NEWS
author wenzelm
Mon May 07 00:52:25 2007 +0200 (2007-05-07)
changeset 22848 f65a76867179
parent 22845 5f9138bcb3d7
child 22863 e1d3fa78b8e1
permissions -rw-r--r--
* Context data interfaces;
     1 Isabelle NEWS -- history user-relevant changes
     2 ==============================================
     3 
     4 New in this Isabelle version
     5 ----------------------------
     6 
     7 *** General ***
     8 
     9 * More uniform information about legacy features, notably a
    10 warning/error of "Legacy feature: ...", depending on the state of the
    11 tolerate_legacy_features flag (default true).
    12 
    13 * Theory syntax: the header format ``theory A = B + C:'' has been
    14 discontinued in favour of ``theory A imports B C begin''.  Use isatool
    15 fixheaders to convert existing theory files.  INCOMPATIBILITY.
    16 
    17 * Theory syntax: the old non-Isar theory file format has been
    18 discontinued altogether.  Note that ML proof scripts may still be used
    19 with Isar theories; migration is usually quite simple with the ML
    20 function use_legacy_bindings.  INCOMPATIBILITY.
    21 
    22 * Theory syntax: some popular names (e.g. "class", "fun", "help",
    23 "if") are now keywords.  INCOMPATIBILITY, use double quotes.
    24 
    25 * Legacy goal package: reduced interface to the bare minimum required
    26 to keep existing proof scripts running.  Most other user-level
    27 functions are now part of the OldGoals structure, which is *not* open
    28 by default (consider isatool expandshort before open OldGoals).
    29 Removed top_sg, prin, printyp, pprint_term/typ altogether, because
    30 these tend to cause confusion about the actual goal (!) context being
    31 used here, which is not necessarily the same as the_context().
    32 
    33 * Command 'find_theorems': support "*" wildcard in "name:" criterion.
    34 
    35 * The ``prems limit'' option (cf. ProofContext.prems_limit) is now -1
    36 by default, which means that "prems" (and also "fixed variables") are
    37 suppressed from proof state output.  Note that the ProofGeneral
    38 settings mechanism allows to change and save options persistently, but
    39 older versions of Isabelle will fail to start up if a negative prems
    40 limit is imposed.
    41 
    42 * Local theory targets may be specified by non-nested blocks of
    43 ``context/locale/class ... begin'' followed by ``end''.  The body may
    44 contain definitions, theorems etc., including any derived mechanism
    45 that has been implemented on top of these primitives.  This concept
    46 generalizes the existing ``theorem (in ...)'' towards more versatility
    47 and scalability.
    48 
    49 * Proof General interface: proper undo of final 'end' command;
    50 discontinued Isabelle/classic mode (ML proof scripts).
    51 
    52 
    53 *** Document preparation ***
    54 
    55 * Added antiquotation @{theory name} which prints the given name,
    56 after checking that it refers to a valid ancestor theory in the
    57 current context.
    58 
    59 * Added antiquotations @{ML_type text} and @{ML_struct text} which
    60 check the given source text as ML type/structure, printing verbatim.
    61 
    62 * Added antiquotation @{abbrev "c args"} which prints the abbreviation
    63 "c args == rhs" given in the current context.  (Any number of
    64 arguments may be given on the LHS.)
    65 
    66 
    67 
    68 *** Pure ***
    69 
    70 * code generator: 
    71   - Isar "definition"s and primitive instance definitions are added explicitly
    72     to the table of defining equations
    73   - primitive definitions are not used as defining equations by default any longer
    74   - defining equations are now definitly restricted to meta "==" and object
    75         equality "="
    76   - HOL theories have been adopted accordingly
    77 
    78 * class_package.ML offers a combination of axclasses and locales to
    79 achieve Haskell-like type classes in Isabelle. See
    80 HOL/ex/Classpackage.thy for examples.
    81 
    82 * Yet another code generator framework allows to generate executable
    83 code for ML and Haskell (including "class"es). A short usage sketch:
    84 
    85     internal compilation:
    86         code_gen <list of constants (term syntax)> (SML #)
    87     writing SML code to a file:
    88         code_gen <list of constants (term syntax)> (SML <filename>)
    89     writing OCaml code to a file:
    90         code_gen <list of constants (term syntax)> (OCaml <filename>)
    91     writing Haskell code to a bunch of files:
    92         code_gen <list of constants (term syntax)> (Haskell <filename>)
    93 
    94 Reasonable default setup of framework in HOL/Main.
    95 
    96 Theorem attributs for selecting and transforming function equations theorems:
    97 
    98     [code fun]:        select a theorem as function equation for a specific constant
    99     [code fun del]:    deselect a theorem as function equation for a specific constant
   100     [code inline]:     select an equation theorem for unfolding (inlining) in place
   101     [code inline del]: deselect an equation theorem for unfolding (inlining) in place
   102 
   103 User-defined serializations (target in {SML, OCaml, Haskell}):
   104 
   105     code_const <and-list of constants (term syntax)>
   106       {(target) <and-list of const target syntax>}+
   107 
   108     code_type <and-list of type constructors>
   109       {(target) <and-list of type target syntax>}+
   110 
   111     code_instance <and-list of instances>
   112       {(target)}+
   113         where instance ::= <type constructor> :: <class>
   114 
   115     code_class <and_list of classes>
   116       {(target) <and-list of class target syntax>}+
   117         where class target syntax ::= <class name> {where {<classop> == <target syntax>}+}?
   118 
   119 code_instance and code_class only apply to target Haskell.
   120 
   121 See HOL theories and HOL/ex/Codegenerator*.thy for usage examples.
   122 Doc/Isar/Advanced/Codegen/ provides a tutorial.
   123 
   124 * Command 'no_translations' removes translation rules from theory
   125 syntax.
   126 
   127 * Overloaded definitions are now actually checked for acyclic
   128 dependencies.  The overloading scheme is slightly more general than
   129 that of Haskell98, although Isabelle does not demand an exact
   130 correspondence to type class and instance declarations.
   131 INCOMPATIBILITY, use ``defs (unchecked overloaded)'' to admit more
   132 exotic versions of overloading -- at the discretion of the user!
   133 
   134 Polymorphic constants are represented via type arguments, i.e. the
   135 instantiation that matches an instance against the most general
   136 declaration given in the signature.  For example, with the declaration
   137 c :: 'a => 'a => 'a, an instance c :: nat => nat => nat is represented
   138 as c(nat).  Overloading is essentially simultaneous structural
   139 recursion over such type arguments.  Incomplete specification patterns
   140 impose global constraints on all occurrences, e.g. c('a * 'a) on the
   141 LHS means that more general c('a * 'b) will be disallowed on any RHS.
   142 Command 'print_theory' outputs the normalized system of recursive
   143 equations, see section "definitions".
   144 
   145 * Isar: improper proof element 'guess' is like 'obtain', but derives
   146 the obtained context from the course of reasoning!  For example:
   147 
   148   assume "EX x y. A x & B y"   -- "any previous fact"
   149   then guess x and y by clarify
   150 
   151 This technique is potentially adventurous, depending on the facts and
   152 proof tools being involved here.
   153 
   154 * Isar: known facts from the proof context may be specified as literal
   155 propositions, using ASCII back-quote syntax.  This works wherever
   156 named facts used to be allowed so far, in proof commands, proof
   157 methods, attributes etc.  Literal facts are retrieved from the context
   158 according to unification of type and term parameters.  For example,
   159 provided that "A" and "A ==> B" and "!!x. P x ==> Q x" are known
   160 theorems in the current context, then these are valid literal facts:
   161 `A` and `A ==> B` and `!!x. P x ==> Q x" as well as `P a ==> Q a` etc.
   162 
   163 There is also a proof method "fact" which does the same composition
   164 for explicit goal states, e.g. the following proof texts coincide with
   165 certain special cases of literal facts:
   166 
   167   have "A" by fact                 ==  note `A`
   168   have "A ==> B" by fact           ==  note `A ==> B`
   169   have "!!x. P x ==> Q x" by fact  ==  note `!!x. P x ==> Q x`
   170   have "P a ==> Q a" by fact       ==  note `P a ==> Q a`
   171 
   172 * Isar: ":" (colon) is no longer a symbolic identifier character in
   173 outer syntax.  Thus symbolic identifiers may be used without
   174 additional white space in declarations like this: ``assume *: A''.
   175 
   176 * Isar: 'print_facts' prints all local facts of the current context,
   177 both named and unnamed ones.
   178 
   179 * Isar: 'def' now admits simultaneous definitions, e.g.:
   180 
   181   def x == "t" and y == "u"
   182 
   183 * Isar: added command 'unfolding', which is structurally similar to
   184 'using', but affects both the goal state and facts by unfolding given
   185 rewrite rules.  Thus many occurrences of the 'unfold' method or
   186 'unfolded' attribute may be replaced by first-class proof text.
   187 
   188 * Isar: methods 'unfold' / 'fold', attributes 'unfolded' / 'folded',
   189 and command 'unfolding' now all support object-level equalities
   190 (potentially conditional).  The underlying notion of rewrite rule is
   191 analogous to the 'rule_format' attribute, but *not* that of the
   192 Simplifier (which is usually more generous).
   193 
   194 * Isar: the goal restriction operator [N] (default N = 1) evaluates a
   195 method expression within a sandbox consisting of the first N
   196 sub-goals, which need to exist.  For example, ``simp_all [3]''
   197 simplifies the first three sub-goals, while (rule foo, simp_all)[]
   198 simplifies all new goals that emerge from applying rule foo to the
   199 originally first one.
   200 
   201 * Isar: schematic goals are no longer restricted to higher-order
   202 patterns; e.g. ``lemma "?P(?x)" by (rule TrueI)'' now works as
   203 expected.
   204 
   205 * Isar: the conclusion of a long theorem statement is now either
   206 'shows' (a simultaneous conjunction, as before), or 'obtains'
   207 (essentially a disjunction of cases with local parameters and
   208 assumptions).  The latter allows to express general elimination rules
   209 adequately; in this notation common elimination rules look like this:
   210 
   211   lemma exE:    -- "EX x. P x ==> (!!x. P x ==> thesis) ==> thesis"
   212     assumes "EX x. P x"
   213     obtains x where "P x"
   214 
   215   lemma conjE:  -- "A & B ==> (A ==> B ==> thesis) ==> thesis"
   216     assumes "A & B"
   217     obtains A and B
   218 
   219   lemma disjE:  -- "A | B ==> (A ==> thesis) ==> (B ==> thesis) ==> thesis"
   220     assumes "A | B"
   221     obtains
   222       A
   223     | B
   224 
   225 The subsequent classical rules even refer to the formal "thesis"
   226 explicitly:
   227 
   228   lemma classical:     -- "(~ thesis ==> thesis) ==> thesis"
   229     obtains "~ thesis"
   230 
   231   lemma Peirce's_Law:  -- "((thesis ==> something) ==> thesis) ==> thesis"
   232     obtains "thesis ==> something"
   233 
   234 The actual proof of an 'obtains' statement is analogous to that of the
   235 Isar proof element 'obtain', only that there may be several cases.
   236 Optional case names may be specified in parentheses; these will be
   237 available both in the present proof and as annotations in the
   238 resulting rule, for later use with the 'cases' method (cf. attribute
   239 case_names).
   240 
   241 * Isar: the assumptions of a long theorem statement are available as
   242 "assms" fact in the proof context.  This is more appropriate than the
   243 (historical) "prems", which refers to all assumptions of the current
   244 context, including those from the target locale, proof body etc.
   245 
   246 * Isar: 'print_statement' prints theorems from the current theory or
   247 proof context in long statement form, according to the syntax of a
   248 top-level lemma.
   249 
   250 * Isar: 'obtain' takes an optional case name for the local context
   251 introduction rule (default "that").
   252 
   253 * Isar: removed obsolete 'concl is' patterns.  INCOMPATIBILITY, use
   254 explicit (is "_ ==> ?foo") in the rare cases where this still happens
   255 to occur.
   256 
   257 * Pure: syntax "CONST name" produces a fully internalized constant
   258 according to the current context.  This is particularly useful for
   259 syntax translations that should refer to internal constant
   260 representations independently of name spaces.
   261 
   262 * Pure: syntax constant for foo (binder "FOO ") is called "foo_binder"
   263 instead of "FOO ". This allows multiple binder declarations to coexist
   264 in the same context.  INCOMPATIBILITY.
   265 
   266 * Isar/locales: 'notation' provides a robust interface to the 'syntax'
   267 primitive that also works in a locale context (both for constants and
   268 fixed variables).  Type declaration and internal syntactic
   269 representation of given constants retrieved from the context.
   270 
   271 * Isar/locales: new derived specification elements 'axiomatization',
   272 'definition', 'abbreviation', which support type-inference, admit
   273 object-level specifications (equality, equivalence).  See also the
   274 isar-ref manual.  Examples:
   275 
   276   axiomatization
   277     eq  (infix "===" 50) where
   278     eq_refl: "x === x" and eq_subst: "x === y ==> P x ==> P y"
   279 
   280   definition "f x y = x + y + 1"
   281   definition g where "g x = f x x"
   282 
   283   abbreviation
   284     neq  (infix "=!=" 50) where
   285     "x =!= y == ~ (x === y)"
   286 
   287 These specifications may be also used in a locale context.  Then the
   288 constants being introduced depend on certain fixed parameters, and the
   289 constant name is qualified by the locale base name.  An internal
   290 abbreviation takes care for convenient input and output, making the
   291 parameters implicit and using the original short name.  See also
   292 HOL/ex/Abstract_NAT.thy for an example of deriving polymorphic
   293 entities from a monomorphic theory.
