NEWS
author wenzelm
Mon Apr 30 13:32:58 2007 +0200 (2007-04-30)
changeset 22826 0f4c501a691e
parent 22799 ed7d53db2170
child 22845 5f9138bcb3d7
permissions -rw-r--r--
explicit treatment of legacy_features;
     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 nofun]:     deselect a theorem as function equation for a specific constant
   100     [code inline]:    select an equation theorem for unfolding (inlining) in place
   101     [code noinline]:  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 * Library/Pretty_Int.thy: maps HOL numerals on target language integer literals
   523     when generating code.
   524 
   525 * Library/Pretty_Char.thy: maps HOL characters on target language character literals
   526     when generating code.
   527 
   528 * Library/Commutative_Ring.thy: switched from recdef to function package;
   529     constants add, mul, pow now curried.  Infix syntax for algebraic operations.
   530 
   531 * Some steps towards more uniform lattice theory development in HOL.
   532 
   533     constants "meet" and "join" now named "inf" and "sup"
   534     constant "Meet" now named "Inf"
   535 
   536     classes "meet_semilorder" and "join_semilorder" now named
   537       "lower_semilattice" and "upper_semilattice"
   538     class "lorder" now named "lattice"
   539     class "comp_lat" now named "complete_lattice"
   540 
   541     Instantiation of lattice classes allows explicit definitions
   542     for "inf" and "sup" operations.
   543 
   544   INCOMPATIBILITY. Theorem renames:
   545 
   546     meet_left_le            ~> inf_le1
   547     meet_right_le           ~> inf_le2
   548     join_left_le            ~> sup_ge1
   549     join_right_le           ~> sup_ge2
   550     meet_join_le            ~> inf_sup_ord
   551     le_meetI                ~> le_infI
   552     join_leI                ~> le_supI
   553     le_meet                 ~> le_inf_iff
   554     le_join                 ~> ge_sup_conv
   555     meet_idempotent         ~> inf_idem
   556     join_idempotent         ~> sup_idem
   557     meet_comm               ~> inf_commute
   558     join_comm               ~> sup_commute
   559     meet_leI1               ~> le_infI1
   560     meet_leI2               ~> le_infI2
   561     le_joinI1               ~> le_supI1
   562     le_joinI2               ~> le_supI2
   563     meet_assoc              ~> inf_assoc
   564     join_assoc              ~> sup_assoc
   565     meet_left_comm          ~> inf_left_commute
   566     meet_left_idempotent    ~> inf_left_idem
   567     join_left_comm          ~> sup_left_commute
   568     join_left_idempotent    ~> sup_left_idem
   569     meet_aci                ~> inf_aci
   570     join_aci                ~> sup_aci
   571     le_def_meet             ~> le_iff_inf
   572     le_def_join             ~> le_iff_sup
   573     join_absorp2            ~> sup_absorb2
   574     join_absorp1            ~> sup_absorb1
   575     meet_absorp1            ~> inf_absorb1
   576     meet_absorp2            ~> inf_absorb2
   577     meet_join_absorp        ~> inf_sup_absorb
   578     join_meet_absorp        ~> sup_inf_absorb
   579     distrib_join_le         ~> distrib_sup_le
   580     distrib_meet_le         ~> distrib_inf_le
   581 
   582     add_meet_distrib_left   ~> add_inf_distrib_left
   583     add_join_distrib_left   ~> add_sup_distrib_left
   584     is_join_neg_meet        ~> is_join_neg_inf
   585     is_meet_neg_join        ~> is_meet_neg_sup
   586     add_meet_distrib_right  ~> add_inf_distrib_right
   587     add_join_distrib_right  ~> add_sup_distrib_right
   588     add_meet_join_distribs  ~> add_sup_inf_distribs
   589     join_eq_neg_meet        ~> sup_eq_neg_inf
   590     meet_eq_neg_join        ~> inf_eq_neg_sup
   591     add_eq_meet_join        ~> add_eq_inf_sup
   592     meet_0_imp_0            ~> inf_0_imp_0
   593     join_0_imp_0            ~> sup_0_imp_0
   594     meet_0_eq_0             ~> inf_0_eq_0
   595     join_0_eq_0             ~> sup_0_eq_0
   596     neg_meet_eq_join        ~> neg_inf_eq_sup
   597     neg_join_eq_meet        ~> neg_sup_eq_inf
   598     join_eq_if              ~> sup_eq_if
   599 
   600     mono_meet               ~> mono_inf
   601     mono_join               ~> mono_sup
   602     meet_bool_eq            ~> inf_bool_eq
   603     join_bool_eq            ~> sup_bool_eq
   604     meet_fun_eq             ~> inf_fun_eq
   605     join_fun_eq             ~> sup_fun_eq
   606     meet_set_eq             ~> inf_set_eq
   607     join_set_eq             ~> sup_set_eq
   608     meet1_iff               ~> inf1_iff
   609     meet2_iff               ~> inf2_iff
   610     meet1I                  ~> inf1I
   611     meet2I                  ~> inf2I
   612     meet1D1                 ~> inf1D1
   613     meet2D1                 ~> inf2D1
   614     meet1D2                 ~> inf1D2
   615     meet2D2                 ~> inf2D2
   616     meet1E                  ~> inf1E
   617     meet2E                  ~> inf2E
   618     join1_iff               ~> sup1_iff
   619     join2_iff               ~> sup2_iff
   620     join1I1                 ~> sup1I1
   621     join2I1                 ~> sup2I1
   622     join1I1                 ~> sup1I1
   623     join2I2                 ~> sup1I2
   624     join1CI                 ~> sup1CI
   625     join2CI                 ~> sup2CI
   626     join1E                  ~> sup1E
   627     join2E                  ~> sup2E
   628 
   629     is_meet_Meet            ~> is_meet_Inf
   630     Meet_bool_def           ~> Inf_bool_def
   631     Meet_fun_def            ~> Inf_fun_def
   632     Meet_greatest           ~> Inf_greatest
   633     Meet_lower              ~> Inf_lower
   634     Meet_set_def            ~> Inf_set_def
   635 
   636     listsp_meetI            ~> listsp_infI
   637     listsp_meet_eq          ~> listsp_inf_eq
   638 
   639     meet_min                ~> inf_min
   640     join_max                ~> sup_max
   641 
   642 * Class (axclass + locale) "preorder" and "linear": facts "refl", "trans" and
   643 "cases" renamed ro "order_refl", "order_trans" and "linorder_cases", to
   644 avoid clashes with HOL "refl" and "trans". INCOMPATIBILITY.
   645 
   646 * Addes class (axclass + locale) "preorder" as superclass of "order";
   647 potential INCOMPATIBILITY: order of proof goals in order/linorder instance
   648 proofs changed.
   649 
   650 * Dropped lemma duplicate def_imp_eq in favor of meta_eq_to_obj_eq.
   651 INCOMPATIBILITY.
   652 
   653 * Dropped lemma duplicate if_def2 in favor of if_bool_eq_conj.
   654 INCOMPATIBILITY.
   655 
   656 * Added syntactic class "size"; overloaded constant "size" now has
   657 type "'a::size ==> bool"
   658 
   659 * Renamed constants "Divides.op div", "Divides.op mod" and "Divides.op
   660 dvd" to "Divides.div", "Divides.mod" and "Divides.dvd". INCOMPATIBILITY.
   661 
   662 * Added method "lexicographic_order" automatically synthesizes
   663 termination relations as lexicographic combinations of size measures
   664 -- 'function' package.
   665 
   666 * HOL/records: generalised field-update to take a function on the
   667 field rather than the new value: r(|A := x|) is translated to A_update
   668 (K x) r The K-combinator that is internally used is called K_record.
   669 INCOMPATIBILITY: Usage of the plain update functions has to be
   670 adapted.
   671  
   672 * axclass "semiring_0" now contains annihilation axioms x * 0 = 0 and
   673 0 * x = 0, which are required for a semiring.  Richer structures do
   674 not inherit from semiring_0 anymore, because this property is a
   675 theorem there, not an axiom.  INCOMPATIBILITY: In instances of
   676 semiring_0, there is more to prove, but this is mostly trivial.
   677 
   678 * axclass "recpower" was generalized to arbitrary monoids, not just
   679 commutative semirings.  INCOMPATIBILITY: If you use recpower and need
   680 commutativity or a semiring property, add the corresponding classes.
   681 
   682 * Unified locale partial_order with class definition (cf. theory
   683 Orderings), added parameter ``less''.  INCOMPATIBILITY.
   684 
   685 * Constant "List.list_all2" in List.thy now uses authentic syntax.
   686 INCOMPATIBILITY: translations containing list_all2 may go wrong.  On
   687 Isar level, use abbreviations instead.
   688 
   689 * Renamed constant "List.op mem" to "List.memberl" INCOMPATIBILITY:
   690 rarely occuring name references (e.g. ``List.op mem.simps'') require
   691 renaming (e.g. ``List.memberl.simps'').
   692 
   693 * Renamed constants "0" to "HOL.zero" and "1" to "HOL.one".
   694 INCOMPATIBILITY.
   695 
   696 * Added theory Code_Generator providing class 'eq', allowing for code
   697 generation with polymorphic equality.
   698 
   699 * Numeral syntax: type 'bin' which was a mere type copy of 'int' has
   700 been abandoned in favour of plain 'int'. INCOMPATIBILITY --
   701 significant changes for setting up numeral syntax for types:
   702 
   703   - new constants Numeral.pred and Numeral.succ instead
   704       of former Numeral.bin_pred and Numeral.bin_succ.
   705   - Use integer operations instead of bin_add, bin_mult and so on.
   706   - Numeral simplification theorems named Numeral.numeral_simps instead of Bin_simps.
   707   - ML structure Bin_Simprocs now named Int_Numeral_Base_Simprocs.
   708 
   709 See HOL/Integ/IntArith.thy for an example setup.
   710 
   711 * New top level command 'normal_form' computes the normal form of a
   712 term that may contain free variables. For example ``normal_form
   713 "rev[a,b,c]"'' produces ``[b,c,a]'' (without proof).  This command is
   714 suitable for heavy-duty computations because the functions are
   715 compiled to ML first.
   716 
   717 * Alternative iff syntax "A <-> B" for equality on bool (with priority
   718 25 like -->); output depends on the "iff" print_mode, the default is
   719 "A = B" (with priority 50).
   720 
   721 * Renamed constants in HOL.thy and Orderings.thy:
   722     op +   ~> HOL.plus
   723     op -   ~> HOL.minus
   724     uminus ~> HOL.uminus
   725     op *   ~> HOL.times
   726     op <   ~> Orderings.less
   727     op <=  ~> Orderings.less_eq
   728 
   729 Adaptions may be required in the following cases:
   730 
   731 a) User-defined constants using any of the names "plus", "minus", "times",
   732 "less" or "less_eq". The standard syntax translations for "+", "-" and "*"
   733 may go wrong.
   734 INCOMPATIBILITY: use more specific names.
   735 
   736 b) Variables named "plus", "minus", "times", "less", "less_eq"
   737 INCOMPATIBILITY: use more specific names.
   738 
   739 c) Permutative equations (e.g. "a + b = b + a")
   740 Since the change of names also changes the order of terms, permutative
   741 rewrite rules may get applied in a different order. Experience shows that
   742 this is rarely the case (only two adaptions in the whole Isabelle
   743 distribution).
   744 INCOMPATIBILITY: rewrite proofs
   745 
   746 d) ML code directly refering to constant names
   747 This in general only affects hand-written proof tactics, simprocs and so on.
   748 INCOMPATIBILITY: grep your sourcecode and replace names.
   749 
   750 * Relations less (<) and less_eq (<=) are also available on type bool.
   751 Modified syntax to disallow nesting without explicit parentheses,
   752 e.g. "(x < y) < z" or "x < (y < z)", but NOT "x < y < z".
   753 
   754 * "LEAST x:A. P" expands to "LEAST x. x:A & P" (input only).
   755 
   756 * Relation composition operator "op O" now has precedence 75 and binds
   757 stronger than union and intersection. INCOMPATIBILITY.
   758 
   759 * The old set interval syntax "{m..n(}" (and relatives) has been
   760 removed.  Use "{m..<n}" (and relatives) instead.
   761 
   762 * In the context of the assumption "~(s = t)" the Simplifier rewrites
   763 "t = s" to False (by simproc "neq_simproc").  For backward
   764 compatibility this can be disabled by ML "reset use_neq_simproc".
   765 
   766 * "m dvd n" where m and n are numbers is evaluated to True/False by
   767 simp.
   768 
   769 * Theorem Cons_eq_map_conv no longer declared as ``simp''.
   770 
   771 * Theorem setsum_mult renamed to setsum_right_distrib.
   772 
   773 * Prefer ex1I over ex_ex1I in single-step reasoning, e.g. by the
   774 ``rule'' method.
   775 
   776 * Reimplemented methods ``sat'' and ``satx'', with several
   777 improvements: goals no longer need to be stated as "<prems> ==>
   778 False", equivalences (i.e. "=" on type bool) are handled, variable
   779 names of the form "lit_<n>" are no longer reserved, significant
   780 speedup.
   781 
   782 * Methods ``sat'' and ``satx'' can now replay MiniSat proof traces.
   783 zChaff is still supported as well.
   784 
   785 * 'inductive' and 'datatype': provide projections of mutual rules,
   786 bundled as foo_bar.inducts;
   787 
   788 * Library: moved theories Parity, GCD, Binomial, Infinite_Set to
   789 Library.
   790 
   791 * Library: moved theory Accessible_Part to main HOL.
   792 
   793 * Library: added theory Coinductive_List of potentially infinite lists
   794 as greatest fixed-point.
   795 
   796 * Library: added theory AssocList which implements (finite) maps as
   797 association lists.
   798 
   799 * Added proof method ``evaluation'' for efficiently solving a goal
   800 (i.e. a boolean expression) by compiling it to ML. The goal is
   801 "proved" (via an oracle) if it evaluates to True.
   802 
   803 * Linear arithmetic now splits certain operators (e.g. min, max, abs)
   804 also when invoked by the simplifier.  This results in the simplifier
   805 being more powerful on arithmetic goals.  INCOMPATIBILITY.  Set
   806 fast_arith_split_limit to 0 to obtain the old behavior.
   807 
   808 * Support for hex (0x20) and binary (0b1001) numerals.
   809 
   810 * New method: reify eqs (t), where eqs are equations for an
   811 interpretation I :: 'a list => 'b => 'c and t::'c is an optional
   812 parameter, computes a term s::'b and a list xs::'a list and proves the
   813 theorem I xs s = t. This is also known as reification or quoting. The
   814 resulting theorem is applied to the subgoal to substitute t with I xs
   815 s.  If t is omitted, the subgoal itself is reified.
   816 
   817 * New method: reflection corr_thm eqs (t). The parameters eqs and (t)
   818 are as explained above. corr_thm is a theorem for I vs (f t) = I vs t,
   819 where f is supposed to be a computable function (in the sense of code
   820 generattion). The method uses reify to compute s and xs as above then
   821 applies corr_thm and uses normalization by evaluation to "prove" f s =
   822 r and finally gets the theorem t = r, which is again applied to the
   823 subgoal. An Example is available in HOL/ex/ReflectionEx.thy.
   824 
   825 * Reflection: Automatic refification now handels binding, an example
   826 is available in HOL/ex/ReflectionEx.thy
   827 
   828 
   829 *** HOL-Algebra ***
   830 
   831 * Formalisation of ideals and the quotient construction over rings.
   832 
   833 * Order and lattice theory no longer based on records.
   834 INCOMPATIBILITY.
   835 
   836 * Renamed lemmas least_carrier -> least_closed and greatest_carrier ->
   837 greatest_closed.  INCOMPATIBILITY.
   838 
   839 * Method algebra is now set up via an attribute.  For examples see
   840 Ring.thy.  INCOMPATIBILITY: the method is now weaker on combinations
   841 of algebraic structures.
   842 
   843 * Renamed theory CRing to Ring.
   844 
   845 
   846 *** HOL-Complex ***
   847 
   848 * Theory Real: new method ferrack implements quantifier elimination
   849 for linear arithmetic over the reals. The quantifier elimination
   850 feature is used only for decision, for compatibility with arith. This
   851 means a goal is either solved or left unchanged, no simplification.
   852 
   853 * Real: New axiomatic classes formalize real normed vector spaces and
   854 algebras, using new overloaded constants scaleR :: real => 'a => 'a
   855 and norm :: 'a => real.
   856 
   857 * Real: New constant of_real :: real => 'a::real_algebra_1 injects
   858 from reals into other types. The overloaded constant Reals :: 'a set
   859 is now defined as range of_real; potential INCOMPATIBILITY.
   860 
   861 * Hyperreal: Several constants that previously worked only for the
   862 reals have been generalized, so they now work over arbitrary vector
   863 spaces. Type annotations may need to be added in some cases; potential
   864 INCOMPATIBILITY.
   865 
   866   Infinitesimal  :: ('a::real_normed_vector) star set"
   867   HFinite        :: ('a::real_normed_vector) star set"
   868   HInfinite      :: ('a::real_normed_vector) star set"
   869   approx         :: ('a::real_normed_vector) star => 'a star => bool
   870   monad          :: ('a::real_normed_vector) star => 'a star set
   871   galaxy         :: ('a::real_normed_vector) star => 'a star set
   872   (NS)LIMSEQ     :: [nat, 'a::real_normed_vector, 'a] => bool
   873   (NS)convergent :: (nat => 'a::real_normed_vector) => bool
   874   (NS)Bseq       :: (nat => 'a::real_normed_vector) => bool
   875   (NS)Cauchy     :: (nat => 'a::real_normed_vector) => bool
   876   (NS)LIM        :: ['a::real_normed_vector => 'b::real_normed_vector, 'a, 'b] => bool
   877   is(NS)Cont     :: ['a::real_normed_vector => 'b::real_normed_vector, 'a] => bool
   878   deriv          :: ['a::real_normed_field => 'a, 'a, 'a] => bool
   879 
   880 * Complex: Some complex-specific constants are now abbreviations for
   881 overloaded ones: complex_of_real = of_real, cmod = norm, hcmod =
   882 hnorm.  Other constants have been entirely removed in favor of the
   883 polymorphic versions (INCOMPATIBILITY):
   884 
   885   approx        <-- capprox
   886   HFinite       <-- CFinite
   887   HInfinite     <-- CInfinite
   888   Infinitesimal <-- CInfinitesimal
   889   monad         <-- cmonad
   890   galaxy        <-- cgalaxy
   891   (NS)LIM       <-- (NS)CLIM, (NS)CRLIM
   892   is(NS)Cont    <-- is(NS)Contc, is(NS)contCR
   893   (ns)deriv     <-- (ns)cderiv
   894 
   895 
   896 *** ML ***
   897 
   898 * ML within Isar: antiquotations allow to embed statically-checked
   899 formal entities in the source, referring to the context available at
   900 compile-time.  For example:
   901 
   902 ML {* @{typ "'a => 'b"} *}
   903 ML {* @{term "%x. x"} *}
   904 ML {* @{prop "x == y"} *}
   905 ML {* @{ctyp "'a => 'b"} *}
   906 ML {* @{cterm "%x. x"} *}
   907 ML {* @{cprop "x == y"} *}
   908 ML {* @{thm asm_rl} *}
   909 ML {* @{thms asm_rl} *}
   910 ML {* @{const_name c} *}
   911 ML {* @{const_syntax c} *}
   912 ML {* @{context} *}
   913 ML {* @{theory} *}
   914 ML {* @{theory Pure} *}
   915 ML {* @{simpset} *}
   916 ML {* @{claset} *}
   917 ML {* @{clasimpset} *}
   918 
   919 The same works for sources being ``used'' within an Isar context.
   920 
   921 * ML in Isar: improved error reporting; extra verbosity with
   922 Toplevel.debug enabled.
   923 
   924 * Pure/library:
   925 
   926   val burrow: ('a list -> 'b list) -> 'a list list -> 'b list list
   927   val fold_burrow: ('a list -> 'c -> 'b list * 'd) -> 'a list list -> 'c -> 'b list list * 'd
   928 
   929 The semantics of "burrow" is: "take a function with *simulatanously*
   930 transforms a list of value, and apply it *simulatanously* to a list of
   931 list of values of the appropriate type". Compare this with "map" which
   932 would *not* apply its argument function simulatanously but in
   933 sequence; "fold_burrow" has an additional context.
   934 
   935 * Pure/library: functions map2 and fold2 with curried syntax for
   936 simultanous mapping and folding:
   937 
   938     val map2: ('a -> 'b -> 'c) -> 'a list -> 'b list -> 'c list
   939     val fold2: ('a -> 'b -> 'c -> 'c) -> 'a list -> 'b list -> 'c -> 'c
   940 
   941 * Pure/library: indexed lists - some functions in the Isabelle library
   942 treating lists over 'a as finite mappings from [0...n] to 'a have been
   943 given more convenient names and signatures reminiscent of similar
   944 functions for alists, tables, etc:
   945 
   946   val nth: 'a list -> int -> 'a 
   947   val nth_map: int -> ('a -> 'a) -> 'a list -> 'a list
   948   val fold_index: (int * 'a -> 'b -> 'b) -> 'a list -> 'b -> 'b
   949 
   950 Note that fold_index starts counting at index 0, not 1 like foldln
   951 used to.
   952 
   953 * Pure/library: added general ``divide_and_conquer'' combinator on
   954 lists.
   955 
   956 * Pure/General/table.ML: the join operations now works via exceptions
   957 DUP/SAME instead of type option.  This is simpler in simple cases, and
   958 admits slightly more efficient complex applications.
   959 
   960 * Pure: datatype Context.generic joins theory/Proof.context and
   961 provides some facilities for code that works in either kind of
   962 context, notably GenericDataFun for uniform theory and proof data.
   963 
   964 * Pure: 'advanced' translation functions (parse_translation etc.) now
   965 use Context.generic instead of just theory.
   966 
   967 * Pure: simplified internal attribute type, which is now always
   968 Context.generic * thm -> Context.generic * thm.  Global (theory)
   969 vs. local (Proof.context) attributes have been discontinued, while
   970 minimizing code duplication.  Thm.rule_attribute and
   971 Thm.declaration_attribute build canonical attributes; see also
   972 structure Context for further operations on Context.generic, notably
   973 GenericDataFun.  INCOMPATIBILITY, need to adapt attribute type
   974 declarations and definitions.
   975 
   976 * Pure/kernel: consts certification ignores sort constraints given in
   977 signature declarations.  (This information is not relevant to the
   978 logic, but only for type inference.)  IMPORTANT INTERNAL CHANGE,
   979 potential INCOMPATIBILITY.
   980 
   981 * Pure: axiomatic type classes are now purely definitional, with
   982 explicit proofs of class axioms and super class relations performed
   983 internally.  See Pure/axclass.ML for the main internal interfaces --
   984 notably AxClass.define_class supercedes AxClass.add_axclass, and
   985 AxClass.axiomatize_class/classrel/arity supercede
   986 Sign.add_classes/classrel/arities.
   987 
   988 * Pure/Isar: Args/Attrib parsers operate on Context.generic --
   989 global/local versions on theory vs. Proof.context have been
   990 discontinued; Attrib.syntax and Method.syntax have been adapted
   991 accordingly.  INCOMPATIBILITY, need to adapt parser expressions for
   992 attributes, methods, etc.
   993 
   994 * Pure: several functions of signature "... -> theory -> theory * ..."
   995 have been reoriented to "... -> theory -> ... * theory" in order to
   996 allow natural usage in combination with the ||>, ||>>, |-> and
   997 fold_map combinators.
   998 
   999 * Pure: official theorem names (closed derivations) and additional
  1000 comments (tags) are now strictly separate.  Name hints -- which are
  1001 maintained as tags -- may be attached any time without affecting the
  1002 derivation.
  1003 
  1004 * Pure: primitive rule lift_rule now takes goal cterm instead of an
  1005 actual goal state (thm).  Use Thm.lift_rule (Thm.cprem_of st i) to
  1006 achieve the old behaviour.
  1007 
  1008 * Pure: the "Goal" constant is now called "prop", supporting a
  1009 slightly more general idea of ``protecting'' meta-level rule
  1010 statements.
  1011 
  1012 * Pure: Logic.(un)varify only works in a global context, which is now
  1013 enforced instead of silently assumed.  INCOMPATIBILITY, may use
  1014 Logic.legacy_(un)varify as temporary workaround.
  1015 
  1016 * Pure: structure Name provides scalable operations for generating
  1017 internal variable names, notably Name.variants etc.  This replaces
  1018 some popular functions from term.ML:
  1019 
  1020   Term.variant		->  Name.variant
  1021   Term.variantlist	->  Name.variant_list  (*canonical argument order*)
  1022   Term.invent_names	->  Name.invent_list
  1023 
  1024 Note that low-level renaming rarely occurs in new code -- operations
  1025 from structure Variable are used instead (see below).
  1026 
  1027 * Pure: structure Variable provides fundamental operations for proper
  1028 treatment of fixed/schematic variables in a context.  For example,
  1029 Variable.import introduces fixes for schematics of given facts and
  1030 Variable.export reverses the effect (up to renaming) -- this replaces
  1031 various freeze_thaw operations.
