NEWS
author haftmann
Sun May 06 21:50:17 2007 +0200 (2007-05-06)
changeset 22845 5f9138bcb3d7
parent 22826 0f4c501a691e
child 22848 f65a76867179
permissions -rw-r--r--
changed code generator invocation syntax
     1 Isabelle NEWS -- history user-relevant changes
     2 ==============================================
     3 
     4 New in this Isabelle version
     5 ----------------------------
     6 
     7 *** General ***
     8 
     9 * More uniform information about legacy features, notably a
    10 warning/error of "Legacy feature: ...", depending on the state of the
    11 tolerate_legacy_features flag (default true).
    12 
    13 * Theory syntax: the header format ``theory A = B + C:'' has been
    14 discontinued in favour of ``theory A imports B C begin''.  Use isatool
    15 fixheaders to convert existing theory files.  INCOMPATIBILITY.
    16 
    17 * Theory syntax: the old non-Isar theory file format has been
    18 discontinued altogether.  Note that ML proof scripts may still be used
    19 with Isar theories; migration is usually quite simple with the ML
    20 function use_legacy_bindings.  INCOMPATIBILITY.
    21 
    22 * Theory syntax: some popular names (e.g. "class", "fun", "help",
    23 "if") are now keywords.  INCOMPATIBILITY, use double quotes.
    24 
    25 * Legacy goal package: reduced interface to the bare minimum required
    26 to keep existing proof scripts running.  Most other user-level
    27 functions are now part of the OldGoals structure, which is *not* open
    28 by default (consider isatool expandshort before open OldGoals).
    29 Removed top_sg, prin, printyp, pprint_term/typ altogether, because
    30 these tend to cause confusion about the actual goal (!) context being
    31 used here, which is not necessarily the same as the_context().
    32 
    33 * Command 'find_theorems': support "*" wildcard in "name:" criterion.
    34 
    35 * The ``prems limit'' option (cf. ProofContext.prems_limit) is now -1
    36 by default, which means that "prems" (and also "fixed variables") are
    37 suppressed from proof state output.  Note that the ProofGeneral
    38 settings mechanism allows to change and save options persistently, but
    39 older versions of Isabelle will fail to start up if a negative prems
    40 limit is imposed.
    41 
    42 * Local theory targets may be specified by non-nested blocks of
    43 ``context/locale/class ... begin'' followed by ``end''.  The body may
    44 contain definitions, theorems etc., including any derived mechanism
    45 that has been implemented on top of these primitives.  This concept
    46 generalizes the existing ``theorem (in ...)'' towards more versatility
    47 and scalability.
    48 
    49 * Proof General interface: proper undo of final 'end' command;
    50 discontinued Isabelle/classic mode (ML proof scripts).
    51 
    52 
    53 *** Document preparation ***
    54 
    55 * Added antiquotation @{theory name} which prints the given name,
    56 after checking that it refers to a valid ancestor theory in the
    57 current context.
    58 
    59 * Added antiquotations @{ML_type text} and @{ML_struct text} which
    60 check the given source text as ML type/structure, printing verbatim.
    61 
    62 * Added antiquotation @{abbrev "c args"} which prints the abbreviation
    63 "c args == rhs" given in the current context.  (Any number of
    64 arguments may be given on the LHS.)
    65 
    66 
    67 
    68 *** Pure ***
    69 
    70 * code generator: 
    71   - Isar "definition"s and primitive instance definitions are added explicitly
    72     to the table of defining equations
    73   - primitive definitions are not used as defining equations by default any longer
    74   - defining equations are now definitly restricted to meta "==" and object
    75         equality "="
    76   - HOL theories have been adopted accordingly
    77 
    78 * class_package.ML offers a combination of axclasses and locales to
    79 achieve Haskell-like type classes in Isabelle. See
    80 HOL/ex/Classpackage.thy for examples.
    81 
    82 * Yet another code generator framework allows to generate executable
    83 code for ML and Haskell (including "class"es). A short usage sketch:
    84 
    85     internal compilation:
    86         code_gen <list of constants (term syntax)> (SML #)
    87     writing SML code to a file:
    88         code_gen <list of constants (term syntax)> (SML <filename>)
    89     writing OCaml code to a file:
    90         code_gen <list of constants (term syntax)> (OCaml <filename>)
    91     writing Haskell code to a bunch of files:
    92         code_gen <list of constants (term syntax)> (Haskell <filename>)
    93 
    94 Reasonable default setup of framework in HOL/Main.
    95 
    96 Theorem attributs for selecting and transforming function equations theorems:
    97 
    98     [code fun]:        select a theorem as function equation for a specific constant
    99     [code fun del]:    deselect a theorem as function equation for a specific constant
   100     [code inline]:     select an equation theorem for unfolding (inlining) in place
   101     [code inline del]: deselect an equation theorem for unfolding (inlining) in place
   102 
   103 User-defined serializations (target in {SML, OCaml, Haskell}):
   104 
   105     code_const <and-list of constants (term syntax)>
   106       {(target) <and-list of const target syntax>}+
   107 
   108     code_type <and-list of type constructors>
   109       {(target) <and-list of type target syntax>}+
   110 
   111     code_instance <and-list of instances>
   112       {(target)}+
   113         where instance ::= <type constructor> :: <class>
   114 
   115     code_class <and_list of classes>
   116       {(target) <and-list of class target syntax>}+
   117         where class target syntax ::= <class name> {where {<classop> == <target syntax>}+}?
   118 
   119 code_instance and code_class only apply to target Haskell.
   120 
   121 See HOL theories and HOL/ex/Codegenerator*.thy for usage examples.
   122 Doc/Isar/Advanced/Codegen/ provides a tutorial.
   123 
   124 * Command 'no_translations' removes translation rules from theory
   125 syntax.
   126 
   127 * Overloaded definitions are now actually checked for acyclic
   128 dependencies.  The overloading scheme is slightly more general than
   129 that of Haskell98, although Isabelle does not demand an exact
   130 correspondence to type class and instance declarations.
   131 INCOMPATIBILITY, use ``defs (unchecked overloaded)'' to admit more
   132 exotic versions of overloading -- at the discretion of the user!
   133 
   134 Polymorphic constants are represented via type arguments, i.e. the
   135 instantiation that matches an instance against the most general
   136 declaration given in the signature.  For example, with the declaration
   137 c :: 'a => 'a => 'a, an instance c :: nat => nat => nat is represented
   138 as c(nat).  Overloading is essentially simultaneous structural
   139 recursion over such type arguments.  Incomplete specification patterns
   140 impose global constraints on all occurrences, e.g. c('a * 'a) on the
   141 LHS means that more general c('a * 'b) will be disallowed on any RHS.
   142 Command 'print_theory' outputs the normalized system of recursive
   143 equations, see section "definitions".
   144 
   145 * Isar: improper proof element 'guess' is like 'obtain', but derives
   146 the obtained context from the course of reasoning!  For example:
   147 
   148   assume "EX x y. A x & B y"   -- "any previous fact"
   149   then guess x and y by clarify
   150 
   151 This technique is potentially adventurous, depending on the facts and
   152 proof tools being involved here.
   153 
   154 * Isar: known facts from the proof context may be specified as literal
   155 propositions, using ASCII back-quote syntax.  This works wherever
   156 named facts used to be allowed so far, in proof commands, proof
   157 methods, attributes etc.  Literal facts are retrieved from the context
   158 according to unification of type and term parameters.  For example,
   159 provided that "A" and "A ==> B" and "!!x. P x ==> Q x" are known
   160 theorems in the current context, then these are valid literal facts:
   161 `A` and `A ==> B` and `!!x. P x ==> Q x" as well as `P a ==> Q a` etc.
   162 
   163 There is also a proof method "fact" which does the same composition
   164 for explicit goal states, e.g. the following proof texts coincide with
   165 certain special cases of literal facts:
   166 
   167   have "A" by fact                 ==  note `A`
   168   have "A ==> B" by fact           ==  note `A ==> B`
   169   have "!!x. P x ==> Q x" by fact  ==  note `!!x. P x ==> Q x`
   170   have "P a ==> Q a" by fact       ==  note `P a ==> Q a`
   171 
   172 * Isar: ":" (colon) is no longer a symbolic identifier character in
   173 outer syntax.  Thus symbolic identifiers may be used without
   174 additional white space in declarations like this: ``assume *: A''.
   175 
   176 * Isar: 'print_facts' prints all local facts of the current context,
   177 both named and unnamed ones.
   178 
   179 * Isar: 'def' now admits simultaneous definitions, e.g.:
   180 
   181   def x == "t" and y == "u"
   182 
   183 * Isar: added command 'unfolding', which is structurally similar to
   184 'using', but affects both the goal state and facts by unfolding given
   185 rewrite rules.  Thus many occurrences of the 'unfold' method or
   186 'unfolded' attribute may be replaced by first-class proof text.
   187 
   188 * Isar: methods 'unfold' / 'fold', attributes 'unfolded' / 'folded',
   189 and command 'unfolding' now all support object-level equalities
   190 (potentially conditional).  The underlying notion of rewrite rule is
   191 analogous to the 'rule_format' attribute, but *not* that of the
   192 Simplifier (which is usually more generous).
   193 
   194 * Isar: the goal restriction operator [N] (default N = 1) evaluates a
   195 method expression within a sandbox consisting of the first N
   196 sub-goals, which need to exist.  For example, ``simp_all [3]''
   197 simplifies the first three sub-goals, while (rule foo, simp_all)[]
   198 simplifies all new goals that emerge from applying rule foo to the
   199 originally first one.
   200 
   201 * Isar: schematic goals are no longer restricted to higher-order
   202 patterns; e.g. ``lemma "?P(?x)" by (rule TrueI)'' now works as
   203 expected.
   204 
   205 * Isar: the conclusion of a long theorem statement is now either
   206 'shows' (a simultaneous conjunction, as before), or 'obtains'
   207 (essentially a disjunction of cases with local parameters and
   208 assumptions).  The latter allows to express general elimination rules
   209 adequately; in this notation common elimination rules look like this:
   210 
   211   lemma exE:    -- "EX x. P x ==> (!!x. P x ==> thesis) ==> thesis"
   212     assumes "EX x. P x"
   213     obtains x where "P x"
   214 
   215   lemma conjE:  -- "A & B ==> (A ==> B ==> thesis) ==> thesis"
   216     assumes "A & B"
   217     obtains A and B
   218 
   219   lemma disjE:  -- "A | B ==> (A ==> thesis) ==> (B ==> thesis) ==> thesis"
   220     assumes "A | B"
   221     obtains
   222       A
   223     | B
   224 
   225 The subsequent classical rules even refer to the formal "thesis"
   226 explicitly:
   227 
   228   lemma classical:     -- "(~ thesis ==> thesis) ==> thesis"
   229     obtains "~ thesis"
   230 
   231   lemma Peirce's_Law:  -- "((thesis ==> something) ==> thesis) ==> thesis"
   232     obtains "thesis ==> something"
   233 
   234 The actual proof of an 'obtains' statement is analogous to that of the
   235 Isar proof element 'obtain', only that there may be several cases.
   236 Optional case names may be specified in parentheses; these will be
   237 available both in the present proof and as annotations in the
   238 resulting rule, for later use with the 'cases' method (cf. attribute
   239 case_names).
   240 
   241 * Isar: the assumptions of a long theorem statement are available as
   242 "assms" fact in the proof context.  This is more appropriate than the
   243 (historical) "prems", which refers to all assumptions of the current
   244 context, including those from the target locale, proof body etc.
   245 
   246 * Isar: 'print_statement' prints theorems from the current theory or
   247 proof context in long statement form, according to the syntax of a
   248 top-level lemma.
   249 
   250 * Isar: 'obtain' takes an optional case name for the local context
   251 introduction rule (default "that").
   252 
   253 * Isar: removed obsolete 'concl is' patterns.  INCOMPATIBILITY, use
   254 explicit (is "_ ==> ?foo") in the rare cases where this still happens
   255 to occur.
   256 
   257 * Pure: syntax "CONST name" produces a fully internalized constant
   258 according to the current context.  This is particularly useful for
   259 syntax translations that should refer to internal constant
   260 representations independently of name spaces.
   261 
   262 * Pure: syntax constant for foo (binder "FOO ") is called "foo_binder"
   263 instead of "FOO ". This allows multiple binder declarations to coexist
   264 in the same context.  INCOMPATIBILITY.
   265 
   266 * Isar/locales: 'notation' provides a robust interface to the 'syntax'
   267 primitive that also works in a locale context (both for constants and
   268 fixed variables).  Type declaration and internal syntactic
   269 representation of given constants retrieved from the context.
   270 
   271 * Isar/locales: new derived specification elements 'axiomatization',
   272 'definition', 'abbreviation', which support type-inference, admit
   273 object-level specifications (equality, equivalence).  See also the
   274 isar-ref manual.  Examples:
   275 
   276   axiomatization
   277     eq  (infix "===" 50) where
   278     eq_refl: "x === x" and eq_subst: "x === y ==> P x ==> P y"
   279 
   280   definition "f x y = x + y + 1"
   281   definition g where "g x = f x x"
   282 
   283   abbreviation
   284     neq  (infix "=!=" 50) where
   285     "x =!= y == ~ (x === y)"
   286 
   287 These specifications may be also used in a locale context.  Then the
   288 constants being introduced depend on certain fixed parameters, and the
   289 constant name is qualified by the locale base name.  An internal
   290 abbreviation takes care for convenient input and output, making the
   291 parameters implicit and using the original short name.  See also
   292 HOL/ex/Abstract_NAT.thy for an example of deriving polymorphic
   293 entities from a monomorphic theory.
   294 
   295 Presently, abbreviations are only available 'in' a target locale, but
   296 not inherited by general import expressions.  Also note that
   297 'abbreviation' may be used as a type-safe replacement for 'syntax' +
   298 'translations' in common applications.
   299 
   300 Concrete syntax is attached to specified constants in internal form,
   301 independently of name spaces.  The parse tree representation is
   302 slightly different -- use 'notation' instead of raw 'syntax', and
   303 'translations' with explicit "CONST" markup to accommodate this.
   304 
   305 * Pure: command 'print_abbrevs' prints all constant abbreviations of
   306 the current context.  Print mode "no_abbrevs" prevents inversion of
   307 abbreviations on output.
   308 
   309 * Isar/locales: improved parameter handling:
   310 - use of locales "var" and "struct" no longer necessary;
   311 - parameter renamings are no longer required to be injective.
   312   This enables, for example, to define a locale for endomorphisms thus:
   313   locale endom = homom mult mult h.
   314 
   315 * Isar/locales: changed the way locales with predicates are defined.
   316 Instead of accumulating the specification, the imported expression is
   317 now an interpretation.  INCOMPATIBILITY: different normal form of
   318 locale expressions.  In particular, in interpretations of locales with
   319 predicates, goals repesenting already interpreted fragments are not
   320 removed automatically.  Use methods `intro_locales' and
   321 `unfold_locales'; see below.
   322 
   323 * Isar/locales: new methods `intro_locales' and `unfold_locales'
   324 provide backward reasoning on locales predicates.  The methods are
   325 aware of interpretations and discharge corresponding goals.
   326 `intro_locales' is less aggressive then `unfold_locales' and does not
   327 unfold predicates to assumptions.
   328 
   329 * Isar/locales: the order in which locale fragments are accumulated
   330 has changed.  This enables to override declarations from fragments due
   331 to interpretations -- for example, unwanted simp rules.
   332 
   333 * Provers/induct: improved internal context management to support
   334 local fixes and defines on-the-fly.  Thus explicit meta-level
   335 connectives !! and ==> are rarely required anymore in inductive goals
   336 (using object-logic connectives for this purpose has been long
   337 obsolete anyway).  The subsequent proof patterns illustrate advanced
   338 techniques of natural induction; general datatypes and inductive sets
   339 work analogously (see also src/HOL/Lambda for realistic examples).
   340 
   341 (1) This is how to ``strengthen'' an inductive goal wrt. certain
   342 parameters:
   343 
   344   lemma
   345     fixes n :: nat and x :: 'a
   346     assumes a: "A n x"
   347     shows "P n x"
   348     using a                     -- {* make induct insert fact a *}
   349   proof (induct n arbitrary: x) -- {* generalize goal to "!!x. A n x ==> P n x" *}
   350     case 0
   351     show ?case sorry
   352   next
   353     case (Suc n)
   354     note `!!x. A n x ==> P n x` -- {* induction hypothesis, according to induction rule *}
   355     note `A (Suc n) x`          -- {* induction premise, stemming from fact a *}
   356     show ?case sorry
   357   qed
   358 
   359 (2) This is how to perform induction over ``expressions of a certain
   360 form'', using a locally defined inductive parameter n == "a x"
   361 together with strengthening (the latter is usually required to get
   362 sufficiently flexible induction hypotheses):
   363 
   364   lemma
   365     fixes a :: "'a => nat"
   366     assumes a: "A (a x)"
   367     shows "P (a x)"
   368     using a
   369   proof (induct n == "a x" arbitrary: x)
   370     ...
   371 
   372 See also HOL/Isar_examples/Puzzle.thy for an application of the this
   373 particular technique.
   374 
   375 (3) This is how to perform existential reasoning ('obtains' or
   376 'obtain') by induction, while avoiding explicit object-logic
   377 encodings:
   378 
   379   lemma
   380     fixes n :: nat
   381     obtains x :: 'a where "P n x" and "Q n x"
   382   proof (induct n arbitrary: thesis)
   383     case 0
   384     obtain x where "P 0 x" and "Q 0 x" sorry
   385     then show thesis by (rule 0)
   386   next
   387     case (Suc n)
   388     obtain x where "P n x" and "Q n x" by (rule Suc.hyps)
   389     obtain x where "P (Suc n) x" and "Q (Suc n) x" sorry
   390     then show thesis by (rule Suc.prems)
   391   qed
   392 
   393 Here the 'arbitrary: thesis' specification essentially modifies the
   394 scope of the formal thesis parameter, in order to the get the whole
   395 existence statement through the induction as expected.
   396 
   397 * Provers/induct: mutual induction rules are now specified as a list
   398 of rule sharing the same induction cases.  HOL packages usually
   399 provide foo_bar.inducts for mutually defined items foo and bar
   400 (e.g. inductive sets or datatypes).  INCOMPATIBILITY, users need to
   401 specify mutual induction rules differently, i.e. like this:
   402 
   403   (induct rule: foo_bar.inducts)
   404   (induct set: foo bar)
   405   (induct type: foo bar)
   406 
   407 The ML function ProjectRule.projections turns old-style rules into the
   408 new format.
   409 
   410 * Provers/induct: improved handling of simultaneous goals.  Instead of
   411 introducing object-level conjunction, the statement is now split into
   412 several conclusions, while the corresponding symbolic cases are
   413 nested accordingly.  INCOMPATIBILITY, proofs need to be structured
   414 explicitly.  For example:
   415 
   416   lemma
   417     fixes n :: nat
   418     shows "P n" and "Q n"
   419   proof (induct n)
   420     case 0 case 1
   421     show "P 0" sorry
   422   next
   423     case 0 case 2
   424     show "Q 0" sorry
   425   next
   426     case (Suc n) case 1
   427     note `P n` and `Q n`
   428     show "P (Suc n)" sorry
   429   next
   430     case (Suc n) case 2
   431     note `P n` and `Q n`
   432     show "Q (Suc n)" sorry
   433   qed
   434 
   435 The split into subcases may be deferred as follows -- this is
   436 particularly relevant for goal statements with local premises.
   437 
   438   lemma
   439     fixes n :: nat
   440     shows "A n ==> P n" and "B n ==> Q n"
   441   proof (induct n)
   442     case 0
   443     {
   444       case 1
   445       note `A 0`
   446       show "P 0" sorry
   447     next
   448       case 2
   449       note `B 0`
   450       show "Q 0" sorry
   451     }
   452   next
   453     case (Suc n)
   454     note `A n ==> P n` and `B n ==> Q n`
   455     {
   456       case 1
   457       note `A (Suc n)`
   458       show "P (Suc n)" sorry
   459     next
   460       case 2
   461       note `B (Suc n)`
   462       show "Q (Suc n)" sorry
   463     }
   464   qed
   465 
   466 If simultaneous goals are to be used with mutual rules, the statement
   467 needs to be structured carefully as a two-level conjunction, using
   468 lists of propositions separated by 'and':
   469 
   470   lemma
   471     shows "a : A ==> P1 a"
   472           "a : A ==> P2 a"
   473       and "b : B ==> Q1 b"
   474           "b : B ==> Q2 b"
   475           "b : B ==> Q3 b"
   476   proof (induct set: A B)
   477 
   478 * Provers/induct: support coinduction as well.  See
   479 src/HOL/Library/Coinductive_List.thy for various examples.
   480 
   481 * Attribute "symmetric" produces result with standardized schematic
   482 variables (index 0).  Potential INCOMPATIBILITY.
   483 
   484 * Simplifier: by default the simplifier trace only shows top level
   485 rewrites now. That is, trace_simp_depth_limit is set to 1 by
   486 default. Thus there is less danger of being flooded by the trace. The
   487 trace indicates where parts have been suppressed.
   488   
   489 * Provers/classical: removed obsolete classical version of elim_format
   490 attribute; classical elim/dest rules are now treated uniformly when
   491 manipulating the claset.
   492 
   493 * Provers/classical: stricter checks to ensure that supplied intro,
   494 dest and elim rules are well-formed; dest and elim rules must have at
   495 least one premise.
   496 
   497 * Provers/classical: attributes dest/elim/intro take an optional
   498 weight argument for the rule (just as the Pure versions).  Weights are
   499 ignored by automated tools, but determine the search order of single
   500 rule steps.
   501 
   502 * Syntax: input syntax now supports dummy variable binding "%_. b",
   503 where the body does not mention the bound variable.  Note that dummy
   504 patterns implicitly depend on their context of bounds, which makes
   505 "{_. _}" match any set comprehension as expected.  Potential
   506 INCOMPATIBILITY -- parse translations need to cope with syntactic
   507 constant "_idtdummy" in the binding position.
   508 
   509 * Syntax: removed obsolete syntactic constant "_K" and its associated
   510 parse translation.  INCOMPATIBILITY -- use dummy abstraction instead,
   511 for example "A -> B" => "Pi A (%_. B)".
   512 
   513 * Pure: 'class_deps' command visualizes the subclass relation, using
   514 the graph browser tool.
   515 
   516 * Pure: 'print_theory' now suppresses entities with internal name
   517 (trailing "_") by default; use '!' option for full details.
   518 
   519 
   520 *** HOL ***
   521 
   522 * case expressions and primrec: missing cases now mapped to "undefined"
   523 instead of "arbitrary"
   524 
   525 * new constant "undefined" with axiom "undefined x = undefined"
   526 
   527 * new class "default" with associated constant "default"
   528 
   529 * Library/Pretty_Int.thy: maps HOL numerals on target language integer literals
   530     when generating code.
   531 
   532 * Library/Pretty_Char.thy: maps HOL characters on target language character literals
   533     when generating code.
   534 
   535 * Library/Commutative_Ring.thy: switched from recdef to function package;
   536     constants add, mul, pow now curried.  Infix syntax for algebraic operations.
   537 
   538 * Some steps towards more uniform lattice theory development in HOL.
   539 
   540     constants "meet" and "join" now named "inf" and "sup"
   541     constant "Meet" now named "Inf"
   542 
   543     classes "meet_semilorder" and "join_semilorder" now named
   544       "lower_semilattice" and "upper_semilattice"
   545     class "lorder" now named "lattice"
   546     class "comp_lat" now named "complete_lattice"
   547 
   548     Instantiation of lattice classes allows explicit definitions
   549     for "inf" and "sup" operations.
   550 
   551   INCOMPATIBILITY. Theorem renames:
   552 
   553     meet_left_le            ~> inf_le1
   554     meet_right_le           ~> inf_le2
   555     join_left_le            ~> sup_ge1
   556     join_right_le           ~> sup_ge2
   557     meet_join_le            ~> inf_sup_ord
   558     le_meetI                ~> le_infI
   559     join_leI                ~> le_supI
   560     le_meet                 ~> le_inf_iff
   561     le_join                 ~> ge_sup_conv
   562     meet_idempotent         ~> inf_idem
   563     join_idempotent         ~> sup_idem
   564     meet_comm               ~> inf_commute
   565     join_comm               ~> sup_commute
   566     meet_leI1               ~> le_infI1
   567     meet_leI2               ~> le_infI2
   568     le_joinI1               ~> le_supI1
   569     le_joinI2               ~> le_supI2
   570     meet_assoc              ~> inf_assoc
   571     join_assoc              ~> sup_assoc
   572     meet_left_comm          ~> inf_left_commute
   573     meet_left_idempotent    ~> inf_left_idem
   574     join_left_comm          ~> sup_left_commute
   575     join_left_idempotent    ~> sup_left_idem
   576     meet_aci                ~> inf_aci
   577     join_aci                ~> sup_aci
   578     le_def_meet             ~> le_iff_inf
   579     le_def_join             ~> le_iff_sup
   580     join_absorp2            ~> sup_absorb2
   581     join_absorp1            ~> sup_absorb1
   582     meet_absorp1            ~> inf_absorb1
   583     meet_absorp2            ~> inf_absorb2
   584     meet_join_absorp        ~> inf_sup_absorb
   585     join_meet_absorp        ~> sup_inf_absorb
   586     distrib_join_le         ~> distrib_sup_le
   587     distrib_meet_le         ~> distrib_inf_le
   588 
   589     add_meet_distrib_left   ~> add_inf_distrib_left
   590     add_join_distrib_left   ~> add_sup_distrib_left
   591     is_join_neg_meet        ~> is_join_neg_inf
   592     is_meet_neg_join        ~> is_meet_neg_sup
   593     add_meet_distrib_right  ~> add_inf_distrib_right
   594     add_join_distrib_right  ~> add_sup_distrib_right
   595     add_meet_join_distribs  ~> add_sup_inf_distribs
   596     join_eq_neg_meet        ~> sup_eq_neg_inf
   597     meet_eq_neg_join        ~> inf_eq_neg_sup
   598     add_eq_meet_join        ~> add_eq_inf_sup
   599     meet_0_imp_0            ~> inf_0_imp_0
   600     join_0_imp_0            ~> sup_0_imp_0
   601     meet_0_eq_0             ~> inf_0_eq_0
   602     join_0_eq_0             ~> sup_0_eq_0
   603     neg_meet_eq_join        ~> neg_inf_eq_sup
   604     neg_join_eq_meet        ~> neg_sup_eq_inf
   605     join_eq_if              ~> sup_eq_if
   606 
   607     mono_meet               ~> mono_inf
   608     mono_join               ~> mono_sup
   609     meet_bool_eq            ~> inf_bool_eq
   610     join_bool_eq            ~> sup_bool_eq
   611     meet_fun_eq             ~> inf_fun_eq
   612     join_fun_eq             ~> sup_fun_eq
   613     meet_set_eq             ~> inf_set_eq
   614     join_set_eq             ~> sup_set_eq
   615     meet1_iff               ~> inf1_iff
   616     meet2_iff               ~> inf2_iff
   617     meet1I                  ~> inf1I
   618     meet2I                  ~> inf2I
   619     meet1D1                 ~> inf1D1
   620     meet2D1                 ~> inf2D1
   621     meet1D2                 ~> inf1D2
   622     meet2D2                 ~> inf2D2
   623     meet1E                  ~> inf1E
   624     meet2E                  ~> inf2E
   625     join1_iff               ~> sup1_iff
   626     join2_iff               ~> sup2_iff
   627     join1I1                 ~> sup1I1
   628     join2I1                 ~> sup2I1
   629     join1I1                 ~> sup1I1
   630     join2I2                 ~> sup1I2
   631     join1CI                 ~> sup1CI
   632     join2CI                 ~> sup2CI
   633     join1E                  ~> sup1E
   634     join2E                  ~> sup2E
   635 
   636     is_meet_Meet            ~> is_meet_Inf
   637     Meet_bool_def           ~> Inf_bool_def
   638     Meet_fun_def            ~> Inf_fun_def
   639     Meet_greatest           ~> Inf_greatest
   640     Meet_lower              ~> Inf_lower
   641     Meet_set_def            ~> Inf_set_def
   642 
   643     listsp_meetI            ~> listsp_infI
   644     listsp_meet_eq          ~> listsp_inf_eq
   645 
   646     meet_min                ~> inf_min
   647     join_max                ~> sup_max
   648 
   649 * Classes "order" and "linorder": facts "refl", "trans" and
   650 "cases" renamed ro "order_refl", "order_trans" and "linorder_cases", to
   651 avoid clashes with HOL "refl" and "trans". INCOMPATIBILITY.