   294 
   295 Presently, abbreviations are only available 'in' a target locale, but
   296 not inherited by general import expressions.  Also note that
   297 'abbreviation' may be used as a type-safe replacement for 'syntax' +
   298 'translations' in common applications.
   299 
   300 Concrete syntax is attached to specified constants in internal form,
   301 independently of name spaces.  The parse tree representation is
   302 slightly different -- use 'notation' instead of raw 'syntax', and
   303 'translations' with explicit "CONST" markup to accommodate this.
   304 
   305 * Pure: command 'print_abbrevs' prints all constant abbreviations of
   306 the current context.  Print mode "no_abbrevs" prevents inversion of
   307 abbreviations on output.
   308 
   309 * Isar/locales: improved parameter handling:
   310 - use of locales "var" and "struct" no longer necessary;
   311 - parameter renamings are no longer required to be injective.
   312   This enables, for example, to define a locale for endomorphisms thus:
   313   locale endom = homom mult mult h.
   314 
   315 * Isar/locales: changed the way locales with predicates are defined.
   316 Instead of accumulating the specification, the imported expression is
   317 now an interpretation.  INCOMPATIBILITY: different normal form of
   318 locale expressions.  In particular, in interpretations of locales with
   319 predicates, goals repesenting already interpreted fragments are not
   320 removed automatically.  Use methods `intro_locales' and
   321 `unfold_locales'; see below.
   322 
   323 * Isar/locales: new methods `intro_locales' and `unfold_locales'
   324 provide backward reasoning on locales predicates.  The methods are
   325 aware of interpretations and discharge corresponding goals.
   326 `intro_locales' is less aggressive then `unfold_locales' and does not
   327 unfold predicates to assumptions.
   328 
   329 * Isar/locales: the order in which locale fragments are accumulated
   330 has changed.  This enables to override declarations from fragments due
   331 to interpretations -- for example, unwanted simp rules.
   332 
   333 * Provers/induct: improved internal context management to support
   334 local fixes and defines on-the-fly.  Thus explicit meta-level
   335 connectives !! and ==> are rarely required anymore in inductive goals
   336 (using object-logic connectives for this purpose has been long
   337 obsolete anyway).  The subsequent proof patterns illustrate advanced
   338 techniques of natural induction; general datatypes and inductive sets
   339 work analogously (see also src/HOL/Lambda for realistic examples).
   340 
   341 (1) This is how to ``strengthen'' an inductive goal wrt. certain
   342 parameters:
   343 
   344   lemma
   345     fixes n :: nat and x :: 'a
   346     assumes a: "A n x"
   347     shows "P n x"
   348     using a                     -- {* make induct insert fact a *}
   349   proof (induct n arbitrary: x) -- {* generalize goal to "!!x. A n x ==> P n x" *}
   350     case 0
   351     show ?case sorry
   352   next
   353     case (Suc n)
   354     note `!!x. A n x ==> P n x` -- {* induction hypothesis, according to induction rule *}
   355     note `A (Suc n) x`          -- {* induction premise, stemming from fact a *}
   356     show ?case sorry
   357   qed
   358 
   359 (2) This is how to perform induction over ``expressions of a certain
   360 form'', using a locally defined inductive parameter n == "a x"
   361 together with strengthening (the latter is usually required to get
   362 sufficiently flexible induction hypotheses):
   363 
   364   lemma
   365     fixes a :: "'a => nat"
   366     assumes a: "A (a x)"
   367     shows "P (a x)"
   368     using a
   369   proof (induct n == "a x" arbitrary: x)
   370     ...
   371 
   372 See also HOL/Isar_examples/Puzzle.thy for an application of the this
   373 particular technique.
   374 
   375 (3) This is how to perform existential reasoning ('obtains' or
   376 'obtain') by induction, while avoiding explicit object-logic
   377 encodings:
   378 
   379   lemma
   380     fixes n :: nat
   381     obtains x :: 'a where "P n x" and "Q n x"
   382   proof (induct n arbitrary: thesis)
   383     case 0
   384     obtain x where "P 0 x" and "Q 0 x" sorry
   385     then show thesis by (rule 0)
   386   next
   387     case (Suc n)
   388     obtain x where "P n x" and "Q n x" by (rule Suc.hyps)
   389     obtain x where "P (Suc n) x" and "Q (Suc n) x" sorry
   390     then show thesis by (rule Suc.prems)
   391   qed
   392 
   393 Here the 'arbitrary: thesis' specification essentially modifies the
   394 scope of the formal thesis parameter, in order to the get the whole
   395 existence statement through the induction as expected.
   396 
   397 * Provers/induct: mutual induction rules are now specified as a list
   398 of rule sharing the same induction cases.  HOL packages usually
   399 provide foo_bar.inducts for mutually defined items foo and bar
   400 (e.g. inductive sets or datatypes).  INCOMPATIBILITY, users need to
   401 specify mutual induction rules differently, i.e. like this:
   402 
   403   (induct rule: foo_bar.inducts)
   404   (induct set: foo bar)
   405   (induct type: foo bar)
   406 
   407 The ML function ProjectRule.projections turns old-style rules into the
   408 new format.
   409 
   410 * Provers/induct: improved handling of simultaneous goals.  Instead of
   411 introducing object-level conjunction, the statement is now split into
   412 several conclusions, while the corresponding symbolic cases are
   413 nested accordingly.  INCOMPATIBILITY, proofs need to be structured
   414 explicitly.  For example:
   415 
   416   lemma
   417     fixes n :: nat
   418     shows "P n" and "Q n"
   419   proof (induct n)
   420     case 0 case 1
   421     show "P 0" sorry
   422   next
   423     case 0 case 2
   424     show "Q 0" sorry
   425   next
   426     case (Suc n) case 1
   427     note `P n` and `Q n`
   428     show "P (Suc n)" sorry
   429   next
   430     case (Suc n) case 2
   431     note `P n` and `Q n`
   432     show "Q (Suc n)" sorry
   433   qed
   434 
   435 The split into subcases may be deferred as follows -- this is
   436 particularly relevant for goal statements with local premises.
   437 
   438   lemma
   439     fixes n :: nat
   440     shows "A n ==> P n" and "B n ==> Q n"
   441   proof (induct n)
   442     case 0
   443     {
   444       case 1
   445       note `A 0`
   446       show "P 0" sorry
   447     next
   448       case 2
   449       note `B 0`
   450       show "Q 0" sorry
   451     }
   452   next
   453     case (Suc n)
   454     note `A n ==> P n` and `B n ==> Q n`
   455     {
   456       case 1
   457       note `A (Suc n)`
   458       show "P (Suc n)" sorry
   459     next
   460       case 2
   461       note `B (Suc n)`
   462       show "Q (Suc n)" sorry
   463     }
   464   qed
   465 
   466 If simultaneous goals are to be used with mutual rules, the statement
   467 needs to be structured carefully as a two-level conjunction, using
   468 lists of propositions separated by 'and':
   469 
   470   lemma
   471     shows "a : A ==> P1 a"
   472           "a : A ==> P2 a"
   473       and "b : B ==> Q1 b"
   474           "b : B ==> Q2 b"
   475           "b : B ==> Q3 b"
   476   proof (induct set: A B)
   477 
   478 * Provers/induct: support coinduction as well.  See
   479 src/HOL/Library/Coinductive_List.thy for various examples.
   480 
   481 * Attribute "symmetric" produces result with standardized schematic
   482 variables (index 0).  Potential INCOMPATIBILITY.
   483 
   484 * Simplifier: by default the simplifier trace only shows top level
   485 rewrites now. That is, trace_simp_depth_limit is set to 1 by
   486 default. Thus there is less danger of being flooded by the trace. The
   487 trace indicates where parts have been suppressed.
   488   
   489 * Provers/classical: removed obsolete classical version of elim_format
   490 attribute; classical elim/dest rules are now treated uniformly when
   491 manipulating the claset.
   492 
   493 * Provers/classical: stricter checks to ensure that supplied intro,
   494 dest and elim rules are well-formed; dest and elim rules must have at
   495 least one premise.
   496 
   497 * Provers/classical: attributes dest/elim/intro take an optional
   498 weight argument for the rule (just as the Pure versions).  Weights are
   499 ignored by automated tools, but determine the search order of single
   500 rule steps.
   501 
   502 * Syntax: input syntax now supports dummy variable binding "%_. b",
   503 where the body does not mention the bound variable.  Note that dummy
   504 patterns implicitly depend on their context of bounds, which makes
   505 "{_. _}" match any set comprehension as expected.  Potential
   506 INCOMPATIBILITY -- parse translations need to cope with syntactic
   507 constant "_idtdummy" in the binding position.
   508 
   509 * Syntax: removed obsolete syntactic constant "_K" and its associated
   510 parse translation.  INCOMPATIBILITY -- use dummy abstraction instead,
   511 for example "A -> B" => "Pi A (%_. B)".
   512 
   513 * Pure: 'class_deps' command visualizes the subclass relation, using
   514 the graph browser tool.
   515 
   516 * Pure: 'print_theory' now suppresses entities with internal name
   517 (trailing "_") by default; use '!' option for full details.
   518 
   519 
   520 *** HOL ***
   521 
   522 * case expressions and primrec: missing cases now mapped to "undefined"
   523 instead of "arbitrary"
   524 
   525 * new constant "undefined" with axiom "undefined x = undefined"
   526 
   527 * new class "default" with associated constant "default"
   528 
   529 * Library/Pretty_Int.thy: maps HOL numerals on target language integer literals
   530     when generating code.
   531 
   532 * Library/Pretty_Char.thy: maps HOL characters on target language character literals
   533     when generating code.
   534 
   535 * Library/Commutative_Ring.thy: switched from recdef to function package;
   536     constants add, mul, pow now curried.  Infix syntax for algebraic operations.
   537 
   538 * Some steps towards more uniform lattice theory development in HOL.
   539 
   540     constants "meet" and "join" now named "inf" and "sup"
   541     constant "Meet" now named "Inf"
   542 
   543     classes "meet_semilorder" and "join_semilorder" now named
   544       "lower_semilattice" and "upper_semilattice"
   545     class "lorder" now named "lattice"
   546     class "comp_lat" now named "complete_lattice"
   547 
   548     Instantiation of lattice classes allows explicit definitions
   549     for "inf" and "sup" operations.
   550 
   551   INCOMPATIBILITY. Theorem renames:
   552 
   553     meet_left_le            ~> inf_le1
   554     meet_right_le           ~> inf_le2
   555     join_left_le            ~> sup_ge1
   556     join_right_le           ~> sup_ge2
   557     meet_join_le            ~> inf_sup_ord
   558     le_meetI                ~> le_infI
   559     join_leI                ~> le_supI
   560     le_meet                 ~> le_inf_iff
   561     le_join                 ~> ge_sup_conv
   562     meet_idempotent         ~> inf_idem
   563     join_idempotent         ~> sup_idem
   564     meet_comm               ~> inf_commute
   565     join_comm               ~> sup_commute
   566     meet_leI1               ~> le_infI1
   567     meet_leI2               ~> le_infI2
   568     le_joinI1               ~> le_supI1
   569     le_joinI2               ~> le_supI2
   570     meet_assoc              ~> inf_assoc
   571     join_assoc              ~> sup_assoc
   572     meet_left_comm          ~> inf_left_commute
   573     meet_left_idempotent    ~> inf_left_idem
   574     join_left_comm          ~> sup_left_commute
   575     join_left_idempotent    ~> sup_left_idem
   576     meet_aci                ~> inf_aci
   577     join_aci                ~> sup_aci
   578     le_def_meet             ~> le_iff_inf
   579     le_def_join             ~> le_iff_sup
   580     join_absorp2            ~> sup_absorb2
   581     join_absorp1            ~> sup_absorb1
   582     meet_absorp1            ~> inf_absorb1
   583     meet_absorp2            ~> inf_absorb2
   584     meet_join_absorp        ~> inf_sup_absorb
   585     join_meet_absorp        ~> sup_inf_absorb
   586     distrib_join_le         ~> distrib_sup_le
   587     distrib_meet_le         ~> distrib_inf_le
   588 
   589     add_meet_distrib_left   ~> add_inf_distrib_left
   590     add_join_distrib_left   ~> add_sup_distrib_left
   591     is_join_neg_meet        ~> is_join_neg_inf
   592     is_meet_neg_join        ~> is_meet_neg_sup
   593     add_meet_distrib_right  ~> add_inf_distrib_right
   594     add_join_distrib_right  ~> add_sup_distrib_right
   595     add_meet_join_distribs  ~> add_sup_inf_distribs
   596     join_eq_neg_meet        ~> sup_eq_neg_inf
   597     meet_eq_neg_join        ~> inf_eq_neg_sup
   598     add_eq_meet_join        ~> add_eq_inf_sup
   599     meet_0_imp_0            ~> inf_0_imp_0
   600     join_0_imp_0            ~> sup_0_imp_0
   601     meet_0_eq_0             ~> inf_0_eq_0
   602     join_0_eq_0             ~> sup_0_eq_0
   603     neg_meet_eq_join        ~> neg_inf_eq_sup
   604     neg_join_eq_meet        ~> neg_sup_eq_inf
   605     join_eq_if              ~> sup_eq_if
   606 
   607     mono_meet               ~> mono_inf
   608     mono_join               ~> mono_sup
   609     meet_bool_eq            ~> inf_bool_eq
   610     join_bool_eq            ~> sup_bool_eq
   611     meet_fun_eq             ~> inf_fun_eq
   612     join_fun_eq             ~> sup_fun_eq
   613     meet_set_eq             ~> inf_set_eq
   614     join_set_eq             ~> sup_set_eq
   615     meet1_iff               ~> inf1_iff
   616     meet2_iff               ~> inf2_iff
   617     meet1I                  ~> inf1I
   618     meet2I                  ~> inf2I
   619     meet1D1                 ~> inf1D1
   620     meet2D1                 ~> inf2D1
   621     meet1D2                 ~> inf1D2
   622     meet2D2                 ~> inf2D2
   623     meet1E                  ~> inf1E
   624     meet2E                  ~> inf2E
   625     join1_iff               ~> sup1_iff
   626     join2_iff               ~> sup2_iff
   627     join1I1                 ~> sup1I1
   628     join2I1                 ~> sup2I1
   629     join1I1                 ~> sup1I1
   630     join2I2                 ~> sup1I2
   631     join1CI                 ~> sup1CI
   632     join2CI                 ~> sup2CI
   633     join1E                  ~> sup1E
   634     join2E                  ~> sup2E
   635 
   636     is_meet_Meet            ~> is_meet_Inf
   637     Meet_bool_def           ~> Inf_bool_def
   638     Meet_fun_def            ~> Inf_fun_def
   639     Meet_greatest           ~> Inf_greatest
   640     Meet_lower              ~> Inf_lower
   641     Meet_set_def            ~> Inf_set_def
   642 
   643     listsp_meetI            ~> listsp_infI
   644     listsp_meet_eq          ~> listsp_inf_eq
   645 
   646     meet_min                ~> inf_min
   647     join_max                ~> sup_max
   648 
   649 * Classes "order" and "linorder": facts "refl", "trans" and
   650 "cases" renamed ro "order_refl", "order_trans" and "linorder_cases", to
   651 avoid clashes with HOL "refl" and "trans". INCOMPATIBILITY.