  1032 
  1033 * Pure: structure Goal provides simple interfaces for
  1034 init/conclude/finish and tactical prove operations (replacing former
  1035 Tactic.prove).  Goal.prove is the canonical way to prove results
  1036 within a given context; Goal.prove_global is a degraded version for
  1037 theory level goals, including a global Drule.standard.  Note that
  1038 OldGoals.prove_goalw_cterm has long been obsolete, since it is
  1039 ill-behaved in a local proof context (e.g. with local fixes/assumes or
  1040 in a locale context).
  1041 
  1042 * Isar: simplified treatment of user-level errors, using exception
  1043 ERROR of string uniformly.  Function error now merely raises ERROR,
  1044 without any side effect on output channels.  The Isar toplevel takes
  1045 care of proper display of ERROR exceptions.  ML code may use plain
  1046 handle/can/try; cat_error may be used to concatenate errors like this:
  1047 
  1048   ... handle ERROR msg => cat_error msg "..."
  1049 
  1050 Toplevel ML code (run directly or through the Isar toplevel) may be
  1051 embedded into the Isar toplevel with exception display/debug like
  1052 this:
  1053 
  1054   Isar.toplevel (fn () => ...)
  1055 
  1056 INCOMPATIBILITY, removed special transform_error facilities, removed
  1057 obsolete variants of user-level exceptions (ERROR_MESSAGE,
  1058 Context.PROOF, ProofContext.CONTEXT, Proof.STATE, ProofHistory.FAIL)
  1059 -- use plain ERROR instead.
  1060 
  1061 * Isar: theory setup now has type (theory -> theory), instead of a
  1062 list.  INCOMPATIBILITY, may use #> to compose setup functions.
  1063 
  1064 * Isar: installed ML toplevel pretty printer for type Proof.context,
  1065 subject to ProofContext.debug/verbose flags.
  1066 
  1067 * Isar: Toplevel.theory_to_proof admits transactions that modify the
  1068 theory before entering a proof state.  Transactions now always see a
  1069 quasi-functional intermediate checkpoint, both in interactive and
  1070 batch mode.
  1071 
  1072 * Simplifier: the simpset of a running simplification process now
  1073 contains a proof context (cf. Simplifier.the_context), which is the
  1074 very context that the initial simpset has been retrieved from (by
  1075 simpset_of/local_simpset_of).  Consequently, all plug-in components
  1076 (solver, looper etc.) may depend on arbitrary proof data.
  1077 
  1078 * Simplifier.inherit_context inherits the proof context (plus the
  1079 local bounds) of the current simplification process; any simproc
  1080 etc. that calls the Simplifier recursively should do this!  Removed
  1081 former Simplifier.inherit_bounds, which is already included here --
  1082 INCOMPATIBILITY.  Tools based on low-level rewriting may even have to
  1083 specify an explicit context using Simplifier.context/theory_context.
  1084 
  1085 * Simplifier/Classical Reasoner: more abstract interfaces
  1086 change_simpset/claset for modifying the simpset/claset reference of a
  1087 theory; raw versions simpset/claset_ref etc. have been discontinued --
  1088 INCOMPATIBILITY.
  1089 
  1090 * Provers: more generic wrt. syntax of object-logics, avoid hardwired
  1091 "Trueprop" etc.
  1092 
  1093 
  1094 *** System ***
  1095 
  1096 * settings: ML_IDENTIFIER -- which is appended to user specific heap
  1097 locations -- now includes the Isabelle version identifier as well.
  1098 This simplifies use of multiple Isabelle installations.
  1099 
  1100 * isabelle-process: option -S (secure mode) disables some critical
  1101 operations, notably runtime compilation and evaluation of ML source
  1102 code.
  1103 
  1104 
  1105 New in Isabelle2005 (October 2005)
  1106 ----------------------------------
  1107 
  1108 *** General ***
  1109 
  1110 * Theory headers: the new header syntax for Isar theories is
  1111 
  1112   theory <name>
  1113   imports <theory1> ... <theoryN>
  1114   uses <file1> ... <fileM>
  1115   begin
  1116 
  1117 where the 'uses' part is optional.  The previous syntax
  1118 
  1119   theory <name> = <theory1> + ... + <theoryN>:
  1120 
  1121 will disappear in the next release.  Use isatool fixheaders to convert
  1122 existing theory files.  Note that there is no change in ancient
  1123 non-Isar theories now, but these will disappear soon.
  1124 
  1125 * Theory loader: parent theories can now also be referred to via
  1126 relative and absolute paths.
  1127 
  1128 * Command 'find_theorems' searches for a list of criteria instead of a
  1129 list of constants. Known criteria are: intro, elim, dest, name:string,
  1130 simp:term, and any term. Criteria can be preceded by '-' to select
  1131 theorems that do not match. Intro, elim, dest select theorems that
  1132 match the current goal, name:s selects theorems whose fully qualified
  1133 name contain s, and simp:term selects all simplification rules whose
  1134 lhs match term.  Any other term is interpreted as pattern and selects
  1135 all theorems matching the pattern. Available in ProofGeneral under
  1136 'ProofGeneral -> Find Theorems' or C-c C-f.  Example:
  1137 
  1138   C-c C-f (100) "(_::nat) + _ + _" intro -name: "HOL."
  1139 
  1140 prints the last 100 theorems matching the pattern "(_::nat) + _ + _",
  1141 matching the current goal as introduction rule and not having "HOL."
  1142 in their name (i.e. not being defined in theory HOL).
  1143 
  1144 * Command 'thms_containing' has been discontinued in favour of
  1145 'find_theorems'; INCOMPATIBILITY.
  1146 
  1147 * Communication with Proof General is now 8bit clean, which means that
  1148 Unicode text in UTF-8 encoding may be used within theory texts (both
  1149 formal and informal parts).  Cf. option -U of the Isabelle Proof
  1150 General interface.  Here are some simple examples (cf. src/HOL/ex):
  1151 
  1152   http://isabelle.in.tum.de/library/HOL/ex/Hebrew.html
  1153   http://isabelle.in.tum.de/library/HOL/ex/Chinese.html
  1154 
  1155 * Improved efficiency of the Simplifier and, to a lesser degree, the
  1156 Classical Reasoner.  Typical big applications run around 2 times
  1157 faster.
  1158 
  1159 
  1160 *** Document preparation ***
  1161 
  1162 * Commands 'display_drafts' and 'print_drafts' perform simple output
  1163 of raw sources.  Only those symbols that do not require additional
  1164 LaTeX packages (depending on comments in isabellesym.sty) are
  1165 displayed properly, everything else is left verbatim.  isatool display
  1166 and isatool print are used as front ends (these are subject to the
  1167 DVI/PDF_VIEWER and PRINT_COMMAND settings, respectively).
  1168 
  1169 * Command tags control specific markup of certain regions of text,
  1170 notably folding and hiding.  Predefined tags include "theory" (for
  1171 theory begin and end), "proof" for proof commands, and "ML" for
  1172 commands involving ML code; the additional tags "visible" and
  1173 "invisible" are unused by default.  Users may give explicit tag
  1174 specifications in the text, e.g. ''by %invisible (auto)''.  The
  1175 interpretation of tags is determined by the LaTeX job during document
  1176 preparation: see option -V of isatool usedir, or options -n and -t of
  1177 isatool document, or even the LaTeX macros \isakeeptag, \isafoldtag,
  1178 \isadroptag.
  1179 
  1180 Several document versions may be produced at the same time via isatool
  1181 usedir (the generated index.html will link all of them).  Typical
  1182 specifications include ''-V document=theory,proof,ML'' to present
  1183 theory/proof/ML parts faithfully, ''-V outline=/proof,/ML'' to fold
  1184 proof and ML commands, and ''-V mutilated=-theory,-proof,-ML'' to omit
  1185 these parts without any formal replacement text.  The Isabelle site
  1186 default settings produce ''document'' and ''outline'' versions as
  1187 specified above.
  1188 
  1189 * Several new antiquotations:
  1190 
  1191   @{term_type term} prints a term with its type annotated;
  1192 
  1193   @{typeof term} prints the type of a term;
  1194 
  1195   @{const const} is the same as @{term const}, but checks that the
  1196   argument is a known logical constant;
  1197 
  1198   @{term_style style term} and @{thm_style style thm} print a term or
  1199   theorem applying a "style" to it
  1200 
  1201   @{ML text}
  1202 
  1203 Predefined styles are 'lhs' and 'rhs' printing the lhs/rhs of
  1204 definitions, equations, inequations etc., 'concl' printing only the
  1205 conclusion of a meta-logical statement theorem, and 'prem1' .. 'prem19'
  1206 to print the specified premise.  TermStyle.add_style provides an ML
  1207 interface for introducing further styles.  See also the "LaTeX Sugar"
  1208 document practical applications.  The ML antiquotation prints
  1209 type-checked ML expressions verbatim.
  1210 
  1211 * Markup commands 'chapter', 'section', 'subsection', 'subsubsection',
  1212 and 'text' support optional locale specification '(in loc)', which
  1213 specifies the default context for interpreting antiquotations.  For
  1214 example: 'text (in lattice) {* @{thm inf_assoc}*}'.
  1215 
  1216 * Option 'locale=NAME' of antiquotations specifies an alternative
  1217 context interpreting the subsequent argument.  For example: @{thm
  1218 [locale=lattice] inf_assoc}.
  1219 
  1220 * Proper output of proof terms (@{prf ...} and @{full_prf ...}) within
  1221 a proof context.
  1222 
  1223 * Proper output of antiquotations for theory commands involving a
  1224 proof context (such as 'locale' or 'theorem (in loc) ...').
  1225 
  1226 * Delimiters of outer tokens (string etc.) now produce separate LaTeX
  1227 macros (\isachardoublequoteopen, isachardoublequoteclose etc.).
  1228 
  1229 * isatool usedir: new option -C (default true) controls whether option
  1230 -D should include a copy of the original document directory; -C false
  1231 prevents unwanted effects such as copying of administrative CVS data.
  1232 
  1233 
  1234 *** Pure ***
  1235 
  1236 * Considerably improved version of 'constdefs' command.  Now performs
  1237 automatic type-inference of declared constants; additional support for
  1238 local structure declarations (cf. locales and HOL records), see also
  1239 isar-ref manual.  Potential INCOMPATIBILITY: need to observe strictly
  1240 sequential dependencies of definitions within a single 'constdefs'
  1241 section; moreover, the declared name needs to be an identifier.  If
  1242 all fails, consider to fall back on 'consts' and 'defs' separately.
  1243 
  1244 * Improved indexed syntax and implicit structures.  First of all,
  1245 indexed syntax provides a notational device for subscripted
  1246 application, using the new syntax \<^bsub>term\<^esub> for arbitrary
  1247 expressions.  Secondly, in a local context with structure
  1248 declarations, number indexes \<^sub>n or the empty index (default
  1249 number 1) refer to a certain fixed variable implicitly; option
  1250 show_structs controls printing of implicit structures.  Typical
  1251 applications of these concepts involve record types and locales.
  1252 
  1253 * New command 'no_syntax' removes grammar declarations (and
  1254 translations) resulting from the given syntax specification, which is
  1255 interpreted in the same manner as for the 'syntax' command.
  1256 
  1257 * 'Advanced' translation functions (parse_translation etc.) may depend
  1258 on the signature of the theory context being presently used for
  1259 parsing/printing, see also isar-ref manual.
  1260 
  1261 * Improved 'oracle' command provides a type-safe interface to turn an
  1262 ML expression of type theory -> T -> term into a primitive rule of
  1263 type theory -> T -> thm (i.e. the functionality of Thm.invoke_oracle
  1264 is already included here); see also FOL/ex/IffExample.thy;
  1265 INCOMPATIBILITY.
  1266 
  1267 * axclass: name space prefix for class "c" is now "c_class" (was "c"
  1268 before); "cI" is no longer bound, use "c.intro" instead.
  1269 INCOMPATIBILITY.  This change avoids clashes of fact bindings for
  1270 axclasses vs. locales.
  1271 
  1272 * Improved internal renaming of symbolic identifiers -- attach primes
  1273 instead of base 26 numbers.
  1274 
  1275 * New flag show_question_marks controls printing of leading question
  1276 marks in schematic variable names.
  1277 
  1278 * In schematic variable names, *any* symbol following \<^isub> or
  1279 \<^isup> is now treated as part of the base name.  For example, the
  1280 following works without printing of awkward ".0" indexes:
  1281 
  1282   lemma "x\<^isub>1 = x\<^isub>2 ==> x\<^isub>2 = x\<^isub>1"
  1283     by simp
  1284 
  1285 * Inner syntax includes (*(*nested*) comments*).
  1286 
  1287 * Pretty printer now supports unbreakable blocks, specified in mixfix
  1288 annotations as "(00...)".
  1289 
  1290 * Clear separation of logical types and nonterminals, where the latter
  1291 may only occur in 'syntax' specifications or type abbreviations.
  1292 Before that distinction was only partially implemented via type class
  1293 "logic" vs. "{}".  Potential INCOMPATIBILITY in rare cases of improper
  1294 use of 'types'/'consts' instead of 'nonterminals'/'syntax'.  Some very
  1295 exotic syntax specifications may require further adaption
  1296 (e.g. Cube/Cube.thy).
  1297 
  1298 * Removed obsolete type class "logic", use the top sort {} instead.
  1299 Note that non-logical types should be declared as 'nonterminals'
  1300 rather than 'types'.  INCOMPATIBILITY for new object-logic
  1301 specifications.
  1302 
  1303 * Attributes 'induct' and 'cases': type or set names may now be
  1304 locally fixed variables as well.
  1305 
  1306 * Simplifier: can now control the depth to which conditional rewriting
  1307 is traced via the PG menu Isabelle -> Settings -> Trace Simp Depth
  1308 Limit.
  1309 
  1310 * Simplifier: simplification procedures may now take the current
  1311 simpset into account (cf. Simplifier.simproc(_i) / mk_simproc
  1312 interface), which is very useful for calling the Simplifier
  1313 recursively.  Minor INCOMPATIBILITY: the 'prems' argument of simprocs
  1314 is gone -- use prems_of_ss on the simpset instead.  Moreover, the
  1315 low-level mk_simproc no longer applies Logic.varify internally, to
  1316 allow for use in a context of fixed variables.
  1317 
  1318 * thin_tac now works even if the assumption being deleted contains !!
  1319 or ==>.  More generally, erule now works even if the major premise of
  1320 the elimination rule contains !! or ==>.
  1321 
  1322 * Method 'rules' has been renamed to 'iprover'. INCOMPATIBILITY.
  1323 
  1324 * Reorganized bootstrapping of the Pure theories; CPure is now derived
  1325 from Pure, which contains all common declarations already.  Both
  1326 theories are defined via plain Isabelle/Isar .thy files.
  1327 INCOMPATIBILITY: elements of CPure (such as the CPure.intro /
  1328 CPure.elim / CPure.dest attributes) now appear in the Pure name space;
  1329 use isatool fixcpure to adapt your theory and ML sources.
  1330 
  1331 * New syntax 'name(i-j, i-, i, ...)' for referring to specific
  1332 selections of theorems in named facts via index ranges.
  1333 
  1334 * 'print_theorems': in theory mode, really print the difference
  1335 wrt. the last state (works for interactive theory development only),
  1336 in proof mode print all local facts (cf. 'print_facts');
  1337 
  1338 * 'hide': option '(open)' hides only base names.
  1339 
  1340 * More efficient treatment of intermediate checkpoints in interactive
  1341 theory development.
  1342 
  1343 * Code generator is now invoked via code_module (incremental code
  1344 generation) and code_library (modular code generation, ML structures
  1345 for each theory).  INCOMPATIBILITY: new keywords 'file' and 'contains'
  1346 must be quoted when used as identifiers.
  1347 
  1348 * New 'value' command for reading, evaluating and printing terms using
  1349 the code generator.  INCOMPATIBILITY: command keyword 'value' must be
  1350 quoted when used as identifier.
  1351 
  1352 
  1353 *** Locales ***
  1354 
  1355 * New commands for the interpretation of locale expressions in
  1356 theories (1), locales (2) and proof contexts (3).  These generate
  1357 proof obligations from the expression specification.  After the
  1358 obligations have been discharged, theorems of the expression are added
  1359 to the theory, target locale or proof context.  The synopsis of the
  1360 commands is a follows:
  1361 
  1362   (1) interpretation expr inst
  1363   (2) interpretation target < expr
  1364   (3) interpret expr inst
  1365 
  1366 Interpretation in theories and proof contexts require a parameter
  1367 instantiation of terms from the current context.  This is applied to
  1368 specifications and theorems of the interpreted expression.
  1369 Interpretation in locales only permits parameter renaming through the
  1370 locale expression.  Interpretation is smart in that interpretations
  1371 that are active already do not occur in proof obligations, neither are
  1372 instantiated theorems stored in duplicate.  Use 'print_interps' to
  1373 inspect active interpretations of a particular locale.  For details,
  1374 see the Isar Reference manual.  Examples can be found in
  1375 HOL/Finite_Set.thy and HOL/Algebra/UnivPoly.thy.
  1376 
  1377 INCOMPATIBILITY: former 'instantiate' has been withdrawn, use
  1378 'interpret' instead.
  1379 
  1380 * New context element 'constrains' for adding type constraints to
  1381 parameters.
  1382 
  1383 * Context expressions: renaming of parameters with syntax
  1384 redeclaration.
  1385 
  1386 * Locale declaration: 'includes' disallowed.
  1387 
  1388 * Proper static binding of attribute syntax -- i.e. types / terms /
  1389 facts mentioned as arguments are always those of the locale definition
  1390 context, independently of the context of later invocations.  Moreover,
  1391 locale operations (renaming and type / term instantiation) are applied
  1392 to attribute arguments as expected.
  1393 
  1394 INCOMPATIBILITY of the ML interface: always pass Attrib.src instead of
  1395 actual attributes; rare situations may require Attrib.attribute to
  1396 embed those attributes into Attrib.src that lack concrete syntax.
  1397 Attribute implementations need to cooperate properly with the static
  1398 binding mechanism.  Basic parsers Args.XXX_typ/term/prop and
  1399 Attrib.XXX_thm etc. already do the right thing without further
  1400 intervention.  Only unusual applications -- such as "where" or "of"
  1401 (cf. src/Pure/Isar/attrib.ML), which process arguments depending both
  1402 on the context and the facts involved -- may have to assign parsed
  1403 values to argument tokens explicitly.
  1404 
  1405 * Changed parameter management in theorem generation for long goal
  1406 statements with 'includes'.  INCOMPATIBILITY: produces a different
  1407 theorem statement in rare situations.
  1408 
  1409 * Locale inspection command 'print_locale' omits notes elements.  Use
  1410 'print_locale!' to have them included in the output.
  1411 
  1412 
  1413 *** Provers ***
  1414 
  1415 * Provers/hypsubst.ML: improved version of the subst method, for
  1416 single-step rewriting: it now works in bound variable contexts. New is
  1417 'subst (asm)', for rewriting an assumption.  INCOMPATIBILITY: may
  1418 rewrite a different subterm than the original subst method, which is
  1419 still available as 'simplesubst'.
  1420 
  1421 * Provers/quasi.ML: new transitivity reasoners for transitivity only
  1422 and quasi orders.
  1423 
  1424 * Provers/trancl.ML: new transitivity reasoner for transitive and
  1425 reflexive-transitive closure of relations.
  1426 
  1427 * Provers/blast.ML: new reference depth_limit to make blast's depth
  1428 limit (previously hard-coded with a value of 20) user-definable.
  1429 
  1430 * Provers/simplifier.ML has been moved to Pure, where Simplifier.setup
  1431 is peformed already.  Object-logics merely need to finish their
  1432 initial simpset configuration as before.  INCOMPATIBILITY.
  1433 
  1434 
  1435 *** HOL ***
  1436 
  1437 * Symbolic syntax of Hilbert Choice Operator is now as follows:
  1438 
  1439   syntax (epsilon)
  1440     "_Eps" :: "[pttrn, bool] => 'a"    ("(3\<some>_./ _)" [0, 10] 10)
  1441 
  1442 The symbol \<some> is displayed as the alternative epsilon of LaTeX
  1443 and x-symbol; use option '-m epsilon' to get it actually printed.
  1444 Moreover, the mathematically important symbolic identifier \<epsilon>
  1445 becomes available as variable, constant etc.  INCOMPATIBILITY,
  1446 
  1447 * "x > y" abbreviates "y < x" and "x >= y" abbreviates "y <= x".
  1448 Similarly for all quantifiers: "ALL x > y" etc.  The x-symbol for >=
  1449 is \<ge>. New transitivity rules have been added to HOL/Orderings.thy to
  1450 support corresponding Isar calculations.
  1451 
  1452 * "{x:A. P}" abbreviates "{x. x:A & P}", and similarly for "\<in>"
  1453 instead of ":".
  1454 
  1455 * theory SetInterval: changed the syntax for open intervals:
  1456 
  1457   Old       New
  1458   {..n(}    {..<n}
  1459   {)n..}    {n<..}
  1460   {m..n(}   {m..<n}
  1461   {)m..n}   {m<..n}
  1462   {)m..n(}  {m<..<n}
  1463 
  1464 The old syntax is still supported but will disappear in the next
  1465 release.  For conversion use the following Emacs search and replace
  1466 patterns (these are not perfect but work quite well):
  1467 
  1468   {)\([^\.]*\)\.\.  ->  {\1<\.\.}
  1469   \.\.\([^(}]*\)(}  ->  \.\.<\1}
  1470 
  1471 * Theory Commutative_Ring (in Library): method comm_ring for proving
  1472 equalities in commutative rings; method 'algebra' provides a generic
  1473 interface.
  1474 
  1475 * Theory Finite_Set: changed the syntax for 'setsum', summation over
  1476 finite sets: "setsum (%x. e) A", which used to be "\<Sum>x:A. e", is
  1477 now either "SUM x:A. e" or "\<Sum>x \<in> A. e". The bound variable can
  1478 be a tuple pattern.
  1479 
  1480 Some new syntax forms are available:
  1481 
  1482   "\<Sum>x | P. e"      for     "setsum (%x. e) {x. P}"
  1483   "\<Sum>x = a..b. e"   for     "setsum (%x. e) {a..b}"
  1484   "\<Sum>x = a..<b. e"  for     "setsum (%x. e) {a..<b}"
  1485   "\<Sum>x < k. e"      for     "setsum (%x. e) {..<k}"
  1486 
  1487 The latter form "\<Sum>x < k. e" used to be based on a separate
  1488 function "Summation", which has been discontinued.
  1489 
  1490 * theory Finite_Set: in structured induction proofs, the insert case
  1491 is now 'case (insert x F)' instead of the old counterintuitive 'case
  1492 (insert F x)'.
  1493 
  1494 * The 'refute' command has been extended to support a much larger
  1495 fragment of HOL, including axiomatic type classes, constdefs and
  1496 typedefs, inductive datatypes and recursion.
  1497 
  1498 * New tactics 'sat' and 'satx' to prove propositional tautologies.
  1499 Requires zChaff with proof generation to be installed.  See
  1500 HOL/ex/SAT_Examples.thy for examples.
  1501 
  1502 * Datatype induction via method 'induct' now preserves the name of the
  1503 induction variable. For example, when proving P(xs::'a list) by
  1504 induction on xs, the induction step is now P(xs) ==> P(a#xs) rather
  1505 than P(list) ==> P(a#list) as previously.  Potential INCOMPATIBILITY
  1506 in unstructured proof scripts.
  1507 
  1508 * Reworked implementation of records.  Improved scalability for
  1509 records with many fields, avoiding performance problems for type
  1510 inference. Records are no longer composed of nested field types, but
  1511 of nested extension types. Therefore the record type only grows linear
  1512 in the number of extensions and not in the number of fields.  The
  1513 top-level (users) view on records is preserved.  Potential
  1514 INCOMPATIBILITY only in strange cases, where the theory depends on the
  1515 old record representation. The type generated for a record is called
  1516 <record_name>_ext_type.
  1517 
  1518 Flag record_quick_and_dirty_sensitive can be enabled to skip the
  1519 proofs triggered by a record definition or a simproc (if
  1520 quick_and_dirty is enabled).  Definitions of large records can take
  1521 quite long.
  1522 
  1523 New simproc record_upd_simproc for simplification of multiple record
  1524 updates enabled by default.  Moreover, trivial updates are also
  1525 removed: r(|x := x r|) = r.  INCOMPATIBILITY: old proofs break
  1526 occasionally, since simplification is more powerful by default.
  1527 
  1528 * typedef: proper support for polymorphic sets, which contain extra
  1529 type-variables in the term.
  1530 
  1531 * Simplifier: automatically reasons about transitivity chains
  1532 involving "trancl" (r^+) and "rtrancl" (r^*) by setting up tactics
  1533 provided by Provers/trancl.ML as additional solvers.  INCOMPATIBILITY:
  1534 old proofs break occasionally as simplification may now solve more
  1535 goals than previously.
  1536 
  1537 * Simplifier: converts x <= y into x = y if assumption y <= x is
  1538 present.  Works for all partial orders (class "order"), in particular
  1539 numbers and sets.  For linear orders (e.g. numbers) it treats ~ x < y
  1540 just like y <= x.