   652 
   653 * Classes "order" and "linorder": 
   654 potential INCOMPATIBILITY: order of proof goals in order/linorder instance
   655 proofs changed.
   656 
   657 * Dropped lemma duplicate def_imp_eq in favor of meta_eq_to_obj_eq.
   658 INCOMPATIBILITY.
   659 
   660 * Dropped lemma duplicate if_def2 in favor of if_bool_eq_conj.
   661 INCOMPATIBILITY.
   662 
   663 * Added syntactic class "size"; overloaded constant "size" now has
   664 type "'a::size ==> bool"
   665 
   666 * Renamed constants "Divides.op div", "Divides.op mod" and "Divides.op
   667 dvd" to "Divides.div", "Divides.mod" and "Divides.dvd". INCOMPATIBILITY.
   668 
   669 * Added method "lexicographic_order" automatically synthesizes
   670 termination relations as lexicographic combinations of size measures
   671 -- 'function' package.
   672 
   673 * HOL/records: generalised field-update to take a function on the
   674 field rather than the new value: r(|A := x|) is translated to A_update
   675 (K x) r The K-combinator that is internally used is called K_record.
   676 INCOMPATIBILITY: Usage of the plain update functions has to be
   677 adapted.
   678  
   679 * axclass "semiring_0" now contains annihilation axioms x * 0 = 0 and
   680 0 * x = 0, which are required for a semiring.  Richer structures do
   681 not inherit from semiring_0 anymore, because this property is a
   682 theorem there, not an axiom.  INCOMPATIBILITY: In instances of
   683 semiring_0, there is more to prove, but this is mostly trivial.
   684 
   685 * axclass "recpower" was generalized to arbitrary monoids, not just
   686 commutative semirings.  INCOMPATIBILITY: If you use recpower and need
   687 commutativity or a semiring property, add the corresponding classes.
   688 
   689 * Unified locale partial_order with class definition (cf. theory
   690 Orderings), added parameter ``less''.  INCOMPATIBILITY.
   691 
   692 * Constant "List.list_all2" in List.thy now uses authentic syntax.
   693 INCOMPATIBILITY: translations containing list_all2 may go wrong.  On
   694 Isar level, use abbreviations instead.
   695 
   696 * Renamed constant "List.op mem" to "List.memberl" INCOMPATIBILITY:
   697 rarely occuring name references (e.g. ``List.op mem.simps'') require
   698 renaming (e.g. ``List.memberl.simps'').
   699 
   700 * Renamed constants "0" to "HOL.zero" and "1" to "HOL.one".
   701 INCOMPATIBILITY.
   702 
   703 * Added theory Code_Generator providing class 'eq', allowing for code
   704 generation with polymorphic equality.
   705 
   706 * Numeral syntax: type 'bin' which was a mere type copy of 'int' has
   707 been abandoned in favour of plain 'int'. INCOMPATIBILITY --
   708 significant changes for setting up numeral syntax for types:
   709 
   710   - new constants Numeral.pred and Numeral.succ instead
   711       of former Numeral.bin_pred and Numeral.bin_succ.
   712   - Use integer operations instead of bin_add, bin_mult and so on.
   713   - Numeral simplification theorems named Numeral.numeral_simps instead of Bin_simps.
   714   - ML structure Bin_Simprocs now named Int_Numeral_Base_Simprocs.
   715 
   716 See HOL/Integ/IntArith.thy for an example setup.
   717 
   718 * New top level command 'normal_form' computes the normal form of a
   719 term that may contain free variables. For example ``normal_form
   720 "rev[a,b,c]"'' produces ``[b,c,a]'' (without proof).  This command is
   721 suitable for heavy-duty computations because the functions are
   722 compiled to ML first.
   723 
   724 * Alternative iff syntax "A <-> B" for equality on bool (with priority
   725 25 like -->); output depends on the "iff" print_mode, the default is
   726 "A = B" (with priority 50).
   727 
   728 * Renamed constants in HOL.thy and Orderings.thy:
   729     op +   ~> HOL.plus
   730     op -   ~> HOL.minus
   731     uminus ~> HOL.uminus
   732     op *   ~> HOL.times
   733     op <   ~> Orderings.less
   734     op <=  ~> Orderings.less_eq
   735 
   736 Adaptions may be required in the following cases:
   737 
   738 a) User-defined constants using any of the names "plus", "minus", "times",
   739 "less" or "less_eq". The standard syntax translations for "+", "-" and "*"
   740 may go wrong.
   741 INCOMPATIBILITY: use more specific names.
   742 
   743 b) Variables named "plus", "minus", "times", "less", "less_eq"
   744 INCOMPATIBILITY: use more specific names.
   745 
   746 c) Permutative equations (e.g. "a + b = b + a")
   747 Since the change of names also changes the order of terms, permutative
   748 rewrite rules may get applied in a different order. Experience shows that
   749 this is rarely the case (only two adaptions in the whole Isabelle
   750 distribution).
   751 INCOMPATIBILITY: rewrite proofs
   752 
   753 d) ML code directly refering to constant names
   754 This in general only affects hand-written proof tactics, simprocs and so on.
   755 INCOMPATIBILITY: grep your sourcecode and replace names.
   756 
   757 * Relations less (<) and less_eq (<=) are also available on type bool.
   758 Modified syntax to disallow nesting without explicit parentheses,
   759 e.g. "(x < y) < z" or "x < (y < z)", but NOT "x < y < z".
   760 
   761 * "LEAST x:A. P" expands to "LEAST x. x:A & P" (input only).
   762 
   763 * Relation composition operator "op O" now has precedence 75 and binds
   764 stronger than union and intersection. INCOMPATIBILITY.
   765 
   766 * The old set interval syntax "{m..n(}" (and relatives) has been
   767 removed.  Use "{m..<n}" (and relatives) instead.
   768 
   769 * In the context of the assumption "~(s = t)" the Simplifier rewrites
   770 "t = s" to False (by simproc "neq_simproc").  For backward
   771 compatibility this can be disabled by ML "reset use_neq_simproc".
   772 
   773 * "m dvd n" where m and n are numbers is evaluated to True/False by
   774 simp.
   775 
   776 * Theorem Cons_eq_map_conv no longer declared as ``simp''.
   777 
   778 * Theorem setsum_mult renamed to setsum_right_distrib.
   779 
   780 * Prefer ex1I over ex_ex1I in single-step reasoning, e.g. by the
   781 ``rule'' method.
   782 
   783 * Reimplemented methods ``sat'' and ``satx'', with several
   784 improvements: goals no longer need to be stated as "<prems> ==>
   785 False", equivalences (i.e. "=" on type bool) are handled, variable
   786 names of the form "lit_<n>" are no longer reserved, significant
   787 speedup.
   788 
   789 * Methods ``sat'' and ``satx'' can now replay MiniSat proof traces.
   790 zChaff is still supported as well.
   791 
   792 * 'inductive' and 'datatype': provide projections of mutual rules,
   793 bundled as foo_bar.inducts;
   794 
   795 * Library: moved theories Parity, GCD, Binomial, Infinite_Set to
   796 Library.
   797 
   798 * Library: moved theory Accessible_Part to main HOL.
   799 
   800 * Library: added theory Coinductive_List of potentially infinite lists
   801 as greatest fixed-point.
   802 
   803 * Library: added theory AssocList which implements (finite) maps as
   804 association lists.
   805 
   806 * Added proof method ``evaluation'' for efficiently solving a goal
   807 (i.e. a boolean expression) by compiling it to ML. The goal is
   808 "proved" (via an oracle) if it evaluates to True.
   809 
   810 * Linear arithmetic now splits certain operators (e.g. min, max, abs)
   811 also when invoked by the simplifier.  This results in the simplifier
   812 being more powerful on arithmetic goals.  INCOMPATIBILITY.  Set
   813 fast_arith_split_limit to 0 to obtain the old behavior.
   814 
   815 * Support for hex (0x20) and binary (0b1001) numerals.
   816 
   817 * New method: reify eqs (t), where eqs are equations for an
   818 interpretation I :: 'a list => 'b => 'c and t::'c is an optional
   819 parameter, computes a term s::'b and a list xs::'a list and proves the
   820 theorem I xs s = t. This is also known as reification or quoting. The
   821 resulting theorem is applied to the subgoal to substitute t with I xs
   822 s.  If t is omitted, the subgoal itself is reified.
   823 
   824 * New method: reflection corr_thm eqs (t). The parameters eqs and (t)
   825 are as explained above. corr_thm is a theorem for I vs (f t) = I vs t,
   826 where f is supposed to be a computable function (in the sense of code
   827 generattion). The method uses reify to compute s and xs as above then
   828 applies corr_thm and uses normalization by evaluation to "prove" f s =
   829 r and finally gets the theorem t = r, which is again applied to the
   830 subgoal. An Example is available in HOL/ex/ReflectionEx.thy.
   831 
   832 * Reflection: Automatic refification now handels binding, an example
   833 is available in HOL/ex/ReflectionEx.thy
   834 
   835 
   836 *** HOL-Algebra ***
   837 
   838 * Formalisation of ideals and the quotient construction over rings.
   839 
   840 * Order and lattice theory no longer based on records.
   841 INCOMPATIBILITY.
   842 
   843 * Renamed lemmas least_carrier -> least_closed and greatest_carrier ->
   844 greatest_closed.  INCOMPATIBILITY.
   845 
   846 * Method algebra is now set up via an attribute.  For examples see
   847 Ring.thy.  INCOMPATIBILITY: the method is now weaker on combinations
   848 of algebraic structures.
   849 
   850 * Renamed theory CRing to Ring.
   851 
   852 
   853 *** HOL-Complex ***
   854 
   855 * Theory Real: new method ferrack implements quantifier elimination
   856 for linear arithmetic over the reals. The quantifier elimination
   857 feature is used only for decision, for compatibility with arith. This
   858 means a goal is either solved or left unchanged, no simplification.
   859 
   860 * Real: New axiomatic classes formalize real normed vector spaces and
   861 algebras, using new overloaded constants scaleR :: real => 'a => 'a
   862 and norm :: 'a => real.
   863 
   864 * Real: New constant of_real :: real => 'a::real_algebra_1 injects
   865 from reals into other types. The overloaded constant Reals :: 'a set
   866 is now defined as range of_real; potential INCOMPATIBILITY.
   867 
   868 * Hyperreal: Several constants that previously worked only for the
   869 reals have been generalized, so they now work over arbitrary vector
   870 spaces. Type annotations may need to be added in some cases; potential
   871 INCOMPATIBILITY.
   872 
   873   Infinitesimal  :: ('a::real_normed_vector) star set"
   874   HFinite        :: ('a::real_normed_vector) star set"
   875   HInfinite      :: ('a::real_normed_vector) star set"
   876   approx         :: ('a::real_normed_vector) star => 'a star => bool
   877   monad          :: ('a::real_normed_vector) star => 'a star set
   878   galaxy         :: ('a::real_normed_vector) star => 'a star set
   879   (NS)LIMSEQ     :: [nat, 'a::real_normed_vector, 'a] => bool
   880   (NS)convergent :: (nat => 'a::real_normed_vector) => bool
   881   (NS)Bseq       :: (nat => 'a::real_normed_vector) => bool
   882   (NS)Cauchy     :: (nat => 'a::real_normed_vector) => bool
   883   (NS)LIM        :: ['a::real_normed_vector => 'b::real_normed_vector, 'a, 'b] => bool
   884   is(NS)Cont     :: ['a::real_normed_vector => 'b::real_normed_vector, 'a] => bool
   885   deriv          :: ['a::real_normed_field => 'a, 'a, 'a] => bool
   886 
   887 * Complex: Some complex-specific constants are now abbreviations for
   888 overloaded ones: complex_of_real = of_real, cmod = norm, hcmod =
   889 hnorm.  Other constants have been entirely removed in favor of the
   890 polymorphic versions (INCOMPATIBILITY):
   891 
   892   approx        <-- capprox
   893   HFinite       <-- CFinite
   894   HInfinite     <-- CInfinite
   895   Infinitesimal <-- CInfinitesimal
   896   monad         <-- cmonad
   897   galaxy        <-- cgalaxy
   898   (NS)LIM       <-- (NS)CLIM, (NS)CRLIM
   899   is(NS)Cont    <-- is(NS)Contc, is(NS)contCR
   900   (ns)deriv     <-- (ns)cderiv
   901 
   902 
   903 *** ML ***
   904 
   905 * ML within Isar: antiquotations allow to embed statically-checked
   906 formal entities in the source, referring to the context available at
   907 compile-time.  For example:
   908 
   909 ML {* @{typ "'a => 'b"} *}
   910 ML {* @{term "%x. x"} *}
   911 ML {* @{prop "x == y"} *}
   912 ML {* @{ctyp "'a => 'b"} *}
   913 ML {* @{cterm "%x. x"} *}
   914 ML {* @{cprop "x == y"} *}
   915 ML {* @{thm asm_rl} *}
   916 ML {* @{thms asm_rl} *}
   917 ML {* @{const_name c} *}
   918 ML {* @{const_syntax c} *}
   919 ML {* @{context} *}
   920 ML {* @{theory} *}
   921 ML {* @{theory Pure} *}
   922 ML {* @{simpset} *}
   923 ML {* @{claset} *}
   924 ML {* @{clasimpset} *}
   925 
   926 The same works for sources being ``used'' within an Isar context.
   927 
   928 * ML in Isar: improved error reporting; extra verbosity with
   929 Toplevel.debug enabled.
   930 
   931 * Pure/library:
   932 
   933   val burrow: ('a list -> 'b list) -> 'a list list -> 'b list list
   934   val fold_burrow: ('a list -> 'c -> 'b list * 'd) -> 'a list list -> 'c -> 'b list list * 'd
   935 
   936 The semantics of "burrow" is: "take a function with *simulatanously*
   937 transforms a list of value, and apply it *simulatanously* to a list of
   938 list of values of the appropriate type". Compare this with "map" which
   939 would *not* apply its argument function simulatanously but in
   940 sequence; "fold_burrow" has an additional context.
   941 
   942 * Pure/library: functions map2 and fold2 with curried syntax for
   943 simultanous mapping and folding:
   944 
   945     val map2: ('a -> 'b -> 'c) -> 'a list -> 'b list -> 'c list
   946     val fold2: ('a -> 'b -> 'c -> 'c) -> 'a list -> 'b list -> 'c -> 'c
   947 
   948 * Pure/library: indexed lists - some functions in the Isabelle library
   949 treating lists over 'a as finite mappings from [0...n] to 'a have been
   950 given more convenient names and signatures reminiscent of similar
   951 functions for alists, tables, etc:
   952 
   953   val nth: 'a list -> int -> 'a 
   954   val nth_map: int -> ('a -> 'a) -> 'a list -> 'a list
   955   val fold_index: (int * 'a -> 'b -> 'b) -> 'a list -> 'b -> 'b
   956 
   957 Note that fold_index starts counting at index 0, not 1 like foldln
   958 used to.
   959 
   960 * Pure/library: added general ``divide_and_conquer'' combinator on
   961 lists.
   962 
   963 * Pure/General/table.ML: the join operations now works via exceptions
   964 DUP/SAME instead of type option.  This is simpler in simple cases, and
   965 admits slightly more efficient complex applications.
   966 
   967 * Pure: datatype Context.generic joins theory/Proof.context and
   968 provides some facilities for code that works in either kind of
   969 context, notably GenericDataFun for uniform theory and proof data.
   970 
   971 * Pure: 'advanced' translation functions (parse_translation etc.) now
   972 use Context.generic instead of just theory.
   973 
   974 * Pure: simplified internal attribute type, which is now always
   975 Context.generic * thm -> Context.generic * thm.  Global (theory)
   976 vs. local (Proof.context) attributes have been discontinued, while
   977 minimizing code duplication.  Thm.rule_attribute and
   978 Thm.declaration_attribute build canonical attributes; see also
   979 structure Context for further operations on Context.generic, notably
   980 GenericDataFun.  INCOMPATIBILITY, need to adapt attribute type
   981 declarations and definitions.
   982 
   983 * Pure/kernel: consts certification ignores sort constraints given in
   984 signature declarations.  (This information is not relevant to the
   985 logic, but only for type inference.)  IMPORTANT INTERNAL CHANGE,
   986 potential INCOMPATIBILITY.
   987 
   988 * Pure: axiomatic type classes are now purely definitional, with
   989 explicit proofs of class axioms and super class relations performed
   990 internally.  See Pure/axclass.ML for the main internal interfaces --
   991 notably AxClass.define_class supercedes AxClass.add_axclass, and
   992 AxClass.axiomatize_class/classrel/arity supercede
   993 Sign.add_classes/classrel/arities.
   994 
   995 * Pure/Isar: Args/Attrib parsers operate on Context.generic --
   996 global/local versions on theory vs. Proof.context have been
   997 discontinued; Attrib.syntax and Method.syntax have been adapted
   998 accordingly.  INCOMPATIBILITY, need to adapt parser expressions for
   999 attributes, methods, etc.
  1000 
  1001 * Pure: several functions of signature "... -> theory -> theory * ..."
  1002 have been reoriented to "... -> theory -> ... * theory" in order to
  1003 allow natural usage in combination with the ||>, ||>>, |-> and
  1004 fold_map combinators.
  1005 
  1006 * Pure: official theorem names (closed derivations) and additional
  1007 comments (tags) are now strictly separate.  Name hints -- which are
  1008 maintained as tags -- may be attached any time without affecting the
  1009 derivation.
  1010 
  1011 * Pure: primitive rule lift_rule now takes goal cterm instead of an
  1012 actual goal state (thm).  Use Thm.lift_rule (Thm.cprem_of st i) to
  1013 achieve the old behaviour.
  1014 
  1015 * Pure: the "Goal" constant is now called "prop", supporting a
  1016 slightly more general idea of ``protecting'' meta-level rule
  1017 statements.
  1018 
  1019 * Pure: Logic.(un)varify only works in a global context, which is now
  1020 enforced instead of silently assumed.  INCOMPATIBILITY, may use
  1021 Logic.legacy_(un)varify as temporary workaround.
  1022 
  1023 * Pure: structure Name provides scalable operations for generating
  1024 internal variable names, notably Name.variants etc.  This replaces
  1025 some popular functions from term.ML:
  1026 
  1027   Term.variant		->  Name.variant
  1028   Term.variantlist	->  Name.variant_list  (*canonical argument order*)
  1029   Term.invent_names	->  Name.invent_list
  1030 
  1031 Note that low-level renaming rarely occurs in new code -- operations
  1032 from structure Variable are used instead (see below).
  1033 
  1034 * Pure: structure Variable provides fundamental operations for proper
  1035 treatment of fixed/schematic variables in a context.  For example,
  1036 Variable.import introduces fixes for schematics of given facts and
  1037 Variable.export reverses the effect (up to renaming) -- this replaces
  1038 various freeze_thaw operations.
  1039 
  1040 * Pure: structure Goal provides simple interfaces for
  1041 init/conclude/finish and tactical prove operations (replacing former
  1042 Tactic.prove).  Goal.prove is the canonical way to prove results
  1043 within a given context; Goal.prove_global is a degraded version for
  1044 theory level goals, including a global Drule.standard.  Note that
  1045 OldGoals.prove_goalw_cterm has long been obsolete, since it is
  1046 ill-behaved in a local proof context (e.g. with local fixes/assumes or
  1047 in a locale context).
  1048 
  1049 * Isar: simplified treatment of user-level errors, using exception
  1050 ERROR of string uniformly.  Function error now merely raises ERROR,
  1051 without any side effect on output channels.  The Isar toplevel takes
  1052 care of proper display of ERROR exceptions.  ML code may use plain
  1053 handle/can/try; cat_error may be used to concatenate errors like this:
  1054 
  1055   ... handle ERROR msg => cat_error msg "..."
  1056 
  1057 Toplevel ML code (run directly or through the Isar toplevel) may be
  1058 embedded into the Isar toplevel with exception display/debug like
  1059 this:
  1060 
  1061   Isar.toplevel (fn () => ...)
  1062 
  1063 INCOMPATIBILITY, removed special transform_error facilities, removed
  1064 obsolete variants of user-level exceptions (ERROR_MESSAGE,
  1065 Context.PROOF, ProofContext.CONTEXT, Proof.STATE, ProofHistory.FAIL)
  1066 -- use plain ERROR instead.
  1067 
  1068 * Isar: theory setup now has type (theory -> theory), instead of a
  1069 list.  INCOMPATIBILITY, may use #> to compose setup functions.
  1070 
  1071 * Isar: installed ML toplevel pretty printer for type Proof.context,
  1072 subject to ProofContext.debug/verbose flags.
  1073 
  1074 * Isar: Toplevel.theory_to_proof admits transactions that modify the
  1075 theory before entering a proof state.  Transactions now always see a
  1076 quasi-functional intermediate checkpoint, both in interactive and
  1077 batch mode.
  1078 
  1079 * Simplifier: the simpset of a running simplification process now
  1080 contains a proof context (cf. Simplifier.the_context), which is the
  1081 very context that the initial simpset has been retrieved from (by
  1082 simpset_of/local_simpset_of).  Consequently, all plug-in components
  1083 (solver, looper etc.) may depend on arbitrary proof data.
  1084 
  1085 * Simplifier.inherit_context inherits the proof context (plus the
  1086 local bounds) of the current simplification process; any simproc
  1087 etc. that calls the Simplifier recursively should do this!  Removed
  1088 former Simplifier.inherit_bounds, which is already included here --
  1089 INCOMPATIBILITY.  Tools based on low-level rewriting may even have to
  1090 specify an explicit context using Simplifier.context/theory_context.
  1091 
  1092 * Simplifier/Classical Reasoner: more abstract interfaces
  1093 change_simpset/claset for modifying the simpset/claset reference of a
  1094 theory; raw versions simpset/claset_ref etc. have been discontinued --
  1095 INCOMPATIBILITY.
  1096 
  1097 * Provers: more generic wrt. syntax of object-logics, avoid hardwired
  1098 "Trueprop" etc.
  1099 
  1100 
  1101 *** System ***
  1102 
  1103 * settings: ML_IDENTIFIER -- which is appended to user specific heap
  1104 locations -- now includes the Isabelle version identifier as well.
  1105 This simplifies use of multiple Isabelle installations.
  1106 
  1107 * isabelle-process: option -S (secure mode) disables some critical
  1108 operations, notably runtime compilation and evaluation of ML source
  1109 code.
  1110 
  1111 
  1112 New in Isabelle2005 (October 2005)
  1113 ----------------------------------
  1114 
  1115 *** General ***
  1116 
  1117 * Theory headers: the new header syntax for Isar theories is
  1118 
  1119   theory <name>
  1120   imports <theory1> ... <theoryN>
  1121   uses <file1> ... <fileM>
  1122   begin
  1123 
  1124 where the 'uses' part is optional.  The previous syntax
  1125 
  1126   theory <name> = <theory1> + ... + <theoryN>:
  1127 
  1128 will disappear in the next release.  Use isatool fixheaders to convert
  1129 existing theory files.  Note that there is no change in ancient
  1130 non-Isar theories now, but these will disappear soon.
  1131 
  1132 * Theory loader: parent theories can now also be referred to via
  1133 relative and absolute paths.
  1134 
  1135 * Command 'find_theorems' searches for a list of criteria instead of a
  1136 list of constants. Known criteria are: intro, elim, dest, name:string,
  1137 simp:term, and any term. Criteria can be preceded by '-' to select
  1138 theorems that do not match. Intro, elim, dest select theorems that
  1139 match the current goal, name:s selects theorems whose fully qualified
  1140 name contain s, and simp:term selects all simplification rules whose
  1141 lhs match term.  Any other term is interpreted as pattern and selects
  1142 all theorems matching the pattern. Available in ProofGeneral under
  1143 'ProofGeneral -> Find Theorems' or C-c C-f.  Example:
  1144 
  1145   C-c C-f (100) "(_::nat) + _ + _" intro -name: "HOL."
  1146 
  1147 prints the last 100 theorems matching the pattern "(_::nat) + _ + _",
  1148 matching the current goal as introduction rule and not having "HOL."
  1149 in their name (i.e. not being defined in theory HOL).
  1150 
  1151 * Command 'thms_containing' has been discontinued in favour of
  1152 'find_theorems'; INCOMPATIBILITY.
  1153 
  1154 * Communication with Proof General is now 8bit clean, which means that
  1155 Unicode text in UTF-8 encoding may be used within theory texts (both
  1156 formal and informal parts).  Cf. option -U of the Isabelle Proof
  1157 General interface.  Here are some simple examples (cf. src/HOL/ex):
  1158 
  1159   http://isabelle.in.tum.de/library/HOL/ex/Hebrew.html
  1160   http://isabelle.in.tum.de/library/HOL/ex/Chinese.html
  1161 
  1162 * Improved efficiency of the Simplifier and, to a lesser degree, the
  1163 Classical Reasoner.  Typical big applications run around 2 times
  1164 faster.
  1165 
  1166 
  1167 *** Document preparation ***
  1168 
  1169 * Commands 'display_drafts' and 'print_drafts' perform simple output
  1170 of raw sources.  Only those symbols that do not require additional
  1171 LaTeX packages (depending on comments in isabellesym.sty) are
  1172 displayed properly, everything else is left verbatim.  isatool display
  1173 and isatool print are used as front ends (these are subject to the
  1174 DVI/PDF_VIEWER and PRINT_COMMAND settings, respectively).
  1175 
  1176 * Command tags control specific markup of certain regions of text,
  1177 notably folding and hiding.  Predefined tags include "theory" (for
  1178 theory begin and end), "proof" for proof commands, and "ML" for
  1179 commands involving ML code; the additional tags "visible" and
  1180 "invisible" are unused by default.  Users may give explicit tag
  1181 specifications in the text, e.g. ''by %invisible (auto)''.  The
  1182 interpretation of tags is determined by the LaTeX job during document
  1183 preparation: see option -V of isatool usedir, or options -n and -t of
  1184 isatool document, or even the LaTeX macros \isakeeptag, \isafoldtag,
  1185 \isadroptag.
  1186 
  1187 Several document versions may be produced at the same time via isatool
  1188 usedir (the generated index.html will link all of them).  Typical
  1189 specifications include ''-V document=theory,proof,ML'' to present
  1190 theory/proof/ML parts faithfully, ''-V outline=/proof,/ML'' to fold
  1191 proof and ML commands, and ''-V mutilated=-theory,-proof,-ML'' to omit
  1192 these parts without any formal replacement text.  The Isabelle site
  1193 default settings produce ''document'' and ''outline'' versions as
  1194 specified above.
  1195 
  1196 * Several new antiquotations:
  1197 
  1198   @{term_type term} prints a term with its type annotated;
  1199 
  1200   @{typeof term} prints the type of a term;
  1201 
  1202   @{const const} is the same as @{term const}, but checks that the
  1203   argument is a known logical constant;
  1204 
  1205   @{term_style style term} and @{thm_style style thm} print a term or
  1206   theorem applying a "style" to it
  1207 
  1208   @{ML text}
  1209 
  1210 Predefined styles are 'lhs' and 'rhs' printing the lhs/rhs of
  1211 definitions, equations, inequations etc., 'concl' printing only the
  1212 conclusion of a meta-logical statement theorem, and 'prem1' .. 'prem19'
  1213 to print the specified premise.  TermStyle.add_style provides an ML
  1214 interface for introducing further styles.  See also the "LaTeX Sugar"
  1215 document practical applications.  The ML antiquotation prints
  1216 type-checked ML expressions verbatim.