   652 
   653 * Classes "order" and "linorder": 
   654 potential INCOMPATIBILITY: order of proof goals in order/linorder instance
   655 proofs changed.
   656 
   657 * Dropped lemma duplicate def_imp_eq in favor of meta_eq_to_obj_eq.
   658 INCOMPATIBILITY.
   659 
   660 * Dropped lemma duplicate if_def2 in favor of if_bool_eq_conj.
   661 INCOMPATIBILITY.
   662 
   663 * Added syntactic class "size"; overloaded constant "size" now has
   664 type "'a::size ==> bool"
   665 
   666 * Renamed constants "Divides.op div", "Divides.op mod" and "Divides.op
   667 dvd" to "Divides.div", "Divides.mod" and "Divides.dvd". INCOMPATIBILITY.
   668 
   669 * Added method "lexicographic_order" automatically synthesizes
   670 termination relations as lexicographic combinations of size measures
   671 -- 'function' package.
   672 
   673 * HOL/records: generalised field-update to take a function on the
   674 field rather than the new value: r(|A := x|) is translated to A_update
   675 (K x) r The K-combinator that is internally used is called K_record.
   676 INCOMPATIBILITY: Usage of the plain update functions has to be
   677 adapted.
   678  
   679 * axclass "semiring_0" now contains annihilation axioms x * 0 = 0 and
   680 0 * x = 0, which are required for a semiring.  Richer structures do
   681 not inherit from semiring_0 anymore, because this property is a
   682 theorem there, not an axiom.  INCOMPATIBILITY: In instances of
   683 semiring_0, there is more to prove, but this is mostly trivial.
   684 
   685 * axclass "recpower" was generalized to arbitrary monoids, not just
   686 commutative semirings.  INCOMPATIBILITY: If you use recpower and need
   687 commutativity or a semiring property, add the corresponding classes.
   688 
   689 * Unified locale partial_order with class definition (cf. theory
   690 Orderings), added parameter ``less''.  INCOMPATIBILITY.
   691 
   692 * Constant "List.list_all2" in List.thy now uses authentic syntax.
   693 INCOMPATIBILITY: translations containing list_all2 may go wrong.  On
   694 Isar level, use abbreviations instead.
   695 
   696 * Renamed constant "List.op mem" to "List.memberl" INCOMPATIBILITY:
   697 rarely occuring name references (e.g. ``List.op mem.simps'') require
   698 renaming (e.g. ``List.memberl.simps'').
   699 
   700 * Renamed constants "0" to "HOL.zero" and "1" to "HOL.one".
   701 INCOMPATIBILITY.
   702 
   703 * Added theory Code_Generator providing class 'eq', allowing for code
   704 generation with polymorphic equality.
   705 
   706 * Numeral syntax: type 'bin' which was a mere type copy of 'int' has
   707 been abandoned in favour of plain 'int'. INCOMPATIBILITY --
   708 significant changes for setting up numeral syntax for types:
   709 
   710   - new constants Numeral.pred and Numeral.succ instead
   711       of former Numeral.bin_pred and Numeral.bin_succ.
   712   - Use integer operations instead of bin_add, bin_mult and so on.
   713   - Numeral simplification theorems named Numeral.numeral_simps instead of Bin_simps.
   714   - ML structure Bin_Simprocs now named Int_Numeral_Base_Simprocs.
   715 
   716 See HOL/Integ/IntArith.thy for an example setup.
   717 
   718 * New top level command 'normal_form' computes the normal form of a
   719 term that may contain free variables. For example ``normal_form
   720 "rev[a,b,c]"'' produces ``[b,c,a]'' (without proof).  This command is
   721 suitable for heavy-duty computations because the functions are
   722 compiled to ML first.
   723 
   724 * Alternative iff syntax "A <-> B" for equality on bool (with priority
   725 25 like -->); output depends on the "iff" print_mode, the default is
   726 "A = B" (with priority 50).
   727 
   728 * Renamed constants in HOL.thy and Orderings.thy:
   729     op +   ~> HOL.plus
   730     op -   ~> HOL.minus
   731     uminus ~> HOL.uminus
   732     op *   ~> HOL.times
   733     op <   ~> Orderings.less
   734     op <=  ~> Orderings.less_eq
   735 
   736 Adaptions may be required in the following cases:
   737 
   738 a) User-defined constants using any of the names "plus", "minus", "times",
   739 "less" or "less_eq". The standard syntax translations for "+", "-" and "*"
   740 may go wrong.
   741 INCOMPATIBILITY: use more specific names.
   742 
   743 b) Variables named "plus", "minus", "times", "less", "less_eq"
   744 INCOMPATIBILITY: use more specific names.
   745 
   746 c) Permutative equations (e.g. "a + b = b + a")
   747 Since the change of names also changes the order of terms, permutative
   748 rewrite rules may get applied in a different order. Experience shows that
   749 this is rarely the case (only two adaptions in the whole Isabelle
   750 distribution).
   751 INCOMPATIBILITY: rewrite proofs
   752 
   753 d) ML code directly refering to constant names
   754 This in general only affects hand-written proof tactics, simprocs and so on.
   755 INCOMPATIBILITY: grep your sourcecode and replace names.
   756 
   757 * Relations less (<) and less_eq (<=) are also available on type bool.
   758 Modified syntax to disallow nesting without explicit parentheses,
   759 e.g. "(x < y) < z" or "x < (y < z)", but NOT "x < y < z".
   760 
   761 * "LEAST x:A. P" expands to "LEAST x. x:A & P" (input only).
   762 
   763 * Relation composition operator "op O" now has precedence 75 and binds
   764 stronger than union and intersection. INCOMPATIBILITY.
   765 
   766 * The old set interval syntax "{m..n(}" (and relatives) has been
   767 removed.  Use "{m..<n}" (and relatives) instead.
   768 
   769 * In the context of the assumption "~(s = t)" the Simplifier rewrites
   770 "t = s" to False (by simproc "neq_simproc").  For backward
   771 compatibility this can be disabled by ML "reset use_neq_simproc".
   772 
   773 * "m dvd n" where m and n are numbers is evaluated to True/False by
   774 simp.
   775 
   776 * Theorem Cons_eq_map_conv no longer declared as ``simp''.
   777 
   778 * Theorem setsum_mult renamed to setsum_right_distrib.
   779 
   780 * Prefer ex1I over ex_ex1I in single-step reasoning, e.g. by the
   781 ``rule'' method.
   782 
   783 * Reimplemented methods ``sat'' and ``satx'', with several
   784 improvements: goals no longer need to be stated as "<prems> ==>
   785 False", equivalences (i.e. "=" on type bool) are handled, variable
   786 names of the form "lit_<n>" are no longer reserved, significant
   787 speedup.
   788 
   789 * Methods ``sat'' and ``satx'' can now replay MiniSat proof traces.
   790 zChaff is still supported as well.
   791 
   792 * 'inductive' and 'datatype': provide projections of mutual rules,
   793 bundled as foo_bar.inducts;
   794 
   795 * Library: moved theories Parity, GCD, Binomial, Infinite_Set to
   796 Library.
   797 
   798 * Library: moved theory Accessible_Part to main HOL.
   799 
   800 * Library: added theory Coinductive_List of potentially infinite lists
   801 as greatest fixed-point.
   802 
   803 * Library: added theory AssocList which implements (finite) maps as
   804 association lists.
   805 
   806 * Added proof method ``evaluation'' for efficiently solving a goal
   807 (i.e. a boolean expression) by compiling it to ML. The goal is
   808 "proved" (via an oracle) if it evaluates to True.
   809 
   810 * Linear arithmetic now splits certain operators (e.g. min, max, abs)
   811 also when invoked by the simplifier.  This results in the simplifier
   812 being more powerful on arithmetic goals.  INCOMPATIBILITY.  Set
   813 fast_arith_split_limit to 0 to obtain the old behavior.
   814 
   815 * Support for hex (0x20) and binary (0b1001) numerals.
   816 
   817 * New method: reify eqs (t), where eqs are equations for an
   818 interpretation I :: 'a list => 'b => 'c and t::'c is an optional
   819 parameter, computes a term s::'b and a list xs::'a list and proves the
   820 theorem I xs s = t. This is also known as reification or quoting. The
   821 resulting theorem is applied to the subgoal to substitute t with I xs
   822 s.  If t is omitted, the subgoal itself is reified.
   823 
   824 * New method: reflection corr_thm eqs (t). The parameters eqs and (t)
   825 are as explained above. corr_thm is a theorem for I vs (f t) = I vs t,
   826 where f is supposed to be a computable function (in the sense of code
   827 generattion). The method uses reify to compute s and xs as above then
   828 applies corr_thm and uses normalization by evaluation to "prove" f s =
   829 r and finally gets the theorem t = r, which is again applied to the
   830 subgoal. An Example is available in HOL/ex/ReflectionEx.thy.
   831 
   832 * Reflection: Automatic refification now handels binding, an example
   833 is available in HOL/ex/ReflectionEx.thy
   834 
   835 
   836 *** HOL-Algebra ***
   837 
   838 * Formalisation of ideals and the quotient construction over rings.
   839 
   840 * Order and lattice theory no longer based on records.
   841 INCOMPATIBILITY.
   842 
   843 * Renamed lemmas least_carrier -> least_closed and greatest_carrier ->
   844 greatest_closed.  INCOMPATIBILITY.
   845 
   846 * Method algebra is now set up via an attribute.  For examples see
   847 Ring.thy.  INCOMPATIBILITY: the method is now weaker on combinations
   848 of algebraic structures.
   849 
   850 * Renamed theory CRing to Ring.
   851 
   852 
   853 *** HOL-Complex ***
   854 
   855 * Theory Real: new method ferrack implements quantifier elimination
   856 for linear arithmetic over the reals. The quantifier elimination
   857 feature is used only for decision, for compatibility with arith. This
   858 means a goal is either solved or left unchanged, no simplification.
   859 
   860 * Real: New axiomatic classes formalize real normed vector spaces and
   861 algebras, using new overloaded constants scaleR :: real => 'a => 'a
   862 and norm :: 'a => real.
   863 
   864 * Real: New constant of_real :: real => 'a::real_algebra_1 injects
   865 from reals into other types. The overloaded constant Reals :: 'a set
   866 is now defined as range of_real; potential INCOMPATIBILITY.