  1541 
  1542 * Simplifier: new simproc for "let x = a in f x".  If a is a free or
  1543 bound variable or a constant then the let is unfolded.  Otherwise
  1544 first a is simplified to b, and then f b is simplified to g. If
  1545 possible we abstract b from g arriving at "let x = b in h x",
  1546 otherwise we unfold the let and arrive at g.  The simproc can be
  1547 enabled/disabled by the reference use_let_simproc.  Potential
  1548 INCOMPATIBILITY since simplification is more powerful by default.
  1549 
  1550 * Classical reasoning: the meson method now accepts theorems as arguments.
  1551 
  1552 * Prover support: pre-release of the Isabelle-ATP linkup, which runs background
  1553 jobs to provide advice on the provability of subgoals.
  1554 
  1555 * Theory OrderedGroup and Ring_and_Field: various additions and
  1556 improvements to faciliate calculations involving equalities and
  1557 inequalities.
  1558 
  1559 The following theorems have been eliminated or modified
  1560 (INCOMPATIBILITY):
  1561 
  1562   abs_eq             now named abs_of_nonneg
  1563   abs_of_ge_0        now named abs_of_nonneg
  1564   abs_minus_eq       now named abs_of_nonpos
  1565   imp_abs_id         now named abs_of_nonneg
  1566   imp_abs_neg_id     now named abs_of_nonpos
  1567   mult_pos           now named mult_pos_pos
  1568   mult_pos_le        now named mult_nonneg_nonneg
  1569   mult_pos_neg_le    now named mult_nonneg_nonpos
  1570   mult_pos_neg2_le   now named mult_nonneg_nonpos2
  1571   mult_neg           now named mult_neg_neg
  1572   mult_neg_le        now named mult_nonpos_nonpos
  1573 
  1574 * Theory Parity: added rules for simplifying exponents.
  1575 
  1576 * Theory List:
  1577 
  1578 The following theorems have been eliminated or modified
  1579 (INCOMPATIBILITY):
  1580 
  1581   list_all_Nil       now named list_all.simps(1)
  1582   list_all_Cons      now named list_all.simps(2)
  1583   list_all_conv      now named list_all_iff
  1584   set_mem_eq         now named mem_iff
  1585 
  1586 * Theories SetsAndFunctions and BigO (see HOL/Library) support
  1587 asymptotic "big O" calculations.  See the notes in BigO.thy.
  1588 
  1589 
  1590 *** HOL-Complex ***
  1591 
  1592 * Theory RealDef: better support for embedding natural numbers and
  1593 integers in the reals.
  1594 
  1595 The following theorems have been eliminated or modified
  1596 (INCOMPATIBILITY):
  1597 
  1598   exp_ge_add_one_self  now requires no hypotheses
  1599   real_of_int_add      reversed direction of equality (use [symmetric])
  1600   real_of_int_minus    reversed direction of equality (use [symmetric])
  1601   real_of_int_diff     reversed direction of equality (use [symmetric])
  1602   real_of_int_mult     reversed direction of equality (use [symmetric])
  1603 
  1604 * Theory RComplete: expanded support for floor and ceiling functions.
  1605 
  1606 * Theory Ln is new, with properties of the natural logarithm
  1607 
  1608 * Hyperreal: There is a new type constructor "star" for making
  1609 nonstandard types.  The old type names are now type synonyms:
  1610 
  1611   hypreal = real star
  1612   hypnat = nat star
  1613   hcomplex = complex star
  1614 
  1615 * Hyperreal: Many groups of similarly-defined constants have been
  1616 replaced by polymorphic versions (INCOMPATIBILITY):
  1617 
  1618   star_of <-- hypreal_of_real, hypnat_of_nat, hcomplex_of_complex
  1619 
  1620   starset      <-- starsetNat, starsetC
  1621   *s*          <-- *sNat*, *sc*
  1622   starset_n    <-- starsetNat_n, starsetC_n
  1623   *sn*         <-- *sNatn*, *scn*
  1624   InternalSets <-- InternalNatSets, InternalCSets
  1625 
  1626   starfun      <-- starfun{Nat,Nat2,C,RC,CR}
  1627   *f*          <-- *fNat*, *fNat2*, *fc*, *fRc*, *fcR*
  1628   starfun_n    <-- starfun{Nat,Nat2,C,RC,CR}_n
  1629   *fn*         <-- *fNatn*, *fNat2n*, *fcn*, *fRcn*, *fcRn*
  1630   InternalFuns <-- InternalNatFuns, InternalNatFuns2, Internal{C,RC,CR}Funs
  1631 
  1632 * Hyperreal: Many type-specific theorems have been removed in favor of
  1633 theorems specific to various axiomatic type classes (INCOMPATIBILITY):
  1634 
  1635   add_commute <-- {hypreal,hypnat,hcomplex}_add_commute
  1636   add_assoc   <-- {hypreal,hypnat,hcomplex}_add_assocs
  1637   OrderedGroup.add_0 <-- {hypreal,hypnat,hcomplex}_add_zero_left
  1638   OrderedGroup.add_0_right <-- {hypreal,hcomplex}_add_zero_right
  1639   right_minus <-- hypreal_add_minus
  1640   left_minus <-- {hypreal,hcomplex}_add_minus_left
  1641   mult_commute <-- {hypreal,hypnat,hcomplex}_mult_commute
  1642   mult_assoc <-- {hypreal,hypnat,hcomplex}_mult_assoc
  1643   mult_1_left <-- {hypreal,hypnat}_mult_1, hcomplex_mult_one_left
  1644   mult_1_right <-- hcomplex_mult_one_right
  1645   mult_zero_left <-- hcomplex_mult_zero_left
  1646   left_distrib <-- {hypreal,hypnat,hcomplex}_add_mult_distrib
  1647   right_distrib <-- hypnat_add_mult_distrib2
  1648   zero_neq_one <-- {hypreal,hypnat,hcomplex}_zero_not_eq_one
  1649   right_inverse <-- hypreal_mult_inverse
  1650   left_inverse <-- hypreal_mult_inverse_left, hcomplex_mult_inv_left
  1651   order_refl <-- {hypreal,hypnat}_le_refl
  1652   order_trans <-- {hypreal,hypnat}_le_trans
  1653   order_antisym <-- {hypreal,hypnat}_le_anti_sym
  1654   order_less_le <-- {hypreal,hypnat}_less_le
  1655   linorder_linear <-- {hypreal,hypnat}_le_linear
  1656   add_left_mono <-- {hypreal,hypnat}_add_left_mono
  1657   mult_strict_left_mono <-- {hypreal,hypnat}_mult_less_mono2
  1658   add_nonneg_nonneg <-- hypreal_le_add_order
  1659 
  1660 * Hyperreal: Separate theorems having to do with type-specific
  1661 versions of constants have been merged into theorems that apply to the
  1662 new polymorphic constants (INCOMPATIBILITY):
  1663 
  1664   STAR_UNIV_set <-- {STAR_real,NatStar_real,STARC_complex}_set
  1665   STAR_empty_set <-- {STAR,NatStar,STARC}_empty_set
  1666   STAR_Un <-- {STAR,NatStar,STARC}_Un
  1667   STAR_Int <-- {STAR,NatStar,STARC}_Int
  1668   STAR_Compl <-- {STAR,NatStar,STARC}_Compl
  1669   STAR_subset <-- {STAR,NatStar,STARC}_subset
  1670   STAR_mem <-- {STAR,NatStar,STARC}_mem
  1671   STAR_mem_Compl <-- {STAR,STARC}_mem_Compl
  1672   STAR_diff <-- {STAR,STARC}_diff
  1673   STAR_star_of_image_subset <-- {STAR_hypreal_of_real, NatStar_hypreal_of_real,
  1674     STARC_hcomplex_of_complex}_image_subset
  1675   starset_n_Un <-- starset{Nat,C}_n_Un
  1676   starset_n_Int <-- starset{Nat,C}_n_Int
  1677   starset_n_Compl <-- starset{Nat,C}_n_Compl
  1678   starset_n_diff <-- starset{Nat,C}_n_diff
  1679   InternalSets_Un <-- Internal{Nat,C}Sets_Un
  1680   InternalSets_Int <-- Internal{Nat,C}Sets_Int
  1681   InternalSets_Compl <-- Internal{Nat,C}Sets_Compl
  1682   InternalSets_diff <-- Internal{Nat,C}Sets_diff
  1683   InternalSets_UNIV_diff <-- Internal{Nat,C}Sets_UNIV_diff
  1684   InternalSets_starset_n <-- Internal{Nat,C}Sets_starset{Nat,C}_n
  1685   starset_starset_n_eq <-- starset{Nat,C}_starset{Nat,C}_n_eq
  1686   starset_n_starset <-- starset{Nat,C}_n_starset{Nat,C}
  1687   starfun_n_starfun <-- starfun{Nat,Nat2,C,RC,CR}_n_starfun{Nat,Nat2,C,RC,CR}
  1688   starfun <-- starfun{Nat,Nat2,C,RC,CR}
  1689   starfun_mult <-- starfun{Nat,Nat2,C,RC,CR}_mult
  1690   starfun_add <-- starfun{Nat,Nat2,C,RC,CR}_add
  1691   starfun_minus <-- starfun{Nat,Nat2,C,RC,CR}_minus
  1692   starfun_diff <-- starfun{C,RC,CR}_diff
  1693   starfun_o <-- starfun{NatNat2,Nat2,_stafunNat,C,C_starfunRC,_starfunCR}_o
  1694   starfun_o2 <-- starfun{NatNat2,_stafunNat,C,C_starfunRC,_starfunCR}_o2
  1695   starfun_const_fun <-- starfun{Nat,Nat2,C,RC,CR}_const_fun
  1696   starfun_inverse <-- starfun{Nat,C,RC,CR}_inverse
  1697   starfun_eq <-- starfun{Nat,Nat2,C,RC,CR}_eq
  1698   starfun_eq_iff <-- starfun{C,RC,CR}_eq_iff
  1699   starfun_Id <-- starfunC_Id
  1700   starfun_approx <-- starfun{Nat,CR}_approx
  1701   starfun_capprox <-- starfun{C,RC}_capprox
  1702   starfun_abs <-- starfunNat_rabs
  1703   starfun_lambda_cancel <-- starfun{C,CR,RC}_lambda_cancel
  1704   starfun_lambda_cancel2 <-- starfun{C,CR,RC}_lambda_cancel2
  1705   starfun_mult_HFinite_approx <-- starfunCR_mult_HFinite_capprox
  1706   starfun_mult_CFinite_capprox <-- starfun{C,RC}_mult_CFinite_capprox
  1707   starfun_add_capprox <-- starfun{C,RC}_add_capprox
  1708   starfun_add_approx <-- starfunCR_add_approx
  1709   starfun_inverse_inverse <-- starfunC_inverse_inverse
  1710   starfun_divide <-- starfun{C,CR,RC}_divide
  1711   starfun_n <-- starfun{Nat,C}_n
  1712   starfun_n_mult <-- starfun{Nat,C}_n_mult
  1713   starfun_n_add <-- starfun{Nat,C}_n_add
  1714   starfun_n_add_minus <-- starfunNat_n_add_minus
  1715   starfun_n_const_fun <-- starfun{Nat,C}_n_const_fun
  1716   starfun_n_minus <-- starfun{Nat,C}_n_minus
  1717   starfun_n_eq <-- starfun{Nat,C}_n_eq
  1718 
  1719   star_n_add <-- {hypreal,hypnat,hcomplex}_add
  1720   star_n_minus <-- {hypreal,hcomplex}_minus
  1721   star_n_diff <-- {hypreal,hcomplex}_diff
  1722   star_n_mult <-- {hypreal,hcomplex}_mult
  1723   star_n_inverse <-- {hypreal,hcomplex}_inverse
  1724   star_n_le <-- {hypreal,hypnat}_le
  1725   star_n_less <-- {hypreal,hypnat}_less
  1726   star_n_zero_num <-- {hypreal,hypnat,hcomplex}_zero_num
  1727   star_n_one_num <-- {hypreal,hypnat,hcomplex}_one_num
  1728   star_n_abs <-- hypreal_hrabs
  1729   star_n_divide <-- hcomplex_divide
  1730 
  1731   star_of_add <-- {hypreal_of_real,hypnat_of_nat,hcomplex_of_complex}_add
  1732   star_of_minus <-- {hypreal_of_real,hcomplex_of_complex}_minus
  1733   star_of_diff <-- hypreal_of_real_diff
  1734   star_of_mult <-- {hypreal_of_real,hypnat_of_nat,hcomplex_of_complex}_mult
  1735   star_of_one <-- {hypreal_of_real,hcomplex_of_complex}_one
  1736   star_of_zero <-- {hypreal_of_real,hypnat_of_nat,hcomplex_of_complex}_zero
  1737   star_of_le <-- {hypreal_of_real,hypnat_of_nat}_le_iff
  1738   star_of_less <-- {hypreal_of_real,hypnat_of_nat}_less_iff
  1739   star_of_eq <-- {hypreal_of_real,hypnat_of_nat,hcomplex_of_complex}_eq_iff
  1740   star_of_inverse <-- {hypreal_of_real,hcomplex_of_complex}_inverse
  1741   star_of_divide <-- {hypreal_of_real,hcomplex_of_complex}_divide
  1742   star_of_of_nat <-- {hypreal_of_real,hcomplex_of_complex}_of_nat
  1743   star_of_of_int <-- {hypreal_of_real,hcomplex_of_complex}_of_int
  1744   star_of_number_of <-- {hypreal,hcomplex}_number_of
  1745   star_of_number_less <-- number_of_less_hypreal_of_real_iff
  1746   star_of_number_le <-- number_of_le_hypreal_of_real_iff
  1747   star_of_eq_number <-- hypreal_of_real_eq_number_of_iff
  1748   star_of_less_number <-- hypreal_of_real_less_number_of_iff
  1749   star_of_le_number <-- hypreal_of_real_le_number_of_iff
  1750   star_of_power <-- hypreal_of_real_power
  1751   star_of_eq_0 <-- hcomplex_of_complex_zero_iff
  1752 
  1753 * Hyperreal: new method "transfer" that implements the transfer
  1754 principle of nonstandard analysis. With a subgoal that mentions
  1755 nonstandard types like "'a star", the command "apply transfer"
  1756 replaces it with an equivalent one that mentions only standard types.
  1757 To be successful, all free variables must have standard types; non-
  1758 standard variables must have explicit universal quantifiers.
  1759 
  1760 * Hyperreal: A theory of Taylor series.
  1761 
  1762 
  1763 *** HOLCF ***
  1764 
  1765 * Discontinued special version of 'constdefs' (which used to support
  1766 continuous functions) in favor of the general Pure one with full
  1767 type-inference.
  1768 
  1769 * New simplification procedure for solving continuity conditions; it
  1770 is much faster on terms with many nested lambda abstractions (cubic
  1771 instead of exponential time).
  1772 
  1773 * New syntax for domain package: selector names are now optional.
  1774 Parentheses should be omitted unless argument is lazy, for example:
  1775 
  1776   domain 'a stream = cons "'a" (lazy "'a stream")
  1777 
  1778 * New command 'fixrec' for defining recursive functions with pattern
  1779 matching; defining multiple functions with mutual recursion is also
  1780 supported.  Patterns may include the constants cpair, spair, up, sinl,
  1781 sinr, or any data constructor defined by the domain package. The given
  1782 equations are proven as rewrite rules. See HOLCF/ex/Fixrec_ex.thy for
  1783 syntax and examples.
  1784 
  1785 * New commands 'cpodef' and 'pcpodef' for defining predicate subtypes
  1786 of cpo and pcpo types. Syntax is exactly like the 'typedef' command,
  1787 but the proof obligation additionally includes an admissibility
  1788 requirement. The packages generate instances of class cpo or pcpo,
  1789 with continuity and strictness theorems for Rep and Abs.
  1790 
  1791 * HOLCF: Many theorems have been renamed according to a more standard naming
  1792 scheme (INCOMPATIBILITY):
  1793 
  1794   foo_inject:  "foo$x = foo$y ==> x = y"
  1795   foo_eq:      "(foo$x = foo$y) = (x = y)"
  1796   foo_less:    "(foo$x << foo$y) = (x << y)"
  1797   foo_strict:  "foo$UU = UU"
  1798   foo_defined: "... ==> foo$x ~= UU"
  1799   foo_defined_iff: "(foo$x = UU) = (x = UU)"
  1800 
  1801 
  1802 *** ZF ***
  1803 
  1804 * ZF/ex: theories Group and Ring provide examples in abstract algebra,
  1805 including the First Isomorphism Theorem (on quotienting by the kernel
  1806 of a homomorphism).
  1807 
  1808 * ZF/Simplifier: install second copy of type solver that actually
  1809 makes use of TC rules declared to Isar proof contexts (or locales);
  1810 the old version is still required for ML proof scripts.
  1811 
  1812 
  1813 *** Cube ***
  1814 
  1815 * Converted to Isar theory format; use locales instead of axiomatic
  1816 theories.
  1817 
  1818 
  1819 *** ML ***
  1820 
  1821 * Pure/library.ML: added ##>, ##>>, #>> -- higher-order counterparts
  1822 for ||>, ||>>, |>>,
  1823 
  1824 * Pure/library.ML no longer defines its own option datatype, but uses
  1825 that of the SML basis, which has constructors NONE and SOME instead of
  1826 None and Some, as well as exception Option.Option instead of OPTION.
  1827 The functions the, if_none, is_some, is_none have been adapted
  1828 accordingly, while Option.map replaces apsome.
  1829 
  1830 * Pure/library.ML: the exception LIST has been given up in favour of
  1831 the standard exceptions Empty and Subscript, as well as
  1832 Library.UnequalLengths.  Function like Library.hd and Library.tl are
  1833 superceded by the standard hd and tl functions etc.
  1834 
  1835 A number of basic list functions are no longer exported to the ML
  1836 toplevel, as they are variants of predefined functions.  The following
  1837 suggests how one can translate existing code:
  1838 
  1839     rev_append xs ys = List.revAppend (xs, ys)
  1840     nth_elem (i, xs) = List.nth (xs, i)
  1841     last_elem xs = List.last xs
  1842     flat xss = List.concat xss
  1843     seq fs = List.app fs
  1844     partition P xs = List.partition P xs
  1845     mapfilter f xs = List.mapPartial f xs
  1846 
  1847 * Pure/library.ML: several combinators for linear functional
  1848 transformations, notably reverse application and composition:
  1849 
  1850   x |> f                f #> g
  1851   (x, y) |-> f          f #-> g
  1852 
  1853 * Pure/library.ML: introduced/changed precedence of infix operators:
  1854 
  1855   infix 1 |> |-> ||> ||>> |>> |>>> #> #->;
  1856   infix 2 ?;
  1857   infix 3 o oo ooo oooo;
  1858   infix 4 ~~ upto downto;
  1859 
  1860 Maybe INCOMPATIBILITY when any of those is used in conjunction with other
  1861 infix operators.
  1862 
  1863 * Pure/library.ML: natural list combinators fold, fold_rev, and
  1864 fold_map support linear functional transformations and nesting.  For
  1865 example:
  1866 
  1867   fold f [x1, ..., xN] y =
  1868     y |> f x1 |> ... |> f xN
  1869 
  1870   (fold o fold) f [xs1, ..., xsN] y =
  1871     y |> fold f xs1 |> ... |> fold f xsN
  1872 
  1873   fold f [x1, ..., xN] =
  1874     f x1 #> ... #> f xN
  1875 
  1876   (fold o fold) f [xs1, ..., xsN] =
  1877     fold f xs1 #> ... #> fold f xsN
  1878 
  1879 * Pure/library.ML: the following selectors on type 'a option are
  1880 available:
  1881 
  1882   the:               'a option -> 'a  (*partial*)
  1883   these:             'a option -> 'a  where 'a = 'b list
  1884   the_default: 'a -> 'a option -> 'a
  1885   the_list:          'a option -> 'a list
  1886 
  1887 * Pure/General: structure AList (cf. Pure/General/alist.ML) provides
  1888 basic operations for association lists, following natural argument
  1889 order; moreover the explicit equality predicate passed here avoids
  1890 potentially expensive polymorphic runtime equality checks.
  1891 The old functions may be expressed as follows:
  1892 
  1893   assoc = uncurry (AList.lookup (op =))
  1894   assocs = these oo AList.lookup (op =)
  1895   overwrite = uncurry (AList.update (op =)) o swap
  1896 
  1897 * Pure/General: structure AList (cf. Pure/General/alist.ML) provides
  1898 
  1899   val make: ('a -> 'b) -> 'a list -> ('a * 'b) list
  1900   val find: ('a * 'b -> bool) -> ('c * 'b) list -> 'a -> 'c list
  1901 
  1902 replacing make_keylist and keyfilter (occassionally used)
  1903 Naive rewrites:
  1904 
  1905   make_keylist = AList.make
  1906   keyfilter = AList.find (op =)
  1907 
  1908 * eq_fst and eq_snd now take explicit equality parameter, thus
  1909   avoiding eqtypes. Naive rewrites:
  1910 
  1911     eq_fst = eq_fst (op =)
  1912     eq_snd = eq_snd (op =)
  1913 
  1914 * Removed deprecated apl and apr (rarely used).
  1915   Naive rewrites:
  1916 
  1917     apl (n, op) =>>= curry op n
  1918     apr (op, m) =>>= fn n => op (n, m)
  1919 
  1920 * Pure/General: structure OrdList (cf. Pure/General/ord_list.ML)
  1921 provides a reasonably efficient light-weight implementation of sets as
  1922 lists.
  1923 
  1924 * Pure/General: generic tables (cf. Pure/General/table.ML) provide a
  1925 few new operations; existing lookup and update are now curried to
  1926 follow natural argument order (for use with fold etc.);
  1927 INCOMPATIBILITY, use (uncurry Symtab.lookup) etc. as last resort.
  1928 
  1929 * Pure/General: output via the Isabelle channels of
  1930 writeln/warning/error etc. is now passed through Output.output, with a
  1931 hook for arbitrary transformations depending on the print_mode
  1932 (cf. Output.add_mode -- the first active mode that provides a output
  1933 function wins).  Already formatted output may be embedded into further
  1934 text via Output.raw; the result of Pretty.string_of/str_of and derived
  1935 functions (string_of_term/cterm/thm etc.) is already marked raw to
  1936 accommodate easy composition of diagnostic messages etc.  Programmers
  1937 rarely need to care about Output.output or Output.raw at all, with
  1938 some notable exceptions: Output.output is required when bypassing the
  1939 standard channels (writeln etc.), or in token translations to produce
  1940 properly formatted results; Output.raw is required when capturing
  1941 already output material that will eventually be presented to the user
  1942 a second time.  For the default print mode, both Output.output and
  1943 Output.raw have no effect.
  1944 
  1945 * Pure/General: Output.time_accumulator NAME creates an operator ('a
  1946 -> 'b) -> 'a -> 'b to measure runtime and count invocations; the
  1947 cumulative results are displayed at the end of a batch session.
  1948 
  1949 * Pure/General: File.sysify_path and File.quote_sysify path have been
  1950 replaced by File.platform_path and File.shell_path (with appropriate
  1951 hooks).  This provides a clean interface for unusual systems where the
  1952 internal and external process view of file names are different.
  1953 
  1954 * Pure: more efficient orders for basic syntactic entities: added
  1955 fast_string_ord, fast_indexname_ord, fast_term_ord; changed sort_ord
  1956 and typ_ord to use fast_string_ord and fast_indexname_ord (term_ord is
  1957 NOT affected); structures Symtab, Vartab, Typtab, Termtab use the fast
  1958 orders now -- potential INCOMPATIBILITY for code that depends on a
  1959 particular order for Symtab.keys, Symtab.dest, etc. (consider using
  1960 Library.sort_strings on result).
  1961 
  1962 * Pure/term.ML: combinators fold_atyps, fold_aterms, fold_term_types,
  1963 fold_types traverse types/terms from left to right, observing natural
  1964 argument order.  Supercedes previous foldl_XXX versions, add_frees,
  1965 add_vars etc. have been adapted as well: INCOMPATIBILITY.
  1966 
  1967 * Pure: name spaces have been refined, with significant changes of the
  1968 internal interfaces -- INCOMPATIBILITY.  Renamed cond_extern(_table)
  1969 to extern(_table).  The plain name entry path is superceded by a
  1970 general 'naming' context, which also includes the 'policy' to produce
  1971 a fully qualified name and external accesses of a fully qualified
  1972 name; NameSpace.extend is superceded by context dependent
  1973 Sign.declare_name.  Several theory and proof context operations modify
  1974 the naming context.  Especially note Theory.restore_naming and
  1975 ProofContext.restore_naming to get back to a sane state; note that
  1976 Theory.add_path is no longer sufficient to recover from
  1977 Theory.absolute_path in particular.
  1978 
  1979 * Pure: new flags short_names (default false) and unique_names
  1980 (default true) for controlling output of qualified names.  If
  1981 short_names is set, names are printed unqualified.  If unique_names is
  1982 reset, the name prefix is reduced to the minimum required to achieve
  1983 the original result when interning again, even if there is an overlap
  1984 with earlier declarations.