  1217 
  1218 * Markup commands 'chapter', 'section', 'subsection', 'subsubsection',
  1219 and 'text' support optional locale specification '(in loc)', which
  1220 specifies the default context for interpreting antiquotations.  For
  1221 example: 'text (in lattice) {* @{thm inf_assoc}*}'.
  1222 
  1223 * Option 'locale=NAME' of antiquotations specifies an alternative
  1224 context interpreting the subsequent argument.  For example: @{thm
  1225 [locale=lattice] inf_assoc}.
  1226 
  1227 * Proper output of proof terms (@{prf ...} and @{full_prf ...}) within
  1228 a proof context.
  1229 
  1230 * Proper output of antiquotations for theory commands involving a
  1231 proof context (such as 'locale' or 'theorem (in loc) ...').
  1232 
  1233 * Delimiters of outer tokens (string etc.) now produce separate LaTeX
  1234 macros (\isachardoublequoteopen, isachardoublequoteclose etc.).
  1235 
  1236 * isatool usedir: new option -C (default true) controls whether option
  1237 -D should include a copy of the original document directory; -C false
  1238 prevents unwanted effects such as copying of administrative CVS data.
  1239 
  1240 
  1241 *** Pure ***
  1242 
  1243 * Considerably improved version of 'constdefs' command.  Now performs
  1244 automatic type-inference of declared constants; additional support for
  1245 local structure declarations (cf. locales and HOL records), see also
  1246 isar-ref manual.  Potential INCOMPATIBILITY: need to observe strictly
  1247 sequential dependencies of definitions within a single 'constdefs'
  1248 section; moreover, the declared name needs to be an identifier.  If
  1249 all fails, consider to fall back on 'consts' and 'defs' separately.
  1250 
  1251 * Improved indexed syntax and implicit structures.  First of all,
  1252 indexed syntax provides a notational device for subscripted
  1253 application, using the new syntax \<^bsub>term\<^esub> for arbitrary
  1254 expressions.  Secondly, in a local context with structure
  1255 declarations, number indexes \<^sub>n or the empty index (default
  1256 number 1) refer to a certain fixed variable implicitly; option
  1257 show_structs controls printing of implicit structures.  Typical
  1258 applications of these concepts involve record types and locales.
  1259 
  1260 * New command 'no_syntax' removes grammar declarations (and
  1261 translations) resulting from the given syntax specification, which is
  1262 interpreted in the same manner as for the 'syntax' command.
  1263 
  1264 * 'Advanced' translation functions (parse_translation etc.) may depend
  1265 on the signature of the theory context being presently used for
  1266 parsing/printing, see also isar-ref manual.
  1267 
  1268 * Improved 'oracle' command provides a type-safe interface to turn an
  1269 ML expression of type theory -> T -> term into a primitive rule of
  1270 type theory -> T -> thm (i.e. the functionality of Thm.invoke_oracle
  1271 is already included here); see also FOL/ex/IffExample.thy;
  1272 INCOMPATIBILITY.
  1273 
  1274 * axclass: name space prefix for class "c" is now "c_class" (was "c"
  1275 before); "cI" is no longer bound, use "c.intro" instead.
  1276 INCOMPATIBILITY.  This change avoids clashes of fact bindings for
  1277 axclasses vs. locales.
  1278 
  1279 * Improved internal renaming of symbolic identifiers -- attach primes
  1280 instead of base 26 numbers.
  1281 
  1282 * New flag show_question_marks controls printing of leading question
  1283 marks in schematic variable names.
  1284 
  1285 * In schematic variable names, *any* symbol following \<^isub> or
  1286 \<^isup> is now treated as part of the base name.  For example, the
  1287 following works without printing of awkward ".0" indexes:
  1288 
  1289   lemma "x\<^isub>1 = x\<^isub>2 ==> x\<^isub>2 = x\<^isub>1"
  1290     by simp
  1291 
  1292 * Inner syntax includes (*(*nested*) comments*).
  1293 
  1294 * Pretty printer now supports unbreakable blocks, specified in mixfix
  1295 annotations as "(00...)".
  1296 
  1297 * Clear separation of logical types and nonterminals, where the latter
  1298 may only occur in 'syntax' specifications or type abbreviations.
  1299 Before that distinction was only partially implemented via type class
  1300 "logic" vs. "{}".  Potential INCOMPATIBILITY in rare cases of improper
  1301 use of 'types'/'consts' instead of 'nonterminals'/'syntax'.  Some very
  1302 exotic syntax specifications may require further adaption
  1303 (e.g. Cube/Cube.thy).
  1304 
  1305 * Removed obsolete type class "logic", use the top sort {} instead.
  1306 Note that non-logical types should be declared as 'nonterminals'
  1307 rather than 'types'.  INCOMPATIBILITY for new object-logic
  1308 specifications.
  1309 
  1310 * Attributes 'induct' and 'cases': type or set names may now be
  1311 locally fixed variables as well.
  1312 
  1313 * Simplifier: can now control the depth to which conditional rewriting
  1314 is traced via the PG menu Isabelle -> Settings -> Trace Simp Depth
  1315 Limit.
  1316 
  1317 * Simplifier: simplification procedures may now take the current
  1318 simpset into account (cf. Simplifier.simproc(_i) / mk_simproc
  1319 interface), which is very useful for calling the Simplifier
  1320 recursively.  Minor INCOMPATIBILITY: the 'prems' argument of simprocs
  1321 is gone -- use prems_of_ss on the simpset instead.  Moreover, the
  1322 low-level mk_simproc no longer applies Logic.varify internally, to
  1323 allow for use in a context of fixed variables.
  1324 
  1325 * thin_tac now works even if the assumption being deleted contains !!
  1326 or ==>.  More generally, erule now works even if the major premise of
  1327 the elimination rule contains !! or ==>.
  1328 
  1329 * Method 'rules' has been renamed to 'iprover'. INCOMPATIBILITY.
  1330 
  1331 * Reorganized bootstrapping of the Pure theories; CPure is now derived
  1332 from Pure, which contains all common declarations already.  Both
  1333 theories are defined via plain Isabelle/Isar .thy files.
  1334 INCOMPATIBILITY: elements of CPure (such as the CPure.intro /
  1335 CPure.elim / CPure.dest attributes) now appear in the Pure name space;
  1336 use isatool fixcpure to adapt your theory and ML sources.
  1337 
  1338 * New syntax 'name(i-j, i-, i, ...)' for referring to specific
  1339 selections of theorems in named facts via index ranges.
  1340 
  1341 * 'print_theorems': in theory mode, really print the difference
  1342 wrt. the last state (works for interactive theory development only),
  1343 in proof mode print all local facts (cf. 'print_facts');
  1344 
  1345 * 'hide': option '(open)' hides only base names.
  1346 
  1347 * More efficient treatment of intermediate checkpoints in interactive
  1348 theory development.
  1349 
  1350 * Code generator is now invoked via code_module (incremental code
  1351 generation) and code_library (modular code generation, ML structures
  1352 for each theory).  INCOMPATIBILITY: new keywords 'file' and 'contains'
  1353 must be quoted when used as identifiers.
  1354 
  1355 * New 'value' command for reading, evaluating and printing terms using
  1356 the code generator.  INCOMPATIBILITY: command keyword 'value' must be
  1357 quoted when used as identifier.
  1358 
  1359 
  1360 *** Locales ***
  1361 
  1362 * New commands for the interpretation of locale expressions in
  1363 theories (1), locales (2) and proof contexts (3).  These generate
  1364 proof obligations from the expression specification.  After the
  1365 obligations have been discharged, theorems of the expression are added
  1366 to the theory, target locale or proof context.  The synopsis of the
  1367 commands is a follows:
  1368 
  1369   (1) interpretation expr inst
  1370   (2) interpretation target < expr
  1371   (3) interpret expr inst
  1372 
  1373 Interpretation in theories and proof contexts require a parameter
  1374 instantiation of terms from the current context.  This is applied to
  1375 specifications and theorems of the interpreted expression.
  1376 Interpretation in locales only permits parameter renaming through the
  1377 locale expression.  Interpretation is smart in that interpretations
  1378 that are active already do not occur in proof obligations, neither are
  1379 instantiated theorems stored in duplicate.  Use 'print_interps' to
  1380 inspect active interpretations of a particular locale.  For details,
  1381 see the Isar Reference manual.  Examples can be found in
  1382 HOL/Finite_Set.thy and HOL/Algebra/UnivPoly.thy.
  1383 
  1384 INCOMPATIBILITY: former 'instantiate' has been withdrawn, use
  1385 'interpret' instead.
  1386 
  1387 * New context element 'constrains' for adding type constraints to
  1388 parameters.
  1389 
  1390 * Context expressions: renaming of parameters with syntax
  1391 redeclaration.
  1392 
  1393 * Locale declaration: 'includes' disallowed.
  1394 
  1395 * Proper static binding of attribute syntax -- i.e. types / terms /
  1396 facts mentioned as arguments are always those of the locale definition
  1397 context, independently of the context of later invocations.  Moreover,
  1398 locale operations (renaming and type / term instantiation) are applied
  1399 to attribute arguments as expected.
  1400 
  1401 INCOMPATIBILITY of the ML interface: always pass Attrib.src instead of
  1402 actual attributes; rare situations may require Attrib.attribute to
  1403 embed those attributes into Attrib.src that lack concrete syntax.
  1404 Attribute implementations need to cooperate properly with the static
  1405 binding mechanism.  Basic parsers Args.XXX_typ/term/prop and
  1406 Attrib.XXX_thm etc. already do the right thing without further
  1407 intervention.  Only unusual applications -- such as "where" or "of"
  1408 (cf. src/Pure/Isar/attrib.ML), which process arguments depending both
  1409 on the context and the facts involved -- may have to assign parsed
  1410 values to argument tokens explicitly.
  1411 
  1412 * Changed parameter management in theorem generation for long goal
  1413 statements with 'includes'.  INCOMPATIBILITY: produces a different
  1414 theorem statement in rare situations.
  1415 
  1416 * Locale inspection command 'print_locale' omits notes elements.  Use
  1417 'print_locale!' to have them included in the output.
  1418 
  1419 
  1420 *** Provers ***
  1421 
  1422 * Provers/hypsubst.ML: improved version of the subst method, for
  1423 single-step rewriting: it now works in bound variable contexts. New is
  1424 'subst (asm)', for rewriting an assumption.  INCOMPATIBILITY: may
  1425 rewrite a different subterm than the original subst method, which is
  1426 still available as 'simplesubst'.
  1427 
  1428 * Provers/quasi.ML: new transitivity reasoners for transitivity only
  1429 and quasi orders.
  1430 
  1431 * Provers/trancl.ML: new transitivity reasoner for transitive and
  1432 reflexive-transitive closure of relations.
  1433 
  1434 * Provers/blast.ML: new reference depth_limit to make blast's depth
  1435 limit (previously hard-coded with a value of 20) user-definable.
  1436 
  1437 * Provers/simplifier.ML has been moved to Pure, where Simplifier.setup
  1438 is peformed already.  Object-logics merely need to finish their
  1439 initial simpset configuration as before.  INCOMPATIBILITY.
  1440 
  1441 
  1442 *** HOL ***
  1443 
  1444 * Symbolic syntax of Hilbert Choice Operator is now as follows:
  1445 
  1446   syntax (epsilon)
  1447     "_Eps" :: "[pttrn, bool] => 'a"    ("(3\<some>_./ _)" [0, 10] 10)
  1448 
  1449 The symbol \<some> is displayed as the alternative epsilon of LaTeX
  1450 and x-symbol; use option '-m epsilon' to get it actually printed.
  1451 Moreover, the mathematically important symbolic identifier \<epsilon>
  1452 becomes available as variable, constant etc.  INCOMPATIBILITY,
  1453 
  1454 * "x > y" abbreviates "y < x" and "x >= y" abbreviates "y <= x".
  1455 Similarly for all quantifiers: "ALL x > y" etc.  The x-symbol for >=
  1456 is \<ge>. New transitivity rules have been added to HOL/Orderings.thy to
  1457 support corresponding Isar calculations.
  1458 
  1459 * "{x:A. P}" abbreviates "{x. x:A & P}", and similarly for "\<in>"
  1460 instead of ":".
  1461 
  1462 * theory SetInterval: changed the syntax for open intervals:
  1463 
  1464   Old       New
  1465   {..n(}    {..<n}
  1466   {)n..}    {n<..}
  1467   {m..n(}   {m..<n}
  1468   {)m..n}   {m<..n}
  1469   {)m..n(}  {m<..<n}
  1470 
  1471 The old syntax is still supported but will disappear in the next
  1472 release.  For conversion use the following Emacs search and replace
  1473 patterns (these are not perfect but work quite well):
  1474 
  1475   {)\([^\.]*\)\.\.  ->  {\1<\.\.}
  1476   \.\.\([^(}]*\)(}  ->  \.\.<\1}
  1477 
  1478 * Theory Commutative_Ring (in Library): method comm_ring for proving
  1479 equalities in commutative rings; method 'algebra' provides a generic
  1480 interface.
  1481 
  1482 * Theory Finite_Set: changed the syntax for 'setsum', summation over
  1483 finite sets: "setsum (%x. e) A", which used to be "\<Sum>x:A. e", is
  1484 now either "SUM x:A. e" or "\<Sum>x \<in> A. e". The bound variable can
  1485 be a tuple pattern.
  1486 
  1487 Some new syntax forms are available:
  1488 
  1489   "\<Sum>x | P. e"      for     "setsum (%x. e) {x. P}"
  1490   "\<Sum>x = a..b. e"   for     "setsum (%x. e) {a..b}"
  1491   "\<Sum>x = a..<b. e"  for     "setsum (%x. e) {a..<b}"
  1492   "\<Sum>x < k. e"      for     "setsum (%x. e) {..<k}"
  1493 
  1494 The latter form "\<Sum>x < k. e" used to be based on a separate
  1495 function "Summation", which has been discontinued.
  1496 
  1497 * theory Finite_Set: in structured induction proofs, the insert case
  1498 is now 'case (insert x F)' instead of the old counterintuitive 'case
  1499 (insert F x)'.
  1500 
  1501 * The 'refute' command has been extended to support a much larger
  1502 fragment of HOL, including axiomatic type classes, constdefs and
  1503 typedefs, inductive datatypes and recursion.
  1504 
  1505 * New tactics 'sat' and 'satx' to prove propositional tautologies.
  1506 Requires zChaff with proof generation to be installed.  See
  1507 HOL/ex/SAT_Examples.thy for examples.
  1508 
  1509 * Datatype induction via method 'induct' now preserves the name of the
  1510 induction variable. For example, when proving P(xs::'a list) by
  1511 induction on xs, the induction step is now P(xs) ==> P(a#xs) rather
  1512 than P(list) ==> P(a#list) as previously.  Potential INCOMPATIBILITY
  1513 in unstructured proof scripts.
  1514 
  1515 * Reworked implementation of records.  Improved scalability for
  1516 records with many fields, avoiding performance problems for type
  1517 inference. Records are no longer composed of nested field types, but
  1518 of nested extension types. Therefore the record type only grows linear
  1519 in the number of extensions and not in the number of fields.  The
  1520 top-level (users) view on records is preserved.  Potential
  1521 INCOMPATIBILITY only in strange cases, where the theory depends on the
  1522 old record representation. The type generated for a record is called
  1523 <record_name>_ext_type.
  1524 
  1525 Flag record_quick_and_dirty_sensitive can be enabled to skip the
  1526 proofs triggered by a record definition or a simproc (if
  1527 quick_and_dirty is enabled).  Definitions of large records can take
  1528 quite long.
  1529 
  1530 New simproc record_upd_simproc for simplification of multiple record
  1531 updates enabled by default.  Moreover, trivial updates are also
  1532 removed: r(|x := x r|) = r.  INCOMPATIBILITY: old proofs break
  1533 occasionally, since simplification is more powerful by default.
  1534 
  1535 * typedef: proper support for polymorphic sets, which contain extra
  1536 type-variables in the term.
  1537 
  1538 * Simplifier: automatically reasons about transitivity chains
  1539 involving "trancl" (r^+) and "rtrancl" (r^*) by setting up tactics
  1540 provided by Provers/trancl.ML as additional solvers.  INCOMPATIBILITY:
  1541 old proofs break occasionally as simplification may now solve more
  1542 goals than previously.
  1543 
  1544 * Simplifier: converts x <= y into x = y if assumption y <= x is
  1545 present.  Works for all partial orders (class "order"), in particular
  1546 numbers and sets.  For linear orders (e.g. numbers) it treats ~ x < y
  1547 just like y <= x.
  1548 
  1549 * Simplifier: new simproc for "let x = a in f x".  If a is a free or
  1550 bound variable or a constant then the let is unfolded.  Otherwise
  1551 first a is simplified to b, and then f b is simplified to g. If
  1552 possible we abstract b from g arriving at "let x = b in h x",
  1553 otherwise we unfold the let and arrive at g.  The simproc can be
  1554 enabled/disabled by the reference use_let_simproc.  Potential
  1555 INCOMPATIBILITY since simplification is more powerful by default.
  1556 
  1557 * Classical reasoning: the meson method now accepts theorems as arguments.
  1558 
  1559 * Prover support: pre-release of the Isabelle-ATP linkup, which runs background
  1560 jobs to provide advice on the provability of subgoals.
  1561 
  1562 * Theory OrderedGroup and Ring_and_Field: various additions and
  1563 improvements to faciliate calculations involving equalities and
  1564 inequalities.
  1565 
  1566 The following theorems have been eliminated or modified
  1567 (INCOMPATIBILITY):
  1568 
  1569   abs_eq             now named abs_of_nonneg
  1570   abs_of_ge_0        now named abs_of_nonneg
  1571   abs_minus_eq       now named abs_of_nonpos
  1572   imp_abs_id         now named abs_of_nonneg
  1573   imp_abs_neg_id     now named abs_of_nonpos
  1574   mult_pos           now named mult_pos_pos
  1575   mult_pos_le        now named mult_nonneg_nonneg
  1576   mult_pos_neg_le    now named mult_nonneg_nonpos
  1577   mult_pos_neg2_le   now named mult_nonneg_nonpos2
  1578   mult_neg           now named mult_neg_neg
  1579   mult_neg_le        now named mult_nonpos_nonpos
  1580 
  1581 * Theory Parity: added rules for simplifying exponents.
  1582 
  1583 * Theory List:
  1584 
  1585 The following theorems have been eliminated or modified
  1586 (INCOMPATIBILITY):
  1587 
  1588   list_all_Nil       now named list_all.simps(1)
  1589   list_all_Cons      now named list_all.simps(2)
  1590   list_all_conv      now named list_all_iff
  1591   set_mem_eq         now named mem_iff
  1592 
  1593 * Theories SetsAndFunctions and BigO (see HOL/Library) support
  1594 asymptotic "big O" calculations.  See the notes in BigO.thy.
  1595 
  1596 
  1597 *** HOL-Complex ***
  1598 
  1599 * Theory RealDef: better support for embedding natural numbers and
  1600 integers in the reals.
  1601 
  1602 The following theorems have been eliminated or modified
  1603 (INCOMPATIBILITY):
  1604 
  1605   exp_ge_add_one_self  now requires no hypotheses
  1606   real_of_int_add      reversed direction of equality (use [symmetric])
  1607   real_of_int_minus    reversed direction of equality (use [symmetric])
  1608   real_of_int_diff     reversed direction of equality (use [symmetric])
  1609   real_of_int_mult     reversed direction of equality (use [symmetric])
  1610 
  1611 * Theory RComplete: expanded support for floor and ceiling functions.
  1612 
  1613 * Theory Ln is new, with properties of the natural logarithm
  1614 
  1615 * Hyperreal: There is a new type constructor "star" for making
  1616 nonstandard types.  The old type names are now type synonyms:
  1617 
  1618   hypreal = real star
  1619   hypnat = nat star
  1620   hcomplex = complex star
  1621 
  1622 * Hyperreal: Many groups of similarly-defined constants have been
  1623 replaced by polymorphic versions (INCOMPATIBILITY):
  1624 
  1625   star_of <-- hypreal_of_real, hypnat_of_nat, hcomplex_of_complex
  1626 
  1627   starset      <-- starsetNat, starsetC
  1628   *s*          <-- *sNat*, *sc*
  1629   starset_n    <-- starsetNat_n, starsetC_n
  1630   *sn*         <-- *sNatn*, *scn*
  1631   InternalSets <-- InternalNatSets, InternalCSets
  1632 
  1633   starfun      <-- starfun{Nat,Nat2,C,RC,CR}
  1634   *f*          <-- *fNat*, *fNat2*, *fc*, *fRc*, *fcR*
  1635   starfun_n    <-- starfun{Nat,Nat2,C,RC,CR}_n
  1636   *fn*         <-- *fNatn*, *fNat2n*, *fcn*, *fRcn*, *fcRn*
  1637   InternalFuns <-- InternalNatFuns, InternalNatFuns2, Internal{C,RC,CR}Funs
  1638 
  1639 * Hyperreal: Many type-specific theorems have been removed in favor of
  1640 theorems specific to various axiomatic type classes (INCOMPATIBILITY):
  1641 
  1642   add_commute <-- {hypreal,hypnat,hcomplex}_add_commute
  1643   add_assoc   <-- {hypreal,hypnat,hcomplex}_add_assocs
  1644   OrderedGroup.add_0 <-- {hypreal,hypnat,hcomplex}_add_zero_left
  1645   OrderedGroup.add_0_right <-- {hypreal,hcomplex}_add_zero_right
  1646   right_minus <-- hypreal_add_minus
  1647   left_minus <-- {hypreal,hcomplex}_add_minus_left
  1648   mult_commute <-- {hypreal,hypnat,hcomplex}_mult_commute
  1649   mult_assoc <-- {hypreal,hypnat,hcomplex}_mult_assoc
  1650   mult_1_left <-- {hypreal,hypnat}_mult_1, hcomplex_mult_one_left
  1651   mult_1_right <-- hcomplex_mult_one_right
  1652   mult_zero_left <-- hcomplex_mult_zero_left
  1653   left_distrib <-- {hypreal,hypnat,hcomplex}_add_mult_distrib
  1654   right_distrib <-- hypnat_add_mult_distrib2
  1655   zero_neq_one <-- {hypreal,hypnat,hcomplex}_zero_not_eq_one
  1656   right_inverse <-- hypreal_mult_inverse
  1657   left_inverse <-- hypreal_mult_inverse_left, hcomplex_mult_inv_left
  1658   order_refl <-- {hypreal,hypnat}_le_refl
  1659   order_trans <-- {hypreal,hypnat}_le_trans
  1660   order_antisym <-- {hypreal,hypnat}_le_anti_sym
  1661   order_less_le <-- {hypreal,hypnat}_less_le
  1662   linorder_linear <-- {hypreal,hypnat}_le_linear
  1663   add_left_mono <-- {hypreal,hypnat}_add_left_mono
  1664   mult_strict_left_mono <-- {hypreal,hypnat}_mult_less_mono2
  1665   add_nonneg_nonneg <-- hypreal_le_add_order
  1666 
  1667 * Hyperreal: Separate theorems having to do with type-specific
  1668 versions of constants have been merged into theorems that apply to the
  1669 new polymorphic constants (INCOMPATIBILITY):
  1670 
  1671   STAR_UNIV_set <-- {STAR_real,NatStar_real,STARC_complex}_set
  1672   STAR_empty_set <-- {STAR,NatStar,STARC}_empty_set
  1673   STAR_Un <-- {STAR,NatStar,STARC}_Un
  1674   STAR_Int <-- {STAR,NatStar,STARC}_Int
  1675   STAR_Compl <-- {STAR,NatStar,STARC}_Compl
  1676   STAR_subset <-- {STAR,NatStar,STARC}_subset
  1677   STAR_mem <-- {STAR,NatStar,STARC}_mem
  1678   STAR_mem_Compl <-- {STAR,STARC}_mem_Compl
  1679   STAR_diff <-- {STAR,STARC}_diff
  1680   STAR_star_of_image_subset <-- {STAR_hypreal_of_real, NatStar_hypreal_of_real,
  1681     STARC_hcomplex_of_complex}_image_subset
  1682   starset_n_Un <-- starset{Nat,C}_n_Un
  1683   starset_n_Int <-- starset{Nat,C}_n_Int
  1684   starset_n_Compl <-- starset{Nat,C}_n_Compl
  1685   starset_n_diff <-- starset{Nat,C}_n_diff
  1686   InternalSets_Un <-- Internal{Nat,C}Sets_Un
  1687   InternalSets_Int <-- Internal{Nat,C}Sets_Int
  1688   InternalSets_Compl <-- Internal{Nat,C}Sets_Compl
  1689   InternalSets_diff <-- Internal{Nat,C}Sets_diff
  1690   InternalSets_UNIV_diff <-- Internal{Nat,C}Sets_UNIV_diff
  1691   InternalSets_starset_n <-- Internal{Nat,C}Sets_starset{Nat,C}_n
  1692   starset_starset_n_eq <-- starset{Nat,C}_starset{Nat,C}_n_eq
  1693   starset_n_starset <-- starset{Nat,C}_n_starset{Nat,C}
  1694   starfun_n_starfun <-- starfun{Nat,Nat2,C,RC,CR}_n_starfun{Nat,Nat2,C,RC,CR}
  1695   starfun <-- starfun{Nat,Nat2,C,RC,CR}
  1696   starfun_mult <-- starfun{Nat,Nat2,C,RC,CR}_mult
  1697   starfun_add <-- starfun{Nat,Nat2,C,RC,CR}_add
  1698   starfun_minus <-- starfun{Nat,Nat2,C,RC,CR}_minus
  1699   starfun_diff <-- starfun{C,RC,CR}_diff
  1700   starfun_o <-- starfun{NatNat2,Nat2,_stafunNat,C,C_starfunRC,_starfunCR}_o
  1701   starfun_o2 <-- starfun{NatNat2,_stafunNat,C,C_starfunRC,_starfunCR}_o2
  1702   starfun_const_fun <-- starfun{Nat,Nat2,C,RC,CR}_const_fun
  1703   starfun_inverse <-- starfun{Nat,C,RC,CR}_inverse
  1704   starfun_eq <-- starfun{Nat,Nat2,C,RC,CR}_eq
  1705   starfun_eq_iff <-- starfun{C,RC,CR}_eq_iff
  1706   starfun_Id <-- starfunC_Id
  1707   starfun_approx <-- starfun{Nat,CR}_approx
  1708   starfun_capprox <-- starfun{C,RC}_capprox
  1709   starfun_abs <-- starfunNat_rabs
  1710   starfun_lambda_cancel <-- starfun{C,CR,RC}_lambda_cancel
  1711   starfun_lambda_cancel2 <-- starfun{C,CR,RC}_lambda_cancel2
  1712   starfun_mult_HFinite_approx <-- starfunCR_mult_HFinite_capprox
  1713   starfun_mult_CFinite_capprox <-- starfun{C,RC}_mult_CFinite_capprox
  1714   starfun_add_capprox <-- starfun{C,RC}_add_capprox
  1715   starfun_add_approx <-- starfunCR_add_approx
  1716   starfun_inverse_inverse <-- starfunC_inverse_inverse
  1717   starfun_divide <-- starfun{C,CR,RC}_divide
  1718   starfun_n <-- starfun{Nat,C}_n
  1719   starfun_n_mult <-- starfun{Nat,C}_n_mult
  1720   starfun_n_add <-- starfun{Nat,C}_n_add
  1721   starfun_n_add_minus <-- starfunNat_n_add_minus
  1722   starfun_n_const_fun <-- starfun{Nat,C}_n_const_fun
  1723   starfun_n_minus <-- starfun{Nat,C}_n_minus
  1724   starfun_n_eq <-- starfun{Nat,C}_n_eq
  1725 
  1726   star_n_add <-- {hypreal,hypnat,hcomplex}_add
  1727   star_n_minus <-- {hypreal,hcomplex}_minus
  1728   star_n_diff <-- {hypreal,hcomplex}_diff
  1729   star_n_mult <-- {hypreal,hcomplex}_mult
  1730   star_n_inverse <-- {hypreal,hcomplex}_inverse
  1731   star_n_le <-- {hypreal,hypnat}_le
  1732   star_n_less <-- {hypreal,hypnat}_less
  1733   star_n_zero_num <-- {hypreal,hypnat,hcomplex}_zero_num
  1734   star_n_one_num <-- {hypreal,hypnat,hcomplex}_one_num
  1735   star_n_abs <-- hypreal_hrabs
  1736   star_n_divide <-- hcomplex_divide
  1737 
  1738   star_of_add <-- {hypreal_of_real,hypnat_of_nat,hcomplex_of_complex}_add
  1739   star_of_minus <-- {hypreal_of_real,hcomplex_of_complex}_minus
  1740   star_of_diff <-- hypreal_of_real_diff
  1741   star_of_mult <-- {hypreal_of_real,hypnat_of_nat,hcomplex_of_complex}_mult
  1742   star_of_one <-- {hypreal_of_real,hcomplex_of_complex}_one
  1743   star_of_zero <-- {hypreal_of_real,hypnat_of_nat,hcomplex_of_complex}_zero
  1744   star_of_le <-- {hypreal_of_real,hypnat_of_nat}_le_iff
  1745   star_of_less <-- {hypreal_of_real,hypnat_of_nat}_less_iff
  1746   star_of_eq <-- {hypreal_of_real,hypnat_of_nat,hcomplex_of_complex}_eq_iff
  1747   star_of_inverse <-- {hypreal_of_real,hcomplex_of_complex}_inverse
  1748   star_of_divide <-- {hypreal_of_real,hcomplex_of_complex}_divide
  1749   star_of_of_nat <-- {hypreal_of_real,hcomplex_of_complex}_of_nat
  1750   star_of_of_int <-- {hypreal_of_real,hcomplex_of_complex}_of_int
  1751   star_of_number_of <-- {hypreal,hcomplex}_number_of
  1752   star_of_number_less <-- number_of_less_hypreal_of_real_iff
  1753   star_of_number_le <-- number_of_le_hypreal_of_real_iff
  1754   star_of_eq_number <-- hypreal_of_real_eq_number_of_iff
  1755   star_of_less_number <-- hypreal_of_real_less_number_of_iff
  1756   star_of_le_number <-- hypreal_of_real_le_number_of_iff
  1757   star_of_power <-- hypreal_of_real_power
  1758   star_of_eq_0 <-- hcomplex_of_complex_zero_iff
  1759 
  1760 * Hyperreal: new method "transfer" that implements the transfer
  1761 principle of nonstandard analysis. With a subgoal that mentions
  1762 nonstandard types like "'a star", the command "apply transfer"
  1763 replaces it with an equivalent one that mentions only standard types.