   867 
   868 * Hyperreal: Several constants that previously worked only for the
   869 reals have been generalized, so they now work over arbitrary vector
   870 spaces. Type annotations may need to be added in some cases; potential
   871 INCOMPATIBILITY.
   872 
   873   Infinitesimal  :: ('a::real_normed_vector) star set"
   874   HFinite        :: ('a::real_normed_vector) star set"
   875   HInfinite      :: ('a::real_normed_vector) star set"
   876   approx         :: ('a::real_normed_vector) star => 'a star => bool
   877   monad          :: ('a::real_normed_vector) star => 'a star set
   878   galaxy         :: ('a::real_normed_vector) star => 'a star set
   879   (NS)LIMSEQ     :: [nat, 'a::real_normed_vector, 'a] => bool
   880   (NS)convergent :: (nat => 'a::real_normed_vector) => bool
   881   (NS)Bseq       :: (nat => 'a::real_normed_vector) => bool
   882   (NS)Cauchy     :: (nat => 'a::real_normed_vector) => bool
   883   (NS)LIM        :: ['a::real_normed_vector => 'b::real_normed_vector, 'a, 'b] => bool
   884   is(NS)Cont     :: ['a::real_normed_vector => 'b::real_normed_vector, 'a] => bool
   885   deriv          :: ['a::real_normed_field => 'a, 'a, 'a] => bool
   886 
   887 * Complex: Some complex-specific constants are now abbreviations for
   888 overloaded ones: complex_of_real = of_real, cmod = norm, hcmod =
   889 hnorm.  Other constants have been entirely removed in favor of the
   890 polymorphic versions (INCOMPATIBILITY):
   891 
   892   approx        <-- capprox
   893   HFinite       <-- CFinite
   894   HInfinite     <-- CInfinite
   895   Infinitesimal <-- CInfinitesimal
   896   monad         <-- cmonad
   897   galaxy        <-- cgalaxy
   898   (NS)LIM       <-- (NS)CLIM, (NS)CRLIM
   899   is(NS)Cont    <-- is(NS)Contc, is(NS)contCR
   900   (ns)deriv     <-- (ns)cderiv
   901 
   902 
   903 *** ML ***
   904 
   905 * Context data interfaces (Theory/Proof/GenericDataFun): removed
   906 name/print, use adhoc value for uninitialized data, init only required
   907 for impure data.
   908 
   909 * ML within Isar: antiquotations allow to embed statically-checked
   910 formal entities in the source, referring to the context available at
   911 compile-time.  For example:
   912 
   913 ML {* @{typ "'a => 'b"} *}
   914 ML {* @{term "%x. x"} *}
   915 ML {* @{prop "x == y"} *}
   916 ML {* @{ctyp "'a => 'b"} *}
   917 ML {* @{cterm "%x. x"} *}
   918 ML {* @{cprop "x == y"} *}
   919 ML {* @{thm asm_rl} *}
   920 ML {* @{thms asm_rl} *}
   921 ML {* @{const_name c} *}
   922 ML {* @{const_syntax c} *}
   923 ML {* @{context} *}
   924 ML {* @{theory} *}
   925 ML {* @{theory Pure} *}
   926 ML {* @{simpset} *}
   927 ML {* @{claset} *}
   928 ML {* @{clasimpset} *}
   929 
   930 The same works for sources being ``used'' within an Isar context.
   931 
   932 * ML in Isar: improved error reporting; extra verbosity with
   933 Toplevel.debug enabled.
   934 
   935 * Pure/library:
   936 
   937   val burrow: ('a list -> 'b list) -> 'a list list -> 'b list list
   938   val fold_burrow: ('a list -> 'c -> 'b list * 'd) -> 'a list list -> 'c -> 'b list list * 'd
   939 
   940 The semantics of "burrow" is: "take a function with *simulatanously*
   941 transforms a list of value, and apply it *simulatanously* to a list of
   942 list of values of the appropriate type". Compare this with "map" which
   943 would *not* apply its argument function simulatanously but in
   944 sequence; "fold_burrow" has an additional context.
   945 
   946 * Pure/library: functions map2 and fold2 with curried syntax for
   947 simultanous mapping and folding:
   948 
   949     val map2: ('a -> 'b -> 'c) -> 'a list -> 'b list -> 'c list
   950     val fold2: ('a -> 'b -> 'c -> 'c) -> 'a list -> 'b list -> 'c -> 'c
   951 
   952 * Pure/library: indexed lists - some functions in the Isabelle library
   953 treating lists over 'a as finite mappings from [0...n] to 'a have been
   954 given more convenient names and signatures reminiscent of similar
   955 functions for alists, tables, etc:
   956 
   957   val nth: 'a list -> int -> 'a 
   958   val nth_map: int -> ('a -> 'a) -> 'a list -> 'a list
   959   val fold_index: (int * 'a -> 'b -> 'b) -> 'a list -> 'b -> 'b
   960 
   961 Note that fold_index starts counting at index 0, not 1 like foldln
   962 used to.
   963 
   964 * Pure/library: added general ``divide_and_conquer'' combinator on
   965 lists.
   966 
   967 * Pure/General/table.ML: the join operations now works via exceptions
   968 DUP/SAME instead of type option.  This is simpler in simple cases, and
   969 admits slightly more efficient complex applications.
   970 
   971 * Pure: datatype Context.generic joins theory/Proof.context and
   972 provides some facilities for code that works in either kind of
   973 context, notably GenericDataFun for uniform theory and proof data.
   974 
   975 * Pure: 'advanced' translation functions (parse_translation etc.) now
   976 use Context.generic instead of just theory.
   977 
   978 * Pure: simplified internal attribute type, which is now always
   979 Context.generic * thm -> Context.generic * thm.  Global (theory)
   980 vs. local (Proof.context) attributes have been discontinued, while
   981 minimizing code duplication.  Thm.rule_attribute and
   982 Thm.declaration_attribute build canonical attributes; see also
   983 structure Context for further operations on Context.generic, notably
   984 GenericDataFun.  INCOMPATIBILITY, need to adapt attribute type
   985 declarations and definitions.
   986 
   987 * Pure/kernel: consts certification ignores sort constraints given in
   988 signature declarations.  (This information is not relevant to the
   989 logic, but only for type inference.)  IMPORTANT INTERNAL CHANGE,
   990 potential INCOMPATIBILITY.
   991 
   992 * Pure: axiomatic type classes are now purely definitional, with
   993 explicit proofs of class axioms and super class relations performed
   994 internally.  See Pure/axclass.ML for the main internal interfaces --
   995 notably AxClass.define_class supercedes AxClass.add_axclass, and
   996 AxClass.axiomatize_class/classrel/arity supercede
   997 Sign.add_classes/classrel/arities.
   998 
   999 * Pure/Isar: Args/Attrib parsers operate on Context.generic --
  1000 global/local versions on theory vs. Proof.context have been
  1001 discontinued; Attrib.syntax and Method.syntax have been adapted
  1002 accordingly.  INCOMPATIBILITY, need to adapt parser expressions for
  1003 attributes, methods, etc.
  1004 
  1005 * Pure: several functions of signature "... -> theory -> theory * ..."
  1006 have been reoriented to "... -> theory -> ... * theory" in order to
  1007 allow natural usage in combination with the ||>, ||>>, |-> and
  1008 fold_map combinators.
  1009 
  1010 * Pure: official theorem names (closed derivations) and additional
  1011 comments (tags) are now strictly separate.  Name hints -- which are
  1012 maintained as tags -- may be attached any time without affecting the
  1013 derivation.
  1014 
  1015 * Pure: primitive rule lift_rule now takes goal cterm instead of an
  1016 actual goal state (thm).  Use Thm.lift_rule (Thm.cprem_of st i) to
  1017 achieve the old behaviour.
  1018 
  1019 * Pure: the "Goal" constant is now called "prop", supporting a
  1020 slightly more general idea of ``protecting'' meta-level rule
  1021 statements.
  1022 
  1023 * Pure: Logic.(un)varify only works in a global context, which is now
  1024 enforced instead of silently assumed.  INCOMPATIBILITY, may use
  1025 Logic.legacy_(un)varify as temporary workaround.
  1026 
  1027 * Pure: structure Name provides scalable operations for generating
  1028 internal variable names, notably Name.variants etc.  This replaces
  1029 some popular functions from term.ML:
  1030 
  1031   Term.variant		->  Name.variant
  1032   Term.variantlist	->  Name.variant_list  (*canonical argument order*)
  1033   Term.invent_names	->  Name.invent_list
  1034 
  1035 Note that low-level renaming rarely occurs in new code -- operations
  1036 from structure Variable are used instead (see below).
  1037 
  1038 * Pure: structure Variable provides fundamental operations for proper
  1039 treatment of fixed/schematic variables in a context.  For example,
  1040 Variable.import introduces fixes for schematics of given facts and
  1041 Variable.export reverses the effect (up to renaming) -- this replaces
  1042 various freeze_thaw operations.
  1043 
  1044 * Pure: structure Goal provides simple interfaces for
  1045 init/conclude/finish and tactical prove operations (replacing former
  1046 Tactic.prove).  Goal.prove is the canonical way to prove results
  1047 within a given context; Goal.prove_global is a degraded version for
  1048 theory level goals, including a global Drule.standard.  Note that
  1049 OldGoals.prove_goalw_cterm has long been obsolete, since it is
  1050 ill-behaved in a local proof context (e.g. with local fixes/assumes or
  1051 in a locale context).
  1052 
  1053 * Isar: simplified treatment of user-level errors, using exception
  1054 ERROR of string uniformly.  Function error now merely raises ERROR,
  1055 without any side effect on output channels.  The Isar toplevel takes
  1056 care of proper display of ERROR exceptions.  ML code may use plain
  1057 handle/can/try; cat_error may be used to concatenate errors like this:
  1058 
  1059   ... handle ERROR msg => cat_error msg "..."
  1060 
  1061 Toplevel ML code (run directly or through the Isar toplevel) may be
  1062 embedded into the Isar toplevel with exception display/debug like
  1063 this:
  1064 
  1065   Isar.toplevel (fn () => ...)
  1066 
  1067 INCOMPATIBILITY, removed special transform_error facilities, removed
  1068 obsolete variants of user-level exceptions (ERROR_MESSAGE,
  1069 Context.PROOF, ProofContext.CONTEXT, Proof.STATE, ProofHistory.FAIL)
  1070 -- use plain ERROR instead.
  1071 
  1072 * Isar: theory setup now has type (theory -> theory), instead of a
  1073 list.  INCOMPATIBILITY, may use #> to compose setup functions.
  1074 
  1075 * Isar: installed ML toplevel pretty printer for type Proof.context,
  1076 subject to ProofContext.debug/verbose flags.
  1077 
  1078 * Isar: Toplevel.theory_to_proof admits transactions that modify the
  1079 theory before entering a proof state.  Transactions now always see a
  1080 quasi-functional intermediate checkpoint, both in interactive and
  1081 batch mode.
  1082 
  1083 * Simplifier: the simpset of a running simplification process now
  1084 contains a proof context (cf. Simplifier.the_context), which is the
  1085 very context that the initial simpset has been retrieved from (by
  1086 simpset_of/local_simpset_of).  Consequently, all plug-in components
  1087 (solver, looper etc.) may depend on arbitrary proof data.
  1088 
  1089 * Simplifier.inherit_context inherits the proof context (plus the
  1090 local bounds) of the current simplification process; any simproc
  1091 etc. that calls the Simplifier recursively should do this!  Removed
  1092 former Simplifier.inherit_bounds, which is already included here --
  1093 INCOMPATIBILITY.  Tools based on low-level rewriting may even have to
  1094 specify an explicit context using Simplifier.context/theory_context.
  1095 
  1096 * Simplifier/Classical Reasoner: more abstract interfaces
  1097 change_simpset/claset for modifying the simpset/claset reference of a
  1098 theory; raw versions simpset/claset_ref etc. have been discontinued --
  1099 INCOMPATIBILITY.
  1100 
  1101 * Provers: more generic wrt. syntax of object-logics, avoid hardwired
  1102 "Trueprop" etc.
  1103 
  1104 
  1105 *** System ***
  1106 
  1107 * settings: ML_IDENTIFIER -- which is appended to user specific heap
  1108 locations -- now includes the Isabelle version identifier as well.
  1109 This simplifies use of multiple Isabelle installations.
  1110 
  1111 * isabelle-process: option -S (secure mode) disables some critical
  1112 operations, notably runtime compilation and evaluation of ML source
  1113 code.
  1114 
  1115 
  1116 New in Isabelle2005 (October 2005)
  1117 ----------------------------------
  1118 
  1119 *** General ***
  1120 
  1121 * Theory headers: the new header syntax for Isar theories is
  1122 
  1123   theory <name>
  1124   imports <theory1> ... <theoryN>
  1125   uses <file1> ... <fileM>
  1126   begin
  1127 
  1128 where the 'uses' part is optional.  The previous syntax
  1129 
  1130   theory <name> = <theory1> + ... + <theoryN>:
  1131 
  1132 will disappear in the next release.  Use isatool fixheaders to convert
  1133 existing theory files.  Note that there is no change in ancient
  1134 non-Isar theories now, but these will disappear soon.
  1135 
  1136 * Theory loader: parent theories can now also be referred to via
  1137 relative and absolute paths.