  1985 
  1986 * Pure/TheoryDataFun: change of the argument structure; 'prep_ext' is
  1987 now 'extend', and 'merge' gets an additional Pretty.pp argument
  1988 (useful for printing error messages).  INCOMPATIBILITY.
  1989 
  1990 * Pure: major reorganization of the theory context.  Type Sign.sg and
  1991 Theory.theory are now identified, referring to the universal
  1992 Context.theory (see Pure/context.ML).  Actual signature and theory
  1993 content is managed as theory data.  The old code and interfaces were
  1994 spread over many files and structures; the new arrangement introduces
  1995 considerable INCOMPATIBILITY to gain more clarity:
  1996 
  1997   Context -- theory management operations (name, identity, inclusion,
  1998     parents, ancestors, merge, etc.), plus generic theory data;
  1999 
  2000   Sign -- logical signature and syntax operations (declaring consts,
  2001     types, etc.), plus certify/read for common entities;
  2002 
  2003   Theory -- logical theory operations (stating axioms, definitions,
  2004     oracles), plus a copy of logical signature operations (consts,
  2005     types, etc.); also a few basic management operations (Theory.copy,
  2006     Theory.merge, etc.)
  2007 
  2008 The most basic sign_of operations (Theory.sign_of, Thm.sign_of_thm
  2009 etc.) as well as the sign field in Thm.rep_thm etc. have been retained
  2010 for convenience -- they merely return the theory.
  2011 
  2012 * Pure: type Type.tsig is superceded by theory in most interfaces.
  2013 
  2014 * Pure: the Isar proof context type is already defined early in Pure
  2015 as Context.proof (note that ProofContext.context and Proof.context are
  2016 aliases, where the latter is the preferred name).  This enables other
  2017 Isabelle components to refer to that type even before Isar is present.
  2018 
  2019 * Pure/sign/theory: discontinued named name spaces (i.e. classK,
  2020 typeK, constK, axiomK, oracleK), but provide explicit operations for
  2021 any of these kinds.  For example, Sign.intern typeK is now
  2022 Sign.intern_type, Theory.hide_space Sign.typeK is now
  2023 Theory.hide_types.  Also note that former
  2024 Theory.hide_classes/types/consts are now
  2025 Theory.hide_classes_i/types_i/consts_i, while the non '_i' versions
  2026 internalize their arguments!  INCOMPATIBILITY.
  2027 
  2028 * Pure: get_thm interface (of PureThy and ProofContext) expects
  2029 datatype thmref (with constructors Name and NameSelection) instead of
  2030 plain string -- INCOMPATIBILITY;
  2031 
  2032 * Pure: cases produced by proof methods specify options, where NONE
  2033 means to remove case bindings -- INCOMPATIBILITY in
  2034 (RAW_)METHOD_CASES.
  2035 
  2036 * Pure: the following operations retrieve axioms or theorems from a
  2037 theory node or theory hierarchy, respectively:
  2038 
  2039   Theory.axioms_of: theory -> (string * term) list
  2040   Theory.all_axioms_of: theory -> (string * term) list
  2041   PureThy.thms_of: theory -> (string * thm) list
  2042   PureThy.all_thms_of: theory -> (string * thm) list
  2043 
  2044 * Pure: print_tac now outputs the goal through the trace channel.
  2045 
  2046 * Isar toplevel: improved diagnostics, mostly for Poly/ML only.
  2047 Reference Toplevel.debug (default false) controls detailed printing
  2048 and tracing of low-level exceptions; Toplevel.profiling (default 0)
  2049 controls execution profiling -- set to 1 for time and 2 for space
  2050 (both increase the runtime).
  2051 
  2052 * Isar session: The initial use of ROOT.ML is now always timed,
  2053 i.e. the log will show the actual process times, in contrast to the
  2054 elapsed wall-clock time that the outer shell wrapper produces.
  2055 
  2056 * Simplifier: improved handling of bound variables (nameless
  2057 representation, avoid allocating new strings).  Simprocs that invoke
  2058 the Simplifier recursively should use Simplifier.inherit_bounds to
  2059 avoid local name clashes.  Failure to do so produces warnings
  2060 "Simplifier: renamed bound variable ..."; set Simplifier.debug_bounds
  2061 for further details.
  2062 
  2063 * ML functions legacy_bindings and use_legacy_bindings produce ML fact
  2064 bindings for all theorems stored within a given theory; this may help
  2065 in porting non-Isar theories to Isar ones, while keeping ML proof
  2066 scripts for the time being.
  2067 
  2068 * ML operator HTML.with_charset specifies the charset begin used for
  2069 generated HTML files.  For example:
  2070 
  2071   HTML.with_charset "utf-8" use_thy "Hebrew";
  2072   HTML.with_charset "utf-8" use_thy "Chinese";
  2073 
  2074 
  2075 *** System ***
  2076 
  2077 * Allow symlinks to all proper Isabelle executables (Isabelle,
  2078 isabelle, isatool etc.).
  2079 
  2080 * ISABELLE_DOC_FORMAT setting specifies preferred document format (for
  2081 isatool doc, isatool mkdir, display_drafts etc.).
  2082 
  2083 * isatool usedir: option -f allows specification of the ML file to be
  2084 used by Isabelle; default is ROOT.ML.
  2085 
  2086 * New isatool version outputs the version identifier of the Isabelle
  2087 distribution being used.
  2088 
  2089 * HOL: new isatool dimacs2hol converts files in DIMACS CNF format
  2090 (containing Boolean satisfiability problems) into Isabelle/HOL
  2091 theories.
  2092 
  2093 
  2094 
  2095 New in Isabelle2004 (April 2004)
  2096 --------------------------------
  2097 
  2098 *** General ***
  2099 
  2100 * Provers/order.ML:  new efficient reasoner for partial and linear orders.
  2101   Replaces linorder.ML.
  2102 
  2103 * Pure: Greek letters (except small lambda, \<lambda>), as well as Gothic
  2104   (\<aa>...\<zz>\<AA>...\<ZZ>), calligraphic (\<A>...\<Z>), and Euler
  2105   (\<a>...\<z>), are now considered normal letters, and can therefore
  2106   be used anywhere where an ASCII letter (a...zA...Z) has until
  2107   now. COMPATIBILITY: This obviously changes the parsing of some
  2108   terms, especially where a symbol has been used as a binder, say
  2109   '\<Pi>x. ...', which is now a type error since \<Pi>x will be parsed
  2110   as an identifier.  Fix it by inserting a space around former
  2111   symbols.  Call 'isatool fixgreek' to try to fix parsing errors in
  2112   existing theory and ML files.
  2113 
  2114 * Pure: Macintosh and Windows line-breaks are now allowed in theory files.
  2115 
  2116 * Pure: single letter sub/superscripts (\<^isub> and \<^isup>) are now
  2117   allowed in identifiers. Similar to Greek letters \<^isub> is now considered
  2118   a normal (but invisible) letter. For multiple letter subscripts repeat
  2119   \<^isub> like this: x\<^isub>1\<^isub>2.
  2120 
  2121 * Pure: There are now sub-/superscripts that can span more than one
  2122   character. Text between \<^bsub> and \<^esub> is set in subscript in
  2123   ProofGeneral and LaTeX, text between \<^bsup> and \<^esup> in
  2124   superscript. The new control characters are not identifier parts.
  2125 
  2126 * Pure: Control-symbols of the form \<^raw:...> will literally print the
  2127   content of "..." to the latex file instead of \isacntrl... . The "..."
  2128   may consist of any printable characters excluding the end bracket >.
  2129 
  2130 * Pure: Using new Isar command "finalconsts" (or the ML functions
  2131   Theory.add_finals or Theory.add_finals_i) it is now possible to
  2132   declare constants "final", which prevents their being given a definition
  2133   later.  It is useful for constants whose behaviour is fixed axiomatically
  2134   rather than definitionally, such as the meta-logic connectives.
  2135 
  2136 * Pure: 'instance' now handles general arities with general sorts
  2137   (i.e. intersections of classes),
  2138 
  2139 * Presentation: generated HTML now uses a CSS style sheet to make layout
  2140   (somewhat) independent of content. It is copied from lib/html/isabelle.css.
  2141   It can be changed to alter the colors/layout of generated pages.
  2142 
  2143 
  2144 *** Isar ***
  2145 
  2146 * Tactic emulation methods rule_tac, erule_tac, drule_tac, frule_tac,
  2147   cut_tac, subgoal_tac and thin_tac:
  2148   - Now understand static (Isar) contexts.  As a consequence, users of Isar
  2149     locales are no longer forced to write Isar proof scripts.
  2150     For details see Isar Reference Manual, paragraph 4.3.2: Further tactic
  2151     emulations.
  2152   - INCOMPATIBILITY: names of variables to be instantiated may no
  2153     longer be enclosed in quotes.  Instead, precede variable name with `?'.
  2154     This is consistent with the instantiation attribute "where".
  2155 
  2156 * Attributes "where" and "of":
  2157   - Now take type variables of instantiated theorem into account when reading
  2158     the instantiation string.  This fixes a bug that caused instantiated
  2159     theorems to have too special types in some circumstances.
  2160   - "where" permits explicit instantiations of type variables.
  2161 
  2162 * Calculation commands "moreover" and "also" no longer interfere with
  2163   current facts ("this"), admitting arbitrary combinations with "then"
  2164   and derived forms.
  2165 
  2166 * Locales:
  2167   - Goal statements involving the context element "includes" no longer
  2168     generate theorems with internal delta predicates (those ending on
  2169     "_axioms") in the premise.
  2170     Resolve particular premise with <locale>.intro to obtain old form.
  2171   - Fixed bug in type inference ("unify_frozen") that prevented mix of target
  2172     specification and "includes" elements in goal statement.
  2173   - Rule sets <locale>.intro and <locale>.axioms no longer declared as
  2174     [intro?] and [elim?] (respectively) by default.
  2175   - Experimental command for instantiation of locales in proof contexts:
  2176         instantiate <label>[<attrs>]: <loc>
  2177     Instantiates locale <loc> and adds all its theorems to the current context
  2178     taking into account their attributes.  Label and attrs are optional
  2179     modifiers, like in theorem declarations.  If present, names of
  2180     instantiated theorems are qualified with <label>, and the attributes
  2181     <attrs> are applied after any attributes these theorems might have already.
  2182       If the locale has assumptions, a chained fact of the form
  2183     "<loc> t1 ... tn" is expected from which instantiations of the parameters
  2184     are derived.  The command does not support old-style locales declared
  2185     with "locale (open)".
  2186       A few (very simple) examples can be found in FOL/ex/LocaleInst.thy.
  2187 
  2188 * HOL: Tactic emulation methods induct_tac and case_tac understand static
  2189   (Isar) contexts.
  2190 
  2191 
  2192 *** HOL ***
  2193 
  2194 * Proof import: new image HOL4 contains the imported library from
  2195   the HOL4 system with about 2500 theorems. It is imported by
  2196   replaying proof terms produced by HOL4 in Isabelle. The HOL4 image
  2197   can be used like any other Isabelle image.  See
  2198   HOL/Import/HOL/README for more information.
  2199 
  2200 * Simplifier:
  2201   - Much improved handling of linear and partial orders.
  2202     Reasoners for linear and partial orders are set up for type classes
  2203     "linorder" and "order" respectively, and are added to the default simpset
  2204     as solvers.  This means that the simplifier can build transitivity chains
  2205     to solve goals from the assumptions.
  2206   - INCOMPATIBILITY: old proofs break occasionally.  Typically, applications
  2207     of blast or auto after simplification become unnecessary because the goal
  2208     is solved by simplification already.
  2209 
  2210 * Numerics: new theory Ring_and_Field contains over 250 basic numerical laws,
  2211     all proved in axiomatic type classes for semirings, rings and fields.
  2212 
  2213 * Numerics:
  2214   - Numeric types (nat, int, and in HOL-Complex rat, real, complex, etc.) are
  2215     now formalized using the Ring_and_Field theory mentioned above.
  2216   - INCOMPATIBILITY: simplification and arithmetic behaves somewhat differently
  2217     than before, because now they are set up once in a generic manner.
  2218   - INCOMPATIBILITY: many type-specific arithmetic laws have gone.
  2219     Look for the general versions in Ring_and_Field (and Power if they concern
  2220     exponentiation).
  2221 
  2222 * Type "rat" of the rational numbers is now available in HOL-Complex.
  2223 
  2224 * Records:
  2225   - Record types are now by default printed with their type abbreviation
  2226     instead of the list of all field types. This can be configured via
  2227     the reference "print_record_type_abbr".
  2228   - Simproc "record_upd_simproc" for simplification of multiple updates added
  2229     (not enabled by default).
  2230   - Simproc "record_ex_sel_eq_simproc" to simplify EX x. sel r = x resp.
  2231     EX x. x = sel r to True (not enabled by default).
  2232   - Tactic "record_split_simp_tac" to split and simplify records added.
  2233 
  2234 * 'specification' command added, allowing for definition by
  2235   specification.  There is also an 'ax_specification' command that
  2236   introduces the new constants axiomatically.
  2237 
  2238 * arith(_tac) is now able to generate counterexamples for reals as well.
  2239 
  2240 * HOL-Algebra: new locale "ring" for non-commutative rings.
  2241 
  2242 * HOL-ex: InductiveInvariant_examples illustrates advanced recursive function
  2243   definitions, thanks to Sava Krsti\'{c} and John Matthews.
  2244 
  2245 * HOL-Matrix: a first theory for matrices in HOL with an application of
  2246   matrix theory to linear programming.
  2247 
  2248 * Unions and Intersections:
  2249   The latex output syntax of UN and INT has been changed
  2250   from "\Union x \in A. B" to "\Union_{x \in A} B"
  2251   i.e. the index formulae has become a subscript.
  2252   Similarly for "\Union x. B", and for \Inter instead of \Union.
  2253 
  2254 * Unions and Intersections over Intervals:
  2255   There is new short syntax "UN i<=n. A" for "UN i:{0..n}. A". There is
  2256   also an x-symbol version with subscripts "\<Union>\<^bsub>i <= n\<^esub>. A"
  2257   like in normal math, and corresponding versions for < and for intersection.
  2258 
  2259 * HOL/List: Ordering "lexico" is renamed "lenlex" and the standard
  2260   lexicographic dictonary ordering has been added as "lexord".
  2261 
  2262 * ML: the legacy theory structures Int and List have been removed. They had
  2263   conflicted with ML Basis Library structures having the same names.
  2264 
  2265 * 'refute' command added to search for (finite) countermodels.  Only works
  2266   for a fragment of HOL.  The installation of an external SAT solver is
  2267   highly recommended.  See "HOL/Refute.thy" for details.
  2268 
  2269 * 'quickcheck' command: Allows to find counterexamples by evaluating
  2270   formulae under an assignment of free variables to random values.
  2271   In contrast to 'refute', it can deal with inductive datatypes,
  2272   but cannot handle quantifiers. See "HOL/ex/Quickcheck_Examples.thy"
  2273   for examples.
  2274 
  2275 
  2276 *** HOLCF ***
  2277 
  2278 * Streams now come with concatenation and are part of the HOLCF image
  2279 
  2280 
  2281 
  2282 New in Isabelle2003 (May 2003)
  2283 ------------------------------
  2284 
  2285 *** General ***
  2286 
  2287 * Provers/simplifier:
  2288 
  2289   - Completely reimplemented method simp (ML: Asm_full_simp_tac):
  2290     Assumptions are now subject to complete mutual simplification,
  2291     not just from left to right. The simplifier now preserves
  2292     the order of assumptions.
  2293 
  2294     Potential INCOMPATIBILITY:
  2295 
  2296     -- simp sometimes diverges where the old version did
  2297        not, e.g. invoking simp on the goal
  2298 
  2299         [| P (f x); y = x; f x = f y |] ==> Q
  2300 
  2301        now gives rise to the infinite reduction sequence
  2302 
  2303         P(f x) --(f x = f y)--> P(f y) --(y = x)--> P(f x) --(f x = f y)--> ...
  2304 
  2305        Using "simp (asm_lr)" (ML: Asm_lr_simp_tac) instead often solves this
  2306        kind of problem.
  2307 
  2308     -- Tactics combining classical reasoner and simplification (such as auto)
  2309        are also affected by this change, because many of them rely on
  2310        simp. They may sometimes diverge as well or yield a different numbers
  2311        of subgoals. Try to use e.g. force, fastsimp, or safe instead of auto
  2312        in case of problems. Sometimes subsequent calls to the classical
  2313        reasoner will fail because a preceeding call to the simplifier too
  2314        eagerly simplified the goal, e.g. deleted redundant premises.
  2315 
  2316   - The simplifier trace now shows the names of the applied rewrite rules
  2317 
  2318   - You can limit the number of recursive invocations of the simplifier
  2319     during conditional rewriting (where the simplifie tries to solve the
  2320     conditions before applying the rewrite rule):
  2321     ML "simp_depth_limit := n"
  2322     where n is an integer. Thus you can force termination where previously
  2323     the simplifier would diverge.
  2324 
  2325   - Accepts free variables as head terms in congruence rules.  Useful in Isar.
  2326 
  2327   - No longer aborts on failed congruence proof.  Instead, the
  2328     congruence is ignored.
  2329 
  2330 * Pure: New generic framework for extracting programs from constructive
  2331   proofs. See HOL/Extraction.thy for an example instantiation, as well
  2332   as HOL/Extraction for some case studies.
  2333 
  2334 * Pure: The main goal of the proof state is no longer shown by default, only
  2335 the subgoals. This behaviour is controlled by a new flag.
  2336    PG menu: Isabelle/Isar -> Settings -> Show Main Goal
  2337 (ML: Proof.show_main_goal).
  2338 
  2339 * Pure: You can find all matching introduction rules for subgoal 1, i.e. all
  2340 rules whose conclusion matches subgoal 1:
  2341       PG menu: Isabelle/Isar -> Show me -> matching rules
  2342 The rules are ordered by how closely they match the subgoal.
  2343 In particular, rules that solve a subgoal outright are displayed first
  2344 (or rather last, the way they are printed).
  2345 (ML: ProofGeneral.print_intros())
  2346 
  2347 * Pure: New flag trace_unify_fail causes unification to print
  2348 diagnostic information (PG: in trace buffer) when it fails. This is
  2349 useful for figuring out why single step proofs like rule, erule or
  2350 assumption failed.
  2351 
  2352 * Pure: Locale specifications now produce predicate definitions
  2353 according to the body of text (covering assumptions modulo local
  2354 definitions); predicate "loc_axioms" covers newly introduced text,
  2355 while "loc" is cumulative wrt. all included locale expressions; the
  2356 latter view is presented only on export into the global theory
  2357 context; potential INCOMPATIBILITY, use "(open)" option to fall back
  2358 on the old view without predicates;
  2359 
  2360 * Pure: predefined locales "var" and "struct" are useful for sharing
  2361 parameters (as in CASL, for example); just specify something like
  2362 ``var x + var y + struct M'' as import;
  2363 
  2364 * Pure: improved thms_containing: proper indexing of facts instead of
  2365 raw theorems; check validity of results wrt. current name space;
  2366 include local facts of proof configuration (also covers active
  2367 locales), cover fixed variables in index; may use "_" in term
  2368 specification; an optional limit for the number of printed facts may
  2369 be given (the default is 40);
  2370 
  2371 * Pure: disallow duplicate fact bindings within new-style theory files
  2372 (batch-mode only);
  2373 
  2374 * Provers: improved induct method: assumptions introduced by case
  2375 "foo" are split into "foo.hyps" (from the rule) and "foo.prems" (from
  2376 the goal statement); "foo" still refers to all facts collectively;
  2377 
  2378 * Provers: the function blast.overloaded has been removed: all constants
  2379 are regarded as potentially overloaded, which improves robustness in exchange
  2380 for slight decrease in efficiency;
  2381 
  2382 * Provers/linorder: New generic prover for transitivity reasoning over
  2383 linear orders.  Note: this prover is not efficient!
  2384 
  2385 * Isar: preview of problems to finish 'show' now produce an error
  2386 rather than just a warning (in interactive mode);
  2387 
  2388 
  2389 *** HOL ***
  2390 
  2391 * arith(_tac)
  2392 
  2393  - Produces a counter example if it cannot prove a goal.
  2394    Note that the counter example may be spurious if the goal is not a formula
  2395    of quantifier-free linear arithmetic.
  2396    In ProofGeneral the counter example appears in the trace buffer.
  2397 
  2398  - Knows about div k and mod k where k is a numeral of type nat or int.
  2399 
  2400  - Calls full Presburger arithmetic (by Amine Chaieb) if quantifier-free
  2401    linear arithmetic fails. This takes account of quantifiers and divisibility.
  2402    Presburger arithmetic can also be called explicitly via presburger(_tac).
  2403 
  2404 * simp's arithmetic capabilities have been enhanced a bit: it now
  2405 takes ~= in premises into account (by performing a case split);
  2406 
  2407 * simp reduces "m*(n div m) + n mod m" to n, even if the two summands
  2408 are distributed over a sum of terms;
  2409 
  2410 * New tactic "trans_tac" and method "trans" instantiate
  2411 Provers/linorder.ML for axclasses "order" and "linorder" (predicates
  2412 "<=", "<" and "=").
  2413 
  2414 * function INCOMPATIBILITIES: Pi-sets have been redefined and moved from main
  2415 HOL to Library/FuncSet; constant "Fun.op o" is now called "Fun.comp";
  2416 
  2417 * 'typedef' command has new option "open" to suppress the set
  2418 definition;
  2419 
  2420 * functions Min and Max on finite sets have been introduced (theory
  2421 Finite_Set);
  2422 
  2423 * attribute [symmetric] now works for relations as well; it turns
  2424 (x,y) : R^-1 into (y,x) : R, and vice versa;
  2425 
  2426 * induct over a !!-quantified statement (say !!x1..xn):
  2427   each "case" automatically performs "fix x1 .. xn" with exactly those names.
  2428 
  2429 * Map: `empty' is no longer a constant but a syntactic abbreviation for
  2430 %x. None. Warning: empty_def now refers to the previously hidden definition
  2431 of the empty set.
  2432 
  2433 * Algebra: formalization of classical algebra.  Intended as base for
  2434 any algebraic development in Isabelle.  Currently covers group theory
  2435 (up to Sylow's theorem) and ring theory (Universal Property of
  2436 Univariate Polynomials).  Contributions welcome;
  2437 
  2438 * GroupTheory: deleted, since its material has been moved to Algebra;
  2439 
  2440 * Complex: new directory of the complex numbers with numeric constants,
  2441 nonstandard complex numbers, and some complex analysis, standard and
  2442 nonstandard (Jacques Fleuriot);
  2443 
  2444 * HOL-Complex: new image for analysis, replacing HOL-Real and HOL-Hyperreal;
  2445 
  2446 * Hyperreal: introduced Gauge integration and hyperreal logarithms (Jacques
  2447 Fleuriot);
  2448 
  2449 * Real/HahnBanach: updated and adapted to locales;
  2450 
  2451 * NumberTheory: added Gauss's law of quadratic reciprocity (by Avigad,
  2452 Gray and Kramer);
  2453 
  2454 * UNITY: added the Meier-Sanders theory of progress sets;
  2455 
  2456 * MicroJava: bytecode verifier and lightweight bytecode verifier
  2457 as abstract algorithms, instantiated to the JVM;
  2458 
  2459 * Bali: Java source language formalization. Type system, operational
  2460 semantics, axiomatic semantics. Supported language features:
  2461 classes, interfaces, objects,virtual methods, static methods,
  2462 static/instance fields, arrays, access modifiers, definite
  2463 assignment, exceptions.
  2464 
  2465 
  2466 *** ZF ***
  2467 
  2468 * ZF/Constructible: consistency proof for AC (Gdel's constructible
  2469 universe, etc.);
  2470 
  2471 * Main ZF: virtually all theories converted to new-style format;
  2472 
  2473 
  2474 *** ML ***
  2475 
  2476 * Pure: Tactic.prove provides sane interface for internal proofs;
  2477 omits the infamous "standard" operation, so this is more appropriate
  2478 than prove_goalw_cterm in many situations (e.g. in simprocs);
  2479 
  2480 * Pure: improved error reporting of simprocs;
  2481 
  2482 * Provers: Simplifier.simproc(_i) provides sane interface for setting
  2483 up simprocs;
  2484 
  2485 
  2486 *** Document preparation ***
  2487 
  2488 * uses \par instead of \\ for line breaks in theory text. This may
  2489 shift some page breaks in large documents. To get the old behaviour
  2490 use \renewcommand{\isanewline}{\mbox{}\\\mbox{}} in root.tex.