  1764 To be successful, all free variables must have standard types; non-
  1765 standard variables must have explicit universal quantifiers.
  1766 
  1767 * Hyperreal: A theory of Taylor series.
  1768 
  1769 
  1770 *** HOLCF ***
  1771 
  1772 * Discontinued special version of 'constdefs' (which used to support
  1773 continuous functions) in favor of the general Pure one with full
  1774 type-inference.
  1775 
  1776 * New simplification procedure for solving continuity conditions; it
  1777 is much faster on terms with many nested lambda abstractions (cubic
  1778 instead of exponential time).
  1779 
  1780 * New syntax for domain package: selector names are now optional.
  1781 Parentheses should be omitted unless argument is lazy, for example:
  1782 
  1783   domain 'a stream = cons "'a" (lazy "'a stream")
  1784 
  1785 * New command 'fixrec' for defining recursive functions with pattern
  1786 matching; defining multiple functions with mutual recursion is also
  1787 supported.  Patterns may include the constants cpair, spair, up, sinl,
  1788 sinr, or any data constructor defined by the domain package. The given
  1789 equations are proven as rewrite rules. See HOLCF/ex/Fixrec_ex.thy for
  1790 syntax and examples.
  1791 
  1792 * New commands 'cpodef' and 'pcpodef' for defining predicate subtypes
  1793 of cpo and pcpo types. Syntax is exactly like the 'typedef' command,
  1794 but the proof obligation additionally includes an admissibility
  1795 requirement. The packages generate instances of class cpo or pcpo,
  1796 with continuity and strictness theorems for Rep and Abs.
  1797 
  1798 * HOLCF: Many theorems have been renamed according to a more standard naming
  1799 scheme (INCOMPATIBILITY):
  1800 
  1801   foo_inject:  "foo$x = foo$y ==> x = y"
  1802   foo_eq:      "(foo$x = foo$y) = (x = y)"
  1803   foo_less:    "(foo$x << foo$y) = (x << y)"
  1804   foo_strict:  "foo$UU = UU"
  1805   foo_defined: "... ==> foo$x ~= UU"
  1806   foo_defined_iff: "(foo$x = UU) = (x = UU)"
  1807 
  1808 
  1809 *** ZF ***
  1810 
  1811 * ZF/ex: theories Group and Ring provide examples in abstract algebra,
  1812 including the First Isomorphism Theorem (on quotienting by the kernel
  1813 of a homomorphism).
  1814 
  1815 * ZF/Simplifier: install second copy of type solver that actually
  1816 makes use of TC rules declared to Isar proof contexts (or locales);
  1817 the old version is still required for ML proof scripts.
  1818 
  1819 
  1820 *** Cube ***
  1821 
  1822 * Converted to Isar theory format; use locales instead of axiomatic
  1823 theories.
  1824 
  1825 
  1826 *** ML ***
  1827 
  1828 * Pure/library.ML: added ##>, ##>>, #>> -- higher-order counterparts
  1829 for ||>, ||>>, |>>,
  1830 
  1831 * Pure/library.ML no longer defines its own option datatype, but uses
  1832 that of the SML basis, which has constructors NONE and SOME instead of
  1833 None and Some, as well as exception Option.Option instead of OPTION.
  1834 The functions the, if_none, is_some, is_none have been adapted
  1835 accordingly, while Option.map replaces apsome.
  1836 
  1837 * Pure/library.ML: the exception LIST has been given up in favour of
  1838 the standard exceptions Empty and Subscript, as well as
  1839 Library.UnequalLengths.  Function like Library.hd and Library.tl are
  1840 superceded by the standard hd and tl functions etc.
  1841 
  1842 A number of basic list functions are no longer exported to the ML
  1843 toplevel, as they are variants of predefined functions.  The following
  1844 suggests how one can translate existing code:
  1845 
  1846     rev_append xs ys = List.revAppend (xs, ys)
  1847     nth_elem (i, xs) = List.nth (xs, i)
  1848     last_elem xs = List.last xs
  1849     flat xss = List.concat xss
  1850     seq fs = List.app fs
  1851     partition P xs = List.partition P xs
  1852     mapfilter f xs = List.mapPartial f xs
  1853 
  1854 * Pure/library.ML: several combinators for linear functional
  1855 transformations, notably reverse application and composition:
  1856 
  1857   x |> f                f #> g
  1858   (x, y) |-> f          f #-> g
  1859 
  1860 * Pure/library.ML: introduced/changed precedence of infix operators:
  1861 
  1862   infix 1 |> |-> ||> ||>> |>> |>>> #> #->;
  1863   infix 2 ?;
  1864   infix 3 o oo ooo oooo;
  1865   infix 4 ~~ upto downto;
  1866 
  1867 Maybe INCOMPATIBILITY when any of those is used in conjunction with other
  1868 infix operators.
  1869 
  1870 * Pure/library.ML: natural list combinators fold, fold_rev, and
  1871 fold_map support linear functional transformations and nesting.  For
  1872 example:
  1873 
  1874   fold f [x1, ..., xN] y =
  1875     y |> f x1 |> ... |> f xN
  1876 
  1877   (fold o fold) f [xs1, ..., xsN] y =
  1878     y |> fold f xs1 |> ... |> fold f xsN
  1879 
  1880   fold f [x1, ..., xN] =
  1881     f x1 #> ... #> f xN
  1882 
  1883   (fold o fold) f [xs1, ..., xsN] =
  1884     fold f xs1 #> ... #> fold f xsN
  1885 
  1886 * Pure/library.ML: the following selectors on type 'a option are
  1887 available:
  1888 
  1889   the:               'a option -> 'a  (*partial*)
  1890   these:             'a option -> 'a  where 'a = 'b list
  1891   the_default: 'a -> 'a option -> 'a
  1892   the_list:          'a option -> 'a list
  1893 
  1894 * Pure/General: structure AList (cf. Pure/General/alist.ML) provides
  1895 basic operations for association lists, following natural argument
  1896 order; moreover the explicit equality predicate passed here avoids
  1897 potentially expensive polymorphic runtime equality checks.
  1898 The old functions may be expressed as follows:
  1899 
  1900   assoc = uncurry (AList.lookup (op =))
  1901   assocs = these oo AList.lookup (op =)
  1902   overwrite = uncurry (AList.update (op =)) o swap
  1903 
  1904 * Pure/General: structure AList (cf. Pure/General/alist.ML) provides
  1905 
  1906   val make: ('a -> 'b) -> 'a list -> ('a * 'b) list
  1907   val find: ('a * 'b -> bool) -> ('c * 'b) list -> 'a -> 'c list
  1908 
  1909 replacing make_keylist and keyfilter (occassionally used)
  1910 Naive rewrites:
  1911 
  1912   make_keylist = AList.make
  1913   keyfilter = AList.find (op =)
  1914 
  1915 * eq_fst and eq_snd now take explicit equality parameter, thus
  1916   avoiding eqtypes. Naive rewrites:
  1917 
  1918     eq_fst = eq_fst (op =)
  1919     eq_snd = eq_snd (op =)
  1920 
  1921 * Removed deprecated apl and apr (rarely used).
  1922   Naive rewrites:
  1923 
  1924     apl (n, op) =>>= curry op n
  1925     apr (op, m) =>>= fn n => op (n, m)
  1926 
  1927 * Pure/General: structure OrdList (cf. Pure/General/ord_list.ML)
  1928 provides a reasonably efficient light-weight implementation of sets as
  1929 lists.
  1930 
  1931 * Pure/General: generic tables (cf. Pure/General/table.ML) provide a
  1932 few new operations; existing lookup and update are now curried to
  1933 follow natural argument order (for use with fold etc.);
  1934 INCOMPATIBILITY, use (uncurry Symtab.lookup) etc. as last resort.
  1935 
  1936 * Pure/General: output via the Isabelle channels of
  1937 writeln/warning/error etc. is now passed through Output.output, with a
  1938 hook for arbitrary transformations depending on the print_mode
  1939 (cf. Output.add_mode -- the first active mode that provides a output
  1940 function wins).  Already formatted output may be embedded into further
  1941 text via Output.raw; the result of Pretty.string_of/str_of and derived
  1942 functions (string_of_term/cterm/thm etc.) is already marked raw to
  1943 accommodate easy composition of diagnostic messages etc.  Programmers
  1944 rarely need to care about Output.output or Output.raw at all, with
  1945 some notable exceptions: Output.output is required when bypassing the
  1946 standard channels (writeln etc.), or in token translations to produce
  1947 properly formatted results; Output.raw is required when capturing
  1948 already output material that will eventually be presented to the user
  1949 a second time.  For the default print mode, both Output.output and
  1950 Output.raw have no effect.
  1951 
  1952 * Pure/General: Output.time_accumulator NAME creates an operator ('a
  1953 -> 'b) -> 'a -> 'b to measure runtime and count invocations; the
  1954 cumulative results are displayed at the end of a batch session.
  1955 
  1956 * Pure/General: File.sysify_path and File.quote_sysify path have been
  1957 replaced by File.platform_path and File.shell_path (with appropriate
  1958 hooks).  This provides a clean interface for unusual systems where the
  1959 internal and external process view of file names are different.
  1960 
  1961 * Pure: more efficient orders for basic syntactic entities: added
  1962 fast_string_ord, fast_indexname_ord, fast_term_ord; changed sort_ord
  1963 and typ_ord to use fast_string_ord and fast_indexname_ord (term_ord is
  1964 NOT affected); structures Symtab, Vartab, Typtab, Termtab use the fast
  1965 orders now -- potential INCOMPATIBILITY for code that depends on a
  1966 particular order for Symtab.keys, Symtab.dest, etc. (consider using
  1967 Library.sort_strings on result).
  1968 
  1969 * Pure/term.ML: combinators fold_atyps, fold_aterms, fold_term_types,
  1970 fold_types traverse types/terms from left to right, observing natural
  1971 argument order.  Supercedes previous foldl_XXX versions, add_frees,
  1972 add_vars etc. have been adapted as well: INCOMPATIBILITY.
  1973 
  1974 * Pure: name spaces have been refined, with significant changes of the
  1975 internal interfaces -- INCOMPATIBILITY.  Renamed cond_extern(_table)
  1976 to extern(_table).  The plain name entry path is superceded by a
  1977 general 'naming' context, which also includes the 'policy' to produce
  1978 a fully qualified name and external accesses of a fully qualified
  1979 name; NameSpace.extend is superceded by context dependent
  1980 Sign.declare_name.  Several theory and proof context operations modify
  1981 the naming context.  Especially note Theory.restore_naming and
  1982 ProofContext.restore_naming to get back to a sane state; note that
  1983 Theory.add_path is no longer sufficient to recover from
  1984 Theory.absolute_path in particular.
  1985 
  1986 * Pure: new flags short_names (default false) and unique_names
  1987 (default true) for controlling output of qualified names.  If
  1988 short_names is set, names are printed unqualified.  If unique_names is
  1989 reset, the name prefix is reduced to the minimum required to achieve
  1990 the original result when interning again, even if there is an overlap
  1991 with earlier declarations.
  1992 
  1993 * Pure/TheoryDataFun: change of the argument structure; 'prep_ext' is
  1994 now 'extend', and 'merge' gets an additional Pretty.pp argument
  1995 (useful for printing error messages).  INCOMPATIBILITY.
  1996 
  1997 * Pure: major reorganization of the theory context.  Type Sign.sg and
  1998 Theory.theory are now identified, referring to the universal
  1999 Context.theory (see Pure/context.ML).  Actual signature and theory
  2000 content is managed as theory data.  The old code and interfaces were
  2001 spread over many files and structures; the new arrangement introduces
  2002 considerable INCOMPATIBILITY to gain more clarity:
  2003 
  2004   Context -- theory management operations (name, identity, inclusion,
  2005     parents, ancestors, merge, etc.), plus generic theory data;
  2006 
  2007   Sign -- logical signature and syntax operations (declaring consts,
  2008     types, etc.), plus certify/read for common entities;
  2009 
  2010   Theory -- logical theory operations (stating axioms, definitions,
  2011     oracles), plus a copy of logical signature operations (consts,
  2012     types, etc.); also a few basic management operations (Theory.copy,
  2013     Theory.merge, etc.)
  2014 
  2015 The most basic sign_of operations (Theory.sign_of, Thm.sign_of_thm
  2016 etc.) as well as the sign field in Thm.rep_thm etc. have been retained
  2017 for convenience -- they merely return the theory.
  2018 
  2019 * Pure: type Type.tsig is superceded by theory in most interfaces.
  2020 
  2021 * Pure: the Isar proof context type is already defined early in Pure
  2022 as Context.proof (note that ProofContext.context and Proof.context are
  2023 aliases, where the latter is the preferred name).  This enables other
  2024 Isabelle components to refer to that type even before Isar is present.
  2025 
  2026 * Pure/sign/theory: discontinued named name spaces (i.e. classK,
  2027 typeK, constK, axiomK, oracleK), but provide explicit operations for
  2028 any of these kinds.  For example, Sign.intern typeK is now
  2029 Sign.intern_type, Theory.hide_space Sign.typeK is now
  2030 Theory.hide_types.  Also note that former
  2031 Theory.hide_classes/types/consts are now
  2032 Theory.hide_classes_i/types_i/consts_i, while the non '_i' versions
  2033 internalize their arguments!  INCOMPATIBILITY.
  2034 
  2035 * Pure: get_thm interface (of PureThy and ProofContext) expects
  2036 datatype thmref (with constructors Name and NameSelection) instead of
  2037 plain string -- INCOMPATIBILITY;
  2038 
  2039 * Pure: cases produced by proof methods specify options, where NONE
  2040 means to remove case bindings -- INCOMPATIBILITY in
  2041 (RAW_)METHOD_CASES.
  2042 
  2043 * Pure: the following operations retrieve axioms or theorems from a
  2044 theory node or theory hierarchy, respectively:
  2045 
  2046   Theory.axioms_of: theory -> (string * term) list
  2047   Theory.all_axioms_of: theory -> (string * term) list
  2048   PureThy.thms_of: theory -> (string * thm) list
  2049   PureThy.all_thms_of: theory -> (string * thm) list
  2050 
  2051 * Pure: print_tac now outputs the goal through the trace channel.
  2052 
  2053 * Isar toplevel: improved diagnostics, mostly for Poly/ML only.
  2054 Reference Toplevel.debug (default false) controls detailed printing
  2055 and tracing of low-level exceptions; Toplevel.profiling (default 0)
  2056 controls execution profiling -- set to 1 for time and 2 for space
  2057 (both increase the runtime).
  2058 
  2059 * Isar session: The initial use of ROOT.ML is now always timed,
  2060 i.e. the log will show the actual process times, in contrast to the
  2061 elapsed wall-clock time that the outer shell wrapper produces.
  2062 
  2063 * Simplifier: improved handling of bound variables (nameless
  2064 representation, avoid allocating new strings).  Simprocs that invoke
  2065 the Simplifier recursively should use Simplifier.inherit_bounds to
  2066 avoid local name clashes.  Failure to do so produces warnings
  2067 "Simplifier: renamed bound variable ..."; set Simplifier.debug_bounds
  2068 for further details.
  2069 
  2070 * ML functions legacy_bindings and use_legacy_bindings produce ML fact
  2071 bindings for all theorems stored within a given theory; this may help
  2072 in porting non-Isar theories to Isar ones, while keeping ML proof
  2073 scripts for the time being.
  2074 
  2075 * ML operator HTML.with_charset specifies the charset begin used for
  2076 generated HTML files.  For example:
  2077 
  2078   HTML.with_charset "utf-8" use_thy "Hebrew";
  2079   HTML.with_charset "utf-8" use_thy "Chinese";
  2080 
  2081 
  2082 *** System ***
  2083 
  2084 * Allow symlinks to all proper Isabelle executables (Isabelle,
  2085 isabelle, isatool etc.).
  2086 
  2087 * ISABELLE_DOC_FORMAT setting specifies preferred document format (for
  2088 isatool doc, isatool mkdir, display_drafts etc.).
  2089 
  2090 * isatool usedir: option -f allows specification of the ML file to be
  2091 used by Isabelle; default is ROOT.ML.
  2092 
  2093 * New isatool version outputs the version identifier of the Isabelle
  2094 distribution being used.
  2095 
  2096 * HOL: new isatool dimacs2hol converts files in DIMACS CNF format
  2097 (containing Boolean satisfiability problems) into Isabelle/HOL
  2098 theories.
  2099 
  2100 
  2101 
  2102 New in Isabelle2004 (April 2004)
  2103 --------------------------------
  2104 
  2105 *** General ***
  2106 
  2107 * Provers/order.ML:  new efficient reasoner for partial and linear orders.
  2108   Replaces linorder.ML.
  2109 
  2110 * Pure: Greek letters (except small lambda, \<lambda>), as well as Gothic
  2111   (\<aa>...\<zz>\<AA>...\<ZZ>), calligraphic (\<A>...\<Z>), and Euler
  2112   (\<a>...\<z>), are now considered normal letters, and can therefore
  2113   be used anywhere where an ASCII letter (a...zA...Z) has until
  2114   now. COMPATIBILITY: This obviously changes the parsing of some
  2115   terms, especially where a symbol has been used as a binder, say
  2116   '\<Pi>x. ...', which is now a type error since \<Pi>x will be parsed
  2117   as an identifier.  Fix it by inserting a space around former
  2118   symbols.  Call 'isatool fixgreek' to try to fix parsing errors in
  2119   existing theory and ML files.
  2120 
  2121 * Pure: Macintosh and Windows line-breaks are now allowed in theory files.
  2122 
  2123 * Pure: single letter sub/superscripts (\<^isub> and \<^isup>) are now
  2124   allowed in identifiers. Similar to Greek letters \<^isub> is now considered
  2125   a normal (but invisible) letter. For multiple letter subscripts repeat
  2126   \<^isub> like this: x\<^isub>1\<^isub>2.
  2127 
  2128 * Pure: There are now sub-/superscripts that can span more than one
  2129   character. Text between \<^bsub> and \<^esub> is set in subscript in
  2130   ProofGeneral and LaTeX, text between \<^bsup> and \<^esup> in
  2131   superscript. The new control characters are not identifier parts.
  2132 
  2133 * Pure: Control-symbols of the form \<^raw:...> will literally print the
  2134   content of "..." to the latex file instead of \isacntrl... . The "..."
  2135   may consist of any printable characters excluding the end bracket >.
  2136 
  2137 * Pure: Using new Isar command "finalconsts" (or the ML functions
  2138   Theory.add_finals or Theory.add_finals_i) it is now possible to
  2139   declare constants "final", which prevents their being given a definition
  2140   later.  It is useful for constants whose behaviour is fixed axiomatically
  2141   rather than definitionally, such as the meta-logic connectives.
  2142 
  2143 * Pure: 'instance' now handles general arities with general sorts
  2144   (i.e. intersections of classes),
  2145 
  2146 * Presentation: generated HTML now uses a CSS style sheet to make layout
  2147   (somewhat) independent of content. It is copied from lib/html/isabelle.css.
  2148   It can be changed to alter the colors/layout of generated pages.
  2149 
  2150 
  2151 *** Isar ***
  2152 
  2153 * Tactic emulation methods rule_tac, erule_tac, drule_tac, frule_tac,
  2154   cut_tac, subgoal_tac and thin_tac:
  2155   - Now understand static (Isar) contexts.  As a consequence, users of Isar
  2156     locales are no longer forced to write Isar proof scripts.
  2157     For details see Isar Reference Manual, paragraph 4.3.2: Further tactic
  2158     emulations.
  2159   - INCOMPATIBILITY: names of variables to be instantiated may no
  2160     longer be enclosed in quotes.  Instead, precede variable name with `?'.
  2161     This is consistent with the instantiation attribute "where".
  2162 
  2163 * Attributes "where" and "of":
  2164   - Now take type variables of instantiated theorem into account when reading
  2165     the instantiation string.  This fixes a bug that caused instantiated
  2166     theorems to have too special types in some circumstances.
  2167   - "where" permits explicit instantiations of type variables.
  2168 
  2169 * Calculation commands "moreover" and "also" no longer interfere with
  2170   current facts ("this"), admitting arbitrary combinations with "then"
  2171   and derived forms.
  2172 
  2173 * Locales:
  2174   - Goal statements involving the context element "includes" no longer
  2175     generate theorems with internal delta predicates (those ending on
  2176     "_axioms") in the premise.
  2177     Resolve particular premise with <locale>.intro to obtain old form.
  2178   - Fixed bug in type inference ("unify_frozen") that prevented mix of target
  2179     specification and "includes" elements in goal statement.
  2180   - Rule sets <locale>.intro and <locale>.axioms no longer declared as
  2181     [intro?] and [elim?] (respectively) by default.
  2182   - Experimental command for instantiation of locales in proof contexts:
  2183         instantiate <label>[<attrs>]: <loc>
  2184     Instantiates locale <loc> and adds all its theorems to the current context
  2185     taking into account their attributes.  Label and attrs are optional
  2186     modifiers, like in theorem declarations.  If present, names of
  2187     instantiated theorems are qualified with <label>, and the attributes
  2188     <attrs> are applied after any attributes these theorems might have already.
  2189       If the locale has assumptions, a chained fact of the form
  2190     "<loc> t1 ... tn" is expected from which instantiations of the parameters
  2191     are derived.  The command does not support old-style locales declared
  2192     with "locale (open)".
  2193       A few (very simple) examples can be found in FOL/ex/LocaleInst.thy.
  2194 
  2195 * HOL: Tactic emulation methods induct_tac and case_tac understand static
  2196   (Isar) contexts.
  2197 
  2198 
  2199 *** HOL ***
  2200 
  2201 * Proof import: new image HOL4 contains the imported library from
  2202   the HOL4 system with about 2500 theorems. It is imported by
  2203   replaying proof terms produced by HOL4 in Isabelle. The HOL4 image
  2204   can be used like any other Isabelle image.  See
  2205   HOL/Import/HOL/README for more information.
  2206 
  2207 * Simplifier:
  2208   - Much improved handling of linear and partial orders.
  2209     Reasoners for linear and partial orders are set up for type classes
  2210     "linorder" and "order" respectively, and are added to the default simpset
  2211     as solvers.  This means that the simplifier can build transitivity chains
  2212     to solve goals from the assumptions.
  2213   - INCOMPATIBILITY: old proofs break occasionally.  Typically, applications
  2214     of blast or auto after simplification become unnecessary because the goal
  2215     is solved by simplification already.
  2216 
  2217 * Numerics: new theory Ring_and_Field contains over 250 basic numerical laws,
  2218     all proved in axiomatic type classes for semirings, rings and fields.
  2219 
  2220 * Numerics:
  2221   - Numeric types (nat, int, and in HOL-Complex rat, real, complex, etc.) are
  2222     now formalized using the Ring_and_Field theory mentioned above.
  2223   - INCOMPATIBILITY: simplification and arithmetic behaves somewhat differently
  2224     than before, because now they are set up once in a generic manner.
  2225   - INCOMPATIBILITY: many type-specific arithmetic laws have gone.
  2226     Look for the general versions in Ring_and_Field (and Power if they concern
  2227     exponentiation).
  2228 
  2229 * Type "rat" of the rational numbers is now available in HOL-Complex.
  2230 
  2231 * Records:
  2232   - Record types are now by default printed with their type abbreviation
  2233     instead of the list of all field types. This can be configured via
  2234     the reference "print_record_type_abbr".
  2235   - Simproc "record_upd_simproc" for simplification of multiple updates added
  2236     (not enabled by default).
  2237   - Simproc "record_ex_sel_eq_simproc" to simplify EX x. sel r = x resp.
  2238     EX x. x = sel r to True (not enabled by default).
  2239   - Tactic "record_split_simp_tac" to split and simplify records added.
  2240 
  2241 * 'specification' command added, allowing for definition by
  2242   specification.  There is also an 'ax_specification' command that
  2243   introduces the new constants axiomatically.
  2244 
  2245 * arith(_tac) is now able to generate counterexamples for reals as well.
  2246 
  2247 * HOL-Algebra: new locale "ring" for non-commutative rings.
  2248 
  2249 * HOL-ex: InductiveInvariant_examples illustrates advanced recursive function
  2250   definitions, thanks to Sava Krsti\'{c} and John Matthews.
  2251 
  2252 * HOL-Matrix: a first theory for matrices in HOL with an application of
  2253   matrix theory to linear programming.
  2254 
  2255 * Unions and Intersections:
  2256   The latex output syntax of UN and INT has been changed
  2257   from "\Union x \in A. B" to "\Union_{x \in A} B"
  2258   i.e. the index formulae has become a subscript.
  2259   Similarly for "\Union x. B", and for \Inter instead of \Union.
  2260 
  2261 * Unions and Intersections over Intervals:
  2262   There is new short syntax "UN i<=n. A" for "UN i:{0..n}. A". There is
  2263   also an x-symbol version with subscripts "\<Union>\<^bsub>i <= n\<^esub>. A"
  2264   like in normal math, and corresponding versions for < and for intersection.