  1138 
  1139 * Command 'find_theorems' searches for a list of criteria instead of a
  1140 list of constants. Known criteria are: intro, elim, dest, name:string,
  1141 simp:term, and any term. Criteria can be preceded by '-' to select
  1142 theorems that do not match. Intro, elim, dest select theorems that
  1143 match the current goal, name:s selects theorems whose fully qualified
  1144 name contain s, and simp:term selects all simplification rules whose
  1145 lhs match term.  Any other term is interpreted as pattern and selects
  1146 all theorems matching the pattern. Available in ProofGeneral under
  1147 'ProofGeneral -> Find Theorems' or C-c C-f.  Example:
  1148 
  1149   C-c C-f (100) "(_::nat) + _ + _" intro -name: "HOL."
  1150 
  1151 prints the last 100 theorems matching the pattern "(_::nat) + _ + _",
  1152 matching the current goal as introduction rule and not having "HOL."
  1153 in their name (i.e. not being defined in theory HOL).
  1154 
  1155 * Command 'thms_containing' has been discontinued in favour of
  1156 'find_theorems'; INCOMPATIBILITY.
  1157 
  1158 * Communication with Proof General is now 8bit clean, which means that
  1159 Unicode text in UTF-8 encoding may be used within theory texts (both
  1160 formal and informal parts).  Cf. option -U of the Isabelle Proof
  1161 General interface.  Here are some simple examples (cf. src/HOL/ex):
  1162 
  1163   http://isabelle.in.tum.de/library/HOL/ex/Hebrew.html
  1164   http://isabelle.in.tum.de/library/HOL/ex/Chinese.html
  1165 
  1166 * Improved efficiency of the Simplifier and, to a lesser degree, the
  1167 Classical Reasoner.  Typical big applications run around 2 times
  1168 faster.
  1169 
  1170 
  1171 *** Document preparation ***
  1172 
  1173 * Commands 'display_drafts' and 'print_drafts' perform simple output
  1174 of raw sources.  Only those symbols that do not require additional
  1175 LaTeX packages (depending on comments in isabellesym.sty) are
  1176 displayed properly, everything else is left verbatim.  isatool display
  1177 and isatool print are used as front ends (these are subject to the
  1178 DVI/PDF_VIEWER and PRINT_COMMAND settings, respectively).
  1179 
  1180 * Command tags control specific markup of certain regions of text,
  1181 notably folding and hiding.  Predefined tags include "theory" (for
  1182 theory begin and end), "proof" for proof commands, and "ML" for
  1183 commands involving ML code; the additional tags "visible" and
  1184 "invisible" are unused by default.  Users may give explicit tag
  1185 specifications in the text, e.g. ''by %invisible (auto)''.  The
  1186 interpretation of tags is determined by the LaTeX job during document
  1187 preparation: see option -V of isatool usedir, or options -n and -t of
  1188 isatool document, or even the LaTeX macros \isakeeptag, \isafoldtag,
  1189 \isadroptag.
  1190 
  1191 Several document versions may be produced at the same time via isatool
  1192 usedir (the generated index.html will link all of them).  Typical
  1193 specifications include ''-V document=theory,proof,ML'' to present
  1194 theory/proof/ML parts faithfully, ''-V outline=/proof,/ML'' to fold
  1195 proof and ML commands, and ''-V mutilated=-theory,-proof,-ML'' to omit
  1196 these parts without any formal replacement text.  The Isabelle site
  1197 default settings produce ''document'' and ''outline'' versions as
  1198 specified above.
  1199 
  1200 * Several new antiquotations:
  1201 
  1202   @{term_type term} prints a term with its type annotated;
  1203 
  1204   @{typeof term} prints the type of a term;
  1205 
  1206   @{const const} is the same as @{term const}, but checks that the
  1207   argument is a known logical constant;
  1208 
  1209   @{term_style style term} and @{thm_style style thm} print a term or
  1210   theorem applying a "style" to it
  1211 
  1212   @{ML text}
  1213 
  1214 Predefined styles are 'lhs' and 'rhs' printing the lhs/rhs of
  1215 definitions, equations, inequations etc., 'concl' printing only the
  1216 conclusion of a meta-logical statement theorem, and 'prem1' .. 'prem19'
  1217 to print the specified premise.  TermStyle.add_style provides an ML
  1218 interface for introducing further styles.  See also the "LaTeX Sugar"
  1219 document practical applications.  The ML antiquotation prints
  1220 type-checked ML expressions verbatim.
  1221 
  1222 * Markup commands 'chapter', 'section', 'subsection', 'subsubsection',
  1223 and 'text' support optional locale specification '(in loc)', which
  1224 specifies the default context for interpreting antiquotations.  For
  1225 example: 'text (in lattice) {* @{thm inf_assoc}*}'.
  1226 
  1227 * Option 'locale=NAME' of antiquotations specifies an alternative
  1228 context interpreting the subsequent argument.  For example: @{thm
  1229 [locale=lattice] inf_assoc}.
  1230 
  1231 * Proper output of proof terms (@{prf ...} and @{full_prf ...}) within
  1232 a proof context.
  1233 
  1234 * Proper output of antiquotations for theory commands involving a
  1235 proof context (such as 'locale' or 'theorem (in loc) ...').
  1236 
  1237 * Delimiters of outer tokens (string etc.) now produce separate LaTeX
  1238 macros (\isachardoublequoteopen, isachardoublequoteclose etc.).
  1239 
  1240 * isatool usedir: new option -C (default true) controls whether option
  1241 -D should include a copy of the original document directory; -C false
  1242 prevents unwanted effects such as copying of administrative CVS data.
  1243 
  1244 
  1245 *** Pure ***
  1246 
  1247 * Considerably improved version of 'constdefs' command.  Now performs
  1248 automatic type-inference of declared constants; additional support for
  1249 local structure declarations (cf. locales and HOL records), see also
  1250 isar-ref manual.  Potential INCOMPATIBILITY: need to observe strictly
  1251 sequential dependencies of definitions within a single 'constdefs'
  1252 section; moreover, the declared name needs to be an identifier.  If
  1253 all fails, consider to fall back on 'consts' and 'defs' separately.
  1254 
  1255 * Improved indexed syntax and implicit structures.  First of all,
  1256 indexed syntax provides a notational device for subscripted
  1257 application, using the new syntax \<^bsub>term\<^esub> for arbitrary
  1258 expressions.  Secondly, in a local context with structure
  1259 declarations, number indexes \<^sub>n or the empty index (default
  1260 number 1) refer to a certain fixed variable implicitly; option
  1261 show_structs controls printing of implicit structures.  Typical
  1262 applications of these concepts involve record types and locales.
  1263 
  1264 * New command 'no_syntax' removes grammar declarations (and
  1265 translations) resulting from the given syntax specification, which is
  1266 interpreted in the same manner as for the 'syntax' command.
  1267 
  1268 * 'Advanced' translation functions (parse_translation etc.) may depend
  1269 on the signature of the theory context being presently used for
  1270 parsing/printing, see also isar-ref manual.
  1271 
  1272 * Improved 'oracle' command provides a type-safe interface to turn an
  1273 ML expression of type theory -> T -> term into a primitive rule of
  1274 type theory -> T -> thm (i.e. the functionality of Thm.invoke_oracle
  1275 is already included here); see also FOL/ex/IffExample.thy;
  1276 INCOMPATIBILITY.
  1277 
  1278 * axclass: name space prefix for class "c" is now "c_class" (was "c"
  1279 before); "cI" is no longer bound, use "c.intro" instead.
  1280 INCOMPATIBILITY.  This change avoids clashes of fact bindings for
  1281 axclasses vs. locales.
  1282 
  1283 * Improved internal renaming of symbolic identifiers -- attach primes
  1284 instead of base 26 numbers.
  1285 
  1286 * New flag show_question_marks controls printing of leading question
  1287 marks in schematic variable names.
  1288 
  1289 * In schematic variable names, *any* symbol following \<^isub> or
  1290 \<^isup> is now treated as part of the base name.  For example, the
  1291 following works without printing of awkward ".0" indexes:
  1292 
  1293   lemma "x\<^isub>1 = x\<^isub>2 ==> x\<^isub>2 = x\<^isub>1"
  1294     by simp
  1295 
  1296 * Inner syntax includes (*(*nested*) comments*).
  1297 
  1298 * Pretty printer now supports unbreakable blocks, specified in mixfix
  1299 annotations as "(00...)".
  1300 
  1301 * Clear separation of logical types and nonterminals, where the latter
  1302 may only occur in 'syntax' specifications or type abbreviations.
  1303 Before that distinction was only partially implemented via type class
  1304 "logic" vs. "{}".  Potential INCOMPATIBILITY in rare cases of improper
  1305 use of 'types'/'consts' instead of 'nonterminals'/'syntax'.  Some very
  1306 exotic syntax specifications may require further adaption
  1307 (e.g. Cube/Cube.thy).
  1308 
  1309 * Removed obsolete type class "logic", use the top sort {} instead.
  1310 Note that non-logical types should be declared as 'nonterminals'
  1311 rather than 'types'.  INCOMPATIBILITY for new object-logic
  1312 specifications.
  1313 
  1314 * Attributes 'induct' and 'cases': type or set names may now be
  1315 locally fixed variables as well.
  1316 
  1317 * Simplifier: can now control the depth to which conditional rewriting
  1318 is traced via the PG menu Isabelle -> Settings -> Trace Simp Depth
  1319 Limit.
  1320 
  1321 * Simplifier: simplification procedures may now take the current
  1322 simpset into account (cf. Simplifier.simproc(_i) / mk_simproc
  1323 interface), which is very useful for calling the Simplifier
  1324 recursively.  Minor INCOMPATIBILITY: the 'prems' argument of simprocs
  1325 is gone -- use prems_of_ss on the simpset instead.  Moreover, the
  1326 low-level mk_simproc no longer applies Logic.varify internally, to
  1327 allow for use in a context of fixed variables.
  1328 
  1329 * thin_tac now works even if the assumption being deleted contains !!
  1330 or ==>.  More generally, erule now works even if the major premise of
  1331 the elimination rule contains !! or ==>.
  1332 
  1333 * Method 'rules' has been renamed to 'iprover'. INCOMPATIBILITY.
  1334 
  1335 * Reorganized bootstrapping of the Pure theories; CPure is now derived
  1336 from Pure, which contains all common declarations already.  Both
  1337 theories are defined via plain Isabelle/Isar .thy files.
  1338 INCOMPATIBILITY: elements of CPure (such as the CPure.intro /
  1339 CPure.elim / CPure.dest attributes) now appear in the Pure name space;
  1340 use isatool fixcpure to adapt your theory and ML sources.
  1341 
  1342 * New syntax 'name(i-j, i-, i, ...)' for referring to specific
  1343 selections of theorems in named facts via index ranges.
  1344 
  1345 * 'print_theorems': in theory mode, really print the difference
  1346 wrt. the last state (works for interactive theory development only),
  1347 in proof mode print all local facts (cf. 'print_facts');
  1348 
  1349 * 'hide': option '(open)' hides only base names.
  1350 
  1351 * More efficient treatment of intermediate checkpoints in interactive
  1352 theory development.
  1353 
  1354 * Code generator is now invoked via code_module (incremental code
  1355 generation) and code_library (modular code generation, ML structures
  1356 for each theory).  INCOMPATIBILITY: new keywords 'file' and 'contains'
  1357 must be quoted when used as identifiers.
  1358 
  1359 * New 'value' command for reading, evaluating and printing terms using
  1360 the code generator.  INCOMPATIBILITY: command keyword 'value' must be
  1361 quoted when used as identifier.
  1362 
  1363 
  1364 *** Locales ***
  1365 
  1366 * New commands for the interpretation of locale expressions in
  1367 theories (1), locales (2) and proof contexts (3).  These generate
  1368 proof obligations from the expression specification.  After the
  1369 obligations have been discharged, theorems of the expression are added
  1370 to the theory, target locale or proof context.  The synopsis of the
  1371 commands is a follows:
  1372 
  1373   (1) interpretation expr inst
  1374   (2) interpretation target < expr
  1375   (3) interpret expr inst
  1376 
  1377 Interpretation in theories and proof contexts require a parameter
  1378 instantiation of terms from the current context.  This is applied to
  1379 specifications and theorems of the interpreted expression.
  1380 Interpretation in locales only permits parameter renaming through the
  1381 locale expression.  Interpretation is smart in that interpretations
  1382 that are active already do not occur in proof obligations, neither are
  1383 instantiated theorems stored in duplicate.  Use 'print_interps' to
  1384 inspect active interpretations of a particular locale.  For details,
  1385 see the Isar Reference manual.  Examples can be found in
  1386 HOL/Finite_Set.thy and HOL/Algebra/UnivPoly.thy.
  1387 
  1388 INCOMPATIBILITY: former 'instantiate' has been withdrawn, use
  1389 'interpret' instead.
  1390 
  1391 * New context element 'constrains' for adding type constraints to
  1392 parameters.
  1393 
  1394 * Context expressions: renaming of parameters with syntax
  1395 redeclaration.
  1396 
  1397 * Locale declaration: 'includes' disallowed.
  1398 
  1399 * Proper static binding of attribute syntax -- i.e. types / terms /
  1400 facts mentioned as arguments are always those of the locale definition
  1401 context, independently of the context of later invocations.  Moreover,
  1402 locale operations (renaming and type / term instantiation) are applied
  1403 to attribute arguments as expected.
  1404 
  1405 INCOMPATIBILITY of the ML interface: always pass Attrib.src instead of
  1406 actual attributes; rare situations may require Attrib.attribute to
  1407 embed those attributes into Attrib.src that lack concrete syntax.