  2491 
  2492 * minimized dependencies of isabelle.sty and isabellesym.sty on
  2493 other packages
  2494 
  2495 * \<euro> now needs package babel/greek instead of marvosym (which
  2496 broke \Rightarrow)
  2497 
  2498 * normal size for \<zero>...\<nine> (uses \mathbf instead of
  2499 textcomp package)
  2500 
  2501 
  2502 
  2503 New in Isabelle2002 (March 2002)
  2504 --------------------------------
  2505 
  2506 *** Document preparation ***
  2507 
  2508 * greatly simplified document preparation setup, including more
  2509 graceful interpretation of isatool usedir -i/-d/-D options, and more
  2510 instructive isatool mkdir; users should basically be able to get
  2511 started with "isatool mkdir HOL Test && isatool make"; alternatively,
  2512 users may run a separate document processing stage manually like this:
  2513 "isatool usedir -D output HOL Test && isatool document Test/output";
  2514 
  2515 * theory dependency graph may now be incorporated into documents;
  2516 isatool usedir -g true will produce session_graph.eps/.pdf for use
  2517 with \includegraphics of LaTeX;
  2518 
  2519 * proper spacing of consecutive markup elements, especially text
  2520 blocks after section headings;
  2521 
  2522 * support bold style (for single symbols only), input syntax is like
  2523 this: "\<^bold>\<alpha>" or "\<^bold>A";
  2524 
  2525 * \<bullet> is now output as bold \cdot by default, which looks much
  2526 better in printed text;
  2527 
  2528 * added default LaTeX bindings for \<tturnstile> and \<TTurnstile>;
  2529 note that these symbols are currently unavailable in Proof General /
  2530 X-Symbol; new symbols \<zero>, \<one>, ..., \<nine>, and \<euro>;
  2531 
  2532 * isatool latex no longer depends on changed TEXINPUTS, instead
  2533 isatool document copies the Isabelle style files to the target
  2534 location;
  2535 
  2536 
  2537 *** Isar ***
  2538 
  2539 * Pure/Provers: improved proof by cases and induction;
  2540   - 'case' command admits impromptu naming of parameters (such as
  2541     "case (Suc n)");
  2542   - 'induct' method divinates rule instantiation from the inductive
  2543     claim; no longer requires excessive ?P bindings for proper
  2544     instantiation of cases;
  2545   - 'induct' method properly enumerates all possibilities of set/type
  2546     rules; as a consequence facts may be also passed through *type*
  2547     rules without further ado;
  2548   - 'induct' method now derives symbolic cases from the *rulified*
  2549     rule (before it used to rulify cases stemming from the internal
  2550     atomized version); this means that the context of a non-atomic
  2551     statement becomes is included in the hypothesis, avoiding the
  2552     slightly cumbersome show "PROP ?case" form;
  2553   - 'induct' may now use elim-style induction rules without chaining
  2554     facts, using ``missing'' premises from the goal state; this allows
  2555     rules stemming from inductive sets to be applied in unstructured
  2556     scripts, while still benefitting from proper handling of non-atomic
  2557     statements; NB: major inductive premises need to be put first, all
  2558     the rest of the goal is passed through the induction;
  2559   - 'induct' proper support for mutual induction involving non-atomic
  2560     rule statements (uses the new concept of simultaneous goals, see
  2561     below);
  2562   - append all possible rule selections, but only use the first
  2563     success (no backtracking);
  2564   - removed obsolete "(simplified)" and "(stripped)" options of methods;
  2565   - undeclared rule case names default to numbers 1, 2, 3, ...;
  2566   - added 'print_induct_rules' (covered by help item in recent Proof
  2567     General versions);
  2568   - moved induct/cases attributes to Pure, methods to Provers;
  2569   - generic method setup instantiated for FOL and HOL;
  2570 
  2571 * Pure: support multiple simultaneous goal statements, for example
  2572 "have a: A and b: B" (same for 'theorem' etc.); being a pure
  2573 meta-level mechanism, this acts as if several individual goals had
  2574 been stated separately; in particular common proof methods need to be
  2575 repeated in order to cover all claims; note that a single elimination
  2576 step is *not* sufficient to establish the two conjunctions, so this
  2577 fails:
  2578 
  2579   assume "A & B" then have A and B ..   (*".." fails*)
  2580 
  2581 better use "obtain" in situations as above; alternative refer to
  2582 multi-step methods like 'auto', 'simp_all', 'blast+' etc.;
  2583 
  2584 * Pure: proper integration with ``locales''; unlike the original
  2585 version by Florian Kammller, Isar locales package high-level proof
  2586 contexts rather than raw logical ones (e.g. we admit to include
  2587 attributes everywhere); operations on locales include merge and
  2588 rename; support for implicit arguments (``structures''); simultaneous
  2589 type-inference over imports and text; see also HOL/ex/Locales.thy for
  2590 some examples;
  2591 
  2592 * Pure: the following commands have been ``localized'', supporting a
  2593 target locale specification "(in name)": 'lemma', 'theorem',
  2594 'corollary', 'lemmas', 'theorems', 'declare'; the results will be
  2595 stored both within the locale and at the theory level (exported and
  2596 qualified by the locale name);
  2597 
  2598 * Pure: theory goals may now be specified in ``long'' form, with
  2599 ad-hoc contexts consisting of arbitrary locale elements. for example
  2600 ``lemma foo: fixes x assumes "A x" shows "B x"'' (local syntax and
  2601 definitions may be given, too); the result is a meta-level rule with
  2602 the context elements being discharged in the obvious way;
  2603 
  2604 * Pure: new proof command 'using' allows to augment currently used
  2605 facts after a goal statement ('using' is syntactically analogous to
  2606 'apply', but acts on the goal's facts only); this allows chained facts
  2607 to be separated into parts given before and after a claim, as in
  2608 ``from a and b have C using d and e <proof>'';
  2609 
  2610 * Pure: renamed "antecedent" case to "rule_context";
  2611 
  2612 * Pure: new 'judgment' command records explicit information about the
  2613 object-logic embedding (used by several tools internally); no longer
  2614 use hard-wired "Trueprop";
  2615 
  2616 * Pure: added 'corollary' command;
  2617 
  2618 * Pure: fixed 'token_translation' command;
  2619 
  2620 * Pure: removed obsolete 'exported' attribute;
  2621 
  2622 * Pure: dummy pattern "_" in is/let is now automatically lifted over
  2623 bound variables: "ALL x. P x --> Q x" (is "ALL x. _ --> ?C x")
  2624 supersedes more cumbersome ... (is "ALL x. _ x --> ?C x");
  2625 
  2626 * Pure: method 'atomize' presents local goal premises as object-level
  2627 statements (atomic meta-level propositions); setup controlled via
  2628 rewrite rules declarations of 'atomize' attribute; example
  2629 application: 'induct' method with proper rule statements in improper
  2630 proof *scripts*;
  2631 
  2632 * Pure: emulation of instantiation tactics (rule_tac, cut_tac, etc.)
  2633 now consider the syntactic context of assumptions, giving a better
  2634 chance to get type-inference of the arguments right (this is
  2635 especially important for locales);
  2636 
  2637 * Pure: "sorry" no longer requires quick_and_dirty in interactive
  2638 mode;
  2639 
  2640 * Pure/obtain: the formal conclusion "thesis", being marked as
  2641 ``internal'', may no longer be reference directly in the text;
  2642 potential INCOMPATIBILITY, may need to use "?thesis" in rare
  2643 situations;
  2644 
  2645 * Pure: generic 'sym' attribute which declares a rule both as pure
  2646 'elim?' and for the 'symmetric' operation;
  2647 
  2648 * Pure: marginal comments ``--'' may now occur just anywhere in the
  2649 text; the fixed correlation with particular command syntax has been
  2650 discontinued;
  2651 
  2652 * Pure: new method 'rules' is particularly well-suited for proof
  2653 search in intuitionistic logic; a bit slower than 'blast' or 'fast',
  2654 but often produces more compact proof terms with less detours;
  2655 
  2656 * Pure/Provers/classical: simplified integration with pure rule
  2657 attributes and methods; the classical "intro?/elim?/dest?"
  2658 declarations coincide with the pure ones; the "rule" method no longer
  2659 includes classically swapped intros; "intro" and "elim" methods no
  2660 longer pick rules from the context; also got rid of ML declarations
  2661 AddXIs/AddXEs/AddXDs; all of this has some potential for
  2662 INCOMPATIBILITY;
  2663 
  2664 * Provers/classical: attribute 'swapped' produces classical inversions
  2665 of introduction rules;
  2666 
  2667 * Provers/simplifier: 'simplified' attribute may refer to explicit
  2668 rules instead of full simplifier context; 'iff' attribute handles
  2669 conditional rules;
  2670 
  2671 * HOL: 'typedef' now allows alternative names for Rep/Abs morphisms;
  2672 
  2673 * HOL: 'recdef' now fails on unfinished automated proofs, use
  2674 "(permissive)" option to recover old behavior;
  2675 
  2676 * HOL: 'inductive' no longer features separate (collective) attributes
  2677 for 'intros' (was found too confusing);
  2678 
  2679 * HOL: properly declared induction rules less_induct and
  2680 wf_induct_rule;
  2681 
  2682 
  2683 *** HOL ***
  2684 
  2685 * HOL: moved over to sane numeral syntax; the new policy is as
  2686 follows:
  2687 
  2688   - 0 and 1 are polymorphic constants, which are defined on any
  2689   numeric type (nat, int, real etc.);
  2690 
  2691   - 2, 3, 4, ... and -1, -2, -3, ... are polymorphic numerals, based
  2692   binary representation internally;
  2693 
  2694   - type nat has special constructor Suc, and generally prefers Suc 0
  2695   over 1::nat and Suc (Suc 0) over 2::nat;
  2696 
  2697 This change may cause significant problems of INCOMPATIBILITY; here
  2698 are some hints on converting existing sources:
  2699 
  2700   - due to the new "num" token, "-0" and "-1" etc. are now atomic
  2701   entities, so expressions involving "-" (unary or binary minus) need
  2702   to be spaced properly;
  2703 
  2704   - existing occurrences of "1" may need to be constraint "1::nat" or
  2705   even replaced by Suc 0; similar for old "2";
  2706 
  2707   - replace "#nnn" by "nnn", and "#-nnn" by "-nnn";
  2708 
  2709   - remove all special provisions on numerals in proofs;
  2710 
  2711 * HOL: simp rules nat_number expand numerals on nat to Suc/0
  2712 representation (depends on bin_arith_simps in the default context);
  2713 
  2714 * HOL: symbolic syntax for x^2 (numeral 2);
  2715 
  2716 * HOL: the class of all HOL types is now called "type" rather than
  2717 "term"; INCOMPATIBILITY, need to adapt references to this type class
  2718 in axclass/classes, instance/arities, and (usually rare) occurrences
  2719 in typings (of consts etc.); internally the class is called
  2720 "HOL.type", ML programs should refer to HOLogic.typeS;
  2721 
  2722 * HOL/record package improvements:
  2723   - new derived operations "fields" to build a partial record section,
  2724     "extend" to promote a fixed record to a record scheme, and
  2725     "truncate" for the reverse; cf. theorems "xxx.defs", which are *not*
  2726     declared as simp by default;
  2727   - shared operations ("more", "fields", etc.) now need to be always
  2728     qualified) --- potential INCOMPATIBILITY;
  2729   - removed "make_scheme" operations (use "make" with "extend") --
  2730     INCOMPATIBILITY;
  2731   - removed "more" class (simply use "term") -- INCOMPATIBILITY;
  2732   - provides cases/induct rules for use with corresponding Isar
  2733     methods (for concrete records, record schemes, concrete more
  2734     parts, and schematic more parts -- in that order);
  2735   - internal definitions directly based on a light-weight abstract
  2736     theory of product types over typedef rather than datatype;
  2737 
  2738 * HOL: generic code generator for generating executable ML code from
  2739 specifications; specific support for HOL constructs such as inductive
  2740 datatypes and sets, as well as recursive functions; can be invoked
  2741 via 'generate_code' theory section;
  2742 
  2743 * HOL: canonical cases/induct rules for n-tuples (n = 3..7);
  2744 
  2745 * HOL: consolidated and renamed several theories.  In particular:
  2746         Ord.thy has been absorbed into HOL.thy
  2747         String.thy has been absorbed into List.thy
  2748 
  2749 * HOL: concrete setsum syntax "\<Sum>i:A. b" == "setsum (%i. b) A"
  2750 (beware of argument permutation!);
  2751 
  2752 * HOL: linorder_less_split superseded by linorder_cases;
  2753 
  2754 * HOL/List: "nodups" renamed to "distinct";
  2755 
  2756 * HOL: added "The" definite description operator; move Hilbert's "Eps"
  2757 to peripheral theory "Hilbert_Choice"; some INCOMPATIBILITIES:
  2758   - Ex_def has changed, now need to use some_eq_ex
  2759 
  2760 * HOL: made split_all_tac safe; EXISTING PROOFS MAY FAIL OR LOOP, so
  2761 in this (rare) case use:
  2762 
  2763   delSWrapper "split_all_tac"
  2764   addSbefore ("unsafe_split_all_tac", unsafe_split_all_tac)
  2765 
  2766 * HOL: added safe wrapper "split_conv_tac" to claset; EXISTING PROOFS
  2767 MAY FAIL;
  2768 
  2769 * HOL: introduced f^n = f o ... o f; warning: due to the limits of
  2770 Isabelle's type classes, ^ on functions and relations has too general
  2771 a domain, namely ('a * 'b) set and 'a => 'b; this means that it may be
  2772 necessary to attach explicit type constraints;
  2773 
  2774 * HOL/Relation: the prefix name of the infix "O" has been changed from
  2775 "comp" to "rel_comp"; INCOMPATIBILITY: a few theorems have been
  2776 renamed accordingly (eg "compI" -> "rel_compI").
  2777 
  2778 * HOL: syntax translations now work properly with numerals and records
  2779 expressions;
  2780 
  2781 * HOL: bounded abstraction now uses syntax "%" / "\<lambda>" instead
  2782 of "lam" -- INCOMPATIBILITY;
  2783 
  2784 * HOL: got rid of some global declarations (potential INCOMPATIBILITY
  2785 for ML tools): const "()" renamed "Product_Type.Unity", type "unit"
  2786 renamed "Product_Type.unit";
  2787 
  2788 * HOL: renamed rtrancl_into_rtrancl2 to converse_rtrancl_into_rtrancl
  2789 
  2790 * HOL: removed obsolete theorem "optionE" (use "option.exhaust", or
  2791 the "cases" method);
  2792 
  2793 * HOL/GroupTheory: group theory examples including Sylow's theorem (by
  2794 Florian Kammller);
  2795 
  2796 * HOL/IMP: updated and converted to new-style theory format; several
  2797 parts turned into readable document, with proper Isar proof texts and
  2798 some explanations (by Gerwin Klein);
  2799 
  2800 * HOL-Real: added Complex_Numbers (by Gertrud Bauer);
  2801 
  2802 * HOL-Hyperreal is now a logic image;
  2803 
  2804 
  2805 *** HOLCF ***
  2806 
  2807 * Isar: consts/constdefs supports mixfix syntax for continuous
  2808 operations;
  2809 
  2810 * Isar: domain package adapted to new-style theory format, e.g. see
  2811 HOLCF/ex/Dnat.thy;
  2812 
  2813 * theory Lift: proper use of rep_datatype lift instead of ML hacks --
  2814 potential INCOMPATIBILITY; now use plain induct_tac instead of former
  2815 lift.induct_tac, always use UU instead of Undef;
  2816 
  2817 * HOLCF/IMP: updated and converted to new-style theory;
  2818 
  2819 
  2820 *** ZF ***
  2821 
  2822 * Isar: proper integration of logic-specific tools and packages,
  2823 including theory commands '(co)inductive', '(co)datatype',
  2824 'rep_datatype', 'inductive_cases', as well as methods 'ind_cases',
  2825 'induct_tac', 'case_tac', and 'typecheck' (with attribute 'TC');
  2826 
  2827 * theory Main no longer includes AC; for the Axiom of Choice, base
  2828 your theory on Main_ZFC;
  2829 
  2830 * the integer library now covers quotients and remainders, with many
  2831 laws relating division to addition, multiplication, etc.;
  2832 
  2833 * ZF/UNITY: Chandy and Misra's UNITY is now available in ZF, giving a
  2834 typeless version of the formalism;
  2835 
  2836 * ZF/AC, Coind, IMP, Resid: updated and converted to new-style theory
  2837 format;
  2838 
  2839 * ZF/Induct: new directory for examples of inductive definitions,
  2840 including theory Multiset for multiset orderings; converted to
  2841 new-style theory format;
  2842 
  2843 * ZF: many new theorems about lists, ordinals, etc.;
  2844 
  2845 
  2846 *** General ***
  2847 
  2848 * Pure/kernel: meta-level proof terms (by Stefan Berghofer); reference
  2849 variable proof controls level of detail: 0 = no proofs (only oracle
  2850 dependencies), 1 = lemma dependencies, 2 = compact proof terms; see
  2851 also ref manual for further ML interfaces;
  2852 
  2853 * Pure/axclass: removed obsolete ML interface
  2854 goal_subclass/goal_arity;
  2855 
  2856 * Pure/syntax: new token syntax "num" for plain numerals (without "#"
  2857 of "xnum"); potential INCOMPATIBILITY, since -0, -1 etc. are now
  2858 separate tokens, so expressions involving minus need to be spaced
  2859 properly;
  2860 
  2861 * Pure/syntax: support non-oriented infixes, using keyword "infix"
  2862 rather than "infixl" or "infixr";
  2863 
  2864 * Pure/syntax: concrete syntax for dummy type variables admits genuine
  2865 sort constraint specifications in type inference; e.g. "x::_::foo"
  2866 ensures that the type of "x" is of sort "foo" (but not necessarily a
  2867 type variable);
  2868 
  2869 * Pure/syntax: print modes "type_brackets" and "no_type_brackets"
  2870 control output of nested => (types); the default behavior is
  2871 "type_brackets";
  2872 
  2873 * Pure/syntax: builtin parse translation for "_constify" turns valued
  2874 tokens into AST constants;
  2875 
  2876 * Pure/syntax: prefer later declarations of translations and print
  2877 translation functions; potential INCOMPATIBILITY: need to reverse
  2878 multiple declarations for same syntax element constant;
  2879 
  2880 * Pure/show_hyps reset by default (in accordance to existing Isar
  2881 practice);
  2882 
  2883 * Provers/classical: renamed addaltern to addafter, addSaltern to
  2884 addSafter;
  2885 
  2886 * Provers/clasimp: ``iff'' declarations now handle conditional rules
  2887 as well;
  2888 
  2889 * system: tested support for MacOS X; should be able to get Isabelle +
  2890 Proof General to work in a plain Terminal after installing Poly/ML
  2891 (e.g. from the Isabelle distribution area) and GNU bash alone
  2892 (e.g. from http://www.apple.com); full X11, XEmacs and X-Symbol
  2893 support requires further installations, e.g. from
  2894 http://fink.sourceforge.net/);
  2895 
  2896 * system: support Poly/ML 4.1.1 (able to manage larger heaps);
  2897 
  2898 * system: reduced base memory usage by Poly/ML (approx. 20 MB instead
  2899 of 40 MB), cf. ML_OPTIONS;
  2900 
  2901 * system: Proof General keywords specification is now part of the
  2902 Isabelle distribution (see etc/isar-keywords.el);
  2903 
  2904 * system: support for persistent Proof General sessions (refrain from
  2905 outdating all loaded theories on startup); user may create writable
  2906 logic images like this: ``isabelle -q HOL Test'';
  2907 
  2908 * system: smart selection of Isabelle process versus Isabelle
  2909 interface, accommodates case-insensitive file systems (e.g. HFS+); may
  2910 run both "isabelle" and "Isabelle" even if file names are badly
  2911 damaged (executable inspects the case of the first letter of its own
  2912 name); added separate "isabelle-process" and "isabelle-interface";
  2913 
  2914 * system: refrain from any attempt at filtering input streams; no
  2915 longer support ``8bit'' encoding of old isabelle font, instead proper
  2916 iso-latin characters may now be used; the related isatools
  2917 "symbolinput" and "nonascii" have disappeared as well;
  2918 
  2919 * system: removed old "xterm" interface (the print modes "xterm" and
  2920 "xterm_color" are still available for direct use in a suitable
  2921 terminal);
  2922 
  2923 
  2924 
  2925 New in Isabelle99-2 (February 2001)
  2926 -----------------------------------
  2927 
  2928 *** Overview of INCOMPATIBILITIES ***
  2929 
  2930 * HOL: please note that theories in the Library and elsewhere often use the
  2931 new-style (Isar) format; to refer to their theorems in an ML script you must
  2932 bind them to ML identifers by e.g.      val thm_name = thm "thm_name";
  2933 
  2934 * HOL: inductive package no longer splits induction rule aggressively,
  2935 but only as far as specified by the introductions given; the old
  2936 format may be recovered via ML function complete_split_rule or attribute
  2937 'split_rule (complete)';
  2938 
  2939 * HOL: induct renamed to lfp_induct, lfp_Tarski to lfp_unfold,
  2940 gfp_Tarski to gfp_unfold;
  2941 
  2942 * HOL: contrapos, contrapos2 renamed to contrapos_nn, contrapos_pp;
  2943 
  2944 * HOL: infix "dvd" now has priority 50 rather than 70 (because it is a
  2945 relation); infix "^^" has been renamed "``"; infix "``" has been
  2946 renamed "`"; "univalent" has been renamed "single_valued";
  2947 
  2948 * HOL/Real: "rinv" and "hrinv" replaced by overloaded "inverse"
  2949 operation;
  2950 
  2951 * HOLCF: infix "`" has been renamed "$"; the symbol syntax is \<cdot>;
  2952 
  2953 * Isar: 'obtain' no longer declares "that" fact as simp/intro;
  2954 
  2955 * Isar/HOL: method 'induct' now handles non-atomic goals; as a
  2956 consequence, it is no longer monotonic wrt. the local goal context
  2957 (which is now passed through the inductive cases);
  2958 
  2959 * Document preparation: renamed standard symbols \<ll> to \<lless> and
  2960 \<gg> to \<ggreater>;
  2961 
  2962 
  2963 *** Document preparation ***
  2964 
  2965 * \isabellestyle{NAME} selects version of Isabelle output (currently
  2966 available: are "it" for near math-mode best-style output, "sl" for
  2967 slanted text style, and "tt" for plain type-writer; if no
  2968 \isabellestyle command is given, output is according to slanted
  2969 type-writer);
  2970 
  2971 * support sub/super scripts (for single symbols only), input syntax is
  2972 like this: "A\<^sup>*" or "A\<^sup>\<star>";
  2973 
  2974 * some more standard symbols; see Appendix A of the system manual for
  2975 the complete list of symbols defined in isabellesym.sty;
  2976 
  2977 * improved isabelle style files; more abstract symbol implementation
  2978 (should now use \isamath{...} and \isatext{...} in custom symbol
  2979 definitions);
  2980 
  2981 * antiquotation @{goals} and @{subgoals} for output of *dynamic* goals
  2982 state; Note that presentation of goal states does not conform to
  2983 actual human-readable proof documents.  Please do not include goal
  2984 states into document output unless you really know what you are doing!
