq_cs is gone but can be put back
  3668 as ZF_cs addSIs [equalityI];
  3669 
  3670 
  3671 
  3672 New in Isabelle94-7 (November 96)
  3673 ---------------------------------
  3674 
  3675 * allowing negative levels (as offsets) in prlev and choplev;
  3676 
  3677 * super-linear speedup for large simplifications;
  3678 
  3679 * FOL, ZF and HOL now use miniscoping: rewriting pushes
  3680 quantifications in as far as possible (COULD MAKE EXISTING PROOFS
  3681 FAIL); can suppress it using the command Delsimps (ex_simps @
  3682 all_simps); De Morgan laws are also now included, by default;
  3683 
  3684 * improved printing of ==>  :  ~:
  3685 
  3686 * new object-logic "Sequents" adds linear logic, while replacing LK
  3687 and Modal (thanks to Sara Kalvala);
  3688 
  3689 * HOL/Auth: correctness proofs for authentication protocols;
  3690 
  3691 * HOL: new auto_tac combines rewriting and classical reasoning (many
  3692 examples on HOL/Auth);
  3693 
  3694 * HOL: new command AddIffs for declaring theorems of the form P=Q to
  3695 the rewriter and classical reasoner simultaneously;
  3696 
  3697 * function uresult no longer returns theorems in "standard" format;
  3698 regain previous version by: val uresult = standard o uresult;
  3699 
  3700 
  3701 
  3702 New in Isabelle94-6
  3703 -------------------
  3704 
  3705 * oracles -- these establish an interface between Isabelle and trusted
  3706 external reasoners, which may deliver results as theorems;
  3707 
  3708 * proof objects (in particular record all uses of oracles);
  3709 
  3710 * Simp_tac, Fast_tac, etc. that refer to implicit simpset / claset;
  3711 
  3712 * "constdefs" section in theory files;
  3713 
  3714 * "primrec" section (HOL) no longer requires names;
  3715 
  3716 * internal type "tactic" now simply "thm -> thm Sequence.seq";
  3717 
  3718 
  3719 
  3720 New in Isabelle94-5
  3721 -------------------
  3722 
  3723 * reduced space requirements;
  3724 
  3725 * automatic HTML generation from theories;
  3726 
  3727 * theory files no longer require "..." (quotes) around most types;
  3728 
  3729 * new examples, including two proofs of the Church-Rosser theorem;
  3730 
  3731 * non-curried (1994) version of HOL is no longer distributed;
  3732 
  3733 
  3734 
  3735 New in Isabelle94-4
  3736 -------------------
  3737 
  3738 * greatly reduced space requirements;
  3739 
  3740 * theory files (.thy) no longer require \...\ escapes at line breaks;
  3741 
  3742 * searchable theorem database (see the section "Retrieving theorems" on
  3743 page 8 of the Reference Manual);
  3744 
  3745 * new examples, including Grabczewski's monumental case study of the
  3746 Axiom of Choice;
  3747 
  3748 * The previous version of HOL renamed to Old_HOL;
  3749 
  3750 * The new version of HOL (previously called CHOL) uses a curried syntax
  3751 for functions.  Application looks like f a b instead of f(a,b);
  3752 
  3753 * Mutually recursive inductive definitions finally work in HOL;
  3754 
  3755 * In ZF, pattern-matching on tuples is now available in all abstractions and
  3756 translates to the operator "split";
  3757 
  3758 
  3759 
  3760 New in Isabelle94-3
  3761 -------------------
  3762 
  3763 * new infix operator, addss, allowing the classical reasoner to
  3764 perform simplification at each step of its search.  Example:
  3765         fast_tac (cs addss ss)
  3766 
  3767 * a new logic, CHOL, the same as HOL, but with a curried syntax
  3768 for functions.  Application looks like f a b instead of f(a,b).  Also pairs
  3769 look like (a,b) instead of <a,b>;
  3770 
  3771 * PLEASE NOTE: CHOL will eventually replace HOL!
  3772 
  3773 * In CHOL, pattern-matching on tuples is now available in all abstractions.
  3774 It translates to the operator "split".  A new theory of integers is available;
  3775 
  3776 * In ZF, integer numerals now denote two's-complement binary integers.
  3777 Arithmetic operations can be performed by rewriting.  See ZF/ex/Bin.ML;
  3778 
  3779 * Many new examples: I/O automata, Church-Rosser theorem, equivalents
  3780 of the Axiom of Choice;
  3781 
  3782 
  3783 
  3784 New in Isabelle94-2
  3785 -------------------
  3786 
  3787 * Significantly faster resolution;
  3788 
  3789 * the different sections in a .thy file can now be mixed and repeated
  3790 freely;
  3791 
  3792 * Database of theorems for FOL, HOL and ZF.  New
  3793 commands including qed, qed_goal and bind_thm store theorems in the database.
  3794 
  3795 * Simple database queries: return a named theorem (get_thm) or all theorems of
  3796 a given theory (thms_of), or find out what theory a theorem was proved in
  3797 (theory_of_thm);
  3798 
  3799 * Bugs fixed in the inductive definition and datatype packages;
  3800 
  3801 * The classical reasoner provides deepen_tac and depth_tac, making FOL_dup_cs
  3802 and HOL_dup_cs obsolete;
  3803 
  3804 * Syntactic ambiguities caused by the new treatment of syntax in Isabelle94-1
  3805 have been removed;
  3806 
  3807 * Simpler definition of function space in ZF;
  3808 
  3809 * new results about cardinal and ordinal arithmetic in ZF;
  3810 
  3811 * 'subtype' facility in HOL for introducing new types as subsets of existing
  3812 types;
  3813 
  3814 
  3815 $Id$