  1408 Attribute implementations need to cooperate properly with the static
  1409 binding mechanism.  Basic parsers Args.XXX_typ/term/prop and
  1410 Attrib.XXX_thm etc. already do the right thing without further
  1411 intervention.  Only unusual applications -- such as "where" or "of"
  1412 (cf. src/Pure/Isar/attrib.ML), which process arguments depending both
  1413 on the context and the facts involved -- may have to assign parsed
  1414 values to argument tokens explicitly.
  1415 
  1416 * Changed parameter management in theorem generation for long goal
  1417 statements with 'includes'.  INCOMPATIBILITY: produces a different
  1418 theorem statement in rare situations.
  1419 
  1420 * Locale inspection command 'print_locale' omits notes elements.  Use
  1421 'print_locale!' to have them included in the output.
  1422 
  1423 
  1424 *** Provers ***
  1425 
  1426 * Provers/hypsubst.ML: improved version of the subst method, for
  1427 single-step rewriting: it now works in bound variable contexts. New is
  1428 'subst (asm)', for rewriting an assumption.  INCOMPATIBILITY: may
  1429 rewrite a different subterm than the original subst method, which is
  1430 still available as 'simplesubst'.
  1431 
  1432 * Provers/quasi.ML: new transitivity reasoners for transitivity only
  1433 and quasi orders.
  1434 
  1435 * Provers/trancl.ML: new transitivity reasoner for transitive and
  1436 reflexive-transitive closure of relations.
  1437 
  1438 * Provers/blast.ML: new reference depth_limit to make blast's depth
  1439 limit (previously hard-coded with a value of 20) user-definable.
  1440 
  1441 * Provers/simplifier.ML has been moved to Pure, where Simplifier.setup
  1442 is peformed already.  Object-logics merely need to finish their
  1443 initial simpset configuration as before.  INCOMPATIBILITY.
  1444 
  1445 
  1446 *** HOL ***
  1447 
  1448 * Symbolic syntax of Hilbert Choice Operator is now as follows:
  1449 
  1450   syntax (epsilon)
  1451     "_Eps" :: "[pttrn, bool] => 'a"    ("(3\<some>_./ _)" [0, 10] 10)
  1452 
  1453 The symbol \<some> is displayed as the alternative epsilon of LaTeX
  1454 and x-symbol; use option '-m epsilon' to get it actually printed.
  1455 Moreover, the mathematically important symbolic identifier \<epsilon>
  1456 becomes available as variable, constant etc.  INCOMPATIBILITY,
  1457 
  1458 * "x > y" abbreviates "y < x" and "x >= y" abbreviates "y <= x".
  1459 Similarly for all quantifiers: "ALL x > y" etc.  The x-symbol for >=
  1460 is \<ge>. New transitivity rules have been added to HOL/Orderings.thy to
  1461 support corresponding Isar calculations.
  1462 
  1463 * "{x:A. P}" abbreviates "{x. x:A & P}", and similarly for "\<in>"
  1464 instead of ":".
  1465 
  1466 * theory SetInterval: changed the syntax for open intervals:
  1467 
  1468   Old       New
  1469   {..n(}    {..<n}
  1470   {)n..}    {n<..}
  1471   {m..n(}   {m..<n}
  1472   {)m..n}   {m<..n}
  1473   {)m..n(}  {m<..<n}
  1474 
  1475 The old syntax is still supported but will disappear in the next
  1476 release.  For conversion use the following Emacs search and replace
  1477 patterns (these are not perfect but work quite well):
  1478 
  1479   {)\([^\.]*\)\.\.  ->  {\1<\.\.}
  1480   \.\.\([^(}]*\)(}  ->  \.\.<\1}
  1481 
  1482 * Theory Commutative_Ring (in Library): method comm_ring for proving
  1483 equalities in commutative rings; method 'algebra' provides a generic
  1484 interface.
  1485 
  1486 * Theory Finite_Set: changed the syntax for 'setsum', summation over
  1487 finite sets: "setsum (%x. e) A", which used to be "\<Sum>x:A. e", is
  1488 now either "SUM x:A. e" or "\<Sum>x \<in> A. e". The bound variable can
  1489 be a tuple pattern.
  1490 
  1491 Some new syntax forms are available:
  1492 
  1493   "\<Sum>x | P. e"      for     "setsum (%x. e) {x. P}"
  1494   "\<Sum>x = a..b. e"   for     "setsum (%x. e) {a..b}"
  1495   "\<Sum>x = a..<b. e"  for     "setsum (%x. e) {a..<b}"
  1496   "\<Sum>x < k. e"      for     "setsum (%x. e) {..<k}"
  1497 
  1498 The latter form "\<Sum>x < k. e" used to be based on a separate
  1499 function "Summation", which has been discontinued.
  1500 
  1501 * theory Finite_Set: in structured induction proofs, the insert case
  1502 is now 'case (insert x F)' instead of the old counterintuitive 'case
  1503 (insert F x)'.
  1504 
  1505 * The 'refute' command has been extended to support a much larger
  1506 fragment of HOL, including axiomatic type classes, constdefs and
  1507 typedefs, inductive datatypes and recursion.
  1508 
  1509 * New tactics 'sat' and 'satx' to prove propositional tautologies.
  1510 Requires zChaff with proof generation to be installed.  See
  1511 HOL/ex/SAT_Examples.thy for examples.
  1512 
  1513 * Datatype induction via method 'induct' now preserves the name of the
  1514 induction variable. For example, when proving P(xs::'a list) by
  1515 induction on xs, the induction step is now P(xs) ==> P(a#xs) rather
  1516 than P(list) ==> P(a#list) as previously.  Potential INCOMPATIBILITY
  1517 in unstructured proof scripts.
  1518 
  1519 * Reworked implementation of records.  Improved scalability for
  1520 records with many fields, avoiding performance problems for type
  1521 inference. Records are no longer composed of nested field types, but
  1522 of nested extension types. Therefore the record type only grows linear
  1523 in the number of extensions and not in the number of fields.  The
  1524 top-level (users) view on records is preserved.  Potential
  1525 INCOMPATIBILITY only in strange cases, where the theory depends on the
  1526 old record representation. The type generated for a record is called
  1527 <record_name>_ext_type.
  1528 
  1529 Flag record_quick_and_dirty_sensitive can be enabled to skip the
  1530 proofs triggered by a record definition or a simproc (if
  1531 quick_and_dirty is enabled).  Definitions of large records can take
  1532 quite long.
  1533 
  1534 New simproc record_upd_simproc for simplification of multiple record
  1535 updates enabled by default.  Moreover, trivial updates are also
  1536 removed: r(|x := x r|) = r.  INCOMPATIBILITY: old proofs break
  1537 occasionally, since simplification is more powerful by default.
  1538 
  1539 * typedef: proper support for polymorphic sets, which contain extra
  1540 type-variables in the term.
  1541 
  1542 * Simplifier: automatically reasons about transitivity chains
  1543 involving "trancl" (r^+) and "rtrancl" (r^*) by setting up tactics
  1544 provided by Provers/trancl.ML as additional solvers.  INCOMPATIBILITY:
  1545 old proofs break occasionally as simplification may now solve more
  1546 goals than previously.
  1547 
  1548 * Simplifier: converts x <= y into x = y if assumption y <= x is
  1549 present.  Works for all partial orders (class "order"), in particular
  1550 numbers and sets.  For linear orders (e.g. numbers) it treats ~ x < y
  1551 just like y <= x.
  1552 
  1553 * Simplifier: new simproc for "let x = a in f x".  If a is a free or
  1554 bound variable or a constant then the let is unfolded.  Otherwise
  1555 first a is simplified to b, and then f b is simplified to g. If
  1556 possible we abstract b from g arriving at "let x = b in h x",
  1557 otherwise we unfold the let and arrive at g.  The simproc can be
  1558 enabled/disabled by the reference use_let_simproc.  Potential
  1559 INCOMPATIBILITY since simplification is more powerful by default.
  1560 
  1561 * Classical reasoning: the meson method now accepts theorems as arguments.
  1562 
  1563 * Prover support: pre-release of the Isabelle-ATP linkup, which runs background
  1564 jobs to provide advice on the provability of subgoals.
  1565 
  1566 * Theory OrderedGroup and Ring_and_Field: various additions and
  1567 improvements to faciliate calculations involving equalities and
  1568 inequalities.
  1569 
  1570 The following theorems have been eliminated or modified
  1571 (INCOMPATIBILITY):
  1572 
  1573   abs_eq             now named abs_of_nonneg
  1574   abs_of_ge_0        now named abs_of_nonneg
  1575   abs_minus_eq       now named abs_of_nonpos
  1576   imp_abs_id         now named abs_of_nonneg
  1577   imp_abs_neg_id     now named abs_of_nonpos
  1578   mult_pos           now named mult_pos_pos
  1579   mult_pos_le        now named mult_nonneg_nonneg
  1580   mult_pos_neg_le    now named mult_nonneg_nonpos
  1581   mult_pos_neg2_le   now named mult_nonneg_nonpos2
  1582   mult_neg           now named mult_neg_neg
  1583   mult_neg_le        now named mult_nonpos_nonpos
  1584 
  1585 * Theory Parity: added rules for simplifying exponents.
  1586 
  1587 * Theory List:
  1588 
  1589 The following theorems have been eliminated or modified
  1590 (INCOMPATIBILITY):
  1591 
  1592   list_all_Nil       now named list_all.simps(1)
  1593   list_all_Cons      now named list_all.simps(2)
  1594   list_all_conv      now named list_all_iff
  1595   set_mem_eq         now named mem_iff
  1596 
  1597 * Theories SetsAndFunctions and BigO (see HOL/Library) support
  1598 asymptotic "big O" calculations.  See the notes in BigO.thy.
  1599 
  1600 
  1601 *** HOL-Complex ***
  1602 
  1603 * Theory RealDef: better support for embedding natural numbers and
  1604 integers in the reals.
  1605 
  1606 The following theorems have been eliminated or modified
  1607 (INCOMPATIBILITY):
  1608 
  1609   exp_ge_add_one_self  now requires no hypotheses
  1610   real_of_int_add      reversed direction of equality (use [symmetric])
  1611   real_of_int_minus    reversed direction of equality (use [symmetric])
  1612   real_of_int_diff     reversed direction of equality (use [symmetric])
  1613   real_of_int_mult     reversed direction of equality (use [symmetric])
  1614 
  1615 * Theory RComplete: expanded support for floor and ceiling functions.