  2265 
  2266 * HOL/List: Ordering "lexico" is renamed "lenlex" and the standard
  2267   lexicographic dictonary ordering has been added as "lexord".
  2268 
  2269 * ML: the legacy theory structures Int and List have been removed. They had
  2270   conflicted with ML Basis Library structures having the same names.
  2271 
  2272 * 'refute' command added to search for (finite) countermodels.  Only works
  2273   for a fragment of HOL.  The installation of an external SAT solver is
  2274   highly recommended.  See "HOL/Refute.thy" for details.
  2275 
  2276 * 'quickcheck' command: Allows to find counterexamples by evaluating
  2277   formulae under an assignment of free variables to random values.
  2278   In contrast to 'refute', it can deal with inductive datatypes,
  2279   but cannot handle quantifiers. See "HOL/ex/Quickcheck_Examples.thy"
  2280   for examples.
  2281 
  2282 
  2283 *** HOLCF ***
  2284 
  2285 * Streams now come with concatenation and are part of the HOLCF image
  2286 
  2287 
  2288 
  2289 New in Isabelle2003 (May 2003)
  2290 ------------------------------
  2291 
  2292 *** General ***
  2293 
  2294 * Provers/simplifier:
  2295 
  2296   - Completely reimplemented method simp (ML: Asm_full_simp_tac):
  2297     Assumptions are now subject to complete mutual simplification,
  2298     not just from left to right. The simplifier now preserves
  2299     the order of assumptions.
  2300 
  2301     Potential INCOMPATIBILITY:
  2302 
  2303     -- simp sometimes diverges where the old version did
  2304        not, e.g. invoking simp on the goal
  2305 
  2306         [| P (f x); y = x; f x = f y |] ==> Q
  2307 
  2308        now gives rise to the infinite reduction sequence
  2309 
  2310         P(f x) --(f x = f y)--> P(f y) --(y = x)--> P(f x) --(f x = f y)--> ...
  2311 
  2312        Using "simp (asm_lr)" (ML: Asm_lr_simp_tac) instead often solves this
  2313        kind of problem.
  2314 
  2315     -- Tactics combining classical reasoner and simplification (such as auto)
  2316        are also affected by this change, because many of them rely on
  2317        simp. They may sometimes diverge as well or yield a different numbers
  2318        of subgoals. Try to use e.g. force, fastsimp, or safe instead of auto
  2319        in case of problems. Sometimes subsequent calls to the classical
  2320        reasoner will fail because a preceeding call to the simplifier too
  2321        eagerly simplified the goal, e.g. deleted redundant premises.
  2322 
  2323   - The simplifier trace now shows the names of the applied rewrite rules
  2324 
  2325   - You can limit the number of recursive invocations of the simplifier
  2326     during conditional rewriting (where the simplifie tries to solve the
  2327     conditions before applying the rewrite rule):
  2328     ML "simp_depth_limit := n"
  2329     where n is an integer. Thus you can force termination where previously
  2330     the simplifier would diverge.
  2331 
  2332   - Accepts free variables as head terms in congruence rules.  Useful in Isar.
  2333 
  2334   - No longer aborts on failed congruence proof.  Instead, the
  2335     congruence is ignored.
  2336 
  2337 * Pure: New generic framework for extracting programs from constructive
  2338   proofs. See HOL/Extraction.thy for an example instantiation, as well
  2339   as HOL/Extraction for some case studies.
  2340 
  2341 * Pure: The main goal of the proof state is no longer shown by default, only
  2342 the subgoals. This behaviour is controlled by a new flag.
  2343    PG menu: Isabelle/Isar -> Settings -> Show Main Goal
  2344 (ML: Proof.show_main_goal).
  2345 
  2346 * Pure: You can find all matching introduction rules for subgoal 1, i.e. all
  2347 rules whose conclusion matches subgoal 1:
  2348       PG menu: Isabelle/Isar -> Show me -> matching rules
  2349 The rules are ordered by how closely they match the subgoal.
  2350 In particular, rules that solve a subgoal outright are displayed first
  2351 (or rather last, the way they are printed).
  2352 (ML: ProofGeneral.print_intros())
  2353 
  2354 * Pure: New flag trace_unify_fail causes unification to print
  2355 diagnostic information (PG: in trace buffer) when it fails. This is
  2356 useful for figuring out why single step proofs like rule, erule or
  2357 assumption failed.
  2358 
  2359 * Pure: Locale specifications now produce predicate definitions
  2360 according to the body of text (covering assumptions modulo local
  2361 definitions); predicate "loc_axioms" covers newly introduced text,
  2362 while "loc" is cumulative wrt. all included locale expressions; the
  2363 latter view is presented only on export into the global theory
  2364 context; potential INCOMPATIBILITY, use "(open)" option to fall back
  2365 on the old view without predicates;
  2366 
  2367 * Pure: predefined locales "var" and "struct" are useful for sharing
  2368 parameters (as in CASL, for example); just specify something like
  2369 ``var x + var y + struct M'' as import;
  2370 
  2371 * Pure: improved thms_containing: proper indexing of facts instead of
  2372 raw theorems; check validity of results wrt. current name space;
  2373 include local facts of proof configuration (also covers active
  2374 locales), cover fixed variables in index; may use "_" in term
  2375 specification; an optional limit for the number of printed facts may
  2376 be given (the default is 40);
  2377 
  2378 * Pure: disallow duplicate fact bindings within new-style theory files
  2379 (batch-mode only);
  2380 
  2381 * Provers: improved induct method: assumptions introduced by case
  2382 "foo" are split into "foo.hyps" (from the rule) and "foo.prems" (from
  2383 the goal statement); "foo" still refers to all facts collectively;
  2384 
  2385 * Provers: the function blast.overloaded has been removed: all constants
  2386 are regarded as potentially overloaded, which improves robustness in exchange
  2387 for slight decrease in efficiency;
  2388 
  2389 * Provers/linorder: New generic prover for transitivity reasoning over
  2390 linear orders.  Note: this prover is not efficient!
  2391 
  2392 * Isar: preview of problems to finish 'show' now produce an error
  2393 rather than just a warning (in interactive mode);
  2394 
  2395 
  2396 *** HOL ***
  2397 
  2398 * arith(_tac)
  2399 
  2400  - Produces a counter example if it cannot prove a goal.
  2401    Note that the counter example may be spurious if the goal is not a formula
  2402    of quantifier-free linear arithmetic.
  2403    In ProofGeneral the counter example appears in the trace buffer.
  2404 
  2405  - Knows about div k and mod k where k is a numeral of type nat or int.
  2406 
  2407  - Calls full Presburger arithmetic (by Amine Chaieb) if quantifier-free
  2408    linear arithmetic fails. This takes account of quantifiers and divisibility.
  2409    Presburger arithmetic can also be called explicitly via presburger(_tac).
  2410 
  2411 * simp's arithmetic capabilities have been enhanced a bit: it now
  2412 takes ~= in premises into account (by performing a case split);
  2413 
  2414 * simp reduces "m*(n div m) + n mod m" to n, even if the two summands
  2415 are distributed over a sum of terms;
  2416 
  2417 * New tactic "trans_tac" and method "trans" instantiate
  2418 Provers/linorder.ML for axclasses "order" and "linorder" (predicates
  2419 "<=", "<" and "=").
  2420 
  2421 * function INCOMPATIBILITIES: Pi-sets have been redefined and moved from main
  2422 HOL to Library/FuncSet; constant "Fun.op o" is now called "Fun.comp";
  2423 
  2424 * 'typedef' command has new option "open" to suppress the set
  2425 definition;
  2426 
  2427 * functions Min and Max on finite sets have been introduced (theory
  2428 Finite_Set);
  2429 
  2430 * attribute [symmetric] now works for relations as well; it turns
  2431 (x,y) : R^-1 into (y,x) : R, and vice versa;
  2432 
  2433 * induct over a !!-quantified statement (say !!x1..xn):
  2434   each "case" automatically performs "fix x1 .. xn" with exactly those names.
  2435 
  2436 * Map: `empty' is no longer a constant but a syntactic abbreviation for
  2437 %x. None. Warning: empty_def now refers to the previously hidden definition
  2438 of the empty set.
  2439 
  2440 * Algebra: formalization of classical algebra.  Intended as base for
  2441 any algebraic development in Isabelle.  Currently covers group theory
  2442 (up to Sylow's theorem) and ring theory (Universal Property of
  2443 Univariate Polynomials).  Contributions welcome;
  2444 
  2445 * GroupTheory: deleted, since its material has been moved to Algebra;
  2446 
  2447 * Complex: new directory of the complex numbers with numeric constants,
  2448 nonstandard complex numbers, and some complex analysis, standard and
  2449 nonstandard (Jacques Fleuriot);
  2450 
  2451 * HOL-Complex: new image for analysis, replacing HOL-Real and HOL-Hyperreal;
  2452 
  2453 * Hyperreal: introduced Gauge integration and hyperreal logarithms (Jacques
  2454 Fleuriot);
  2455 
  2456 * Real/HahnBanach: updated and adapted to locales;
  2457 
  2458 * NumberTheory: added Gauss's law of quadratic reciprocity (by Avigad,
  2459 Gray and Kramer);
  2460 
  2461 * UNITY: added the Meier-Sanders theory of progress sets;
  2462 
  2463 * MicroJava: bytecode verifier and lightweight bytecode verifier
  2464 as abstract algorithms, instantiated to the JVM;
  2465 
  2466 * Bali: Java source language formalization. Type system, operational
  2467 semantics, axiomatic semantics. Supported language features:
  2468 classes, interfaces, objects,virtual methods, static methods,
  2469 static/instance fields, arrays, access modifiers, definite
  2470 assignment, exceptions.
  2471 
  2472 
  2473 *** ZF ***
  2474 
  2475 * ZF/Constructible: consistency proof for AC (Gdel's constructible
  2476 universe, etc.);
  2477 
  2478 * Main ZF: virtually all theories converted to new-style format;
  2479 
  2480 
  2481 *** ML ***
  2482 
  2483 * Pure: Tactic.prove provides sane interface for internal proofs;
  2484 omits the infamous "standard" operation, so this is more appropriate
  2485 than prove_goalw_cterm in many situations (e.g. in simprocs);
  2486 
  2487 * Pure: improved error reporting of simprocs;
  2488 
  2489 * Provers: Simplifier.simproc(_i) provides sane interface for setting
  2490 up simprocs;
  2491 
  2492 
  2493 *** Document preparation ***
  2494 
  2495 * uses \par instead of \\ for line breaks in theory text. This may
  2496 shift some page breaks in large documents. To get the old behaviour
  2497 use \renewcommand{\isanewline}{\mbox{}\\\mbox{}} in root.tex.
  2498 
  2499 * minimized dependencies of isabelle.sty and isabellesym.sty on
  2500 other packages
  2501 
  2502 * \<euro> now needs package babel/greek instead of marvosym (which
  2503 broke \Rightarrow)
  2504 
  2505 * normal size for \<zero>...\<nine> (uses \mathbf instead of
  2506 textcomp package)
  2507 
  2508 
  2509 
  2510 New in Isabelle2002 (March 2002)
  2511 --------------------------------
  2512 
  2513 *** Document preparation ***
  2514 
  2515 * greatly simplified document preparation setup, including more
  2516 graceful interpretation of isatool usedir -i/-d/-D options, and more
  2517 instructive isatool mkdir; users should basically be able to get
  2518 started with "isatool mkdir HOL Test && isatool make"; alternatively,
  2519 users may run a separate document processing stage manually like this:
  2520 "isatool usedir -D output HOL Test && isatool document Test/output";
  2521 
  2522 * theory dependency graph may now be incorporated into documents;
  2523 isatool usedir -g true will produce session_graph.eps/.pdf for use
  2524 with \includegraphics of LaTeX;
  2525 
  2526 * proper spacing of consecutive markup elements, especially text
  2527 blocks after section headings;
  2528 
  2529 * support bold style (for single symbols only), input syntax is like
  2530 this: "\<^bold>\<alpha>" or "\<^bold>A";
  2531 
  2532 * \<bullet> is now output as bold \cdot by default, which looks much
  2533 better in printed text;
  2534 
  2535 * added default LaTeX bindings for \<tturnstile> and \<TTurnstile>;
  2536 note that these symbols are currently unavailable in Proof General /
  2537 X-Symbol; new symbols \<zero>, \<one>, ..., \<nine>, and \<euro>;
  2538 
  2539 * isatool latex no longer depends on changed TEXINPUTS, instead
  2540 isatool document copies the Isabelle style files to the target
  2541 location;
  2542 
  2543 
  2544 *** Isar ***
  2545 
  2546 * Pure/Provers: improved proof by cases and induction;
  2547   - 'case' command admits impromptu naming of parameters (such as
  2548     "case (Suc n)");
  2549   - 'induct' method divinates rule instantiation from the inductive
  2550     claim; no longer requires excessive ?P bindings for proper
  2551     instantiation of cases;
  2552   - 'induct' method properly enumerates all possibilities of set/type
  2553     rules; as a consequence facts may be also passed through *type*
  2554     rules without further ado;
  2555   - 'induct' method now derives symbolic cases from the *rulified*
  2556     rule (before it used to rulify cases stemming from the internal
  2557     atomized version); this means that the context of a non-atomic
  2558     statement becomes is included in the hypothesis, avoiding the
  2559     slightly cumbersome show "PROP ?case" form;
  2560   - 'induct' may now use elim-style induction rules without chaining
  2561     facts, using ``missing'' premises from the goal state; this allows
  2562     rules stemming from inductive sets to be applied in unstructured
  2563     scripts, while still benefitting from proper handling of non-atomic
  2564     statements; NB: major inductive premises need to be put first, all
  2565     the rest of the goal is passed through the induction;
  2566   - 'induct' proper support for mutual induction involving non-atomic
  2567     rule statements (uses the new concept of simultaneous goals, see
  2568     below);
  2569   - append all possible rule selections, but only use the first
  2570     success (no backtracking);
  2571   - removed obsolete "(simplified)" and "(stripped)" options of methods;
  2572   - undeclared rule case names default to numbers 1, 2, 3, ...;
  2573   - added 'print_induct_rules' (covered by help item in recent Proof
  2574     General versions);
  2575   - moved induct/cases attributes to Pure, methods to Provers;
  2576   - generic method setup instantiated for FOL and HOL;
  2577 
  2578 * Pure: support multiple simultaneous goal statements, for example
  2579 "have a: A and b: B" (same for 'theorem' etc.); being a pure
  2580 meta-level mechanism, this acts as if several individual goals had
  2581 been stated separately; in particular common proof methods need to be
  2582 repeated in order to cover all claims; note that a single elimination
  2583 step is *not* sufficient to establish the two conjunctions, so this
  2584 fails:
  2585 
  2586   assume "A & B" then have A and B ..   (*".." fails*)
  2587 
  2588 better use "obtain" in situations as above; alternative refer to
  2589 multi-step methods like 'auto', 'simp_all', 'blast+' etc.;
  2590 
  2591 * Pure: proper integration with ``locales''; unlike the original
  2592 version by Florian Kammller, Isar locales package high-level proof
  2593 contexts rather than raw logical ones (e.g. we admit to include
  2594 attributes everywhere); operations on locales include merge and
  2595 rename; support for implicit arguments (``structures''); simultaneous
  2596 type-inference over imports and text; see also HOL/ex/Locales.thy for
  2597 some examples;
  2598 
  2599 * Pure: the following commands have been ``localized'', supporting a
  2600 target locale specification "(in name)": 'lemma', 'theorem',
  2601 'corollary', 'lemmas', 'theorems', 'declare'; the results will be
  2602 stored both within the locale and at the theory level (exported and
  2603 qualified by the locale name);
  2604 
  2605 * Pure: theory goals may now be specified in ``long'' form, with
  2606 ad-hoc contexts consisting of arbitrary locale elements. for example
  2607 ``lemma foo: fixes x assumes "A x" shows "B x"'' (local syntax and
  2608 definitions may be given, too); the result is a meta-level rule with
  2609 the context elements being discharged in the obvious way;
  2610 
  2611 * Pure: new proof command 'using' allows to augment currently used
  2612 facts after a goal statement ('using' is syntactically analogous to
  2613 'apply', but acts on the goal's facts only); this allows chained facts
  2614 to be separated into parts given before and after a claim, as in
  2615 ``from a and b have C using d and e <proof>'';
  2616 
  2617 * Pure: renamed "antecedent" case to "rule_context";
  2618 
  2619 * Pure: new 'judgment' command records explicit information about the
  2620 object-logic embedding (used by several tools internally); no longer
  2621 use hard-wired "Trueprop";
  2622 
  2623 * Pure: added 'corollary' command;
  2624 
  2625 * Pure: fixed 'token_translation' command;
  2626 
  2627 * Pure: removed obsolete 'exported' attribute;
  2628 
  2629 * Pure: dummy pattern "_" in is/let is now automatically lifted over
  2630 bound variables: "ALL x. P x --> Q x" (is "ALL x. _ --> ?C x")
  2631 supersedes more cumbersome ... (is "ALL x. _ x --> ?C x");
  2632 
  2633 * Pure: method 'atomize' presents local goal premises as object-level
  2634 statements (atomic meta-level propositions); setup controlled via
  2635 rewrite rules declarations of 'atomize' attribute; example
  2636 application: 'induct' method with proper rule statements in improper
  2637 proof *scripts*;
  2638 
  2639 * Pure: emulation of instantiation tactics (rule_tac, cut_tac, etc.)
  2640 now consider the syntactic context of assumptions, giving a better
  2641 chance to get type-inference of the arguments right (this is
  2642 especially important for locales);
  2643 
  2644 * Pure: "sorry" no longer requires quick_and_dirty in interactive
  2645 mode;
  2646 
  2647 * Pure/obtain: the formal conclusion "thesis", being marked as
  2648 ``internal'', may no longer be reference directly in the text;
  2649 potential INCOMPATIBILITY, may need to use "?thesis" in rare
  2650 situations;
  2651 
  2652 * Pure: generic 'sym' attribute which declares a rule both as pure
  2653 'elim?' and for the 'symmetric' operation;
  2654 
  2655 * Pure: marginal comments ``--'' may now occur just anywhere in the
  2656 text; the fixed correlation with particular command syntax has been
  2657 discontinued;
  2658 
  2659 * Pure: new method 'rules' is particularly well-suited for proof
  2660 search in intuitionistic logic; a bit slower than 'blast' or 'fast',
  2661 but often produces more compact proof terms with less detours;
  2662 
  2663 * Pure/Provers/classical: simplified integration with pure rule
  2664 attributes and methods; the classical "intro?/elim?/dest?"
  2665 declarations coincide with the pure ones; the "rule" method no longer
  2666 includes classically swapped intros; "intro" and "elim" methods no
  2667 longer pick rules from the context; also got rid of ML declarations
  2668 AddXIs/AddXEs/AddXDs; all of this has some potential for
  2669 INCOMPATIBILITY;
  2670 
  2671 * Provers/classical: attribute 'swapped' produces classical inversions
  2672 of introduction rules;
  2673 
  2674 * Provers/simplifier: 'simplified' attribute may refer to explicit
  2675 rules instead of full simplifier context; 'iff' attribute handles
  2676 conditional rules;
  2677 
  2678 * HOL: 'typedef' now allows alternative names for Rep/Abs morphisms;
  2679 
  2680 * HOL: 'recdef' now fails on unfinished automated proofs, use
  2681 "(permissive)" option to recover old behavior;
  2682 
  2683 * HOL: 'inductive' no longer features separate (collective) attributes
  2684 for 'intros' (was found too confusing);
  2685 
  2686 * HOL: properly declared induction rules less_induct and
  2687 wf_induct_rule;
  2688 
  2689 
  2690 *** HOL ***
  2691 
  2692 * HOL: moved over to sane numeral syntax; the new policy is as
  2693 follows:
  2694 
  2695   - 0 and 1 are polymorphic constants, which are defined on any
  2696   numeric type (nat, int, real etc.);
  2697 
  2698   - 2, 3, 4, ... and -1, -2, -3, ... are polymorphic numerals, based
  2699   binary representation internally;
  2700 
  2701   - type nat has special constructor Suc, and generally prefers Suc 0
  2702   over 1::nat and Suc (Suc 0) over 2::nat;
  2703 
  2704 This change may cause significant problems of INCOMPATIBILITY; here
  2705 are some hints on converting existing sources:
  2706 
  2707   - due to the new "num" token, "-0" and "-1" etc. are now atomic
  2708   entities, so expressions involving "-" (unary or binary minus) need
  2709   to be spaced properly;
  2710 
  2711   - existing occurrences of "1" may need to be constraint "1::nat" or
  2712   even replaced by Suc 0; similar for old "2";
  2713 
  2714   - replace "#nnn" by "nnn", and "#-nnn" by "-nnn";
  2715 
  2716   - remove all special provisions on numerals in proofs;
  2717 
  2718 * HOL: simp rules nat_number expand numerals on nat to Suc/0
  2719 representation (depends on bin_arith_simps in the default context);
  2720 
  2721 * HOL: symbolic syntax for x^2 (numeral 2);
  2722 
  2723 * HOL: the class of all HOL types is now called "type" rather than
  2724 "term"; INCOMPATIBILITY, need to adapt references to this type class
  2725 in axclass/classes, instance/arities, and (usually rare) occurrences
  2726 in typings (of consts etc.); internally the class is called
  2727 "HOL.type", ML programs should refer to HOLogic.typeS;
  2728 
  2729 * HOL/record package improvements:
  2730   - new derived operations "fields" to build a partial record section,
  2731     "extend" to promote a fixed record to a record scheme, and
  2732     "truncate" for the reverse; cf. theorems "xxx.defs", which are *not*
  2733     declared as simp by default;
  2734   - shared operations ("more", "fields", etc.) now need to be always
  2735     qualified) --- potential INCOMPATIBILITY;
  2736   - removed "make_scheme" operations (use "make" with "extend") --
  2737     INCOMPATIBILITY;
  2738   - removed "more" class (simply use "term") -- INCOMPATIBILITY;
  2739   - provides cases/induct rules for use with corresponding Isar
  2740     methods (for concrete records, record schemes, concrete more
  2741     parts, and schematic more parts -- in that order);
  2742   - internal definitions directly based on a light-weight abstract
  2743     theory of product types over typedef rather than datatype;
  2744 
  2745 * HOL: generic code generator for generating executable ML code from
  2746 specifications; specific support for HOL constructs such as inductive
  2747 datatypes and sets, as well as recursive functions; can be invoked
  2748 via 'generate_code' theory section;
  2749 
  2750 * HOL: canonical cases/induct rules for n-tuples (n = 3..7);
  2751 
  2752 * HOL: consolidated and renamed several theories.  In particular:
  2753         Ord.thy has been absorbed into HOL.thy
  2754         String.thy has been absorbed into List.thy
  2755 
  2756 * HOL: concrete setsum syntax "\<Sum>i:A. b" == "setsum (%i. b) A"
  2757 (beware of argument permutation!);
  2758 
  2759 * HOL: linorder_less_split superseded by linorder_cases;
  2760 
  2761 * HOL/List: "nodups" renamed to "distinct";
  2762 
  2763 * HOL: added "The" definite description operator; move Hilbert's "Eps"
  2764 to peripheral theory "Hilbert_Choice"; some INCOMPATIBILITIES:
  2765   - Ex_def has changed, now need to use some_eq_ex
  2766 
  2767 * HOL: made split_all_tac safe; EXISTING PROOFS MAY FAIL OR LOOP, so
  2768 in this (rare) case use:
  2769 
  2770   delSWrapper "split_all_tac"
  2771   addSbefore ("unsafe_split_all_tac", unsafe_split_all_tac)
  2772 
  2773 * HOL: added safe wrapper "split_conv_tac" to claset; EXISTING PROOFS
  2774 MAY FAIL;
  2775 
  2776 * HOL: introduced f^n = f o ... o f; warning: due to the limits of
  2777 Isabelle's type classes, ^ on functions and relations has too general
  2778 a domain, namely ('a * 'b) set and 'a => 'b; this means that it may be
  2779 necessary to attach explicit type constraints;
  2780 
  2781 * HOL/Relation: the prefix name of the infix "O" has been changed from
  2782 "comp" to "rel_comp"; INCOMPATIBILITY: a few theorems have been
  2783 renamed accordingly (eg "compI" -> "rel_compI").