  2985 
  2986 * proper indentation of antiquoted output with proportional LaTeX
  2987 fonts;
  2988 
  2989 * no_document ML operator temporarily disables LaTeX document
  2990 generation;
  2991 
  2992 * isatool unsymbolize tunes sources for plain ASCII communication;
  2993 
  2994 
  2995 *** Isar ***
  2996 
  2997 * Pure: Isar now suffers initial goal statements to contain unbound
  2998 schematic variables (this does not conform to actual readable proof
  2999 documents, due to unpredictable outcome and non-compositional proof
  3000 checking); users who know what they are doing may use schematic goals
  3001 for Prolog-style synthesis of proven results;
  3002 
  3003 * Pure: assumption method (an implicit finishing) now handles actual
  3004 rules as well;
  3005 
  3006 * Pure: improved 'obtain' --- moved to Pure, insert "that" into
  3007 initial goal, declare "that" only as Pure intro (only for single
  3008 steps); the "that" rule assumption may now be involved in implicit
  3009 finishing, thus ".." becomes a feasible for trivial obtains;
  3010 
  3011 * Pure: default proof step now includes 'intro_classes'; thus trivial
  3012 instance proofs may be performed by "..";
  3013 
  3014 * Pure: ?thesis / ?this / "..." now work for pure meta-level
  3015 statements as well;
  3016 
  3017 * Pure: more robust selection of calculational rules;
  3018 
  3019 * Pure: the builtin notion of 'finished' goal now includes the ==-refl
  3020 rule (as well as the assumption rule);
  3021 
  3022 * Pure: 'thm_deps' command visualizes dependencies of theorems and
  3023 lemmas, using the graph browser tool;
  3024 
  3025 * Pure: predict failure of "show" in interactive mode;
  3026 
  3027 * Pure: 'thms_containing' now takes actual terms as arguments;
  3028 
  3029 * HOL: improved method 'induct' --- now handles non-atomic goals
  3030 (potential INCOMPATIBILITY); tuned error handling;
  3031 
  3032 * HOL: cases and induct rules now provide explicit hints about the
  3033 number of facts to be consumed (0 for "type" and 1 for "set" rules);
  3034 any remaining facts are inserted into the goal verbatim;
  3035 
  3036 * HOL: local contexts (aka cases) may now contain term bindings as
  3037 well; the 'cases' and 'induct' methods new provide a ?case binding for
  3038 the result to be shown in each case;
  3039 
  3040 * HOL: added 'recdef_tc' command;
  3041 
  3042 * isatool convert assists in eliminating legacy ML scripts;
  3043 
  3044 
  3045 *** HOL ***
  3046 
  3047 * HOL/Library: a collection of generic theories to be used together
  3048 with main HOL; the theory loader path already includes this directory
  3049 by default; the following existing theories have been moved here:
  3050 HOL/Induct/Multiset, HOL/Induct/Acc (as Accessible_Part), HOL/While
  3051 (as While_Combinator), HOL/Lex/Prefix (as List_Prefix);
  3052 
  3053 * HOL/Unix: "Some aspects of Unix file-system security", a typical
  3054 modelling and verification task performed in Isabelle/HOL +
  3055 Isabelle/Isar + Isabelle document preparation (by Markus Wenzel).
  3056 
  3057 * HOL/Algebra: special summation operator SUM no longer exists, it has
  3058 been replaced by setsum; infix 'assoc' now has priority 50 (like
  3059 'dvd'); axiom 'one_not_zero' has been moved from axclass 'ring' to
  3060 'domain', this makes the theory consistent with mathematical
  3061 literature;
  3062 
  3063 * HOL basics: added overloaded operations "inverse" and "divide"
  3064 (infix "/"), syntax for generic "abs" operation, generic summation
  3065 operator \<Sum>;
  3066 
  3067 * HOL/typedef: simplified package, provide more useful rules (see also
  3068 HOL/subset.thy);
  3069 
  3070 * HOL/datatype: induction rule for arbitrarily branching datatypes is
  3071 now expressed as a proper nested rule (old-style tactic scripts may
  3072 require atomize_strip_tac to cope with non-atomic premises);
  3073 
  3074 * HOL: renamed theory "Prod" to "Product_Type", renamed "split" rule
  3075 to "split_conv" (old name still available for compatibility);
  3076 
  3077 * HOL: improved concrete syntax for strings (e.g. allows translation
  3078 rules with string literals);
  3079 
  3080 * HOL-Real-Hyperreal: this extends HOL-Real with the hyperreals
  3081  and Fleuriot's mechanization of analysis, including the transcendental
  3082  functions for the reals;
  3083 
  3084 * HOL/Real, HOL/Hyperreal: improved arithmetic simplification;
  3085 
  3086 
  3087 *** CTT ***
  3088 
  3089 * CTT: x-symbol support for Pi, Sigma, -->, : (membership); note that
  3090 "lam" is displayed as TWO lambda-symbols
  3091 
  3092 * CTT: theory Main now available, containing everything (that is, Bool
  3093 and Arith);
  3094 
  3095 
  3096 *** General ***
  3097 
  3098 * Pure: the Simplifier has been implemented properly as a derived rule
  3099 outside of the actual kernel (at last!); the overall performance
  3100 penalty in practical applications is about 50%, while reliability of
  3101 the Isabelle inference kernel has been greatly improved;
  3102 
  3103 * print modes "brackets" and "no_brackets" control output of nested =>
  3104 (types) and ==> (props); the default behaviour is "brackets";
  3105 
  3106 * Provers: fast_tac (and friends) now handle actual object-logic rules
  3107 as assumptions as well;
  3108 
  3109 * system: support Poly/ML 4.0;
  3110 
  3111 * system: isatool install handles KDE version 1 or 2;
  3112 
  3113 
  3114 
  3115 New in Isabelle99-1 (October 2000)
  3116 ----------------------------------
  3117 
  3118 *** Overview of INCOMPATIBILITIES ***
  3119 
  3120 * HOL: simplification of natural numbers is much changed; to partly
  3121 recover the old behaviour (e.g. to prevent n+n rewriting to #2*n)
  3122 issue the following ML commands:
  3123 
  3124   Delsimprocs Nat_Numeral_Simprocs.cancel_numerals;
  3125   Delsimprocs [Nat_Numeral_Simprocs.combine_numerals];
  3126 
  3127 * HOL: simplification no longer dives into case-expressions; this is
  3128 controlled by "t.weak_case_cong" for each datatype t;
  3129 
  3130 * HOL: nat_less_induct renamed to less_induct;
  3131 
  3132 * HOL: systematic renaming of the SOME (Eps) rules, may use isatool
  3133 fixsome to patch .thy and .ML sources automatically;
  3134 
  3135   select_equality  -> some_equality
  3136   select_eq_Ex     -> some_eq_ex
  3137   selectI2EX       -> someI2_ex
  3138   selectI2         -> someI2
  3139   selectI          -> someI
  3140   select1_equality -> some1_equality
  3141   Eps_sym_eq       -> some_sym_eq_trivial
  3142   Eps_eq           -> some_eq_trivial
  3143 
  3144 * HOL: exhaust_tac on datatypes superceded by new generic case_tac;
  3145 
  3146 * HOL: removed obsolete theorem binding expand_if (refer to split_if
  3147 instead);
  3148 
  3149 * HOL: the recursion equations generated by 'recdef' are now called
  3150 f.simps instead of f.rules;
  3151 
  3152 * HOL: qed_spec_mp now also handles bounded ALL as well;
  3153 
  3154 * HOL: 0 is now overloaded, so the type constraint ":: nat" may
  3155 sometimes be needed;
  3156 
  3157 * HOL: the constant for "f``x" is now "image" rather than "op ``";
  3158 
  3159 * HOL: the constant for "f-``x" is now "vimage" rather than "op -``";
  3160 
  3161 * HOL: the disjoint sum is now "<+>" instead of "Plus"; the cartesian
  3162 product is now "<*>" instead of "Times"; the lexicographic product is
  3163 now "<*lex*>" instead of "**";
  3164 
  3165 * HOL: theory Sexp is now in HOL/Induct examples (it used to be part
  3166 of main HOL, but was unused); better use HOL's datatype package;
  3167 
  3168 * HOL: removed "symbols" syntax for constant "override" of theory Map;
  3169 the old syntax may be recovered as follows:
  3170 
  3171   syntax (symbols)
  3172     override  :: "('a ~=> 'b) => ('a ~=> 'b) => ('a ~=> 'b)"
  3173       (infixl "\\<oplus>" 100)
  3174 
  3175 * HOL/Real: "rabs" replaced by overloaded "abs" function;
  3176 
  3177 * HOL/ML: even fewer consts are declared as global (see theories Ord,
  3178 Lfp, Gfp, WF); this only affects ML packages that refer to const names
  3179 internally;
  3180 
  3181 * HOL and ZF: syntax for quotienting wrt an equivalence relation
  3182 changed from A/r to A//r;
  3183 
  3184 * ZF: new treatment of arithmetic (nat & int) may break some old
  3185 proofs;
  3186 
  3187 * Isar: renamed some attributes (RS -> THEN, simplify -> simplified,
  3188 rulify -> rule_format, elimify -> elim_format, ...);
  3189 
  3190 * Isar/Provers: intro/elim/dest attributes changed; renamed
  3191 intro/intro!/intro!! flags to intro!/intro/intro? (in most cases, one
  3192 should have to change intro!! to intro? only); replaced "delrule" by
  3193 "rule del";
  3194 
  3195 * Isar/HOL: renamed "intrs" to "intros" in inductive definitions;
  3196 
  3197 * Provers: strengthened force_tac by using new first_best_tac;
  3198 
  3199 * LaTeX document preparation: several changes of isabelle.sty (see
  3200 lib/texinputs);
  3201 
  3202 
  3203 *** Document preparation ***
  3204 
  3205 * formal comments (text blocks etc.) in new-style theories may now
  3206 contain antiquotations of thm/prop/term/typ/text to be presented
  3207 according to latex print mode; concrete syntax is like this:
  3208 @{term[show_types] "f(x) = a + x"};
  3209 
  3210 * isatool mkdir provides easy setup of Isabelle session directories,
  3211 including proper document sources;
  3212 
  3213 * generated LaTeX sources are now deleted after successful run
  3214 (isatool document -c); may retain a copy somewhere else via -D option
  3215 of isatool usedir;
  3216 
  3217 * isatool usedir -D now lets isatool latex -o sty update the Isabelle
  3218 style files, achieving self-contained LaTeX sources and simplifying
  3219 LaTeX debugging;
  3220 
  3221 * old-style theories now produce (crude) LaTeX output as well;
  3222 
  3223 * browser info session directories are now self-contained (may be put
  3224 on WWW server seperately); improved graphs of nested sessions; removed
  3225 graph for 'all sessions';
  3226 
  3227 * several improvements in isabelle style files; \isabellestyle{it}
  3228 produces fake math mode output; \isamarkupheader is now \section by
  3229 default; see lib/texinputs/isabelle.sty etc.;
  3230 
  3231 
  3232 *** Isar ***
  3233 
  3234 * Isar/Pure: local results and corresponding term bindings are now
  3235 subject to Hindley-Milner polymorphism (similar to ML); this
  3236 accommodates incremental type-inference very nicely;
  3237 
  3238 * Isar/Pure: new derived language element 'obtain' supports
  3239 generalized existence reasoning;
  3240 
  3241 * Isar/Pure: new calculational elements 'moreover' and 'ultimately'
  3242 support accumulation of results, without applying any rules yet;
  3243 useful to collect intermediate results without explicit name
  3244 references, and for use with transitivity rules with more than 2
  3245 premises;
  3246 
  3247 * Isar/Pure: scalable support for case-analysis type proofs: new
  3248 'case' language element refers to local contexts symbolically, as
  3249 produced by certain proof methods; internally, case names are attached
  3250 to theorems as "tags";
  3251 
  3252 * Isar/Pure: theory command 'hide' removes declarations from
  3253 class/type/const name spaces;
  3254 
  3255 * Isar/Pure: theory command 'defs' supports option "(overloaded)" to
  3256 indicate potential overloading;
  3257 
  3258 * Isar/Pure: changed syntax of local blocks from {{ }} to { };
  3259 
  3260 * Isar/Pure: syntax of sorts made 'inner', i.e. have to write
  3261 "{a,b,c}" instead of {a,b,c};
  3262 
  3263 * Isar/Pure now provides its own version of intro/elim/dest
  3264 attributes; useful for building new logics, but beware of confusion
  3265 with the version in Provers/classical;
  3266 
  3267 * Isar/Pure: the local context of (non-atomic) goals is provided via
  3268 case name 'antecedent';
  3269 
  3270 * Isar/Pure: removed obsolete 'transfer' attribute (transfer of thms
  3271 to the current context is now done automatically);
  3272 
  3273 * Isar/Pure: theory command 'method_setup' provides a simple interface
  3274 for definining proof methods in ML;
  3275 
  3276 * Isar/Provers: intro/elim/dest attributes changed; renamed
  3277 intro/intro!/intro!! flags to intro!/intro/intro? (INCOMPATIBILITY, in
  3278 most cases, one should have to change intro!! to intro? only);
  3279 replaced "delrule" by "rule del";
  3280 
  3281 * Isar/Provers: new 'hypsubst' method, plain 'subst' method and
  3282 'symmetric' attribute (the latter supercedes [RS sym]);
  3283 
  3284 * Isar/Provers: splitter support (via 'split' attribute and 'simp'
  3285 method modifier); 'simp' method: 'only:' modifier removes loopers as
  3286 well (including splits);
  3287 
  3288 * Isar/Provers: Simplifier and Classical methods now support all kind
  3289 of modifiers used in the past, including 'cong', 'iff', etc.
  3290 
  3291 * Isar/Provers: added 'fastsimp' and 'clarsimp' methods (combination
  3292 of Simplifier and Classical reasoner);
  3293 
  3294 * Isar/HOL: new proof method 'cases' and improved version of 'induct'
  3295 now support named cases; major packages (inductive, datatype, primrec,
  3296 recdef) support case names and properly name parameters;
  3297 
  3298 * Isar/HOL: new transitivity rules for substitution in inequalities --
  3299 monotonicity conditions are extracted to be proven at end of
  3300 calculations;
  3301 
  3302 * Isar/HOL: removed 'case_split' thm binding, should use 'cases' proof
  3303 method anyway;
  3304 
  3305 * Isar/HOL: removed old expand_if = split_if; theorems if_splits =
  3306 split_if split_if_asm; datatype package provides theorems foo.splits =
  3307 foo.split foo.split_asm for each datatype;
  3308 
  3309 * Isar/HOL: tuned inductive package, rename "intrs" to "intros"
  3310 (potential INCOMPATIBILITY), emulation of mk_cases feature for proof
  3311 scripts: new 'inductive_cases' command and 'ind_cases' method; (Note:
  3312 use "(cases (simplified))" method in proper proof texts);
  3313 
  3314 * Isar/HOL: added global 'arith_split' attribute for 'arith' method;
  3315 
  3316 * Isar: names of theorems etc. may be natural numbers as well;
  3317 
  3318 * Isar: 'pr' command: optional arguments for goals_limit and
  3319 ProofContext.prems_limit; no longer prints theory contexts, but only
  3320 proof states;
  3321 
  3322 * Isar: diagnostic commands 'pr', 'thm', 'prop', 'term', 'typ' admit
  3323 additional print modes to be specified; e.g. "pr(latex)" will print
  3324 proof state according to the Isabelle LaTeX style;
  3325 
  3326 * Isar: improved support for emulating tactic scripts, including proof
  3327 methods 'rule_tac' etc., 'cut_tac', 'thin_tac', 'subgoal_tac',
  3328 'rename_tac', 'rotate_tac', 'tactic', and 'case_tac' / 'induct_tac'
  3329 (for HOL datatypes);
  3330 
  3331 * Isar: simplified (more robust) goal selection of proof methods: 1st
  3332 goal, all goals, or explicit goal specifier (tactic emulation); thus
  3333 'proof method scripts' have to be in depth-first order;
  3334 
  3335 * Isar: tuned 'let' syntax: replaced 'as' keyword by 'and';
  3336 
  3337 * Isar: removed 'help' command, which hasn't been too helpful anyway;
  3338 should instead use individual commands for printing items
  3339 (print_commands, print_methods etc.);
  3340 
  3341 * Isar: added 'nothing' --- the empty list of theorems;
  3342 
  3343 
  3344 *** HOL ***
  3345 
  3346 * HOL/MicroJava: formalization of a fragment of Java, together with a
  3347 corresponding virtual machine and a specification of its bytecode
  3348 verifier and a lightweight bytecode verifier, including proofs of
  3349 type-safety; by Gerwin Klein, Tobias Nipkow, David von Oheimb, and
  3350 Cornelia Pusch (see also the homepage of project Bali at
  3351 http://isabelle.in.tum.de/Bali/);
  3352 
  3353 * HOL/Algebra: new theory of rings and univariate polynomials, by
  3354 Clemens Ballarin;
  3355 
  3356 * HOL/NumberTheory: fundamental Theorem of Arithmetic, Chinese
  3357 Remainder Theorem, Fermat/Euler Theorem, Wilson's Theorem, by Thomas M
  3358 Rasmussen;
  3359 
  3360 * HOL/Lattice: fundamental concepts of lattice theory and order
  3361 structures, including duals, properties of bounds versus algebraic
  3362 laws, lattice operations versus set-theoretic ones, the Knaster-Tarski
  3363 Theorem for complete lattices etc.; may also serve as a demonstration
  3364 for abstract algebraic reasoning using axiomatic type classes, and
  3365 mathematics-style proof in Isabelle/Isar; by Markus Wenzel;
  3366 
  3367 * HOL/Prolog: a (bare-bones) implementation of Lambda-Prolog, by David
  3368 von Oheimb;
  3369 
  3370 * HOL/IMPP: extension of IMP with local variables and mutually
  3371 recursive procedures, by David von Oheimb;
  3372 
  3373 * HOL/Lambda: converted into new-style theory and document;
  3374 
  3375 * HOL/ex/Multiquote: example of multiple nested quotations and
  3376 anti-quotations -- basically a generalized version of de-Bruijn
  3377 representation; very useful in avoiding lifting of operations;
  3378 
  3379 * HOL/record: added general record equality rule to simpset; fixed
  3380 select-update simplification procedure to handle extended records as
  3381 well; admit "r" as field name;
  3382 
  3383 * HOL: 0 is now overloaded over the new sort "zero", allowing its use with
  3384 other numeric types and also as the identity of groups, rings, etc.;
  3385 
  3386 * HOL: new axclass plus_ac0 for addition with the AC-laws and 0 as identity.
  3387 Types nat and int belong to this axclass;
  3388 
  3389 * HOL: greatly improved simplification involving numerals of type nat, int, real:
  3390    (i + #8 + j) = Suc k simplifies to  #7 + (i + j) = k
  3391    i*j + k + j*#3*i     simplifies to  #4*(i*j) + k
  3392   two terms #m*u and #n*u are replaced by #(m+n)*u
  3393     (where #m, #n and u can implicitly be 1; this is simproc combine_numerals)
  3394   and the term/formula #m*u+x ~~ #n*u+y simplifies simplifies to #(m-n)+x ~~ y
  3395     or x ~~ #(n-m)+y, where ~~ is one of = < <= or - (simproc cancel_numerals);
  3396 
  3397 * HOL: meson_tac is available (previously in ex/meson.ML); it is a
  3398 powerful prover for predicate logic but knows nothing of clasets; see
  3399 ex/mesontest.ML and ex/mesontest2.ML for example applications;
  3400 
  3401 * HOL: new version of "case_tac" subsumes both boolean case split and
  3402 "exhaust_tac" on datatypes; INCOMPATIBILITY: exhaust_tac no longer
  3403 exists, may define val exhaust_tac = case_tac for ad-hoc portability;
  3404 
  3405 * HOL: simplification no longer dives into case-expressions: only the
  3406 selector expression is simplified, but not the remaining arms; to
  3407 enable full simplification of case-expressions for datatype t, you may
  3408 remove t.weak_case_cong from the simpset, either globally (Delcongs
  3409 [thm"t.weak_case_cong"];) or locally (delcongs [...]).
  3410 
  3411 * HOL/recdef: the recursion equations generated by 'recdef' for
  3412 function 'f' are now called f.simps instead of f.rules; if all
  3413 termination conditions are proved automatically, these simplification
  3414 rules are added to the simpset, as in primrec; rules may be named
  3415 individually as well, resulting in a separate list of theorems for
  3416 each equation;
  3417 
  3418 * HOL/While is a new theory that provides a while-combinator. It
  3419 permits the definition of tail-recursive functions without the
  3420 provision of a termination measure. The latter is necessary once the
  3421 invariant proof rule for while is applied.
  3422 
  3423 * HOL: new (overloaded) notation for the set of elements below/above
  3424 some element: {..u}, {..u(}, {l..}, {)l..}. See theory SetInterval.
  3425 
  3426 * HOL: theorems impI, allI, ballI bound as "strip";
  3427 
  3428 * HOL: new tactic induct_thm_tac: thm -> string -> int -> tactic
  3429 induct_tac th "x1 ... xn" expects th to have a conclusion of the form
  3430 P v1 ... vn and abbreviates res_inst_tac [("v1","x1"),...,("vn","xn")] th;
  3431 
  3432 * HOL/Real: "rabs" replaced by overloaded "abs" function;
  3433 
  3434 * HOL: theory Sexp now in HOL/Induct examples (it used to be part of
  3435 main HOL, but was unused);
  3436 
  3437 * HOL: fewer consts declared as global (e.g. have to refer to
  3438 "Lfp.lfp" instead of "lfp" internally; affects ML packages only);
  3439 
  3440 * HOL: tuned AST representation of nested pairs, avoiding bogus output
  3441 in case of overlap with user translations (e.g. judgements over
  3442 tuples); (note that the underlying logical represenation is still
  3443 bogus);
  3444 
  3445 
  3446 *** ZF ***
  3447 
  3448 * ZF: simplification automatically cancels common terms in arithmetic
  3449 expressions over nat and int;
  3450 
  3451 * ZF: new treatment of nat to minimize type-checking: all operators
  3452 coerce their operands to a natural number using the function natify,
  3453 making the algebraic laws unconditional;
  3454 
  3455 * ZF: as above, for int: operators coerce their operands to an integer
  3456 using the function intify;
  3457 
  3458 * ZF: the integer library now contains many of the usual laws for the
  3459 orderings, including $<=, and monotonicity laws for $+ and $*;
  3460 
  3461 * ZF: new example ZF/ex/NatSum to demonstrate integer arithmetic
  3462 simplification;
  3463 
  3464 * FOL and ZF: AddIffs now available, giving theorems of the form P<->Q
  3465 to the simplifier and classical reasoner simultaneously;
  3466 
  3467 
  3468 *** General ***
  3469 
  3470 * Provers: blast_tac now handles actual object-logic rules as
  3471 assumptions; note that auto_tac uses blast_tac internally as well;
  3472 
  3473 * Provers: new functions rulify/rulify_no_asm: thm -> thm for turning
  3474 outer -->/All/Ball into ==>/!!; qed_spec_mp now uses rulify_no_asm;
  3475 
  3476 * Provers: delrules now handles destruct rules as well (no longer need
  3477 explicit make_elim);
  3478 
  3479 * Provers: Blast_tac now warns of and ignores "weak elimination rules" e.g.
  3480   [| inj ?f;          ?f ?x = ?f ?y; ?x = ?y ==> ?W |] ==> ?W
  3481 use instead the strong form,
  3482   [| inj ?f; ~ ?W ==> ?f ?x = ?f ?y; ?x = ?y ==> ?W |] ==> ?W
  3483 in HOL, FOL and ZF the function cla_make_elim will create such rules
  3484 from destruct-rules;
  3485 
  3486 * Provers: Simplifier.easy_setup provides a fast path to basic
  3487 Simplifier setup for new object-logics;
  3488 
  3489 * Pure: AST translation rules no longer require constant head on LHS;
  3490 
  3491 * Pure: improved name spaces: ambiguous output is qualified; support
  3492 for hiding of names;
  3493 
  3494 * system: smart setup of canonical ML_HOME, ISABELLE_INTERFACE, and
  3495 XSYMBOL_HOME; no longer need to do manual configuration in most
  3496 situations;
  3497 
  3498 * system: compression of ML heaps images may now be controlled via -c
  3499 option of isabelle and isatool usedir (currently only observed by
  3500 Poly/ML);
  3501 
  3502 * system: isatool installfonts may handle X-Symbol fonts as well (very
  3503 useful for remote X11);
  3504 
  3505 * system: provide TAGS file for Isabelle sources;
  3506 
  3507 * ML: infix 'OF' is a version of 'MRS' with more appropriate argument
  3508 order;
  3509 
  3510 * ML: renamed flags Syntax.trace_norm_ast to Syntax.trace_ast; global
  3511 timing flag supersedes proof_timing and Toplevel.trace;
  3512 
  3513 * ML: new combinators |>> and |>>> for incremental transformations
  3514 with secondary results (e.g. certain theory extensions):
  3515 
  3516 * ML: PureThy.add_defs gets additional argument to indicate potential
  3517 overloading (usually false);
  3518 
  3519 * ML: PureThy.add_thms/add_axioms/add_defs now return theorems as
  3520 results;
  3521 
  3522 
  3523 
  3524 New in Isabelle99 (October 1999)
  3525 --------------------------------
  3526 
  3527 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  3528 
  3529 * HOL: The THEN and ELSE parts of conditional expressions (if P then x else y)
  3530 are no longer simplified.  (This allows the simplifier to unfold recursive
  3531 functional programs.)  To restore the old behaviour, declare
  3532 
  3533     Delcongs [if_weak_cong];
  3534 
  3535 * HOL: Removed the obsolete syntax "Compl A"; use -A for set
  3536 complement;
  3537 
  3538 * HOL: the predicate "inj" is now defined by translation to "inj_on";
  3539 
  3540 * HOL/datatype: mutual_induct_tac no longer exists --
  3541   use induct_tac "x_1 ... x_n" instead of mutual_induct_tac ["x_1", ..., "x_n"]
  3542 
  3543 * HOL/typedef: fixed type inference for representing set; type
  3544 arguments now have to occur explicitly on the rhs as type constraints;
  3545 
  3546 * ZF: The con_defs part of an inductive definition may no longer refer
  3547 to constants declared in the same theory;
  3548 
  3549 * HOL, ZF: the function mk_cases, generated by the inductive
  3550 definition package, has lost an argument.  To simplify its result, it
  3551 uses the default simpset instead of a supplied list of theorems.
  3552 
  3553 * HOL/List: the constructors of type list are now Nil and Cons;
  3554 
  3555 * Simplifier: the type of the infix ML functions
  3556         setSSolver addSSolver setSolver addSolver
  3557 is now  simpset * solver -> simpset  where `solver' is a new abstract type
  3558 for packaging solvers. A solver is created via
  3559         mk_solver: string -> (thm list -> int -> tactic) -> solver
  3560 where the string argument is only a comment.
  3561 
  3562 
  3563 *** Proof tools ***
  3564 
  3565 * Provers/Arith/fast_lin_arith.ML contains a functor for creating a
  3566 decision procedure for linear arithmetic. Currently it is used for
  3567 types `nat', `int', and `real' in HOL (see below); it can, should and
  3568 will be instantiated for other types and logics as well.
  3569 
  3570 * The simplifier now accepts rewrite rules with flexible heads, eg
  3571      hom ?f ==> ?f(?x+?y) = ?f ?x + ?f ?y
  3572   They are applied like any rule with a non-pattern lhs, i.e. by first-order
  3573   matching.