  1616 
  1617 * Theory Ln is new, with properties of the natural logarithm
  1618 
  1619 * Hyperreal: There is a new type constructor "star" for making
  1620 nonstandard types.  The old type names are now type synonyms:
  1621 
  1622   hypreal = real star
  1623   hypnat = nat star
  1624   hcomplex = complex star
  1625 
  1626 * Hyperreal: Many groups of similarly-defined constants have been
  1627 replaced by polymorphic versions (INCOMPATIBILITY):
  1628 
  1629   star_of <-- hypreal_of_real, hypnat_of_nat, hcomplex_of_complex
  1630 
  1631   starset      <-- starsetNat, starsetC
  1632   *s*          <-- *sNat*, *sc*
  1633   starset_n    <-- starsetNat_n, starsetC_n
  1634   *sn*         <-- *sNatn*, *scn*
  1635   InternalSets <-- InternalNatSets, InternalCSets
  1636 
  1637   starfun      <-- starfun{Nat,Nat2,C,RC,CR}
  1638   *f*          <-- *fNat*, *fNat2*, *fc*, *fRc*, *fcR*
  1639   starfun_n    <-- starfun{Nat,Nat2,C,RC,CR}_n
  1640   *fn*         <-- *fNatn*, *fNat2n*, *fcn*, *fRcn*, *fcRn*
  1641   InternalFuns <-- InternalNatFuns, InternalNatFuns2, Internal{C,RC,CR}Funs
  1642 
  1643 * Hyperreal: Many type-specific theorems have been removed in favor of
  1644 theorems specific to various axiomatic type classes (INCOMPATIBILITY):
  1645 
  1646   add_commute <-- {hypreal,hypnat,hcomplex}_add_commute
  1647   add_assoc   <-- {hypreal,hypnat,hcomplex}_add_assocs
  1648   OrderedGroup.add_0 <-- {hypreal,hypnat,hcomplex}_add_zero_left
  1649   OrderedGroup.add_0_right <-- {hypreal,hcomplex}_add_zero_right
  1650   right_minus <-- hypreal_add_minus
  1651   left_minus <-- {hypreal,hcomplex}_add_minus_left
  1652   mult_commute <-- {hypreal,hypnat,hcomplex}_mult_commute
  1653   mult_assoc <-- {hypreal,hypnat,hcomplex}_mult_assoc
  1654   mult_1_left <-- {hypreal,hypnat}_mult_1, hcomplex_mult_one_left
  1655   mult_1_right <-- hcomplex_mult_one_right
  1656   mult_zero_left <-- hcomplex_mult_zero_left
  1657   left_distrib <-- {hypreal,hypnat,hcomplex}_add_mult_distrib
  1658   right_distrib <-- hypnat_add_mult_distrib2
  1659   zero_neq_one <-- {hypreal,hypnat,hcomplex}_zero_not_eq_one
  1660   right_inverse <-- hypreal_mult_inverse
  1661   left_inverse <-- hypreal_mult_inverse_left, hcomplex_mult_inv_left
  1662   order_refl <-- {hypreal,hypnat}_le_refl
  1663   order_trans <-- {hypreal,hypnat}_le_trans
  1664   order_antisym <-- {hypreal,hypnat}_le_anti_sym
  1665   order_less_le <-- {hypreal,hypnat}_less_le
  1666   linorder_linear <-- {hypreal,hypnat}_le_linear
  1667   add_left_mono <-- {hypreal,hypnat}_add_left_mono
  1668   mult_strict_left_mono <-- {hypreal,hypnat}_mult_less_mono2
  1669   add_nonneg_nonneg <-- hypreal_le_add_order
  1670 
  1671 * Hyperreal: Separate theorems having to do with type-specific
  1672 versions of constants have been merged into theorems that apply to the
  1673 new polymorphic constants (INCOMPATIBILITY):
  1674 
  1675   STAR_UNIV_set <-- {STAR_real,NatStar_real,STARC_complex}_set
  1676   STAR_empty_set <-- {STAR,NatStar,STARC}_empty_set
  1677   STAR_Un <-- {STAR,NatStar,STARC}_Un
  1678   STAR_Int <-- {STAR,NatStar,STARC}_Int
  1679   STAR_Compl <-- {STAR,NatStar,STARC}_Compl
  1680   STAR_subset <-- {STAR,NatStar,STARC}_subset
  1681   STAR_mem <-- {STAR,NatStar,STARC}_mem
  1682   STAR_mem_Compl <-- {STAR,STARC}_mem_Compl
  1683   STAR_diff <-- {STAR,STARC}_diff
  1684   STAR_star_of_image_subset <-- {STAR_hypreal_of_real, NatStar_hypreal_of_real,
  1685     STARC_hcomplex_of_complex}_image_subset
  1686   starset_n_Un <-- starset{Nat,C}_n_Un
  1687   starset_n_Int <-- starset{Nat,C}_n_Int
  1688   starset_n_Compl <-- starset{Nat,C}_n_Compl
  1689   starset_n_diff <-- starset{Nat,C}_n_diff
  1690   InternalSets_Un <-- Internal{Nat,C}Sets_Un
  1691   InternalSets_Int <-- Internal{Nat,C}Sets_Int
  1692   InternalSets_Compl <-- Internal{Nat,C}Sets_Compl
  1693   InternalSets_diff <-- Internal{Nat,C}Sets_diff
  1694   InternalSets_UNIV_diff <-- Internal{Nat,C}Sets_UNIV_diff
  1695   InternalSets_starset_n <-- Internal{Nat,C}Sets_starset{Nat,C}_n
  1696   starset_starset_n_eq <-- starset{Nat,C}_starset{Nat,C}_n_eq
  1697   starset_n_starset <-- starset{Nat,C}_n_starset{Nat,C}
  1698   starfun_n_starfun <-- starfun{Nat,Nat2,C,RC,CR}_n_starfun{Nat,Nat2,C,RC,CR}
  1699   starfun <-- starfun{Nat,Nat2,C,RC,CR}
  1700   starfun_mult <-- starfun{Nat,Nat2,C,RC,CR}_mult
  1701   starfun_add <-- starfun{Nat,Nat2,C,RC,CR}_add
  1702   starfun_minus <-- starfun{Nat,Nat2,C,RC,CR}_minus
  1703   starfun_diff <-- starfun{C,RC,CR}_diff
  1704   starfun_o <-- starfun{NatNat2,Nat2,_stafunNat,C,C_starfunRC,_starfunCR}_o
  1705   starfun_o2 <-- starfun{NatNat2,_stafunNat,C,C_starfunRC,_starfunCR}_o2
  1706   starfun_const_fun <-- starfun{Nat,Nat2,C,RC,CR}_const_fun
  1707   starfun_inverse <-- starfun{Nat,C,RC,CR}_inverse
  1708   starfun_eq <-- starfun{Nat,Nat2,C,RC,CR}_eq
  1709   starfun_eq_iff <-- starfun{C,RC,CR}_eq_iff
  1710   starfun_Id <-- starfunC_Id
  1711   starfun_approx <-- starfun{Nat,CR}_approx
  1712   starfun_capprox <-- starfun{C,RC}_capprox
  1713   starfun_abs <-- starfunNat_rabs
  1714   starfun_lambda_cancel <-- starfun{C,CR,RC}_lambda_cancel
  1715   starfun_lambda_cancel2 <-- starfun{C,CR,RC}_lambda_cancel2
  1716   starfun_mult_HFinite_approx <-- starfunCR_mult_HFinite_capprox
  1717   starfun_mult_CFinite_capprox <-- starfun{C,RC}_mult_CFinite_capprox
  1718   starfun_add_capprox <-- starfun{C,RC}_add_capprox
  1719   starfun_add_approx <-- starfunCR_add_approx
  1720   starfun_inverse_inverse <-- starfunC_inverse_inverse
  1721   starfun_divide <-- starfun{C,CR,RC}_divide
  1722   starfun_n <-- starfun{Nat,C}_n
  1723   starfun_n_mult <-- starfun{Nat,C}_n_mult
  1724   starfun_n_add <-- starfun{Nat,C}_n_add
  1725   starfun_n_add_minus <-- starfunNat_n_add_minus
  1726   starfun_n_const_fun <-- starfun{Nat,C}_n_const_fun
  1727   starfun_n_minus <-- starfun{Nat,C}_n_minus
  1728   starfun_n_eq <-- starfun{Nat,C}_n_eq
  1729 
  1730   star_n_add <-- {hypreal,hypnat,hcomplex}_add
  1731   star_n_minus <-- {hypreal,hcomplex}_minus
  1732   star_n_diff <-- {hypreal,hcomplex}_diff
  1733   star_n_mult <-- {hypreal,hcomplex}_mult
  1734   star_n_inverse <-- {hypreal,hcomplex}_inverse
  1735   star_n_le <-- {hypreal,hypnat}_le
  1736   star_n_less <-- {hypreal,hypnat}_less
  1737   star_n_zero_num <-- {hypreal,hypnat,hcomplex}_zero_num
  1738   star_n_one_num <-- {hypreal,hypnat,hcomplex}_one_num
  1739   star_n_abs <-- hypreal_hrabs
  1740   star_n_divide <-- hcomplex_divide
  1741 
  1742   star_of_add <-- {hypreal_of_real,hypnat_of_nat,hcomplex_of_complex}_add
  1743   star_of_minus <-- {hypreal_of_real,hcomplex_of_complex}_minus
  1744   star_of_diff <-- hypreal_of_real_diff
  1745   star_of_mult <-- {hypreal_of_real,hypnat_of_nat,hcomplex_of_complex}_mult
  1746   star_of_one <-- {hypreal_of_real,hcomplex_of_complex}_one
  1747   star_of_zero <-- {hypreal_of_real,hypnat_of_nat,hcomplex_of_complex}_zero
  1748   star_of_le <-- {hypreal_of_real,hypnat_of_nat}_le_iff
  1749   star_of_less <-- {hypreal_of_real,hypnat_of_nat}_less_iff
  1750   star_of_eq <-- {hypreal_of_real,hypnat_of_nat,hcomplex_of_complex}_eq_iff
  1751   star_of_inverse <-- {hypreal_of_real,hcomplex_of_complex}_inverse
  1752   star_of_divide <-- {hypreal_of_real,hcomplex_of_complex}_divide
  1753   star_of_of_nat <-- {hypreal_of_real,hcomplex_of_complex}_of_nat
  1754   star_of_of_int <-- {hypreal_of_real,hcomplex_of_complex}_of_int
  1755   star_of_number_of <-- {hypreal,hcomplex}_number_of
  1756   star_of_number_less <-- number_of_less_hypreal_of_real_iff
  1757   star_of_number_le <-- number_of_le_hypreal_of_real_iff
  1758   star_of_eq_number <-- hypreal_of_real_eq_number_of_iff
  1759   star_of_less_number <-- hypreal_of_real_less_number_of_iff
  1760   star_of_le_number <-- hypreal_of_real_le_number_of_iff
  1761   star_of_power <-- hypreal_of_real_power
  1762   star_of_eq_0 <-- hcomplex_of_complex_zero_iff
  1763 
  1764 * Hyperreal: new method "transfer" that implements the transfer
  1765 principle of nonstandard analysis. With a subgoal that mentions
  1766 nonstandard types like "'a star", the command "apply transfer"
  1767 replaces it with an equivalent one that mentions only standard types.
  1768 To be successful, all free variables must have standard types; non-
  1769 standard variables must have explicit universal quantifiers.
  1770 
  1771 * Hyperreal: A theory of Taylor series.
  1772 
  1773 
  1774 *** HOLCF ***
  1775 
  1776 * Discontinued special version of 'constdefs' (which used to support
  1777 continuous functions) in favor of the general Pure one with full
  1778 type-inference.
  1779 
  1780 * New simplification procedure for solving continuity conditions; it
  1781 is much faster on terms with many nested lambda abstractions (cubic
  1782 instead of exponential time).
  1783 
  1784 * New syntax for domain package: selector names are now optional.
  1785 Parentheses should be omitted unless argument is lazy, for example:
  1786 
  1787   domain 'a stream = cons "'a" (lazy "'a stream")
  1788 
  1789 * New command 'fixrec' for defining recursive functions with pattern
  1790 matching; defining multiple functions with mutual recursion is also
  1791 supported.  Patterns may include the constants cpair, spair, up, sinl,
  1792 sinr, or any data constructor defined by the domain package. The given
  1793 equations are proven as rewrite rules. See HOLCF/ex/Fixrec_ex.thy for
  1794 syntax and examples.
  1795 
  1796 * New commands 'cpodef' and 'pcpodef' for defining predicate subtypes
  1797 of cpo and pcpo types. Syntax is exactly like the 'typedef' command,
  1798 but the proof obligation additionally includes an admissibility
  1799 requirement. The packages generate instances of class cpo or pcpo,
  1800 with continuity and strictness theorems for Rep and Abs.
  1801 
  1802 * HOLCF: Many theorems have been renamed according to a more standard naming
  1803 scheme (INCOMPATIBILITY):
  1804 
  1805   foo_inject:  "foo$x = foo$y ==> x = y"
  1806   foo_eq:      "(foo$x = foo$y) = (x = y)"
  1807   foo_less:    "(foo$x << foo$y) = (x << y)"
  1808   foo_strict:  "foo$UU = UU"
  1809   foo_defined: "... ==> foo$x ~= UU"
  1810   foo_defined_iff: "(foo$x = UU) = (x = UU)"
  1811 
  1812 
  1813 *** ZF ***
  1814 
  1815 * ZF/ex: theories Group and Ring provide examples in abstract algebra,
  1816 including the First Isomorphism Theorem (on quotienting by the kernel
  1817 of a homomorphism).
  1818 
  1819 * ZF/Simplifier: install second copy of type solver that actually
  1820 makes use of TC rules declared to Isar proof contexts (or locales);
  1821 the old version is still required for ML proof scripts.
  1822 
  1823 
  1824 *** Cube ***
  1825 
  1826 * Converted to Isar theory format; use locales instead of axiomatic
  1827 theories.
  1828 
  1829 
  1830 *** ML ***
  1831 
  1832 * Pure/library.ML: added ##>, ##>>, #>> -- higher-order counterparts
  1833 for ||>, ||>>, |>>,
  1834 
  1835 * Pure/library.ML no longer defines its own option datatype, but uses
  1836 that of the SML basis, which has constructors NONE and SOME instead of
  1837 None and Some, as well as exception Option.Option instead of OPTION.
  1838 The functions the, if_none, is_some, is_none have been adapted
  1839 accordingly, while Option.map replaces apsome.
  1840 
  1841 * Pure/library.ML: the exception LIST has been given up in favour of
  1842 the standard exceptions Empty and Subscript, as well as
  1843 Library.UnequalLengths.  Function like Library.hd and Library.tl are
  1844 superceded by the standard hd and tl functions etc.
  1845 
  1846 A number of basic list functions are no longer exported to the ML
  1847 toplevel, as they are variants of predefined functions.  The following
  1848 suggests how one can translate existing code:
  1849 
  1850     rev_append xs ys = List.revAppend (xs, ys)
  1851     nth_elem (i, xs) = List.nth (xs, i)
  1852     last_elem xs = List.last xs
  1853     flat xss = List.concat xss
  1854     seq fs = List.app fs
  1855     partition P xs = List.partition P xs
  1856     mapfilter f xs = List.mapPartial f xs
  1857 
  1858 * Pure/library.ML: several combinators for linear functional
  1859 transformations, notably reverse application and composition:
  1860 
  1861   x |> f                f #> g
  1862   (x, y) |-> f          f #-> g
  1863 
  1864 * Pure/library.ML: introduced/changed precedence of infix operators:
  1865 
  1866   infix 1 |> |-> ||> ||>> |>> |>>> #> #->;
  1867   infix 2 ?;
  1868   infix 3 o oo ooo oooo;
  1869   infix 4 ~~ upto downto;
  1870 
  1871 Maybe INCOMPATIBILITY when any of those is used in conjunction with other
  1872 infix operators.