  2784 
  2785 * HOL: syntax translations now work properly with numerals and records
  2786 expressions;
  2787 
  2788 * HOL: bounded abstraction now uses syntax "%" / "\<lambda>" instead
  2789 of "lam" -- INCOMPATIBILITY;
  2790 
  2791 * HOL: got rid of some global declarations (potential INCOMPATIBILITY
  2792 for ML tools): const "()" renamed "Product_Type.Unity", type "unit"
  2793 renamed "Product_Type.unit";
  2794 
  2795 * HOL: renamed rtrancl_into_rtrancl2 to converse_rtrancl_into_rtrancl
  2796 
  2797 * HOL: removed obsolete theorem "optionE" (use "option.exhaust", or
  2798 the "cases" method);
  2799 
  2800 * HOL/GroupTheory: group theory examples including Sylow's theorem (by
  2801 Florian Kammller);
  2802 
  2803 * HOL/IMP: updated and converted to new-style theory format; several
  2804 parts turned into readable document, with proper Isar proof texts and
  2805 some explanations (by Gerwin Klein);
  2806 
  2807 * HOL-Real: added Complex_Numbers (by Gertrud Bauer);
  2808 
  2809 * HOL-Hyperreal is now a logic image;
  2810 
  2811 
  2812 *** HOLCF ***
  2813 
  2814 * Isar: consts/constdefs supports mixfix syntax for continuous
  2815 operations;
  2816 
  2817 * Isar: domain package adapted to new-style theory format, e.g. see
  2818 HOLCF/ex/Dnat.thy;
  2819 
  2820 * theory Lift: proper use of rep_datatype lift instead of ML hacks --
  2821 potential INCOMPATIBILITY; now use plain induct_tac instead of former
  2822 lift.induct_tac, always use UU instead of Undef;
  2823 
  2824 * HOLCF/IMP: updated and converted to new-style theory;
  2825 
  2826 
  2827 *** ZF ***
  2828 
  2829 * Isar: proper integration of logic-specific tools and packages,
  2830 including theory commands '(co)inductive', '(co)datatype',
  2831 'rep_datatype', 'inductive_cases', as well as methods 'ind_cases',
  2832 'induct_tac', 'case_tac', and 'typecheck' (with attribute 'TC');
  2833 
  2834 * theory Main no longer includes AC; for the Axiom of Choice, base
  2835 your theory on Main_ZFC;
  2836 
  2837 * the integer library now covers quotients and remainders, with many
  2838 laws relating division to addition, multiplication, etc.;
  2839 
  2840 * ZF/UNITY: Chandy and Misra's UNITY is now available in ZF, giving a
  2841 typeless version of the formalism;
  2842 
  2843 * ZF/AC, Coind, IMP, Resid: updated and converted to new-style theory
  2844 format;
  2845 
  2846 * ZF/Induct: new directory for examples of inductive definitions,
  2847 including theory Multiset for multiset orderings; converted to
  2848 new-style theory format;
  2849 
  2850 * ZF: many new theorems about lists, ordinals, etc.;
  2851 
  2852 
  2853 *** General ***
  2854 
  2855 * Pure/kernel: meta-level proof terms (by Stefan Berghofer); reference
  2856 variable proof controls level of detail: 0 = no proofs (only oracle
  2857 dependencies), 1 = lemma dependencies, 2 = compact proof terms; see
  2858 also ref manual for further ML interfaces;
  2859 
  2860 * Pure/axclass: removed obsolete ML interface
  2861 goal_subclass/goal_arity;
  2862 
  2863 * Pure/syntax: new token syntax "num" for plain numerals (without "#"
  2864 of "xnum"); potential INCOMPATIBILITY, since -0, -1 etc. are now
  2865 separate tokens, so expressions involving minus need to be spaced
  2866 properly;
  2867 
  2868 * Pure/syntax: support non-oriented infixes, using keyword "infix"
  2869 rather than "infixl" or "infixr";
  2870 
  2871 * Pure/syntax: concrete syntax for dummy type variables admits genuine
  2872 sort constraint specifications in type inference; e.g. "x::_::foo"
  2873 ensures that the type of "x" is of sort "foo" (but not necessarily a
  2874 type variable);
  2875 
  2876 * Pure/syntax: print modes "type_brackets" and "no_type_brackets"
  2877 control output of nested => (types); the default behavior is
  2878 "type_brackets";
  2879 
  2880 * Pure/syntax: builtin parse translation for "_constify" turns valued
  2881 tokens into AST constants;
  2882 
  2883 * Pure/syntax: prefer later declarations of translations and print
  2884 translation functions; potential INCOMPATIBILITY: need to reverse
  2885 multiple declarations for same syntax element constant;
  2886 
  2887 * Pure/show_hyps reset by default (in accordance to existing Isar
  2888 practice);
  2889 
  2890 * Provers/classical: renamed addaltern to addafter, addSaltern to
  2891 addSafter;
  2892 
  2893 * Provers/clasimp: ``iff'' declarations now handle conditional rules
  2894 as well;
  2895 
  2896 * system: tested support for MacOS X; should be able to get Isabelle +
  2897 Proof General to work in a plain Terminal after installing Poly/ML
  2898 (e.g. from the Isabelle distribution area) and GNU bash alone
  2899 (e.g. from http://www.apple.com); full X11, XEmacs and X-Symbol
  2900 support requires further installations, e.g. from
  2901 http://fink.sourceforge.net/);
  2902 
  2903 * system: support Poly/ML 4.1.1 (able to manage larger heaps);
  2904 
  2905 * system: reduced base memory usage by Poly/ML (approx. 20 MB instead
  2906 of 40 MB), cf. ML_OPTIONS;
  2907 
  2908 * system: Proof General keywords specification is now part of the
  2909 Isabelle distribution (see etc/isar-keywords.el);
  2910 
  2911 * system: support for persistent Proof General sessions (refrain from
  2912 outdating all loaded theories on startup); user may create writable
  2913 logic images like this: ``isabelle -q HOL Test'';
  2914 
  2915 * system: smart selection of Isabelle process versus Isabelle
  2916 interface, accommodates case-insensitive file systems (e.g. HFS+); may
  2917 run both "isabelle" and "Isabelle" even if file names are badly
  2918 damaged (executable inspects the case of the first letter of its own
  2919 name); added separate "isabelle-process" and "isabelle-interface";
  2920 
  2921 * system: refrain from any attempt at filtering input streams; no
  2922 longer support ``8bit'' encoding of old isabelle font, instead proper
  2923 iso-latin characters may now be used; the related isatools
  2924 "symbolinput" and "nonascii" have disappeared as well;
  2925 
  2926 * system: removed old "xterm" interface (the print modes "xterm" and
  2927 "xterm_color" are still available for direct use in a suitable
  2928 terminal);
  2929 
  2930 
  2931 
  2932 New in Isabelle99-2 (February 2001)
  2933 -----------------------------------
  2934 
  2935 *** Overview of INCOMPATIBILITIES ***
  2936 
  2937 * HOL: please note that theories in the Library and elsewhere often use the
  2938 new-style (Isar) format; to refer to their theorems in an ML script you must
  2939 bind them to ML identifers by e.g.      val thm_name = thm "thm_name";
  2940 
  2941 * HOL: inductive package no longer splits induction rule aggressively,
  2942 but only as far as specified by the introductions given; the old
  2943 format may be recovered via ML function complete_split_rule or attribute
  2944 'split_rule (complete)';
  2945 
  2946 * HOL: induct renamed to lfp_induct, lfp_Tarski to lfp_unfold,
  2947 gfp_Tarski to gfp_unfold;
  2948 
  2949 * HOL: contrapos, contrapos2 renamed to contrapos_nn, contrapos_pp;
  2950 
  2951 * HOL: infix "dvd" now has priority 50 rather than 70 (because it is a
  2952 relation); infix "^^" has been renamed "``"; infix "``" has been
  2953 renamed "`"; "univalent" has been renamed "single_valued";
  2954 
  2955 * HOL/Real: "rinv" and "hrinv" replaced by overloaded "inverse"
  2956 operation;
  2957 
  2958 * HOLCF: infix "`" has been renamed "$"; the symbol syntax is \<cdot>;
  2959 
  2960 * Isar: 'obtain' no longer declares "that" fact as simp/intro;
  2961 
  2962 * Isar/HOL: method 'induct' now handles non-atomic goals; as a
  2963 consequence, it is no longer monotonic wrt. the local goal context
  2964 (which is now passed through the inductive cases);
  2965 
  2966 * Document preparation: renamed standard symbols \<ll> to \<lless> and
  2967 \<gg> to \<ggreater>;
  2968 
  2969 
  2970 *** Document preparation ***
  2971 
  2972 * \isabellestyle{NAME} selects version of Isabelle output (currently
  2973 available: are "it" for near math-mode best-style output, "sl" for
  2974 slanted text style, and "tt" for plain type-writer; if no
  2975 \isabellestyle command is given, output is according to slanted
  2976 type-writer);
  2977 
  2978 * support sub/super scripts (for single symbols only), input syntax is
  2979 like this: "A\<^sup>*" or "A\<^sup>\<star>";
  2980 
  2981 * some more standard symbols; see Appendix A of the system manual for
  2982 the complete list of symbols defined in isabellesym.sty;
  2983 
  2984 * improved isabelle style files; more abstract symbol implementation
  2985 (should now use \isamath{...} and \isatext{...} in custom symbol
  2986 definitions);
  2987 
  2988 * antiquotation @{goals} and @{subgoals} for output of *dynamic* goals
  2989 state; Note that presentation of goal states does not conform to
  2990 actual human-readable proof documents.  Please do not include goal
  2991 states into document output unless you really know what you are doing!
  2992 
  2993 * proper indentation of antiquoted output with proportional LaTeX
  2994 fonts;
  2995 
  2996 * no_document ML operator temporarily disables LaTeX document
  2997 generation;
  2998 
  2999 * isatool unsymbolize tunes sources for plain ASCII communication;
  3000 
  3001 
  3002 *** Isar ***
  3003 
  3004 * Pure: Isar now suffers initial goal statements to contain unbound
  3005 schematic variables (this does not conform to actual readable proof
  3006 documents, due to unpredictable outcome and non-compositional proof
  3007 checking); users who know what they are doing may use schematic goals
  3008 for Prolog-style synthesis of proven results;
  3009 
  3010 * Pure: assumption method (an implicit finishing) now handles actual
  3011 rules as well;
  3012 
  3013 * Pure: improved 'obtain' --- moved to Pure, insert "that" into
  3014 initial goal, declare "that" only as Pure intro (only for single
  3015 steps); the "that" rule assumption may now be involved in implicit
  3016 finishing, thus ".." becomes a feasible for trivial obtains;
  3017 
  3018 * Pure: default proof step now includes 'intro_classes'; thus trivial
  3019 instance proofs may be performed by "..";
  3020 
  3021 * Pure: ?thesis / ?this / "..." now work for pure meta-level
  3022 statements as well;
  3023 
  3024 * Pure: more robust selection of calculational rules;
  3025 
  3026 * Pure: the builtin notion of 'finished' goal now includes the ==-refl
  3027 rule (as well as the assumption rule);
  3028 
  3029 * Pure: 'thm_deps' command visualizes dependencies of theorems and
  3030 lemmas, using the graph browser tool;
  3031 
  3032 * Pure: predict failure of "show" in interactive mode;
  3033 
  3034 * Pure: 'thms_containing' now takes actual terms as arguments;
  3035 
  3036 * HOL: improved method 'induct' --- now handles non-atomic goals
  3037 (potential INCOMPATIBILITY); tuned error handling;
  3038 
  3039 * HOL: cases and induct rules now provide explicit hints about the
  3040 number of facts to be consumed (0 for "type" and 1 for "set" rules);
  3041 any remaining facts are inserted into the goal verbatim;
  3042 
  3043 * HOL: local contexts (aka cases) may now contain term bindings as
  3044 well; the 'cases' and 'induct' methods new provide a ?case binding for
  3045 the result to be shown in each case;
  3046 
  3047 * HOL: added 'recdef_tc' command;
  3048 
  3049 * isatool convert assists in eliminating legacy ML scripts;
  3050 
  3051 
  3052 *** HOL ***
  3053 
  3054 * HOL/Library: a collection of generic theories to be used together
  3055 with main HOL; the theory loader path already includes this directory
  3056 by default; the following existing theories have been moved here:
  3057 HOL/Induct/Multiset, HOL/Induct/Acc (as Accessible_Part), HOL/While
  3058 (as While_Combinator), HOL/Lex/Prefix (as List_Prefix);
  3059 
  3060 * HOL/Unix: "Some aspects of Unix file-system security", a typical
  3061 modelling and verification task performed in Isabelle/HOL +
  3062 Isabelle/Isar + Isabelle document preparation (by Markus Wenzel).
  3063 
  3064 * HOL/Algebra: special summation operator SUM no longer exists, it has
  3065 been replaced by setsum; infix 'assoc' now has priority 50 (like
  3066 'dvd'); axiom 'one_not_zero' has been moved from axclass 'ring' to
  3067 'domain', this makes the theory consistent with mathematical
  3068 literature;
  3069 
  3070 * HOL basics: added overloaded operations "inverse" and "divide"
  3071 (infix "/"), syntax for generic "abs" operation, generic summation
  3072 operator \<Sum>;
  3073 
  3074 * HOL/typedef: simplified package, provide more useful rules (see also
  3075 HOL/subset.thy);
  3076 
  3077 * HOL/datatype: induction rule for arbitrarily branching datatypes is
  3078 now expressed as a proper nested rule (old-style tactic scripts may
  3079 require atomize_strip_tac to cope with non-atomic premises);
  3080 
  3081 * HOL: renamed theory "Prod" to "Product_Type", renamed "split" rule
  3082 to "split_conv" (old name still available for compatibility);
  3083 
  3084 * HOL: improved concrete syntax for strings (e.g. allows translation
  3085 rules with string literals);
  3086 
  3087 * HOL-Real-Hyperreal: this extends HOL-Real with the hyperreals
  3088  and Fleuriot's mechanization of analysis, including the transcendental
  3089  functions for the reals;
  3090 
  3091 * HOL/Real, HOL/Hyperreal: improved arithmetic simplification;
  3092 
  3093 
  3094 *** CTT ***
  3095 
  3096 * CTT: x-symbol support for Pi, Sigma, -->, : (membership); note that
  3097 "lam" is displayed as TWO lambda-symbols
  3098 
  3099 * CTT: theory Main now available, containing everything (that is, Bool
  3100 and Arith);
  3101 
  3102 
  3103 *** General ***
  3104 
  3105 * Pure: the Simplifier has been implemented properly as a derived rule
  3106 outside of the actual kernel (at last!); the overall performance
  3107 penalty in practical applications is about 50%, while reliability of
  3108 the Isabelle inference kernel has been greatly improved;
  3109 
  3110 * print modes "brackets" and "no_brackets" control output of nested =>
  3111 (types) and ==> (props); the default behaviour is "brackets";
  3112 
  3113 * Provers: fast_tac (and friends) now handle actual object-logic rules
  3114 as assumptions as well;
  3115 
  3116 * system: support Poly/ML 4.0;
  3117 
  3118 * system: isatool install handles KDE version 1 or 2;
  3119 
  3120 
  3121 
  3122 New in Isabelle99-1 (October 2000)
  3123 ----------------------------------
  3124 
  3125 *** Overview of INCOMPATIBILITIES ***
  3126 
  3127 * HOL: simplification of natural numbers is much changed; to partly
  3128 recover the old behaviour (e.g. to prevent n+n rewriting to #2*n)
  3129 issue the following ML commands:
  3130 
  3131   Delsimprocs Nat_Numeral_Simprocs.cancel_numerals;
  3132   Delsimprocs [Nat_Numeral_Simprocs.combine_numerals];
  3133 
  3134 * HOL: simplification no longer dives into case-expressions; this is
  3135 controlled by "t.weak_case_cong" for each datatype t;
  3136 
  3137 * HOL: nat_less_induct renamed to less_induct;
  3138 
  3139 * HOL: systematic renaming of the SOME (Eps) rules, may use isatool
  3140 fixsome to patch .thy and .ML sources automatically;
  3141 
  3142   select_equality  -> some_equality
  3143   select_eq_Ex     -> some_eq_ex
  3144   selectI2EX       -> someI2_ex
  3145   selectI2         -> someI2
  3146   selectI          -> someI
  3147   select1_equality -> some1_equality
  3148   Eps_sym_eq       -> some_sym_eq_trivial
  3149   Eps_eq           -> some_eq_trivial
  3150 
  3151 * HOL: exhaust_tac on datatypes superceded by new generic case_tac;
  3152 
  3153 * HOL: removed obsolete theorem binding expand_if (refer to split_if
  3154 instead);
  3155 
  3156 * HOL: the recursion equations generated by 'recdef' are now called
  3157 f.simps instead of f.rules;
  3158 
  3159 * HOL: qed_spec_mp now also handles bounded ALL as well;
  3160 
  3161 * HOL: 0 is now overloaded, so the type constraint ":: nat" may
  3162 sometimes be needed;
  3163 
  3164 * HOL: the constant for "f``x" is now "image" rather than "op ``";
  3165 
  3166 * HOL: the constant for "f-``x" is now "vimage" rather than "op -``";
  3167 
  3168 * HOL: the disjoint sum is now "<+>" instead of "Plus"; the cartesian
  3169 product is now "<*>" instead of "Times"; the lexicographic product is
  3170 now "<*lex*>" instead of "**";
  3171 
  3172 * HOL: theory Sexp is now in HOL/Induct examples (it used to be part
  3173 of main HOL, but was unused); better use HOL's datatype package;
  3174 
  3175 * HOL: removed "symbols" syntax for constant "override" of theory Map;
  3176 the old syntax may be recovered as follows:
  3177 
  3178   syntax (symbols)
  3179     override  :: "('a ~=> 'b) => ('a ~=> 'b) => ('a ~=> 'b)"
  3180       (infixl "\\<oplus>" 100)
  3181 
  3182 * HOL/Real: "rabs" replaced by overloaded "abs" function;
  3183 
  3184 * HOL/ML: even fewer consts are declared as global (see theories Ord,
  3185 Lfp, Gfp, WF); this only affects ML packages that refer to const names
  3186 internally;
  3187 
  3188 * HOL and ZF: syntax for quotienting wrt an equivalence relation
  3189 changed from A/r to A//r;
  3190 
  3191 * ZF: new treatment of arithmetic (nat & int) may break some old
  3192 proofs;
  3193 
  3194 * Isar: renamed some attributes (RS -> THEN, simplify -> simplified,
  3195 rulify -> rule_format, elimify -> elim_format, ...);
  3196 
  3197 * Isar/Provers: intro/elim/dest attributes changed; renamed
  3198 intro/intro!/intro!! flags to intro!/intro/intro? (in most cases, one
  3199 should have to change intro!! to intro? only); replaced "delrule" by
  3200 "rule del";
  3201 
  3202 * Isar/HOL: renamed "intrs" to "intros" in inductive definitions;
  3203 
  3204 * Provers: strengthened force_tac by using new first_best_tac;
  3205 
  3206 * LaTeX document preparation: several changes of isabelle.sty (see
  3207 lib/texinputs);
  3208 
  3209 
  3210 *** Document preparation ***
  3211 
  3212 * formal comments (text blocks etc.) in new-style theories may now
  3213 contain antiquotations of thm/prop/term/typ/text to be presented
  3214 according to latex print mode; concrete syntax is like this:
  3215 @{term[show_types] "f(x) = a + x"};
  3216 
  3217 * isatool mkdir provides easy setup of Isabelle session directories,
  3218 including proper document sources;
  3219 
  3220 * generated LaTeX sources are now deleted after successful run
  3221 (isatool document -c); may retain a copy somewhere else via -D option
  3222 of isatool usedir;
  3223 
  3224 * isatool usedir -D now lets isatool latex -o sty update the Isabelle
  3225 style files, achieving self-contained LaTeX sources and simplifying
  3226 LaTeX debugging;
  3227 
  3228 * old-style theories now produce (crude) LaTeX output as well;
  3229 
  3230 * browser info session directories are now self-contained (may be put
  3231 on WWW server seperately); improved graphs of nested sessions; removed
  3232 graph for 'all sessions';
  3233 
  3234 * several improvements in isabelle style files; \isabellestyle{it}
  3235 produces fake math mode output; \isamarkupheader is now \section by
  3236 default; see lib/texinputs/isabelle.sty etc.;
  3237 
  3238 
  3239 *** Isar ***
  3240 
  3241 * Isar/Pure: local results and corresponding term bindings are now
  3242 subject to Hindley-Milner polymorphism (similar to ML); this
  3243 accommodates incremental type-inference very nicely;
  3244 
  3245 * Isar/Pure: new derived language element 'obtain' supports
  3246 generalized existence reasoning;
  3247 
  3248 * Isar/Pure: new calculational elements 'moreover' and 'ultimately'
  3249 support accumulation of results, without applying any rules yet;
  3250 useful to collect intermediate results without explicit name
  3251 references, and for use with transitivity rules with more than 2
  3252 premises;
  3253 
  3254 * Isar/Pure: scalable support for case-analysis type proofs: new
  3255 'case' language element refers to local contexts symbolically, as
  3256 produced by certain proof methods; internally, case names are attached
  3257 to theorems as "tags";
  3258 
  3259 * Isar/Pure: theory command 'hide' removes declarations from
  3260 class/type/const name spaces;
  3261 
  3262 * Isar/Pure: theory command 'defs' supports option "(overloaded)" to
  3263 indicate potential overloading;
  3264 
  3265 * Isar/Pure: changed syntax of local blocks from {{ }} to { };
  3266 
  3267 * Isar/Pure: syntax of sorts made 'inner', i.e. have to write
  3268 "{a,b,c}" instead of {a,b,c};
  3269 
  3270 * Isar/Pure now provides its own version of intro/elim/dest
  3271 attributes; useful for building new logics, but beware of confusion
  3272 with the version in Provers/classical;
  3273 
  3274 * Isar/Pure: the local context of (non-atomic) goals is provided via
  3275 case name 'antecedent';
  3276 
  3277 * Isar/Pure: removed obsolete 'transfer' attribute (transfer of thms
  3278 to the current context is now done automatically);
  3279 
  3280 * Isar/Pure: theory command 'method_setup' provides a simple interface
  3281 for definining proof methods in ML;
  3282 
  3283 * Isar/Provers: intro/elim/dest attributes changed; renamed
  3284 intro/intro!/intro!! flags to intro!/intro/intro? (INCOMPATIBILITY, in
  3285 most cases, one should have to change intro!! to intro? only);
  3286 replaced "delrule" by "rule del";
  3287 
  3288 * Isar/Provers: new 'hypsubst' method, plain 'subst' method and
  3289 'symmetric' attribute (the latter supercedes [RS sym]);
  3290 
  3291 * Isar/Provers: splitter support (via 'split' attribute and 'simp'
  3292 method modifier); 'simp' method: 'only:' modifier removes loopers as
  3293 well (including splits);
  3294 
  3295 * Isar/Provers: Simplifier and Classical methods now support all kind
  3296 of modifiers used in the past, including 'cong', 'iff', etc.
  3297 
  3298 * Isar/Provers: added 'fastsimp' and 'clarsimp' methods (combination
  3299 of Simplifier and Classical reasoner);
  3300 
  3301 * Isar/HOL: new proof method 'cases' and improved version of 'induct'
  3302 now support named cases; major packages (inductive, datatype, primrec,
  3303 recdef) support case names and properly name parameters;
  3304 
  3305 * Isar/HOL: new transitivity rules for substitution in inequalities --
  3306 monotonicity conditions are extracted to be proven at end of
  3307 calculations;
  3308 
  3309 * Isar/HOL: removed 'case_split' thm binding, should use 'cases' proof
  3310 method anyway;
  3311 
  3312 * Isar/HOL: removed old expand_if = split_if; theorems if_splits =
  3313 split_if split_if_asm; datatype package provides theorems foo.splits =
  3314 foo.split foo.split_asm for each datatype;
  3315 
  3316 * Isar/HOL: tuned inductive package, rename "intrs" to "intros"
  3317 (potential INCOMPATIBILITY), emulation of mk_cases feature for proof
  3318 scripts: new 'inductive_cases' command and 'ind_cases' method; (Note:
  3319 use "(cases (simplified))" method in proper proof texts);
  3320 
  3321 * Isar/HOL: added global 'arith_split' attribute for 'arith' method;
  3322 
  3323 * Isar: names of theorems etc. may be natural numbers as well;
  3324 
  3325 * Isar: 'pr' command: optional arguments for goals_limit and
  3326 ProofContext.prems_limit; no longer prints theory contexts, but only
  3327 proof states;
  3328 
  3329 * Isar: diagnostic commands 'pr', 'thm', 'prop', 'term', 'typ' admit
  3330 additional print modes to be specified; e.g. "pr(latex)" will print
  3331 proof state according to the Isabelle LaTeX style;
  3332 
  3333 * Isar: improved support for emulating tactic scripts, including proof
  3334 methods 'rule_tac' etc., 'cut_tac', 'thin_tac', 'subgoal_tac',
  3335 'rename_tac', 'rotate_tac', 'tactic', and 'case_tac' / 'induct_tac'
  3336 (for HOL datatypes);
  3337 
  3338 * Isar: simplified (more robust) goal selection of proof methods: 1st
  3339 goal, all goals, or explicit goal specifier (tactic emulation); thus
  3340 'proof method scripts' have to be in depth-first order;
  3341 
  3342 * Isar: tuned 'let' syntax: replaced 'as' keyword by 'and';
  3343 
  3344 * Isar: removed 'help' command, which hasn't been too helpful anyway;
  3345 should instead use individual commands for printing items
  3346 (print_commands, print_methods etc.);
  3347 
  3348 * Isar: added 'nothing' --- the empty list of theorems;
  3349 
  3350 
  3351 *** HOL ***
  3352 
  3353 * HOL/MicroJava: formalization of a fragment of Java, together with a
  3354 corresponding virtual machine and a specification of its bytecode
  3355 verifier and a lightweight bytecode verifier, including proofs of
  3356 type-safety; by Gerwin Klein, Tobias Nipkow, David von Oheimb, and
  3357 Cornelia Pusch (see also the homepage of project Bali at
  3358 http://isabelle.in.tum.de/Bali/);
  3359 
  3360 * HOL/Algebra: new theory of rings and univariate polynomials, by
  3361 Clemens Ballarin;
  3362 
  3363 * HOL/NumberTheory: fundamental Theorem of Arithmetic, Chinese
  3364 Remainder Theorem, Fermat/Euler Theorem, Wilson's Theorem, by Thomas M
  3365 Rasmussen;
  3366 
  3367 * HOL/Lattice: fundamental concepts of lattice theory and order
  3368 structures, including duals, properties of bounds versus algebraic
  3369 laws, lattice operations versus set-theoretic ones, the Knaster-Tarski
  3370 Theorem for complete lattices etc.; may also serve as a demonstration
  3371 for abstract algebraic reasoning using axiomatic type classes, and
  3372 mathematics-style proof in Isabelle/Isar; by Markus Wenzel;
  3373 
  3374 * HOL/Prolog: a (bare-bones) implementation of Lambda-Prolog, by David
  3375 von Oheimb;
  3376 
  3377 * HOL/IMPP: extension of IMP with local variables and mutually
  3378 recursive procedures, by David von Oheimb;
  3379 
  3380 * HOL/Lambda: converted into new-style theory and document;
  3381 
  3382 * HOL/ex/Multiquote: example of multiple nested quotations and
  3383 anti-quotations -- basically a generalized version of de-Bruijn
  3384 representation; very useful in avoiding lifting of operations;
  3385 
  3386 * HOL/record: added general record equality rule to simpset; fixed
  3387 select-update simplification procedure to handle extended records as
  3388 well; admit "r" as field name;
  3389 
  3390 * HOL: 0 is now overloaded over the new sort "zero", allowing its use with
  3391 other numeric types and also as the identity of groups, rings, etc.;
  3392 
  3393 * HOL: new axclass plus_ac0 for addition with the AC-laws and 0 as identity.
  3394 Types nat and int belong to this axclass;
  3395 
  3396 * HOL: greatly improved simplification involving numerals of type nat, int, real:
  3397    (i + #8 + j) = Suc k simplifies to  #7 + (i + j) = k
  3398    i*j + k + j*#3*i     simplifies to  #4*(i*j) + k
  3399   two terms #m*u and #n*u are replaced by #(m+n)*u
  3400     (where #m, #n and u can implicitly be 1; this is simproc combine_numerals)
  3401   and the term/formula #m*u+x ~~ #n*u+y simplifies simplifies to #(m-n)+x ~~ y
  3402     or x ~~ #(n-m)+y, where ~~ is one of = < <= or - (simproc cancel_numerals);
  3403 
  3404 * HOL: meson_tac is available (previously in ex/meson.ML); it is a
  3405 powerful prover for predicate logic but knows nothing of clasets; see
  3406 ex/mesontest.ML and ex/mesontest2.ML for example applications;
  3407 
  3408 * HOL: new version of "case_tac" subsumes both boolean case split and
  3409 "exhaust_tac" on datatypes; INCOMPATIBILITY: exhaust_tac no longer
  3410 exists, may define val exhaust_tac = case_tac for ad-hoc portability;
  3411 
  3412 * HOL: simplification no longer dives into case-expressions: only the
  3413 selector expression is simplified, but not the remaining arms; to
  3414 enable full simplification of case-expressions for datatype t, you may
  3415 remove t.weak_case_cong from the simpset, either globally (Delcongs
  3416 [thm"t.weak_case_cong"];) or locally (delcongs [...]).
  3417 
  3418 * HOL/recdef: the recursion equations generated by 'recdef' for
  3419 function 'f' are now called f.simps instead of f.rules; if all
  3420 termination conditions are proved automatically, these simplification
  3421 rules are added to the simpset, as in primrec; rules may be named
  3422 individually as well, resulting in a separate list of theorems for
  3423 each equation;
  3424 
  3425 * HOL/While is a new theory that provides a while-combinator. It
  3426 permits the definition of tail-recursive functions without the
  3427 provision of a termination measure. The latter is necessary once the
  3428 invariant proof rule for while is applied.
  3429 
  3430 * HOL: new (overloaded) notation for the set of elements below/above
  3431 some element: {..u}, {..u(}, {l..}, {)l..}. See theory SetInterval.
  3432 
  3433 * HOL: theorems impI, allI, ballI bound as "strip";
  3434 
  3435 * HOL: new tactic induct_thm_tac: thm -> string -> int -> tactic
  3436 induct_tac th "x1 ... xn" expects th to have a conclusion of the form
  3437 P v1 ... vn and abbreviates res_inst_tac [("v1","x1"),...,("vn","xn")] th;
  3438 
  3439 * HOL/Real: "rabs" replaced by overloaded "abs" function;
  3440 
  3441 * HOL: theory Sexp now in HOL/Induct examples (it used to be part of
  3442 main HOL, but was unused);
  3443 
  3444 * HOL: fewer consts declared as global (e.g. have to refer to
  3445 "Lfp.lfp" instead of "lfp" internally; affects ML packages only);
  3446 
  3447 * HOL: tuned AST representation of nested pairs, avoiding bogus output
  3448 in case of overlap with user translations (e.g. judgements over
  3449 tuples); (note that the underlying logical represenation is still
  3450 bogus);
  3451 
  3452 
  3453 *** ZF ***
  3454 
  3455 * ZF: simplification automatically cancels common terms in arithmetic
  3456 expressions over nat and int;
  3457 
  3458 * ZF: new treatment of nat to minimize type-checking: all operators
  3459 coerce their operands to a natural number using the function natify,
  3460 making the algebraic laws unconditional;
  3461 
  3462 * ZF: as above, for int: operators coerce their operands to an integer
  3463 using the function intify;
  3464 
  3465 * ZF: the integer library now contains many of the usual laws for the
  3466 orderings, including $<=, and monotonicity laws for $+ and $*;
  3467 
  3468 * ZF: new example ZF/ex/NatSum to demonstrate integer arithmetic
  3469 simplification;
  3470 
  3471 * FOL and ZF: AddIffs now available, giving theorems of the form P<->Q
  3472 to the simplifier and classical reasoner simultaneously;
  3473 
  3474 
  3475 *** General ***
  3476 
  3477 * Provers: blast_tac now handles actual object-logic rules as
  3478 assumptions; note that auto_tac uses blast_tac internally as well;
  3479 
  3480 * Provers: new functions rulify/rulify_no_asm: thm -> thm for turning
  3481 outer -->/All/Ball into ==>/!!; qed_spec_mp now uses rulify_no_asm;
  3482 
  3483 * Provers: delrules now handles destruct rules as well (no longer need
  3484 explicit make_elim);
  3485 
  3486 * Provers: Blast_tac now warns of and ignores "weak elimination rules" e.g.