  3574 
  3575 
  3576 *** General ***
  3577 
  3578 * New Isabelle/Isar subsystem provides an alternative to traditional
  3579 tactical theorem proving; together with the ProofGeneral/isar user
  3580 interface it offers an interactive environment for developing human
  3581 readable proof documents (Isar == Intelligible semi-automated
  3582 reasoning); for further information see isatool doc isar-ref,
  3583 src/HOL/Isar_examples and http://isabelle.in.tum.de/Isar/
  3584 
  3585 * improved and simplified presentation of theories: better HTML markup
  3586 (including colors), graph views in several sizes; isatool usedir now
  3587 provides a proper interface for user theories (via -P option); actual
  3588 document preparation based on (PDF)LaTeX is available as well (for
  3589 new-style theories only); see isatool doc system for more information;
  3590 
  3591 * native support for Proof General, both for classic Isabelle and
  3592 Isabelle/Isar;
  3593 
  3594 * ML function thm_deps visualizes dependencies of theorems and lemmas,
  3595 using the graph browser tool;
  3596 
  3597 * Isabelle manuals now also available as PDF;
  3598 
  3599 * theory loader rewritten from scratch (may not be fully
  3600 bug-compatible); old loadpath variable has been replaced by show_path,
  3601 add_path, del_path, reset_path functions; new operations such as
  3602 update_thy, touch_thy, remove_thy, use/update_thy_only (see also
  3603 isatool doc ref);
  3604 
  3605 * improved isatool install: option -k creates KDE application icon,
  3606 option -p DIR installs standalone binaries;
  3607 
  3608 * added ML_PLATFORM setting (useful for cross-platform installations);
  3609 more robust handling of platform specific ML images for SML/NJ;
  3610 
  3611 * the settings environment is now statically scoped, i.e. it is never
  3612 created again in sub-processes invoked from isabelle, isatool, or
  3613 Isabelle;
  3614 
  3615 * path element specification '~~' refers to '$ISABELLE_HOME';
  3616 
  3617 * in locales, the "assumes" and "defines" parts may be omitted if
  3618 empty;
  3619 
  3620 * new print_mode "xsymbols" for extended symbol support (e.g. genuine
  3621 long arrows);
  3622 
  3623 * new print_mode "HTML";
  3624 
  3625 * new flag show_tags controls display of tags of theorems (which are
  3626 basically just comments that may be attached by some tools);
  3627 
  3628 * Isamode 2.6 requires patch to accomodate change of Isabelle font
  3629 mode and goal output format:
  3630 
  3631 diff -r Isamode-2.6/elisp/isa-load.el Isamode/elisp/isa-load.el
  3632 244c244
  3633 <       (list (isa-getenv "ISABELLE") "-msymbols" logic-name)
  3634 ---
  3635 >       (list (isa-getenv "ISABELLE") "-misabelle_font" "-msymbols" logic-name)
  3636 diff -r Isabelle-2.6/elisp/isa-proofstate.el Isamode/elisp/isa-proofstate.el
  3637 181c181
  3638 < (defconst proofstate-proofstart-regexp "^Level [0-9]+$"
  3639 ---
  3640 > (defconst proofstate-proofstart-regexp "^Level [0-9]+"
  3641 
  3642 * function bind_thms stores lists of theorems (cf. bind_thm);
  3643 
  3644 * new shorthand tactics ftac, eatac, datac, fatac;
  3645 
  3646 * qed (and friends) now accept "" as result name; in that case the
  3647 theorem is not stored, but proper checks and presentation of the
  3648 result still apply;
  3649 
  3650 * theorem database now also indexes constants "Trueprop", "all",
  3651 "==>", "=="; thus thms_containing, findI etc. may retrieve more rules;
  3652 
  3653 
  3654 *** HOL ***
  3655 
  3656 ** HOL arithmetic **
  3657 
  3658 * There are now decision procedures for linear arithmetic over nat and
  3659 int:
  3660 
  3661 1. arith_tac copes with arbitrary formulae involving `=', `<', `<=',
  3662 `+', `-', `Suc', `min', `max' and numerical constants; other subterms
  3663 are treated as atomic; subformulae not involving type `nat' or `int'
  3664 are ignored; quantified subformulae are ignored unless they are
  3665 positive universal or negative existential. The tactic has to be
  3666 invoked by hand and can be a little bit slow. In particular, the
  3667 running time is exponential in the number of occurrences of `min' and
  3668 `max', and `-' on `nat'.
  3669 
  3670 2. fast_arith_tac is a cut-down version of arith_tac: it only takes
  3671 (negated) (in)equalities among the premises and the conclusion into
  3672 account (i.e. no compound formulae) and does not know about `min' and
  3673 `max', and `-' on `nat'. It is fast and is used automatically by the
  3674 simplifier.
  3675 
  3676 NB: At the moment, these decision procedures do not cope with mixed
  3677 nat/int formulae where the two parts interact, such as `m < n ==>
  3678 int(m) < int(n)'.
  3679 
  3680 * HOL/Numeral provides a generic theory of numerals (encoded
  3681 efficiently as bit strings); setup for types nat/int/real is in place;
  3682 INCOMPATIBILITY: since numeral syntax is now polymorphic, rather than
  3683 int, existing theories and proof scripts may require a few additional
  3684 type constraints;
  3685 
  3686 * integer division and remainder can now be performed on constant
  3687 arguments;
  3688 
  3689 * many properties of integer multiplication, division and remainder
  3690 are now available;
  3691 
  3692 * An interface to the Stanford Validity Checker (SVC) is available through the
  3693 tactic svc_tac.  Propositional tautologies and theorems of linear arithmetic
  3694 are proved automatically.  SVC must be installed separately, and its results
  3695 must be TAKEN ON TRUST (Isabelle does not check the proofs, but tags any
  3696 invocation of the underlying oracle).  For SVC see
  3697   http://verify.stanford.edu/SVC
  3698 
  3699 * IsaMakefile: the HOL-Real target now builds an actual image;
  3700 
  3701 
  3702 ** HOL misc **
  3703 
  3704 * HOL/Real/HahnBanach: the Hahn-Banach theorem for real vector spaces
  3705 (in Isabelle/Isar) -- by Gertrud Bauer;
  3706 
  3707 * HOL/BCV: generic model of bytecode verification, i.e. data-flow
  3708 analysis for assembly languages with subtypes;
  3709 
  3710 * HOL/TLA (Lamport's Temporal Logic of Actions): major reorganization
  3711 -- avoids syntactic ambiguities and treats state, transition, and
  3712 temporal levels more uniformly; introduces INCOMPATIBILITIES due to
  3713 changed syntax and (many) tactics;
  3714 
  3715 * HOL/inductive: Now also handles more general introduction rules such
  3716   as "ALL y. (y, x) : r --> y : acc r ==> x : acc r"; monotonicity
  3717   theorems are now maintained within the theory (maintained via the
  3718   "mono" attribute);
  3719 
  3720 * HOL/datatype: Now also handles arbitrarily branching datatypes
  3721   (using function types) such as
  3722 
  3723   datatype 'a tree = Atom 'a | Branch "nat => 'a tree"
  3724 
  3725 * HOL/record: record_simproc (part of the default simpset) takes care
  3726 of selectors applied to updated records; record_split_tac is no longer
  3727 part of the default claset; update_defs may now be removed from the
  3728 simpset in many cases; COMPATIBILITY: old behavior achieved by
  3729 
  3730   claset_ref () := claset() addSWrapper record_split_wrapper;
  3731   Delsimprocs [record_simproc]
  3732 
  3733 * HOL/typedef: fixed type inference for representing set; type
  3734 arguments now have to occur explicitly on the rhs as type constraints;
  3735 
  3736 * HOL/recdef (TFL): 'congs' syntax now expects comma separated list of theorem
  3737 names rather than an ML expression;
  3738 
  3739 * HOL/defer_recdef (TFL): like recdef but the well-founded relation can be
  3740 supplied later.  Program schemes can be defined, such as
  3741     "While B C s = (if B s then While B C (C s) else s)"
  3742 where the well-founded relation can be chosen after B and C have been given.
  3743 
  3744 * HOL/List: the constructors of type list are now Nil and Cons;
  3745 INCOMPATIBILITY: while [] and infix # syntax is still there, of
  3746 course, ML tools referring to List.list.op # etc. have to be adapted;
  3747 
  3748 * HOL_quantifiers flag superseded by "HOL" print mode, which is
  3749 disabled by default; run isabelle with option -m HOL to get back to
  3750 the original Gordon/HOL-style output;
  3751 
  3752 * HOL/Ord.thy: new bounded quantifier syntax (input only): ALL x<y. P,
  3753 ALL x<=y. P, EX x<y. P, EX x<=y. P;
  3754 
  3755 * HOL basic syntax simplified (more orthogonal): all variants of
  3756 All/Ex now support plain / symbolic / HOL notation; plain syntax for
  3757 Eps operator is provided as well: "SOME x. P[x]";
  3758 
  3759 * HOL/Sum.thy: sum_case has been moved to HOL/Datatype;
  3760 
  3761 * HOL/Univ.thy: infix syntax <*>, <+>, <**>, <+> eliminated and made
  3762 thus available for user theories;
  3763 
  3764 * HOLCF/IOA/Sequents: renamed 'Cons' to 'Consq' to avoid clash with
  3765 HOL/List; hardly an INCOMPATIBILITY since '>>' syntax is used all the
  3766 time;
  3767 
  3768 * HOL: new tactic smp_tac: int -> int -> tactic, which applies spec
  3769 several times and then mp;
  3770 
  3771 
  3772 *** LK ***
  3773 
  3774 * the notation <<...>> is now available as a notation for sequences of
  3775 formulas;
  3776 
  3777 * the simplifier is now installed
  3778 
  3779 * the axiom system has been generalized (thanks to Soren Heilmann)
  3780 
  3781 * the classical reasoner now has a default rule database
  3782 
  3783 
  3784 *** ZF ***
  3785 
  3786 * new primrec section allows primitive recursive functions to be given
  3787 directly (as in HOL) over datatypes and the natural numbers;
  3788 
  3789 * new tactics induct_tac and exhaust_tac for induction (or case
  3790 analysis) over datatypes and the natural numbers;
  3791 
  3792 * the datatype declaration of type T now defines the recursor T_rec;
  3793 
  3794 * simplification automatically does freeness reasoning for datatype
  3795 constructors;
  3796 
  3797 * automatic type-inference, with AddTCs command to insert new
  3798 type-checking rules;
  3799 
  3800 * datatype introduction rules are now added as Safe Introduction rules
  3801 to the claset;
  3802 
  3803 * the syntax "if P then x else y" is now available in addition to
  3804 if(P,x,y);
  3805 
  3806 
  3807 *** Internal programming interfaces ***
  3808 
  3809 * tuned simplifier trace output; new flag debug_simp;
  3810 
  3811 * structures Vartab / Termtab (instances of TableFun) offer efficient
  3812 tables indexed by indexname_ord / term_ord (compatible with aconv);
  3813 
  3814 * AxClass.axclass_tac lost the theory argument;
  3815 
  3816 * tuned current_goals_markers semantics: begin / end goal avoids
  3817 printing empty lines;
  3818 
  3819 * removed prs and prs_fn hook, which was broken because it did not
  3820 include \n in its semantics, forcing writeln to add one
  3821 uncoditionally; replaced prs_fn by writeln_fn; consider std_output:
  3822 string -> unit if you really want to output text without newline;
  3823 
  3824 * Symbol.output subject to print mode; INCOMPATIBILITY: defaults to
  3825 plain output, interface builders may have to enable 'isabelle_font'
  3826 mode to get Isabelle font glyphs as before;
  3827 
  3828 * refined token_translation interface; INCOMPATIBILITY: output length
  3829 now of type real instead of int;
  3830 
  3831 * theory loader actions may be traced via new ThyInfo.add_hook
  3832 interface (see src/Pure/Thy/thy_info.ML); example application: keep
  3833 your own database of information attached to *whole* theories -- as
  3834 opposed to intra-theory data slots offered via TheoryDataFun;
  3835 
  3836 * proper handling of dangling sort hypotheses (at last!);
  3837 Thm.strip_shyps and Drule.strip_shyps_warning take care of removing
  3838 extra sort hypotheses that can be witnessed from the type signature;
  3839 the force_strip_shyps flag is gone, any remaining shyps are simply
  3840 left in the theorem (with a warning issued by strip_shyps_warning);
  3841 
  3842 
  3843 
  3844 New in Isabelle98-1 (October 1998)
  3845 ----------------------------------
  3846 
  3847 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  3848 
  3849 * several changes of automated proof tools;
  3850 
  3851 * HOL: major changes to the inductive and datatype packages, including
  3852 some minor incompatibilities of theory syntax;
  3853 
  3854 * HOL: renamed r^-1 to 'converse' from 'inverse'; 'inj_onto' is now
  3855 called `inj_on';
  3856 
  3857 * HOL: removed duplicate thms in Arith:
  3858   less_imp_add_less  should be replaced by  trans_less_add1
  3859   le_imp_add_le      should be replaced by  trans_le_add1
  3860 
  3861 * HOL: unary minus is now overloaded (new type constraints may be
  3862 required);
  3863 
  3864 * HOL and ZF: unary minus for integers is now #- instead of #~.  In
  3865 ZF, expressions such as n#-1 must be changed to n#- 1, since #-1 is
  3866 now taken as an integer constant.
  3867 
  3868 * Pure: ML function 'theory_of' renamed to 'theory';
  3869 
  3870 
  3871 *** Proof tools ***
  3872 
  3873 * Simplifier:
  3874   1. Asm_full_simp_tac is now more aggressive.
  3875      1. It will sometimes reorient premises if that increases their power to
  3876         simplify.
  3877      2. It does no longer proceed strictly from left to right but may also
  3878         rotate premises to achieve further simplification.
  3879      For compatibility reasons there is now Asm_lr_simp_tac which is like the
  3880      old Asm_full_simp_tac in that it does not rotate premises.
  3881   2. The simplifier now knows a little bit about nat-arithmetic.
  3882 
  3883 * Classical reasoner: wrapper mechanism for the classical reasoner now
  3884 allows for selected deletion of wrappers, by introduction of names for
  3885 wrapper functionals.  This implies that addbefore, addSbefore,
  3886 addaltern, and addSaltern now take a pair (name, tactic) as argument,
  3887 and that adding two tactics with the same name overwrites the first
  3888 one (emitting a warning).
  3889   type wrapper = (int -> tactic) -> (int -> tactic)
  3890   setWrapper, setSWrapper, compWrapper and compSWrapper are replaced by
  3891   addWrapper, addSWrapper: claset * (string * wrapper) -> claset
  3892   delWrapper, delSWrapper: claset *  string            -> claset
  3893   getWrapper is renamed to appWrappers, getSWrapper to appSWrappers;
  3894 
  3895 * Classical reasoner: addbefore/addSbefore now have APPEND/ORELSE
  3896 semantics; addbefore now affects only the unsafe part of step_tac
  3897 etc.; this affects addss/auto_tac/force_tac, so EXISTING PROOFS MAY
  3898 FAIL, but proofs should be fixable easily, e.g. by replacing Auto_tac
  3899 by Force_tac;
  3900 
  3901 * Classical reasoner: setwrapper to setWrapper and compwrapper to
  3902 compWrapper; added safe wrapper (and access functions for it);
  3903 
  3904 * HOL/split_all_tac is now much faster and fails if there is nothing
  3905 to split.  Some EXISTING PROOFS MAY REQUIRE ADAPTION because the order
  3906 and the names of the automatically generated variables have changed.
  3907 split_all_tac has moved within claset() from unsafe wrappers to safe
  3908 wrappers, which means that !!-bound variables are split much more
  3909 aggressively, and safe_tac and clarify_tac now split such variables.
  3910 If this splitting is not appropriate, use delSWrapper "split_all_tac".
  3911 Note: the same holds for record_split_tac, which does the job of
  3912 split_all_tac for record fields.
  3913 
  3914 * HOL/Simplifier: Rewrite rules for case distinctions can now be added
  3915 permanently to the default simpset using Addsplits just like
  3916 Addsimps. They can be removed via Delsplits just like
  3917 Delsimps. Lower-case versions are also available.
  3918 
  3919 * HOL/Simplifier: The rule split_if is now part of the default
  3920 simpset. This means that the simplifier will eliminate all occurrences
  3921 of if-then-else in the conclusion of a goal. To prevent this, you can
  3922 either remove split_if completely from the default simpset by
  3923 `Delsplits [split_if]' or remove it in a specific call of the
  3924 simplifier using `... delsplits [split_if]'.  You can also add/delete
  3925 other case splitting rules to/from the default simpset: every datatype
  3926 generates suitable rules `split_t_case' and `split_t_case_asm' (where
  3927 t is the name of the datatype).
  3928 
  3929 * Classical reasoner / Simplifier combination: new force_tac (and
  3930 derivatives Force_tac, force) combines rewriting and classical
  3931 reasoning (and whatever other tools) similarly to auto_tac, but is
  3932 aimed to solve the given subgoal completely.
  3933 
  3934 
  3935 *** General ***
  3936 
  3937 * new top-level commands `Goal' and `Goalw' that improve upon `goal'
  3938 and `goalw': the theory is no longer needed as an explicit argument -
  3939 the current theory context is used; assumptions are no longer returned
  3940 at the ML-level unless one of them starts with ==> or !!; it is
  3941 recommended to convert to these new commands using isatool fixgoal
  3942 (backup your sources first!);
  3943 
  3944 * new top-level commands 'thm' and 'thms' for retrieving theorems from
  3945 the current theory context, and 'theory' to lookup stored theories;
  3946 
  3947 * new theory section 'locale' for declaring constants, assumptions and
  3948 definitions that have local scope;
  3949 
  3950 * new theory section 'nonterminals' for purely syntactic types;
  3951 
  3952 * new theory section 'setup' for generic ML setup functions
  3953 (e.g. package initialization);
  3954 
  3955 * the distribution now includes Isabelle icons: see
  3956 lib/logo/isabelle-{small,tiny}.xpm;
  3957 
  3958 * isatool install - install binaries with absolute references to
  3959 ISABELLE_HOME/bin;
  3960 
  3961 * isatool logo -- create instances of the Isabelle logo (as EPS);
  3962 
  3963 * print mode 'emacs' reserved for Isamode;
  3964 
  3965 * support multiple print (ast) translations per constant name;
  3966 
  3967 * theorems involving oracles are now printed with a suffixed [!];
  3968 
  3969 
  3970 *** HOL ***
  3971 
  3972 * there is now a tutorial on Isabelle/HOL (do 'isatool doc tutorial');
  3973 
  3974 * HOL/inductive package reorganized and improved: now supports mutual
  3975 definitions such as
  3976 
  3977   inductive EVEN ODD
  3978     intrs
  3979       null "0 : EVEN"
  3980       oddI "n : EVEN ==> Suc n : ODD"
  3981       evenI "n : ODD ==> Suc n : EVEN"
  3982 
  3983 new theorem list "elims" contains an elimination rule for each of the
  3984 recursive sets; inductive definitions now handle disjunctive premises
  3985 correctly (also ZF);
  3986 
  3987 INCOMPATIBILITIES: requires Inductive as an ancestor; component
  3988 "mutual_induct" no longer exists - the induction rule is always
  3989 contained in "induct";
  3990 
  3991 
  3992 * HOL/datatype package re-implemented and greatly improved: now
  3993 supports mutually recursive datatypes such as
  3994 
  3995   datatype
  3996     'a aexp = IF_THEN_ELSE ('a bexp) ('a aexp) ('a aexp)
  3997             | SUM ('a aexp) ('a aexp)
  3998             | DIFF ('a aexp) ('a aexp)
  3999             | NUM 'a
  4000   and
  4001     'a bexp = LESS ('a aexp) ('a aexp)
  4002             | AND ('a bexp) ('a bexp)
  4003             | OR ('a bexp) ('a bexp)
  4004 
  4005 as well as indirectly recursive datatypes such as
  4006 
  4007   datatype
  4008     ('a, 'b) term = Var 'a
  4009                   | App 'b ((('a, 'b) term) list)
  4010 
  4011 The new tactic  mutual_induct_tac [<var_1>, ..., <var_n>] i  performs
  4012 induction on mutually / indirectly recursive datatypes.
  4013 
  4014 Primrec equations are now stored in theory and can be accessed via
  4015 <function_name>.simps.
  4016 
  4017 INCOMPATIBILITIES:
  4018 
  4019   - Theories using datatypes must now have theory Datatype as an
  4020     ancestor.
  4021   - The specific <typename>.induct_tac no longer exists - use the
  4022     generic induct_tac instead.
  4023   - natE has been renamed to nat.exhaust - use exhaust_tac
  4024     instead of res_inst_tac ... natE. Note that the variable
  4025     names in nat.exhaust differ from the names in natE, this
  4026     may cause some "fragile" proofs to fail.
  4027   - The theorems split_<typename>_case and split_<typename>_case_asm
  4028     have been renamed to <typename>.split and <typename>.split_asm.
  4029   - Since default sorts of type variables are now handled correctly,
  4030     some datatype definitions may have to be annotated with explicit
  4031     sort constraints.
  4032   - Primrec definitions no longer require function name and type
  4033     of recursive argument.
  4034 
  4035 Consider using isatool fixdatatype to adapt your theories and proof
  4036 scripts to the new package (backup your sources first!).
  4037 
  4038 
  4039 * HOL/record package: considerably improved implementation; now
  4040 includes concrete syntax for record types, terms, updates; theorems
  4041 for surjective pairing and splitting !!-bound record variables; proof
  4042 support is as follows:
  4043 
  4044   1) standard conversions (selectors or updates applied to record
  4045 constructor terms) are part of the standard simpset;
  4046 
  4047   2) inject equations of the form ((x, y) = (x', y')) == x=x' & y=y' are
  4048 made part of standard simpset and claset via addIffs;
  4049 
  4050   3) a tactic for record field splitting (record_split_tac) is part of
  4051 the standard claset (addSWrapper);
  4052 
  4053 To get a better idea about these rules you may retrieve them via
  4054 something like 'thms "foo.simps"' or 'thms "foo.iffs"', where "foo" is
  4055 the name of your record type.
  4056 
  4057 The split tactic 3) conceptually simplifies by the following rule:
  4058 
  4059   "(!!x. PROP ?P x) == (!!a b. PROP ?P (a, b))"
  4060 
  4061 Thus any record variable that is bound by meta-all will automatically
  4062 blow up into some record constructor term, consequently the
  4063 simplifications of 1), 2) apply.  Thus force_tac, auto_tac etc. shall
  4064 solve record problems automatically.
  4065 
  4066 
  4067 * reorganized the main HOL image: HOL/Integ and String loaded by
  4068 default; theory Main includes everything;
  4069 
  4070 * automatic simplification of integer sums and comparisons, using cancellation;
  4071 
  4072 * added option_map_eq_Some and not_Some_eq to the default simpset and claset;
  4073 
  4074 * added disj_not1 = "(~P | Q) = (P --> Q)" to the default simpset;
  4075 
  4076 * many new identities for unions, intersections, set difference, etc.;
  4077 
  4078 * expand_if, expand_split, expand_sum_case and expand_nat_case are now
  4079 called split_if, split_split, split_sum_case and split_nat_case (to go
  4080 with add/delsplits);
  4081 
  4082 * HOL/Prod introduces simplification procedure unit_eq_proc rewriting
  4083 (?x::unit) = (); this is made part of the default simpset, which COULD
  4084 MAKE EXISTING PROOFS FAIL under rare circumstances (consider
  4085 'Delsimprocs [unit_eq_proc];' as last resort); also note that
  4086 unit_abs_eta_conv is added in order to counter the effect of
  4087 unit_eq_proc on (%u::unit. f u), replacing it by f rather than by
  4088 %u.f();
  4089 
  4090 * HOL/Fun INCOMPATIBILITY: `inj_onto' is now called `inj_on' (which
  4091 makes more sense);
  4092 
  4093 * HOL/Set INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
  4094   It and 'sym RS equals0D' are now in the default  claset, giving automatic
  4095   disjointness reasoning but breaking a few old proofs.
  4096 
  4097 * HOL/Relation INCOMPATIBILITY: renamed the relational operator r^-1
  4098 to 'converse' from 'inverse' (for compatibility with ZF and some
  4099 literature);
  4100 
  4101 * HOL/recdef can now declare non-recursive functions, with {} supplied as
  4102 the well-founded relation;
  4103 
  4104 * HOL/Set INCOMPATIBILITY: the complement of set A is now written -A instead of
  4105     Compl A.  The "Compl" syntax remains available as input syntax for this
  4106     release ONLY.
  4107 
  4108 * HOL/Update: new theory of function updates:
  4109     f(a:=b) == %x. if x=a then b else f x
  4110 may also be iterated as in f(a:=b,c:=d,...);
  4111 
  4112 * HOL/Vimage: new theory for inverse image of a function, syntax f-``B;
  4113 
  4114 * HOL/List:
  4115   - new function list_update written xs[i:=v] that updates the i-th
  4116     list position. May also be iterated as in xs[i:=a,j:=b,...].
  4117   - new function `upt' written [i..j(] which generates the list
  4118     [i,i+1,...,j-1], i.e. the upper bound is excluded. To include the upper
  4119     bound write [i..j], which is a shorthand for [i..j+1(].