  3487   [| inj ?f;          ?f ?x = ?f ?y; ?x = ?y ==> ?W |] ==> ?W
  3488 use instead the strong form,
  3489   [| inj ?f; ~ ?W ==> ?f ?x = ?f ?y; ?x = ?y ==> ?W |] ==> ?W
  3490 in HOL, FOL and ZF the function cla_make_elim will create such rules
  3491 from destruct-rules;
  3492 
  3493 * Provers: Simplifier.easy_setup provides a fast path to basic
  3494 Simplifier setup for new object-logics;
  3495 
  3496 * Pure: AST translation rules no longer require constant head on LHS;
  3497 
  3498 * Pure: improved name spaces: ambiguous output is qualified; support
  3499 for hiding of names;
  3500 
  3501 * system: smart setup of canonical ML_HOME, ISABELLE_INTERFACE, and
  3502 XSYMBOL_HOME; no longer need to do manual configuration in most
  3503 situations;
  3504 
  3505 * system: compression of ML heaps images may now be controlled via -c
  3506 option of isabelle and isatool usedir (currently only observed by
  3507 Poly/ML);
  3508 
  3509 * system: isatool installfonts may handle X-Symbol fonts as well (very
  3510 useful for remote X11);
  3511 
  3512 * system: provide TAGS file for Isabelle sources;
  3513 
  3514 * ML: infix 'OF' is a version of 'MRS' with more appropriate argument
  3515 order;
  3516 
  3517 * ML: renamed flags Syntax.trace_norm_ast to Syntax.trace_ast; global
  3518 timing flag supersedes proof_timing and Toplevel.trace;
  3519 
  3520 * ML: new combinators |>> and |>>> for incremental transformations
  3521 with secondary results (e.g. certain theory extensions):
  3522 
  3523 * ML: PureThy.add_defs gets additional argument to indicate potential
  3524 overloading (usually false);
  3525 
  3526 * ML: PureThy.add_thms/add_axioms/add_defs now return theorems as
  3527 results;
  3528 
  3529 
  3530 
  3531 New in Isabelle99 (October 1999)
  3532 --------------------------------
  3533 
  3534 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  3535 
  3536 * HOL: The THEN and ELSE parts of conditional expressions (if P then x else y)
  3537 are no longer simplified.  (This allows the simplifier to unfold recursive
  3538 functional programs.)  To restore the old behaviour, declare
  3539 
  3540     Delcongs [if_weak_cong];
  3541 
  3542 * HOL: Removed the obsolete syntax "Compl A"; use -A for set
  3543 complement;
  3544 
  3545 * HOL: the predicate "inj" is now defined by translation to "inj_on";
  3546 
  3547 * HOL/datatype: mutual_induct_tac no longer exists --
  3548   use induct_tac "x_1 ... x_n" instead of mutual_induct_tac ["x_1", ..., "x_n"]
  3549 
  3550 * HOL/typedef: fixed type inference for representing set; type
  3551 arguments now have to occur explicitly on the rhs as type constraints;
  3552 
  3553 * ZF: The con_defs part of an inductive definition may no longer refer
  3554 to constants declared in the same theory;
  3555 
  3556 * HOL, ZF: the function mk_cases, generated by the inductive
  3557 definition package, has lost an argument.  To simplify its result, it
  3558 uses the default simpset instead of a supplied list of theorems.
  3559 
  3560 * HOL/List: the constructors of type list are now Nil and Cons;
  3561 
  3562 * Simplifier: the type of the infix ML functions
  3563         setSSolver addSSolver setSolver addSolver
  3564 is now  simpset * solver -> simpset  where `solver' is a new abstract type
  3565 for packaging solvers. A solver is created via
  3566         mk_solver: string -> (thm list -> int -> tactic) -> solver
  3567 where the string argument is only a comment.
  3568 
  3569 
  3570 *** Proof tools ***
  3571 
  3572 * Provers/Arith/fast_lin_arith.ML contains a functor for creating a
  3573 decision procedure for linear arithmetic. Currently it is used for
  3574 types `nat', `int', and `real' in HOL (see below); it can, should and
  3575 will be instantiated for other types and logics as well.
  3576 
  3577 * The simplifier now accepts rewrite rules with flexible heads, eg
  3578      hom ?f ==> ?f(?x+?y) = ?f ?x + ?f ?y
  3579   They are applied like any rule with a non-pattern lhs, i.e. by first-order
  3580   matching.
  3581 
  3582 
  3583 *** General ***
  3584 
  3585 * New Isabelle/Isar subsystem provides an alternative to traditional
  3586 tactical theorem proving; together with the ProofGeneral/isar user
  3587 interface it offers an interactive environment for developing human
  3588 readable proof documents (Isar == Intelligible semi-automated
  3589 reasoning); for further information see isatool doc isar-ref,
  3590 src/HOL/Isar_examples and http://isabelle.in.tum.de/Isar/
  3591 
  3592 * improved and simplified presentation of theories: better HTML markup
  3593 (including colors), graph views in several sizes; isatool usedir now
  3594 provides a proper interface for user theories (via -P option); actual
  3595 document preparation based on (PDF)LaTeX is available as well (for
  3596 new-style theories only); see isatool doc system for more information;
  3597 
  3598 * native support for Proof General, both for classic Isabelle and
  3599 Isabelle/Isar;
  3600 
  3601 * ML function thm_deps visualizes dependencies of theorems and lemmas,
  3602 using the graph browser tool;
  3603 
  3604 * Isabelle manuals now also available as PDF;
  3605 
  3606 * theory loader rewritten from scratch (may not be fully
  3607 bug-compatible); old loadpath variable has been replaced by show_path,
  3608 add_path, del_path, reset_path functions; new operations such as
  3609 update_thy, touch_thy, remove_thy, use/update_thy_only (see also
  3610 isatool doc ref);
  3611 
  3612 * improved isatool install: option -k creates KDE application icon,
  3613 option -p DIR installs standalone binaries;
  3614 
  3615 * added ML_PLATFORM setting (useful for cross-platform installations);
  3616 more robust handling of platform specific ML images for SML/NJ;
  3617 
  3618 * the settings environment is now statically scoped, i.e. it is never
  3619 created again in sub-processes invoked from isabelle, isatool, or
  3620 Isabelle;
  3621 
  3622 * path element specification '~~' refers to '$ISABELLE_HOME';
  3623 
  3624 * in locales, the "assumes" and "defines" parts may be omitted if
  3625 empty;
  3626 
  3627 * new print_mode "xsymbols" for extended symbol support (e.g. genuine
  3628 long arrows);
  3629 
  3630 * new print_mode "HTML";
  3631 
  3632 * new flag show_tags controls display of tags of theorems (which are
  3633 basically just comments that may be attached by some tools);
  3634 
  3635 * Isamode 2.6 requires patch to accomodate change of Isabelle font
  3636 mode and goal output format:
  3637 
  3638 diff -r Isamode-2.6/elisp/isa-load.el Isamode/elisp/isa-load.el
  3639 244c244
  3640 <       (list (isa-getenv "ISABELLE") "-msymbols" logic-name)
  3641 ---
  3642 >       (list (isa-getenv "ISABELLE") "-misabelle_font" "-msymbols" logic-name)
  3643 diff -r Isabelle-2.6/elisp/isa-proofstate.el Isamode/elisp/isa-proofstate.el
  3644 181c181
  3645 < (defconst proofstate-proofstart-regexp "^Level [0-9]+$"
  3646 ---
  3647 > (defconst proofstate-proofstart-regexp "^Level [0-9]+"
  3648 
  3649 * function bind_thms stores lists of theorems (cf. bind_thm);
  3650 
  3651 * new shorthand tactics ftac, eatac, datac, fatac;
  3652 
  3653 * qed (and friends) now accept "" as result name; in that case the
  3654 theorem is not stored, but proper checks and presentation of the
  3655 result still apply;
  3656 
  3657 * theorem database now also indexes constants "Trueprop", "all",
  3658 "==>", "=="; thus thms_containing, findI etc. may retrieve more rules;
  3659 
  3660 
  3661 *** HOL ***
  3662 
  3663 ** HOL arithmetic **
  3664 
  3665 * There are now decision procedures for linear arithmetic over nat and
  3666 int:
  3667 
  3668 1. arith_tac copes with arbitrary formulae involving `=', `<', `<=',
  3669 `+', `-', `Suc', `min', `max' and numerical constants; other subterms
  3670 are treated as atomic; subformulae not involving type `nat' or `int'
  3671 are ignored; quantified subformulae are ignored unless they are
  3672 positive universal or negative existential. The tactic has to be
  3673 invoked by hand and can be a little bit slow. In particular, the
  3674 running time is exponential in the number of occurrences of `min' and
  3675 `max', and `-' on `nat'.
  3676 
  3677 2. fast_arith_tac is a cut-down version of arith_tac: it only takes
  3678 (negated) (in)equalities among the premises and the conclusion into
  3679 account (i.e. no compound formulae) and does not know about `min' and
  3680 `max', and `-' on `nat'. It is fast and is used automatically by the
  3681 simplifier.
  3682 
  3683 NB: At the moment, these decision procedures do not cope with mixed
  3684 nat/int formulae where the two parts interact, such as `m < n ==>
  3685 int(m) < int(n)'.
  3686 
  3687 * HOL/Numeral provides a generic theory of numerals (encoded
  3688 efficiently as bit strings); setup for types nat/int/real is in place;
  3689 INCOMPATIBILITY: since numeral syntax is now polymorphic, rather than
  3690 int, existing theories and proof scripts may require a few additional
  3691 type constraints;
  3692 
  3693 * integer division and remainder can now be performed on constant
  3694 arguments;
  3695 
  3696 * many properties of integer multiplication, division and remainder
  3697 are now available;
  3698 
  3699 * An interface to the Stanford Validity Checker (SVC) is available through the
  3700 tactic svc_tac.  Propositional tautologies and theorems of linear arithmetic
  3701 are proved automatically.  SVC must be installed separately, and its results
  3702 must be TAKEN ON TRUST (Isabelle does not check the proofs, but tags any
  3703 invocation of the underlying oracle).  For SVC see
  3704   http://verify.stanford.edu/SVC
  3705 
  3706 * IsaMakefile: the HOL-Real target now builds an actual image;
  3707 
  3708 
  3709 ** HOL misc **
  3710 
  3711 * HOL/Real/HahnBanach: the Hahn-Banach theorem for real vector spaces
  3712 (in Isabelle/Isar) -- by Gertrud Bauer;
  3713 
  3714 * HOL/BCV: generic model of bytecode verification, i.e. data-flow
  3715 analysis for assembly languages with subtypes;
  3716 
  3717 * HOL/TLA (Lamport's Temporal Logic of Actions): major reorganization
  3718 -- avoids syntactic ambiguities and treats state, transition, and
  3719 temporal levels more uniformly; introduces INCOMPATIBILITIES due to
  3720 changed syntax and (many) tactics;
  3721 
  3722 * HOL/inductive: Now also handles more general introduction rules such
  3723   as "ALL y. (y, x) : r --> y : acc r ==> x : acc r"; monotonicity
  3724   theorems are now maintained within the theory (maintained via the
  3725   "mono" attribute);
  3726 
  3727 * HOL/datatype: Now also handles arbitrarily branching datatypes
  3728   (using function types) such as
  3729 
  3730   datatype 'a tree = Atom 'a | Branch "nat => 'a tree"
  3731 
  3732 * HOL/record: record_simproc (part of the default simpset) takes care
  3733 of selectors applied to updated records; record_split_tac is no longer
  3734 part of the default claset; update_defs may now be removed from the
  3735 simpset in many cases; COMPATIBILITY: old behavior achieved by
  3736 
  3737   claset_ref () := claset() addSWrapper record_split_wrapper;
  3738   Delsimprocs [record_simproc]
  3739 
  3740 * HOL/typedef: fixed type inference for representing set; type
  3741 arguments now have to occur explicitly on the rhs as type constraints;
  3742 
  3743 * HOL/recdef (TFL): 'congs' syntax now expects comma separated list of theorem
  3744 names rather than an ML expression;
  3745 
  3746 * HOL/defer_recdef (TFL): like recdef but the well-founded relation can be
  3747 supplied later.  Program schemes can be defined, such as
  3748     "While B C s = (if B s then While B C (C s) else s)"
  3749 where the well-founded relation can be chosen after B and C have been given.
  3750 
  3751 * HOL/List: the constructors of type list are now Nil and Cons;
  3752 INCOMPATIBILITY: while [] and infix # syntax is still there, of
  3753 course, ML tools referring to List.list.op # etc. have to be adapted;
  3754 
  3755 * HOL_quantifiers flag superseded by "HOL" print mode, which is
  3756 disabled by default; run isabelle with option -m HOL to get back to
  3757 the original Gordon/HOL-style output;
  3758 
  3759 * HOL/Ord.thy: new bounded quantifier syntax (input only): ALL x<y. P,
  3760 ALL x<=y. P, EX x<y. P, EX x<=y. P;
  3761 
  3762 * HOL basic syntax simplified (more orthogonal): all variants of
  3763 All/Ex now support plain / symbolic / HOL notation; plain syntax for
  3764 Eps operator is provided as well: "SOME x. P[x]";
  3765 
  3766 * HOL/Sum.thy: sum_case has been moved to HOL/Datatype;
  3767 
  3768 * HOL/Univ.thy: infix syntax <*>, <+>, <**>, <+> eliminated and made
  3769 thus available for user theories;
  3770 
  3771 * HOLCF/IOA/Sequents: renamed 'Cons' to 'Consq' to avoid clash with
  3772 HOL/List; hardly an INCOMPATIBILITY since '>>' syntax is used all the
  3773 time;
  3774 
  3775 * HOL: new tactic smp_tac: int -> int -> tactic, which applies spec
  3776 several times and then mp;
  3777 
  3778 
  3779 *** LK ***
  3780 
  3781 * the notation <<...>> is now available as a notation for sequences of
  3782 formulas;
  3783 
  3784 * the simplifier is now installed
  3785 
  3786 * the axiom system has been generalized (thanks to Soren Heilmann)
  3787 
  3788 * the classical reasoner now has a default rule database
  3789 
  3790 
  3791 *** ZF ***
  3792 
  3793 * new primrec section allows primitive recursive functions to be given
  3794 directly (as in HOL) over datatypes and the natural numbers;
  3795 
  3796 * new tactics induct_tac and exhaust_tac for induction (or case
  3797 analysis) over datatypes and the natural numbers;
  3798 
  3799 * the datatype declaration of type T now defines the recursor T_rec;
  3800 
  3801 * simplification automatically does freeness reasoning for datatype
  3802 constructors;
  3803 
  3804 * automatic type-inference, with AddTCs command to insert new
  3805 type-checking rules;
  3806 
  3807 * datatype introduction rules are now added as Safe Introduction rules
  3808 to the claset;
  3809 
  3810 * the syntax "if P then x else y" is now available in addition to
  3811 if(P,x,y);
  3812 
  3813 
  3814 *** Internal programming interfaces ***
  3815 
  3816 * tuned simplifier trace output; new flag debug_simp;
  3817 
  3818 * structures Vartab / Termtab (instances of TableFun) offer efficient
  3819 tables indexed by indexname_ord / term_ord (compatible with aconv);
  3820 
  3821 * AxClass.axclass_tac lost the theory argument;
  3822 
  3823 * tuned current_goals_markers semantics: begin / end goal avoids
  3824 printing empty lines;
  3825 
  3826 * removed prs and prs_fn hook, which was broken because it did not
  3827 include \n in its semantics, forcing writeln to add one
  3828 uncoditionally; replaced prs_fn by writeln_fn; consider std_output:
  3829 string -> unit if you really want to output text without newline;
  3830 
  3831 * Symbol.output subject to print mode; INCOMPATIBILITY: defaults to
  3832 plain output, interface builders may have to enable 'isabelle_font'
  3833 mode to get Isabelle font glyphs as before;
  3834 
  3835 * refined token_translation interface; INCOMPATIBILITY: output length
  3836 now of type real instead of int;
  3837 
  3838 * theory loader actions may be traced via new ThyInfo.add_hook
  3839 interface (see src/Pure/Thy/thy_info.ML); example application: keep
  3840 your own database of information attached to *whole* theories -- as
  3841 opposed to intra-theory data slots offered via TheoryDataFun;
  3842 
  3843 * proper handling of dangling sort hypotheses (at last!);
  3844 Thm.strip_shyps and Drule.strip_shyps_warning take care of removing
  3845 extra sort hypotheses that can be witnessed from the type signature;
  3846 the force_strip_shyps flag is gone, any remaining shyps are simply
  3847 left in the theorem (with a warning issued by strip_shyps_warning);
  3848 
  3849 
  3850 
  3851 New in Isabelle98-1 (October 1998)
  3852 ----------------------------------
  3853 
  3854 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  3855 
  3856 * several changes of automated proof tools;
  3857 
  3858 * HOL: major changes to the inductive and datatype packages, including
  3859 some minor incompatibilities of theory syntax;
  3860 
  3861 * HOL: renamed r^-1 to 'converse' from 'inverse'; 'inj_onto' is now
  3862 called `inj_on';
  3863 
  3864 * HOL: removed duplicate thms in Arith:
  3865   less_imp_add_less  should be replaced by  trans_less_add1
  3866   le_imp_add_le      should be replaced by  trans_le_add1
  3867 
  3868 * HOL: unary minus is now overloaded (new type constraints may be
  3869 required);
  3870 
  3871 * HOL and ZF: unary minus for integers is now #- instead of #~.  In
  3872 ZF, expressions such as n#-1 must be changed to n#- 1, since #-1 is
  3873 now taken as an integer constant.
  3874 
  3875 * Pure: ML function 'theory_of' renamed to 'theory';
  3876 
  3877 
  3878 *** Proof tools ***
  3879 
  3880 * Simplifier:
  3881   1. Asm_full_simp_tac is now more aggressive.
  3882      1. It will sometimes reorient premises if that increases their power to
  3883         simplify.
  3884      2. It does no longer proceed strictly from left to right but may also
  3885         rotate premises to achieve further simplification.
  3886      For compatibility reasons there is now Asm_lr_simp_tac which is like the
  3887      old Asm_full_simp_tac in that it does not rotate premises.
  3888   2. The simplifier now knows a little bit about nat-arithmetic.
  3889 
  3890 * Classical reasoner: wrapper mechanism for the classical reasoner now
  3891 allows for selected deletion of wrappers, by introduction of names for
  3892 wrapper functionals.  This implies that addbefore, addSbefore,
  3893 addaltern, and addSaltern now take a pair (name, tactic) as argument,
  3894 and that adding two tactics with the same name overwrites the first
  3895 one (emitting a warning).
  3896   type wrapper = (int -> tactic) -> (int -> tactic)
  3897   setWrapper, setSWrapper, compWrapper and compSWrapper are replaced by
  3898   addWrapper, addSWrapper: claset * (string * wrapper) -> claset
  3899   delWrapper, delSWrapper: claset *  string            -> claset
  3900   getWrapper is renamed to appWrappers, getSWrapper to appSWrappers;
  3901 
  3902 * Classical reasoner: addbefore/addSbefore now have APPEND/ORELSE
  3903 semantics; addbefore now affects only the unsafe part of step_tac
  3904 etc.; this affects addss/auto_tac/force_tac, so EXISTING PROOFS MAY
  3905 FAIL, but proofs should be fixable easily, e.g. by replacing Auto_tac
  3906 by Force_tac;
  3907 
  3908 * Classical reasoner: setwrapper to setWrapper and compwrapper to
  3909 compWrapper; added safe wrapper (and access functions for it);
  3910 
  3911 * HOL/split_all_tac is now much faster and fails if there is nothing
  3912 to split.  Some EXISTING PROOFS MAY REQUIRE ADAPTION because the order
  3913 and the names of the automatically generated variables have changed.
  3914 split_all_tac has moved within claset() from unsafe wrappers to safe
  3915 wrappers, which means that !!-bound variables are split much more
  3916 aggressively, and safe_tac and clarify_tac now split such variables.
  3917 If this splitting is not appropriate, use delSWrapper "split_all_tac".
  3918 Note: the same holds for record_split_tac, which does the job of
  3919 split_all_tac for record fields.
  3920 
  3921 * HOL/Simplifier: Rewrite rules for case distinctions can now be added
  3922 permanently to the default simpset using Addsplits just like
  3923 Addsimps. They can be removed via Delsplits just like
  3924 Delsimps. Lower-case versions are also available.
  3925 
  3926 * HOL/Simplifier: The rule split_if is now part of the default
  3927 simpset. This means that the simplifier will eliminate all occurrences
  3928 of if-then-else in the conclusion of a goal. To prevent this, you can
  3929 either remove split_if completely from the default simpset by
  3930 `Delsplits [split_if]' or remove it in a specific call of the
  3931 simplifier using `... delsplits [split_if]'.  You can also add/delete
  3932 other case splitting rules to/from the default simpset: every datatype
  3933 generates suitable rules `split_t_case' and `split_t_case_asm' (where
  3934 t is the name of the datatype).
  3935 
  3936 * Classical reasoner / Simplifier combination: new force_tac (and
  3937 derivatives Force_tac, force) combines rewriting and classical
  3938 reasoning (and whatever other tools) similarly to auto_tac, but is
  3939 aimed to solve the given subgoal completely.
  3940 
  3941 
  3942 *** General ***
  3943 
  3944 * new top-level commands `Goal' and `Goalw' that improve upon `goal'
  3945 and `goalw': the theory is no longer needed as an explicit argument -
  3946 the current theory context is used; assumptions are no longer returned
  3947 at the ML-level unless one of them starts with ==> or !!; it is
  3948 recommended to convert to these new commands using isatool fixgoal
  3949 (backup your sources first!);
  3950 
  3951 * new top-level commands 'thm' and 'thms' for retrieving theorems from
  3952 the current theory context, and 'theory' to lookup stored theories;
  3953 
  3954 * new theory section 'locale' for declaring constants, assumptions and
  3955 definitions that have local scope;
  3956 
  3957 * new theory section 'nonterminals' for purely syntactic types;
  3958 
  3959 * new theory section 'setup' for generic ML setup functions
  3960 (e.g. package initialization);
  3961 
  3962 * the distribution now includes Isabelle icons: see
  3963 lib/logo/isabelle-{small,tiny}.xpm;
  3964 
  3965 * isatool install - install binaries with absolute references to
  3966 ISABELLE_HOME/bin;
  3967 
  3968 * isatool logo -- create instances of the Isabelle logo (as EPS);
  3969 
  3970 * print mode 'emacs' reserved for Isamode;
  3971 
  3972 * support multiple print (ast) translations per constant name;
  3973 
  3974 * theorems involving oracles are now printed with a suffixed [!];
  3975 
  3976 
  3977 *** HOL ***
  3978 
  3979 * there is now a tutorial on Isabelle/HOL (do 'isatool doc tutorial');
  3980 
  3981 * HOL/inductive package reorganized and improved: now supports mutual
  3982 definitions such as
  3983 
  3984   inductive EVEN ODD
  3985     intrs
  3986       null "0 : EVEN"
  3987       oddI "n : EVEN ==> Suc n : ODD"
  3988       evenI "n : ODD ==> Suc n : EVEN"
  3989 
  3990 new theorem list "elims" contains an elimination rule for each of the
  3991 recursive sets; inductive definitions now handle disjunctive premises
  3992 correctly (also ZF);
  3993 
  3994 INCOMPATIBILITIES: requires Inductive as an ancestor; component
  3995 "mutual_induct" no longer exists - the induction rule is always
  3996 contained in "induct";
  3997 
  3998 
  3999 * HOL/datatype package re-implemented and greatly improved: now
  4000 supports mutually recursive datatypes such as
  4001 
  4002   datatype
  4003     'a aexp = IF_THEN_ELSE ('a bexp) ('a aexp) ('a aexp)
  4004             | SUM ('a aexp) ('a aexp)
  4005             | DIFF ('a aexp) ('a aexp)
  4006             | NUM 'a
  4007   and
  4008     'a bexp = LESS ('a aexp) ('a aexp)
  4009             | AND ('a bexp) ('a bexp)
  4010             | OR ('a bexp) ('a bexp)
  4011 
  4012 as well as indirectly recursive datatypes such as
  4013 
  4014   datatype
  4015     ('a, 'b) term = Var 'a
  4016                   | App 'b ((('a, 'b) term) list)
  4017 
  4018 The new tactic  mutual_induct_tac [<var_1>, ..., <var_n>] i  performs
  4019 induction on mutually / indirectly recursive datatypes.
  4020 
  4021 Primrec equations are now stored in theory and can be accessed via
  4022 <function_name>.simps.
  4023 
  4024 INCOMPATIBILITIES:
  4025 
  4026   - Theories using datatypes must now have theory Datatype as an
  4027     ancestor.
  4028   - The specific <typename>.induct_tac no longer exists - use the
  4029     generic induct_tac instead.
  4030   - natE has been renamed to nat.exhaust - use exhaust_tac
  4031     instead of res_inst_tac ... natE. Note that the variable
  4032     names in nat.exhaust differ from the names in natE, this
  4033     may cause some "fragile" proofs to fail.
  4034   - The theorems split_<typename>_case and split_<typename>_case_asm
  4035     have been renamed to <typename>.split and <typename>.split_asm.
  4036   - Since default sorts of type variables are now handled correctly,
  4037     some datatype definitions may have to be annotated with explicit
  4038     sort constraints.
  4039   - Primrec definitions no longer require function name and type
  4040     of recursive argument.
  4041 
  4042 Consider using isatool fixdatatype to adapt your theories and proof
  4043 scripts to the new package (backup your sources first!).
  4044 
  4045 
  4046 * HOL/record package: considerably improved implementation; now
  4047 includes concrete syntax for record types, terms, updates; theorems
  4048 for surjective pairing and splitting !!-bound record variables; proof
  4049 support is as follows:
  4050 
  4051   1) standard conversions (selectors or updates applied to record
  4052 constructor terms) are part of the standard simpset;
  4053 
  4054   2) inject equations of the form ((x, y) = (x', y')) == x=x' & y=y' are
  4055 made part of standard simpset and claset via addIffs;
  4056 
  4057   3) a tactic for record field splitting (record_split_tac) is part of
  4058 the standard claset (addSWrapper);
  4059 
  4060 To get a better idea about these rules you may retrieve them via
  4061 something like 'thms "foo.simps"' or 'thms "foo.iffs"', where "foo" is
  4062 the name of your record type.
  4063 
  4064 The split tactic 3) conceptually simplifies by the following rule:
  4065 
  4066   "(!!x. PROP ?P x) == (!!a b. PROP ?P (a, b))"
  4067 
  4068 Thus any record variable that is bound by meta-all will automatically
  4069 blow up into some record constructor term, consequently the
  4070 simplifications of 1), 2) apply.  Thus force_tac, auto_tac etc. shall
  4071 solve record problems automatically.