  4120   - new lexicographic orderings and corresponding wellfoundedness theorems.
  4121 
  4122 * HOL/Arith:
  4123   - removed 'pred' (predecessor) function;
  4124   - generalized some theorems about n-1;
  4125   - many new laws about "div" and "mod";
  4126   - new laws about greatest common divisors (see theory ex/Primes);
  4127 
  4128 * HOL/Relation: renamed the relational operator r^-1 "converse"
  4129 instead of "inverse";
  4130 
  4131 * HOL/Induct/Multiset: a theory of multisets, including the wellfoundedness
  4132   of the multiset ordering;
  4133 
  4134 * directory HOL/Real: a construction of the reals using Dedekind cuts
  4135   (not included by default);
  4136 
  4137 * directory HOL/UNITY: Chandy and Misra's UNITY formalism;
  4138 
  4139 * directory HOL/Hoare: a new version of Hoare logic which permits many-sorted
  4140   programs, i.e. different program variables may have different types.
  4141 
  4142 * calling (stac rew i) now fails if "rew" has no effect on the goal
  4143   [previously, this check worked only if the rewrite rule was unconditional]
  4144   Now rew can involve either definitions or equalities (either == or =).
  4145 
  4146 
  4147 *** ZF ***
  4148 
  4149 * theory Main includes everything; INCOMPATIBILITY: theory ZF.thy contains
  4150   only the theorems proved on ZF.ML;
  4151 
  4152 * ZF INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
  4153   It and 'sym RS equals0D' are now in the default  claset, giving automatic
  4154   disjointness reasoning but breaking a few old proofs.
  4155 
  4156 * ZF/Update: new theory of function updates
  4157     with default rewrite rule  f(x:=y) ` z = if(z=x, y, f`z)
  4158   may also be iterated as in f(a:=b,c:=d,...);
  4159 
  4160 * in  let x=t in u(x), neither t nor u(x) has to be an FOL term.
  4161 
  4162 * calling (stac rew i) now fails if "rew" has no effect on the goal
  4163   [previously, this check worked only if the rewrite rule was unconditional]
  4164   Now rew can involve either definitions or equalities (either == or =).
  4165 
  4166 * case_tac provided for compatibility with HOL
  4167     (like the old excluded_middle_tac, but with subgoals swapped)
  4168 
  4169 
  4170 *** Internal programming interfaces ***
  4171 
  4172 * Pure: several new basic modules made available for general use, see
  4173 also src/Pure/README;
  4174 
  4175 * improved the theory data mechanism to support encapsulation (data
  4176 kind name replaced by private Object.kind, acting as authorization
  4177 key); new type-safe user interface via functor TheoryDataFun; generic
  4178 print_data function becomes basically useless;
  4179 
  4180 * removed global_names compatibility flag -- all theory declarations
  4181 are qualified by default;
  4182 
  4183 * module Pure/Syntax now offers quote / antiquote translation
  4184 functions (useful for Hoare logic etc. with implicit dependencies);
  4185 see HOL/ex/Antiquote for an example use;
  4186 
  4187 * Simplifier now offers conversions (asm_)(full_)rewrite: simpset ->
  4188 cterm -> thm;
  4189 
  4190 * new tactical CHANGED_GOAL for checking that a tactic modifies a
  4191 subgoal;
  4192 
  4193 * Display.print_goals function moved to Locale.print_goals;
  4194 
  4195 * standard print function for goals supports current_goals_markers
  4196 variable for marking begin of proof, end of proof, start of goal; the
  4197 default is ("", "", ""); setting current_goals_markers := ("<proof>",
  4198 "</proof>", "<goal>") causes SGML like tagged proof state printing,
  4199 for example;
  4200 
  4201 
  4202 
  4203 New in Isabelle98 (January 1998)
  4204 --------------------------------
  4205 
  4206 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  4207 
  4208 * changed lexical syntax of terms / types: dots made part of long
  4209 identifiers, e.g. "%x.x" no longer possible, should be "%x. x";
  4210 
  4211 * simpset (and claset) reference variable replaced by functions
  4212 simpset / simpset_ref;
  4213 
  4214 * no longer supports theory aliases (via merge) and non-trivial
  4215 implicit merge of thms' signatures;
  4216 
  4217 * most internal names of constants changed due to qualified names;
  4218 
  4219 * changed Pure/Sequence interface (see Pure/seq.ML);
  4220 
  4221 
  4222 *** General Changes ***
  4223 
  4224 * hierachically structured name spaces (for consts, types, axms, thms
  4225 etc.); new lexical class 'longid' (e.g. Foo.bar.x) may render much of
  4226 old input syntactically incorrect (e.g. "%x.x"); COMPATIBILITY:
  4227 isatool fixdots ensures space after dots (e.g. "%x. x"); set
  4228 long_names for fully qualified output names; NOTE: ML programs
  4229 (special tactics, packages etc.) referring to internal names may have
  4230 to be adapted to cope with fully qualified names; in case of severe
  4231 backward campatibility problems try setting 'global_names' at compile
  4232 time to have enrything declared within a flat name space; one may also
  4233 fine tune name declarations in theories via the 'global' and 'local'
  4234 section;
  4235 
  4236 * reimplemented the implicit simpset and claset using the new anytype
  4237 data filed in signatures; references simpset:simpset ref etc. are
  4238 replaced by functions simpset:unit->simpset and
  4239 simpset_ref:unit->simpset ref; COMPATIBILITY: use isatool fixclasimp
  4240 to patch your ML files accordingly;
  4241 
  4242 * HTML output now includes theory graph data for display with Java
  4243 applet or isatool browser; data generated automatically via isatool
  4244 usedir (see -i option, ISABELLE_USEDIR_OPTIONS);
  4245 
  4246 * defs may now be conditional; improved rewrite_goals_tac to handle
  4247 conditional equations;
  4248 
  4249 * defs now admits additional type arguments, using TYPE('a) syntax;
  4250 
  4251 * theory aliases via merge (e.g. M=A+B+C) no longer supported, always
  4252 creates a new theory node; implicit merge of thms' signatures is
  4253 restricted to 'trivial' ones; COMPATIBILITY: one may have to use
  4254 transfer:theory->thm->thm in (rare) cases;
  4255 
  4256 * improved handling of draft signatures / theories; draft thms (and
  4257 ctyps, cterms) are automatically promoted to real ones;
  4258 
  4259 * slightly changed interfaces for oracles: admit many per theory, named
  4260 (e.g. oracle foo = mlfun), additional name argument for invoke_oracle;
  4261 
  4262 * print_goals: optional output of const types (set show_consts and
  4263 show_types);
  4264 
  4265 * improved output of warnings (###) and errors (***);
  4266 
  4267 * subgoal_tac displays a warning if the new subgoal has type variables;
  4268 
  4269 * removed old README and Makefiles;
  4270 
  4271 * replaced print_goals_ref hook by print_current_goals_fn and result_error_fn;
  4272 
  4273 * removed obsolete init_pps and init_database;
  4274 
  4275 * deleted the obsolete tactical STATE, which was declared by
  4276     fun STATE tacfun st = tacfun st st;
  4277 
  4278 * cd and use now support path variables, e.g. $ISABELLE_HOME, or ~
  4279 (which abbreviates $HOME);
  4280 
  4281 * changed Pure/Sequence interface (see Pure/seq.ML); COMPATIBILITY:
  4282 use isatool fixseq to adapt your ML programs (this works for fully
  4283 qualified references to the Sequence structure only!);
  4284 
  4285 * use_thy no longer requires writable current directory; it always
  4286 reloads .ML *and* .thy file, if either one is out of date;
  4287 
  4288 
  4289 *** Classical Reasoner ***
  4290 
  4291 * Clarify_tac, clarify_tac, clarify_step_tac, Clarify_step_tac: new
  4292 tactics that use classical reasoning to simplify a subgoal without
  4293 splitting it into several subgoals;
  4294 
  4295 * Safe_tac: like safe_tac but uses the default claset;
  4296 
  4297 
  4298 *** Simplifier ***
  4299 
  4300 * added simplification meta rules:
  4301     (asm_)(full_)simplify: simpset -> thm -> thm;
  4302 
  4303 * simplifier.ML no longer part of Pure -- has to be loaded by object
  4304 logics (again);
  4305 
  4306 * added prems argument to simplification procedures;
  4307 
  4308 * HOL, FOL, ZF: added infix function `addsplits':
  4309   instead of `<simpset> setloop (split_tac <thms>)'
  4310   you can simply write `<simpset> addsplits <thms>'
  4311 
  4312 
  4313 *** Syntax ***
  4314 
  4315 * TYPE('a) syntax for type reflection terms;
  4316 
  4317 * no longer handles consts with name "" -- declare as 'syntax' instead;
  4318 
  4319 * pretty printer: changed order of mixfix annotation preference (again!);
  4320 
  4321 * Pure: fixed idt/idts vs. pttrn/pttrns syntactic categories;
  4322 
  4323 
  4324 *** HOL ***
  4325 
  4326 * HOL: there is a new splitter `split_asm_tac' that can be used e.g.
  4327   with `addloop' of the simplifier to faciliate case splitting in premises.
  4328 
  4329 * HOL/TLA: Stephan Merz's formalization of Lamport's Temporal Logic of Actions;
  4330 
  4331 * HOL/Auth: new protocol proofs including some for the Internet
  4332   protocol TLS;
  4333 
  4334 * HOL/Map: new theory of `maps' a la VDM;
  4335 
  4336 * HOL/simplifier: simplification procedures nat_cancel_sums for
  4337 cancelling out common nat summands from =, <, <= (in)equalities, or
  4338 differences; simplification procedures nat_cancel_factor for
  4339 cancelling common factor from =, <, <= (in)equalities over natural
  4340 sums; nat_cancel contains both kinds of procedures, it is installed by
  4341 default in Arith.thy -- this COULD MAKE EXISTING PROOFS FAIL;
  4342 
  4343 * HOL/simplifier: terms of the form
  4344   `? x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x)'  (or t=x)
  4345   are rewritten to
  4346   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t)',
  4347   and those of the form
  4348   `! x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x) --> R(x)'  (or t=x)
  4349   are rewritten to
  4350   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t) --> R(t)',
  4351 
  4352 * HOL/datatype
  4353   Each datatype `t' now comes with a theorem `split_t_case' of the form
  4354 
  4355   P(t_case f1 ... fn x) =
  4356      ( (!y1 ... ym1. x = C1 y1 ... ym1 --> P(f1 y1 ... ym1)) &
  4357         ...
  4358        (!y1 ... ymn. x = Cn y1 ... ymn --> P(f1 y1 ... ymn))
  4359      )
  4360 
  4361   and a theorem `split_t_case_asm' of the form
  4362 
  4363   P(t_case f1 ... fn x) =
  4364     ~( (? y1 ... ym1. x = C1 y1 ... ym1 & ~P(f1 y1 ... ym1)) |
  4365         ...
  4366        (? y1 ... ymn. x = Cn y1 ... ymn & ~P(f1 y1 ... ymn))
  4367      )
  4368   which can be added to a simpset via `addsplits'. The existing theorems
  4369   expand_list_case and expand_option_case have been renamed to
  4370   split_list_case and split_option_case.
  4371 
  4372 * HOL/Arithmetic:
  4373   - `pred n' is automatically converted to `n-1'.
  4374     Users are strongly encouraged not to use `pred' any longer,
  4375     because it will disappear altogether at some point.
  4376   - Users are strongly encouraged to write "0 < n" rather than
  4377     "n ~= 0". Theorems and proof tools have been modified towards this
  4378     `standard'.
  4379 
  4380 * HOL/Lists:
  4381   the function "set_of_list" has been renamed "set" (and its theorems too);
  4382   the function "nth" now takes its arguments in the reverse order and
  4383   has acquired the infix notation "!" as in "xs!n".
  4384 
  4385 * HOL/Set: UNIV is now a constant and is no longer translated to Compl{};
  4386 
  4387 * HOL/Set: The operator (UN x.B x) now abbreviates (UN x:UNIV. B x) and its
  4388   specialist theorems (like UN1_I) are gone.  Similarly for (INT x.B x);
  4389 
  4390 * HOL/record: extensible records with schematic structural subtyping
  4391 (single inheritance); EXPERIMENTAL version demonstrating the encoding,
  4392 still lacks various theorems and concrete record syntax;
  4393 
  4394 
  4395 *** HOLCF ***
  4396 
  4397 * removed "axioms" and "generated by" sections;
  4398 
  4399 * replaced "ops" section by extended "consts" section, which is capable of
  4400   handling the continuous function space "->" directly;
  4401 
  4402 * domain package:
  4403   . proves theorems immediately and stores them in the theory,
  4404   . creates hierachical name space,
  4405   . now uses normal mixfix annotations (instead of cinfix...),
  4406   . minor changes to some names and values (for consistency),
  4407   . e.g. cases -> casedist, dists_eq -> dist_eqs, [take_lemma] -> take_lemmas,
  4408   . separator between mutual domain defs: changed "," to "and",
  4409   . improved handling of sort constraints;  now they have to
  4410     appear on the left-hand side of the equations only;
  4411 
  4412 * fixed LAM <x,y,zs>.b syntax;
  4413 
  4414 * added extended adm_tac to simplifier in HOLCF -- can now discharge
  4415 adm (%x. P (t x)), where P is chainfinite and t continuous;
  4416 
  4417 
  4418 *** FOL and ZF ***
  4419 
  4420 * FOL: there is a new splitter `split_asm_tac' that can be used e.g.
  4421   with `addloop' of the simplifier to faciliate case splitting in premises.
  4422 
  4423 * qed_spec_mp, qed_goal_spec_mp, qed_goalw_spec_mp are available, as
  4424 in HOL, they strip ALL and --> from proved theorems;
  4425 
  4426 
  4427 
  4428 New in Isabelle94-8 (May 1997)
  4429 ------------------------------
  4430 
  4431 *** General Changes ***
  4432 
  4433 * new utilities to build / run / maintain Isabelle etc. (in parts
  4434 still somewhat experimental); old Makefiles etc. still functional;
  4435 
  4436 * new 'Isabelle System Manual';
  4437 
  4438 * INSTALL text, together with ./configure and ./build scripts;
  4439 
  4440 * reimplemented type inference for greater efficiency, better error
  4441 messages and clean internal interface;
  4442 
  4443 * prlim command for dealing with lots of subgoals (an easier way of
  4444 setting goals_limit);
  4445 
  4446 
  4447 *** Syntax ***
  4448 
  4449 * supports alternative (named) syntax tables (parser and pretty
  4450 printer); internal interface is provided by add_modesyntax(_i);
  4451 
  4452 * Pure, FOL, ZF, HOL, HOLCF now support symbolic input and output; to
  4453 be used in conjunction with the Isabelle symbol font; uses the
  4454 "symbols" syntax table;
  4455 
  4456 * added token_translation interface (may translate name tokens in
  4457 arbitrary ways, dependent on their type (free, bound, tfree, ...) and
  4458 the current print_mode); IMPORTANT: user print translation functions
  4459 are responsible for marking newly introduced bounds
  4460 (Syntax.mark_boundT);
  4461 
  4462 * token translations for modes "xterm" and "xterm_color" that display
  4463 names in bold, underline etc. or colors (which requires a color
  4464 version of xterm);
  4465 
  4466 * infixes may now be declared with names independent of their syntax;
  4467 
  4468 * added typed_print_translation (like print_translation, but may
  4469 access type of constant);
  4470 
  4471 
  4472 *** Classical Reasoner ***
  4473 
  4474 Blast_tac: a new tactic!  It is often more powerful than fast_tac, but has
  4475 some limitations.  Blast_tac...
  4476   + ignores addss, addbefore, addafter; this restriction is intrinsic
  4477   + ignores elimination rules that don't have the correct format
  4478         (the conclusion MUST be a formula variable)
  4479   + ignores types, which can make HOL proofs fail
  4480   + rules must not require higher-order unification, e.g. apply_type in ZF
  4481     [message "Function Var's argument not a bound variable" relates to this]
  4482   + its proof strategy is more general but can actually be slower
  4483 
  4484 * substitution with equality assumptions no longer permutes other
  4485 assumptions;
  4486 
  4487 * minor changes in semantics of addafter (now called addaltern); renamed
  4488 setwrapper to setWrapper and compwrapper to compWrapper; added safe wrapper
  4489 (and access functions for it);
  4490 
  4491 * improved combination of classical reasoner and simplifier:
  4492   + functions for handling clasimpsets
  4493   + improvement of addss: now the simplifier is called _after_ the
  4494     safe steps.
  4495   + safe variant of addss called addSss: uses safe simplifications
  4496     _during_ the safe steps. It is more complete as it allows multiple
  4497     instantiations of unknowns (e.g. with slow_tac).
  4498 
  4499 *** Simplifier ***
  4500 
  4501 * added interface for simplification procedures (functions that
  4502 produce *proven* rewrite rules on the fly, depending on current
  4503 redex);
  4504 
  4505 * ordering on terms as parameter (used for ordered rewriting);
  4506 
  4507 * new functions delcongs, deleqcongs, and Delcongs. richer rep_ss;
  4508 
  4509 * the solver is now split into a safe and an unsafe part.
  4510 This should be invisible for the normal user, except that the
  4511 functions setsolver and addsolver have been renamed to setSolver and
  4512 addSolver; added safe_asm_full_simp_tac;
  4513 
  4514 
  4515 *** HOL ***
  4516 
  4517 * a generic induction tactic `induct_tac' which works for all datatypes and
  4518 also for type `nat';
  4519 
  4520 * a generic case distinction tactic `exhaust_tac' which works for all
  4521 datatypes and also for type `nat';
  4522 
  4523 * each datatype comes with a function `size';
  4524 
  4525 * patterns in case expressions allow tuple patterns as arguments to
  4526 constructors, for example `case x of [] => ... | (x,y,z)#ps => ...';
  4527 
  4528 * primrec now also works with type nat;
  4529 
  4530 * recdef: a new declaration form, allows general recursive functions to be
  4531 defined in theory files.  See HOL/ex/Fib, HOL/ex/Primes, HOL/Subst/Unify.
  4532 
  4533 * the constant for negation has been renamed from "not" to "Not" to
  4534 harmonize with FOL, ZF, LK, etc.;
  4535 
  4536 * HOL/ex/LFilter theory of a corecursive "filter" functional for
  4537 infinite lists;
  4538 
  4539 * HOL/Modelcheck demonstrates invocation of model checker oracle;
  4540 
  4541 * HOL/ex/Ring.thy declares cring_simp, which solves equational
  4542 problems in commutative rings, using axiomatic type classes for + and *;
  4543 
  4544 * more examples in HOL/MiniML and HOL/Auth;
  4545 
  4546 * more default rewrite rules for quantifiers, union/intersection;
  4547 
  4548 * a new constant `arbitrary == @x.False';
  4549 
  4550 * HOLCF/IOA replaces old HOL/IOA;
  4551 
  4552 * HOLCF changes: derived all rules and arities
  4553   + axiomatic type classes instead of classes
  4554   + typedef instead of faking type definitions
  4555   + eliminated the internal constants less_fun, less_cfun, UU_fun, UU_cfun etc.
  4556   + new axclasses cpo, chfin, flat with flat < chfin < pcpo < cpo < po
  4557   + eliminated the types void, one, tr
  4558   + use unit lift and bool lift (with translations) instead of one and tr
  4559   + eliminated blift from Lift3.thy (use Def instead of blift)
  4560   all eliminated rules are derived as theorems --> no visible changes ;
  4561 
  4562 
  4563 *** ZF ***
  4564 
  4565 * ZF now has Fast_tac, Simp_tac and Auto_tac.  Union_iff is a now a default
  4566 rewrite rule; this may affect some proofs.  eq_cs is gone but can be put back
  4567 as ZF_cs addSIs [equalityI];
  4568 
  4569 
  4570 
  4571 New in Isabelle94-7 (November 96)
  4572 ---------------------------------
  4573 
  4574 * allowing negative levels (as offsets) in prlev and choplev;
  4575 
  4576 * super-linear speedup for large simplifications;
  4577 
  4578 * FOL, ZF and HOL now use miniscoping: rewriting pushes
  4579 quantifications in as far as possible (COULD MAKE EXISTING PROOFS
  4580 FAIL); can suppress it using the command Delsimps (ex_simps @
  4581 all_simps); De Morgan laws are also now included, by default;
  4582 
  4583 * improved printing of ==>  :  ~:
  4584 
  4585 * new object-logic "Sequents" adds linear logic, while replacing LK
  4586 and Modal (thanks to Sara Kalvala);
  4587 
  4588 * HOL/Auth: correctness proofs for authentication protocols;
  4589 
  4590 * HOL: new auto_tac combines rewriting and classical reasoning (many
  4591 examples on HOL/Auth);
  4592 
  4593 * HOL: new command AddIffs for declaring theorems of the form P=Q to
  4594 the rewriter and classical reasoner simultaneously;
  4595 
  4596 * function uresult no longer returns theorems in "standard" format;
  4597 regain previous version by: val uresult = standard o uresult;
  4598 
  4599 
  4600 
  4601 New in Isabelle94-6
  4602 -------------------
  4603 
  4604 * oracles -- these establish an interface between Isabelle and trusted
  4605 external reasoners, which may deliver results as theorems;
  4606 
  4607 * proof objects (in particular record all uses of oracles);
  4608 
  4609 * Simp_tac, Fast_tac, etc. that refer to implicit simpset / claset;
  4610 
  4611 * "constdefs" section in theory files;
  4612 
  4613 * "primrec" section (HOL) no longer requires names;
  4614 
  4615 * internal type "tactic" now simply "thm -> thm Sequence.seq";
  4616 
  4617 
  4618 
  4619 New in Isabelle94-5
  4620 -------------------
  4621 
  4622 * reduced space requirements;
  4623 
  4624 * automatic HTML generation from theories;
  4625 
  4626 * theory files no longer require "..." (quotes) around most types;
  4627 
  4628 * new examples, including two proofs of the Church-Rosser theorem;
  4629 
  4630 * non-curried (1994) version of HOL is no longer distributed;
  4631 
  4632 
  4633 
  4634 New in Isabelle94-4
  4635 -------------------
  4636 
  4637 * greatly reduced space requirements;
  4638 
  4639 * theory files (.thy) no longer require \...\ escapes at line breaks;
  4640 
  4641 * searchable theorem database (see the section "Retrieving theorems" on
  4642 page 8 of the Reference Manual);
  4643 
  4644 * new examples, including Grabczewski's monumental case study of the
  4645 Axiom of Choice;
  4646 
  4647 * The previous version of HOL renamed to Old_HOL;
  4648 
  4649 * The new version of HOL (previously called CHOL) uses a curried syntax
  4650 for functions.  Application looks like f a b instead of f(a,b);
  4651 
  4652 * Mutually recursive inductive definitions finally work in HOL;
  4653 
  4654 * In ZF, pattern-matching on tuples is now available in all abstractions and
  4655 translates to the operator "split";
  4656 
  4657 
  4658 
  4659 New in Isabelle94-3
  4660 -------------------
  4661 
  4662 * new infix operator, addss, allowing the classical reasoner to
  4663 perform simplification at each step of its search.  Example:
  4664         fast_tac (cs addss ss)
  4665 
  4666 * a new logic, CHOL, the same as HOL, but with a curried syntax
  4667 for functions.  Application looks like f a b instead of f(a,b).  Also pairs
  4668 look like (a,b) instead of <a,b>;
  4669 
  4670 * PLEASE NOTE: CHOL will eventually replace HOL!
  4671 
  4672 * In CHOL, pattern-matching on tuples is now available in all abstractions.
  4673 It translates to the operator "split".  A new theory of integers is available;
  4674 
  4675 * In ZF, integer numerals now denote two's-complement binary integers.
  4676 Arithmetic operations can be performed by rewriting.  See ZF/ex/Bin.ML;
  4677 
  4678 * Many new examples: I/O automata, Church-Rosser theorem, equivalents
  4679 of the Axiom of Choice;
  4680 
  4681 
  4682 
  4683 New in Isabelle94-2
  4684 -------------------
  4685 
  4686 * Significantly faster resolution;
  4687 
  4688 * the different sections in a .thy file can now be mixed and repeated
  4689 freely;
  4690 
  4691 * Database of theorems for FOL, HOL and ZF.  New
  4692 commands including qed, qed_goal and bind_thm store theorems in the database.
  4693 
  4694 * Simple database queries: return a named theorem (get_thm) or all theorems of
  4695 a given theory (thms_of), or find out what theory a theorem was proved in
  4696 (theory_of_thm);
  4697 
  4698 * Bugs fixed in the inductive definition and datatype packages;
  4699 
  4700 * The classical reasoner provides deepen_tac and depth_tac, making FOL_dup_cs
  4701 and HOL_dup_cs obsolete;
  4702 
  4703 * Syntactic ambiguities caused by the new treatment of syntax in Isabelle94-1
  4704 have been removed;
  4705 
  4706 * Simpler definition of function space in ZF;
  4707 
  4708 * new results about cardinal and ordinal arithmetic in ZF;
  4709 
  4710 * 'subtype' facility in HOL for introducing new types as subsets of existing
  4711 types;
  4712 
  4713 
  4714 $Id$