  4072 
  4073 
  4074 * reorganized the main HOL image: HOL/Integ and String loaded by
  4075 default; theory Main includes everything;
  4076 
  4077 * automatic simplification of integer sums and comparisons, using cancellation;
  4078 
  4079 * added option_map_eq_Some and not_Some_eq to the default simpset and claset;
  4080 
  4081 * added disj_not1 = "(~P | Q) = (P --> Q)" to the default simpset;
  4082 
  4083 * many new identities for unions, intersections, set difference, etc.;
  4084 
  4085 * expand_if, expand_split, expand_sum_case and expand_nat_case are now
  4086 called split_if, split_split, split_sum_case and split_nat_case (to go
  4087 with add/delsplits);
  4088 
  4089 * HOL/Prod introduces simplification procedure unit_eq_proc rewriting
  4090 (?x::unit) = (); this is made part of the default simpset, which COULD
  4091 MAKE EXISTING PROOFS FAIL under rare circumstances (consider
  4092 'Delsimprocs [unit_eq_proc];' as last resort); also note that
  4093 unit_abs_eta_conv is added in order to counter the effect of
  4094 unit_eq_proc on (%u::unit. f u), replacing it by f rather than by
  4095 %u.f();
  4096 
  4097 * HOL/Fun INCOMPATIBILITY: `inj_onto' is now called `inj_on' (which
  4098 makes more sense);
  4099 
  4100 * HOL/Set INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
  4101   It and 'sym RS equals0D' are now in the default  claset, giving automatic
  4102   disjointness reasoning but breaking a few old proofs.
  4103 
  4104 * HOL/Relation INCOMPATIBILITY: renamed the relational operator r^-1
  4105 to 'converse' from 'inverse' (for compatibility with ZF and some
  4106 literature);
  4107 
  4108 * HOL/recdef can now declare non-recursive functions, with {} supplied as
  4109 the well-founded relation;
  4110 
  4111 * HOL/Set INCOMPATIBILITY: the complement of set A is now written -A instead of
  4112     Compl A.  The "Compl" syntax remains available as input syntax for this
  4113     release ONLY.
  4114 
  4115 * HOL/Update: new theory of function updates:
  4116     f(a:=b) == %x. if x=a then b else f x
  4117 may also be iterated as in f(a:=b,c:=d,...);
  4118 
  4119 * HOL/Vimage: new theory for inverse image of a function, syntax f-``B;
  4120 
  4121 * HOL/List:
  4122   - new function list_update written xs[i:=v] that updates the i-th
  4123     list position. May also be iterated as in xs[i:=a,j:=b,...].
  4124   - new function `upt' written [i..j(] which generates the list
  4125     [i,i+1,...,j-1], i.e. the upper bound is excluded. To include the upper
  4126     bound write [i..j], which is a shorthand for [i..j+1(].
  4127   - new lexicographic orderings and corresponding wellfoundedness theorems.
  4128 
  4129 * HOL/Arith:
  4130   - removed 'pred' (predecessor) function;
  4131   - generalized some theorems about n-1;
  4132   - many new laws about "div" and "mod";
  4133   - new laws about greatest common divisors (see theory ex/Primes);
  4134 
  4135 * HOL/Relation: renamed the relational operator r^-1 "converse"
  4136 instead of "inverse";
  4137 
  4138 * HOL/Induct/Multiset: a theory of multisets, including the wellfoundedness
  4139   of the multiset ordering;
  4140 
  4141 * directory HOL/Real: a construction of the reals using Dedekind cuts
  4142   (not included by default);
  4143 
  4144 * directory HOL/UNITY: Chandy and Misra's UNITY formalism;
  4145 
  4146 * directory HOL/Hoare: a new version of Hoare logic which permits many-sorted
  4147   programs, i.e. different program variables may have different types.
  4148 
  4149 * calling (stac rew i) now fails if "rew" has no effect on the goal
  4150   [previously, this check worked only if the rewrite rule was unconditional]
  4151   Now rew can involve either definitions or equalities (either == or =).
  4152 
  4153 
  4154 *** ZF ***
  4155 
  4156 * theory Main includes everything; INCOMPATIBILITY: theory ZF.thy contains
  4157   only the theorems proved on ZF.ML;
  4158 
  4159 * ZF INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
  4160   It and 'sym RS equals0D' are now in the default  claset, giving automatic
  4161   disjointness reasoning but breaking a few old proofs.
  4162 
  4163 * ZF/Update: new theory of function updates
  4164     with default rewrite rule  f(x:=y) ` z = if(z=x, y, f`z)
  4165   may also be iterated as in f(a:=b,c:=d,...);
  4166 
  4167 * in  let x=t in u(x), neither t nor u(x) has to be an FOL term.
  4168 
  4169 * calling (stac rew i) now fails if "rew" has no effect on the goal
  4170   [previously, this check worked only if the rewrite rule was unconditional]
  4171   Now rew can involve either definitions or equalities (either == or =).
  4172 
  4173 * case_tac provided for compatibility with HOL
  4174     (like the old excluded_middle_tac, but with subgoals swapped)
  4175 
  4176 
  4177 *** Internal programming interfaces ***
  4178 
  4179 * Pure: several new basic modules made available for general use, see
  4180 also src/Pure/README;
  4181 
  4182 * improved the theory data mechanism to support encapsulation (data
  4183 kind name replaced by private Object.kind, acting as authorization
  4184 key); new type-safe user interface via functor TheoryDataFun; generic
  4185 print_data function becomes basically useless;
  4186 
  4187 * removed global_names compatibility flag -- all theory declarations
  4188 are qualified by default;
  4189 
  4190 * module Pure/Syntax now offers quote / antiquote translation
  4191 functions (useful for Hoare logic etc. with implicit dependencies);
  4192 see HOL/ex/Antiquote for an example use;
  4193 
  4194 * Simplifier now offers conversions (asm_)(full_)rewrite: simpset ->
  4195 cterm -> thm;
  4196 
  4197 * new tactical CHANGED_GOAL for checking that a tactic modifies a
  4198 subgoal;
  4199 
  4200 * Display.print_goals function moved to Locale.print_goals;
  4201 
  4202 * standard print function for goals supports current_goals_markers
  4203 variable for marking begin of proof, end of proof, start of goal; the
  4204 default is ("", "", ""); setting current_goals_markers := ("<proof>",
  4205 "</proof>", "<goal>") causes SGML like tagged proof state printing,
  4206 for example;
  4207 
  4208 
  4209 
  4210 New in Isabelle98 (January 1998)
  4211 --------------------------------
  4212 
  4213 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  4214 
  4215 * changed lexical syntax of terms / types: dots made part of long
  4216 identifiers, e.g. "%x.x" no longer possible, should be "%x. x";
  4217 
  4218 * simpset (and claset) reference variable replaced by functions
  4219 simpset / simpset_ref;
  4220 
  4221 * no longer supports theory aliases (via merge) and non-trivial
  4222 implicit merge of thms' signatures;
  4223 
  4224 * most internal names of constants changed due to qualified names;
  4225 
  4226 * changed Pure/Sequence interface (see Pure/seq.ML);
  4227 
  4228 
  4229 *** General Changes ***
  4230 
  4231 * hierachically structured name spaces (for consts, types, axms, thms
  4232 etc.); new lexical class 'longid' (e.g. Foo.bar.x) may render much of
  4233 old input syntactically incorrect (e.g. "%x.x"); COMPATIBILITY:
  4234 isatool fixdots ensures space after dots (e.g. "%x. x"); set
  4235 long_names for fully qualified output names; NOTE: ML programs
  4236 (special tactics, packages etc.) referring to internal names may have
  4237 to be adapted to cope with fully qualified names; in case of severe
  4238 backward campatibility problems try setting 'global_names' at compile
  4239 time to have enrything declared within a flat name space; one may also
  4240 fine tune name declarations in theories via the 'global' and 'local'
  4241 section;
  4242 
  4243 * reimplemented the implicit simpset and claset using the new anytype
  4244 data filed in signatures; references simpset:simpset ref etc. are
  4245 replaced by functions simpset:unit->simpset and
  4246 simpset_ref:unit->simpset ref; COMPATIBILITY: use isatool fixclasimp
  4247 to patch your ML files accordingly;
  4248 
  4249 * HTML output now includes theory graph data for display with Java
  4250 applet or isatool browser; data generated automatically via isatool
  4251 usedir (see -i option, ISABELLE_USEDIR_OPTIONS);
  4252 
  4253 * defs may now be conditional; improved rewrite_goals_tac to handle
  4254 conditional equations;
  4255 
  4256 * defs now admits additional type arguments, using TYPE('a) syntax;
  4257 
  4258 * theory aliases via merge (e.g. M=A+B+C) no longer supported, always
  4259 creates a new theory node; implicit merge of thms' signatures is
  4260 restricted to 'trivial' ones; COMPATIBILITY: one may have to use
  4261 transfer:theory->thm->thm in (rare) cases;
  4262 
  4263 * improved handling of draft signatures / theories; draft thms (and
  4264 ctyps, cterms) are automatically promoted to real ones;
  4265 
  4266 * slightly changed interfaces for oracles: admit many per theory, named
  4267 (e.g. oracle foo = mlfun), additional name argument for invoke_oracle;
  4268 
  4269 * print_goals: optional output of const types (set show_consts and
  4270 show_types);
  4271 
  4272 * improved output of warnings (###) and errors (***);
  4273 
  4274 * subgoal_tac displays a warning if the new subgoal has type variables;
  4275 
  4276 * removed old README and Makefiles;
  4277 
  4278 * replaced print_goals_ref hook by print_current_goals_fn and result_error_fn;
  4279 
  4280 * removed obsolete init_pps and init_database;
  4281 
  4282 * deleted the obsolete tactical STATE, which was declared by
  4283     fun STATE tacfun st = tacfun st st;
  4284 
  4285 * cd and use now support path variables, e.g. $ISABELLE_HOME, or ~
  4286 (which abbreviates $HOME);
  4287 
  4288 * changed Pure/Sequence interface (see Pure/seq.ML); COMPATIBILITY:
  4289 use isatool fixseq to adapt your ML programs (this works for fully
  4290 qualified references to the Sequence structure only!);
  4291 
  4292 * use_thy no longer requires writable current directory; it always
  4293 reloads .ML *and* .thy file, if either one is out of date;
  4294 
  4295 
  4296 *** Classical Reasoner ***
  4297 
  4298 * Clarify_tac, clarify_tac, clarify_step_tac, Clarify_step_tac: new
  4299 tactics that use classical reasoning to simplify a subgoal without
  4300 splitting it into several subgoals;
  4301 
  4302 * Safe_tac: like safe_tac but uses the default claset;
  4303 
  4304 
  4305 *** Simplifier ***
  4306 
  4307 * added simplification meta rules:
  4308     (asm_)(full_)simplify: simpset -> thm -> thm;
  4309 
  4310 * simplifier.ML no longer part of Pure -- has to be loaded by object
  4311 logics (again);
  4312 
  4313 * added prems argument to simplification procedures;
  4314 
  4315 * HOL, FOL, ZF: added infix function `addsplits':
  4316   instead of `<simpset> setloop (split_tac <thms>)'
  4317   you can simply write `<simpset> addsplits <thms>'
  4318 
  4319 
  4320 *** Syntax ***
  4321 
  4322 * TYPE('a) syntax for type reflection terms;
  4323 
  4324 * no longer handles consts with name "" -- declare as 'syntax' instead;
  4325 
  4326 * pretty printer: changed order of mixfix annotation preference (again!);
  4327 
  4328 * Pure: fixed idt/idts vs. pttrn/pttrns syntactic categories;
  4329 
  4330 
  4331 *** HOL ***
  4332 
  4333 * HOL: there is a new splitter `split_asm_tac' that can be used e.g.
  4334   with `addloop' of the simplifier to faciliate case splitting in premises.
  4335 
  4336 * HOL/TLA: Stephan Merz's formalization of Lamport's Temporal Logic of Actions;
  4337 
  4338 * HOL/Auth: new protocol proofs including some for the Internet
  4339   protocol TLS;
  4340 
  4341 * HOL/Map: new theory of `maps' a la VDM;
  4342 
  4343 * HOL/simplifier: simplification procedures nat_cancel_sums for
  4344 cancelling out common nat summands from =, <, <= (in)equalities, or
  4345 differences; simplification procedures nat_cancel_factor for
  4346 cancelling common factor from =, <, <= (in)equalities over natural
  4347 sums; nat_cancel contains both kinds of procedures, it is installed by
  4348 default in Arith.thy -- this COULD MAKE EXISTING PROOFS FAIL;
  4349 
  4350 * HOL/simplifier: terms of the form
  4351   `? x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x)'  (or t=x)
  4352   are rewritten to
  4353   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t)',
  4354   and those of the form
  4355   `! x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x) --> R(x)'  (or t=x)
  4356   are rewritten to
  4357   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t) --> R(t)',
  4358 
  4359 * HOL/datatype
  4360   Each datatype `t' now comes with a theorem `split_t_case' of the form
  4361 
  4362   P(t_case f1 ... fn x) =
  4363      ( (!y1 ... ym1. x = C1 y1 ... ym1 --> P(f1 y1 ... ym1)) &
  4364         ...
  4365        (!y1 ... ymn. x = Cn y1 ... ymn --> P(f1 y1 ... ymn))
  4366      )
  4367 
  4368   and a theorem `split_t_case_asm' of the form
  4369 
  4370   P(t_case f1 ... fn x) =
  4371     ~( (? y1 ... ym1. x = C1 y1 ... ym1 & ~P(f1 y1 ... ym1)) |
  4372         ...
  4373        (? y1 ... ymn. x = Cn y1 ... ymn & ~P(f1 y1 ... ymn))
  4374      )
  4375   which can be added to a simpset via `addsplits'. The existing theorems
  4376   expand_list_case and expand_option_case have been renamed to
  4377   split_list_case and split_option_case.
  4378 
  4379 * HOL/Arithmetic:
  4380   - `pred n' is automatically converted to `n-1'.
  4381     Users are strongly encouraged not to use `pred' any longer,
  4382     because it will disappear altogether at some point.
  4383   - Users are strongly encouraged to write "0 < n" rather than
  4384     "n ~= 0". Theorems and proof tools have been modified towards this
  4385     `standard'.
  4386 
  4387 * HOL/Lists:
  4388   the function "set_of_list" has been renamed "set" (and its theorems too);
  4389   the function "nth" now takes its arguments in the reverse order and
  4390   has acquired the infix notation "!" as in "xs!n".
  4391 
  4392 * HOL/Set: UNIV is now a constant and is no longer translated to Compl{};
  4393 
  4394 * HOL/Set: The operator (UN x.B x) now abbreviates (UN x:UNIV. B x) and its
  4395   specialist theorems (like UN1_I) are gone.  Similarly for (INT x.B x);
  4396 
  4397 * HOL/record: extensible records with schematic structural subtyping
  4398 (single inheritance); EXPERIMENTAL version demonstrating the encoding,
  4399 still lacks various theorems and concrete record syntax;
  4400 
  4401 
  4402 *** HOLCF ***
  4403 
  4404 * removed "axioms" and "generated by" sections;
  4405 
  4406 * replaced "ops" section by extended "consts" section, which is capable of
  4407   handling the continuous function space "->" directly;
  4408 
  4409 * domain package:
  4410   . proves theorems immediately and stores them in the theory,
  4411   . creates hierachical name space,
  4412   . now uses normal mixfix annotations (instead of cinfix...),
  4413   . minor changes to some names and values (for consistency),
  4414   . e.g. cases -> casedist, dists_eq -> dist_eqs, [take_lemma] -> take_lemmas,
  4415   . separator between mutual domain defs: changed "," to "and",
  4416   . improved handling of sort constraints;  now they have to
  4417     appear on the left-hand side of the equations only;
  4418 
  4419 * fixed LAM <x,y,zs>.b syntax;
  4420 
  4421 * added extended adm_tac to simplifier in HOLCF -- can now discharge
  4422 adm (%x. P (t x)), where P is chainfinite and t continuous;
  4423 
  4424 
  4425 *** FOL and ZF ***
  4426 
  4427 * FOL: there is a new splitter `split_asm_tac' that can be used e.g.
  4428   with `addloop' of the simplifier to faciliate case splitting in premises.
  4429 
  4430 * qed_spec_mp, qed_goal_spec_mp, qed_goalw_spec_mp are available, as
  4431 in HOL, they strip ALL and --> from proved theorems;
  4432 
  4433 
  4434 
  4435 New in Isabelle94-8 (May 1997)
  4436 ------------------------------
  4437 
  4438 *** General Changes ***
  4439 
  4440 * new utilities to build / run / maintain Isabelle etc. (in parts
  4441 still somewhat experimental); old Makefiles etc. still functional;
  4442 
  4443 * new 'Isabelle System Manual';
  4444 
  4445 * INSTALL text, together with ./configure and ./build scripts;
  4446 
  4447 * reimplemented type inference for greater efficiency, better error
  4448 messages and clean internal interface;
  4449 
  4450 * prlim command for dealing with lots of subgoals (an easier way of
  4451 setting goals_limit);
  4452 
  4453 
  4454 *** Syntax ***
  4455 
  4456 * supports alternative (named) syntax tables (parser and pretty
  4457 printer); internal interface is provided by add_modesyntax(_i);
  4458 
  4459 * Pure, FOL, ZF, HOL, HOLCF now support symbolic input and output; to
  4460 be used in conjunction with the Isabelle symbol font; uses the
  4461 "symbols" syntax table;
  4462 
  4463 * added token_translation interface (may translate name tokens in
  4464 arbitrary ways, dependent on their type (free, bound, tfree, ...) and
  4465 the current print_mode); IMPORTANT: user print translation functions
  4466 are responsible for marking newly introduced bounds
  4467 (Syntax.mark_boundT);
  4468 
  4469 * token translations for modes "xterm" and "xterm_color" that display
  4470 names in bold, underline etc. or colors (which requires a color
  4471 version of xterm);
  4472 
  4473 * infixes may now be declared with names independent of their syntax;
  4474 
  4475 * added typed_print_translation (like print_translation, but may
  4476 access type of constant);
  4477 
  4478 
  4479 *** Classical Reasoner ***
  4480 
  4481 Blast_tac: a new tactic!  It is often more powerful than fast_tac, but has
  4482 some limitations.  Blast_tac...
  4483   + ignores addss, addbefore, addafter; this restriction is intrinsic
  4484   + ignores elimination rules that don't have the correct format
  4485         (the conclusion MUST be a formula variable)
  4486   + ignores types, which can make HOL proofs fail
  4487   + rules must not require higher-order unification, e.g. apply_type in ZF
  4488     [message "Function Var's argument not a bound variable" relates to this]
  4489   + its proof strategy is more general but can actually be slower
  4490 
  4491 * substitution with equality assumptions no longer permutes other
  4492 assumptions;
  4493 
  4494 * minor changes in semantics of addafter (now called addaltern); renamed
  4495 setwrapper to setWrapper and compwrapper to compWrapper; added safe wrapper
  4496 (and access functions for it);
  4497 
  4498 * improved combination of classical reasoner and simplifier:
  4499   + functions for handling clasimpsets
  4500   + improvement of addss: now the simplifier is called _after_ the
  4501     safe steps.
  4502   + safe variant of addss called addSss: uses safe simplifications
  4503     _during_ the safe steps. It is more complete as it allows multiple
  4504     instantiations of unknowns (e.g. with slow_tac).
  4505 
  4506 *** Simplifier ***
  4507 
  4508 * added interface for simplification procedures (functions that
  4509 produce *proven* rewrite rules on the fly, depending on current
  4510 redex);
  4511 
  4512 * ordering on terms as parameter (used for ordered rewriting);
  4513 
  4514 * new functions delcongs, deleqcongs, and Delcongs. richer rep_ss;
  4515 
  4516 * the solver is now split into a safe and an unsafe part.
  4517 This should be invisible for the normal user, except that the
  4518 functions setsolver and addsolver have been renamed to setSolver and
  4519 addSolver; added safe_asm_full_simp_tac;
  4520 
  4521 
  4522 *** HOL ***
  4523 
  4524 * a generic induction tactic `induct_tac' which works for all datatypes and
  4525 also for type `nat';
  4526 
  4527 * a generic case distinction tactic `exhaust_tac' which works for all
  4528 datatypes and also for type `nat';
  4529 
  4530 * each datatype comes with a function `size';
  4531 
  4532 * patterns in case expressions allow tuple patterns as arguments to
  4533 constructors, for example `case x of [] => ... | (x,y,z)#ps => ...';
  4534 
  4535 * primrec now also works with type nat;
  4536 
  4537 * recdef: a new declaration form, allows general recursive functions to be
  4538 defined in theory files.  See HOL/ex/Fib, HOL/ex/Primes, HOL/Subst/Unify.
  4539 
  4540 * the constant for negation has been renamed from "not" to "Not" to
  4541 harmonize with FOL, ZF, LK, etc.;
  4542 
  4543 * HOL/ex/LFilter theory of a corecursive "filter" functional for
  4544 infinite lists;
  4545 
  4546 * HOL/Modelcheck demonstrates invocation of model checker oracle;
  4547 
  4548 * HOL/ex/Ring.thy declares cring_simp, which solves equational
  4549 problems in commutative rings, using axiomatic type classes for + and *;
  4550 
  4551 * more examples in HOL/MiniML and HOL/Auth;
  4552 
  4553 * more default rewrite rules for quantifiers, union/intersection;
  4554 
  4555 * a new constant `arbitrary == @x.False';
  4556 
  4557 * HOLCF/IOA replaces old HOL/IOA;
  4558 
  4559 * HOLCF changes: derived all rules and arities
  4560   + axiomatic type classes instead of classes
  4561   + typedef instead of faking type definitions
  4562   + eliminated the internal constants less_fun, less_cfun, UU_fun, UU_cfun etc.
  4563   + new axclasses cpo, chfin, flat with flat < chfin < pcpo < cpo < po
  4564   + eliminated the types void, one, tr
  4565   + use unit lift and bool lift (with translations) instead of one and tr
  4566   + eliminated blift from Lift3.thy (use Def instead of blift)
  4567   all eliminated rules are derived as theorems --> no visible changes ;
  4568 
  4569 
  4570 *** ZF ***
  4571 
  4572 * ZF now has Fast_tac, Simp_tac and Auto_tac.  Union_iff is a now a default
  4573 rewrite rule; this may affect some proofs.  eq_cs is gone but can be put back
  4574 as ZF_cs addSIs [equalityI];
  4575 
  4576 
  4577 
  4578 New in Isabelle94-7 (November 96)
  4579 ---------------------------------
  4580 
  4581 * allowing negative levels (as offsets) in prlev and choplev;
  4582 
  4583 * super-linear speedup for large simplifications;
  4584 
  4585 * FOL, ZF and HOL now use miniscoping: rewriting pushes
  4586 quantifications in as far as possible (COULD MAKE EXISTING PROOFS
  4587 FAIL); can suppress it using the command Delsimps (ex_simps @
  4588 all_simps); De Morgan laws are also now included, by default;
  4589 
  4590 * improved printing of ==>  :  ~:
  4591 
  4592 * new object-logic "Sequents" adds linear logic, while replacing LK
  4593 and Modal (thanks to Sara Kalvala);
  4594 
  4595 * HOL/Auth: correctness proofs for authentication protocols;
  4596 
  4597 * HOL: new auto_tac combines rewriting and classical reasoning (many
  4598 examples on HOL/Auth);
  4599 
  4600 * HOL: new command AddIffs for declaring theorems of the form P=Q to
  4601 the rewriter and classical reasoner simultaneously;
  4602 
  4603 * function uresult no longer returns theorems in "standard" format;
  4604 regain previous version by: val uresult = standard o uresult;
  4605 
  4606 
  4607 
  4608 New in Isabelle94-6
  4609 -------------------
  4610 
  4611 * oracles -- these establish an interface between Isabelle and trusted
  4612 external reasoners, which may deliver results as theorems;
  4613 
  4614 * proof objects (in particular record all uses of oracles);
  4615 
  4616 * Simp_tac, Fast_tac, etc. that refer to implicit simpset / claset;
  4617 
  4618 * "constdefs" section in theory files;
  4619 
  4620 * "primrec" section (HOL) no longer requires names;
  4621 
  4622 * internal type "tactic" now simply "thm -> thm Sequence.seq";
  4623 
  4624 
  4625 
  4626 New in Isabelle94-5
  4627 -------------------
  4628 
  4629 * reduced space requirements;
  4630 
  4631 * automatic HTML generation from theories;
  4632 
  4633 * theory files no longer require "..." (quotes) around most types;
  4634 
  4635 * new examples, including two proofs of the Church-Rosser theorem;
  4636 
  4637 * non-curried (1994) version of HOL is no longer distributed;
  4638 
  4639 
  4640 
  4641 New in Isabelle94-4
  4642 -------------------
  4643 
  4644 * greatly reduced space requirements;
  4645 
  4646 * theory files (.thy) no longer require \...\ escapes at line breaks;
  4647 
  4648 * searchable theorem database (see the section "Retrieving theorems" on
  4649 page 8 of the Reference Manual);
  4650 
  4651 * new examples, including Grabczewski's monumental case study of the
  4652 Axiom of Choice;
  4653 
  4654 * The previous version of HOL renamed to Old_HOL;
  4655 
  4656 * The new version of HOL (previously called CHOL) uses a curried syntax
  4657 for functions.  Application looks like f a b instead of f(a,b);
  4658 
  4659 * Mutually recursive inductive definitions finally work in HOL;
  4660 
  4661 * In ZF, pattern-matching on tuples is now available in all abstractions and
  4662 translates to the operator "split";
  4663 
  4664 
  4665 
  4666 New in Isabelle94-3
  4667 -------------------
  4668 
  4669 * new infix operator, addss, allowing the classical reasoner to
  4670 perform simplification at each step of its search.  Example:
  4671         fast_tac (cs addss ss)
  4672 
  4673 * a new logic, CHOL, the same as HOL, but with a curried syntax
  4674 for functions.  Application looks like f a b instead of f(a,b).  Also pairs
  4675 look like (a,b) instead of <a,b>;
  4676 
  4677 * PLEASE NOTE: CHOL will eventually replace HOL!
  4678 
  4679 * In CHOL, pattern-matching on tuples is now available in all abstractions.
  4680 It translates to the operator "split".  A new theory of integers is available;
  4681 
  4682 * In ZF, integer numerals now denote two's-complement binary integers.
  4683 Arithmetic operations can be performed by rewriting.  See ZF/ex/Bin.ML;
  4684 
  4685 * Many new examples: I/O automata, Church-Rosser theorem, equivalents
  4686 of the Axiom of Choice;
  4687 
  4688 
  4689 
  4690 New in Isabelle94-2
  4691 -------------------
  4692 
  4693 * Significantly faster resolution;
  4694 
  4695 * the different sections in a .thy file can now be mixed and repeated
  4696 freely;
  4697 
  4698 * Database of theorems for FOL, HOL and ZF.  New
  4699 commands including qed, qed_goal and bind_thm store theorems in the database.
  4700 
  4701 * Simple database queries: return a named theorem (get_thm) or all theorems of
  4702 a given theory (thms_of), or find out what theory a theorem was proved in
  4703 (theory_of_thm);
  4704 
  4705 * Bugs fixed in the inductive definition and datatype packages;
  4706 
  4707 * The classical reasoner provides deepen_tac and depth_tac, making FOL_dup_cs
  4708 and HOL_dup_cs obsolete;
  4709 
  4710 * Syntactic ambiguities caused by the new treatment of syntax in Isabelle94-1
  4711 have been removed;
  4712 
  4713 * Simpler definition of function space in ZF;
  4714 
  4715 * new results about cardinal and ordinal arithmetic in ZF;
  4716 
  4717 * 'subtype' facility in HOL for introducing new types as subsets of existing
  4718 types;
  4719 
  4720 
  4721 $Id$