  1873 
  1874 * Pure/library.ML: natural list combinators fold, fold_rev, and
  1875 fold_map support linear functional transformations and nesting.  For
  1876 example:
  1877 
  1878   fold f [x1, ..., xN] y =
  1879     y |> f x1 |> ... |> f xN
  1880 
  1881   (fold o fold) f [xs1, ..., xsN] y =
  1882     y |> fold f xs1 |> ... |> fold f xsN
  1883 
  1884   fold f [x1, ..., xN] =
  1885     f x1 #> ... #> f xN
  1886 
  1887   (fold o fold) f [xs1, ..., xsN] =
  1888     fold f xs1 #> ... #> fold f xsN
  1889 
  1890 * Pure/library.ML: the following selectors on type 'a option are
  1891 available:
  1892 
  1893   the:               'a option -> 'a  (*partial*)
  1894   these:             'a option -> 'a  where 'a = 'b list
  1895   the_default: 'a -> 'a option -> 'a
  1896   the_list:          'a option -> 'a list
  1897 
  1898 * Pure/General: structure AList (cf. Pure/General/alist.ML) provides
  1899 basic operations for association lists, following natural argument
  1900 order; moreover the explicit equality predicate passed here avoids
  1901 potentially expensive polymorphic runtime equality checks.
  1902 The old functions may be expressed as follows:
  1903 
  1904   assoc = uncurry (AList.lookup (op =))
  1905   assocs = these oo AList.lookup (op =)
  1906   overwrite = uncurry (AList.update (op =)) o swap
  1907 
  1908 * Pure/General: structure AList (cf. Pure/General/alist.ML) provides
  1909 
  1910   val make: ('a -> 'b) -> 'a list -> ('a * 'b) list
  1911   val find: ('a * 'b -> bool) -> ('c * 'b) list -> 'a -> 'c list
  1912 
  1913 replacing make_keylist and keyfilter (occassionally used)
  1914 Naive rewrites:
  1915 
  1916   make_keylist = AList.make
  1917   keyfilter = AList.find (op =)
  1918 
  1919 * eq_fst and eq_snd now take explicit equality parameter, thus
  1920   avoiding eqtypes. Naive rewrites:
  1921 
  1922     eq_fst = eq_fst (op =)
  1923     eq_snd = eq_snd (op =)
  1924 
  1925 * Removed deprecated apl and apr (rarely used).
  1926   Naive rewrites:
  1927 
  1928     apl (n, op) =>>= curry op n
  1929     apr (op, m) =>>= fn n => op (n, m)
  1930 
  1931 * Pure/General: structure OrdList (cf. Pure/General/ord_list.ML)
  1932 provides a reasonably efficient light-weight implementation of sets as
  1933 lists.
  1934 
  1935 * Pure/General: generic tables (cf. Pure/General/table.ML) provide a
  1936 few new operations; existing lookup and update are now curried to
  1937 follow natural argument order (for use with fold etc.);
  1938 INCOMPATIBILITY, use (uncurry Symtab.lookup) etc. as last resort.
  1939 
  1940 * Pure/General: output via the Isabelle channels of
  1941 writeln/warning/error etc. is now passed through Output.output, with a
  1942 hook for arbitrary transformations depending on the print_mode
  1943 (cf. Output.add_mode -- the first active mode that provides a output
  1944 function wins).  Already formatted output may be embedded into further
  1945 text via Output.raw; the result of Pretty.string_of/str_of and derived
  1946 functions (string_of_term/cterm/thm etc.) is already marked raw to
  1947 accommodate easy composition of diagnostic messages etc.  Programmers
  1948 rarely need to care about Output.output or Output.raw at all, with
  1949 some notable exceptions: Output.output is required when bypassing the
  1950 standard channels (writeln etc.), or in token translations to produce
  1951 properly formatted results; Output.raw is required when capturing
  1952 already output material that will eventually be presented to the user
  1953 a second time.  For the default print mode, both Output.output and
  1954 Output.raw have no effect.
  1955 
  1956 * Pure/General: Output.time_accumulator NAME creates an operator ('a
  1957 -> 'b) -> 'a -> 'b to measure runtime and count invocations; the
  1958 cumulative results are displayed at the end of a batch session.
  1959 
  1960 * Pure/General: File.sysify_path and File.quote_sysify path have been
  1961 replaced by File.platform_path and File.shell_path (with appropriate
  1962 hooks).  This provides a clean interface for unusual systems where the
  1963 internal and external process view of file names are different.
  1964 
  1965 * Pure: more efficient orders for basic syntactic entities: added
  1966 fast_string_ord, fast_indexname_ord, fast_term_ord; changed sort_ord
  1967 and typ_ord to use fast_string_ord and fast_indexname_ord (term_ord is
  1968 NOT affected); structures Symtab, Vartab, Typtab, Termtab use the fast
  1969 orders now -- potential INCOMPATIBILITY for code that depends on a
  1970 particular order for Symtab.keys, Symtab.dest, etc. (consider using
  1971 Library.sort_strings on result).
  1972 
  1973 * Pure/term.ML: combinators fold_atyps, fold_aterms, fold_term_types,
  1974 fold_types traverse types/terms from left to right, observing natural
  1975 argument order.  Supercedes previous foldl_XXX versions, add_frees,
  1976 add_vars etc. have been adapted as well: INCOMPATIBILITY.
  1977 
  1978 * Pure: name spaces have been refined, with significant changes of the
  1979 internal interfaces -- INCOMPATIBILITY.  Renamed cond_extern(_table)
  1980 to extern(_table).  The plain name entry path is superceded by a
  1981 general 'naming' context, which also includes the 'policy' to produce
  1982 a fully qualified name and external accesses of a fully qualified
  1983 name; NameSpace.extend is superceded by context dependent
  1984 Sign.declare_name.  Several theory and proof context operations modify
  1985 the naming context.  Especially note Theory.restore_naming and
  1986 ProofContext.restore_naming to get back to a sane state; note that
  1987 Theory.add_path is no longer sufficient to recover from
  1988 Theory.absolute_path in particular.
  1989 
  1990 * Pure: new flags short_names (default false) and unique_names
  1991 (default true) for controlling output of qualified names.  If
  1992 short_names is set, names are printed unqualified.  If unique_names is
  1993 reset, the name prefix is reduced to the minimum required to achieve
  1994 the original result when interning again, even if there is an overlap
  1995 with earlier declarations.
  1996 
  1997 * Pure/TheoryDataFun: change of the argument structure; 'prep_ext' is
  1998 now 'extend', and 'merge' gets an additional Pretty.pp argument
  1999 (useful for printing error messages).  INCOMPATIBILITY.
  2000 
  2001 * Pure: major reorganization of the theory context.  Type Sign.sg and
  2002 Theory.theory are now identified, referring to the universal
  2003 Context.theory (see Pure/context.ML).  Actual signature and theory
  2004 content is managed as theory data.  The old code and interfaces were
  2005 spread over many files and structures; the new arrangement introduces
  2006 considerable INCOMPATIBILITY to gain more clarity:
  2007 
  2008   Context -- theory management operations (name, identity, inclusion,
  2009     parents, ancestors, merge, etc.), plus generic theory data;
  2010 
  2011   Sign -- logical signature and syntax operations (declaring consts,
  2012     types, etc.), plus certify/read for common entities;
  2013 
  2014   Theory -- logical theory operations (stating axioms, definitions,
  2015     oracles), plus a copy of logical signature operations (consts,
  2016     types, etc.); also a few basic management operations (Theory.copy,
  2017     Theory.merge, etc.)
  2018 
  2019 The most basic sign_of operations (Theory.sign_of, Thm.sign_of_thm
  2020 etc.) as well as the sign field in Thm.rep_thm etc. have been retained
  2021 for convenience -- they merely return the theory.
  2022 
  2023 * Pure: type Type.tsig is superceded by theory in most interfaces.
  2024 
  2025 * Pure: the Isar proof context type is already defined early in Pure
  2026 as Context.proof (note that ProofContext.context and Proof.context are
  2027 aliases, where the latter is the preferred name).  This enables other
  2028 Isabelle components to refer to that type even before Isar is present.
  2029 
  2030 * Pure/sign/theory: discontinued named name spaces (i.e. classK,
  2031 typeK, constK, axiomK, oracleK), but provide explicit operations for
  2032 any of these kinds.  For example, Sign.intern typeK is now
  2033 Sign.intern_type, Theory.hide_space Sign.typeK is now
  2034 Theory.hide_types.  Also note that former
  2035 Theory.hide_classes/types/consts are now
  2036 Theory.hide_classes_i/types_i/consts_i, while the non '_i' versions
  2037 internalize their arguments!  INCOMPATIBILITY.
  2038 
  2039 * Pure: get_thm interface (of PureThy and ProofContext) expects
  2040 datatype thmref (with constructors Name and NameSelection) instead of
  2041 plain string -- INCOMPATIBILITY;
  2042 
  2043 * Pure: cases produced by proof methods specify options, where NONE
  2044 means to remove case bindings -- INCOMPATIBILITY in
  2045 (RAW_)METHOD_CASES.
  2046 
  2047 * Pure: the following operations retrieve axioms or theorems from a
  2048 theory node or theory hierarchy, respectively:
  2049 
  2050   Theory.axioms_of: theory -> (string * term) list
  2051   Theory.all_axioms_of: theory -> (string * term) list
  2052   PureThy.thms_of: theory -> (string * thm) list
  2053   PureThy.all_thms_of: theory -> (string * thm) list
  2054 
  2055 * Pure: print_tac now outputs the goal through the trace channel.
  2056 
  2057 * Isar toplevel: improved diagnostics, mostly for Poly/ML only.
  2058 Reference Toplevel.debug (default false) controls detailed printing
  2059 and tracing of low-level exceptions; Toplevel.profiling (default 0)
  2060 controls execution profiling -- set to 1 for time and 2 for space
  2061 (both increase the runtime).
  2062 
  2063 * Isar session: The initial use of ROOT.ML is now always timed,
  2064 i.e. the log will show the actual process times, in contrast to the
  2065 elapsed wall-clock time that the outer shell wrapper produces.
  2066 
  2067 * Simplifier: improved handling of bound variables (nameless
  2068 representation, avoid allocating new strings).  Simprocs that invoke
  2069 the Simplifier recursively should use Simplifier.inherit_bounds to
  2070 avoid local name clashes.  Failure to do so produces warnings
  2071 "Simplifier: renamed bound variable ..."; set Simplifier.debug_bounds
  2072 for further details.
  2073 
  2074 * ML functions legacy_bindings and use_legacy_bindings produce ML fact
  2075 bindings for all theorems stored within a given theory; this may help
  2076 in porting non-Isar theories to Isar ones, while keeping ML proof
  2077 scripts for the time being.
  2078 
  2079 * ML operator HTML.with_charset specifies the charset begin used for
  2080 generated HTML files.  For example:
  2081 
  2082   HTML.with_charset "utf-8" use_thy "Hebrew";
  2083   HTML.with_charset "utf-8" use_thy "Chinese";
  2084 
  2085 
  2086 *** System ***
  2087 
  2088 * Allow symlinks to all proper Isabelle executables (Isabelle,
  2089 isabelle, isatool etc.).
  2090 
  2091 * ISABELLE_DOC_FORMAT setting specifies preferred document format (for
  2092 isatool doc, isatool mkdir, display_drafts etc.).
  2093 
  2094 * isatool usedir: option -f allows specification of the ML file to be
  2095 used by Isabelle; default is ROOT.ML.
  2096 
  2097 * New isatool version outputs the version identifier of the Isabelle
  2098 distribution being used.
  2099 
  2100 * HOL: new isatool dimacs2hol converts files in DIMACS CNF format
  2101 (containing Boolean satisfiability problems) into Isabelle/HOL
  2102 theories.
  2103 
  2104 
  2105 
  2106 New in Isabelle2004 (April 2004)
  2107 --------------------------------
  2108 
  2109 *** General ***
  2110 
  2111 * Provers/order.ML:  new efficient reasoner for partial and linear orders.
  2112   Replaces linorder.ML.
  2113 
  2114 * Pure: Greek letters (except small lambda, \<lambda>), as well as Gothic
  2115   (\<aa>...\<zz>\<AA>...\<ZZ>), calligraphic (\<A>...\<Z>), and Euler
  2116   (\<a>...\<z>), are now considered normal letters, and can therefore
  2117   be used anywhere where an ASCII letter (a...zA...Z) has until
  2118   now. COMPATIBILITY: This obviously changes the parsing of some
  2119   terms, especially where a symbol has been used as a binder, say
  2120   '\<Pi>x. ...', which is now a type error since \<Pi>x will be parsed
  2121   as an identifier.  Fix it by inserting a space around former
  2122   symbols.  Call 'isatool fixgreek' to try to fix parsing errors in
  2123   existing theory and ML files.
  2124 
  2125 * Pure: Macintosh and Windows line-breaks are now allowed in theory files.
  2126 
  2127 * Pure: single letter sub/superscripts (\<^isub> and \<^isup>) are now
  2128   allowed in identifiers. Similar to Greek letters \<^isub> is now considered
  2129   a normal (but invisible) letter. For multiple letter subscripts repeat
  2130   \<^isub> like this: x\<^isub>1\<^isub>2.
  2131 
  2132 * Pure: There are now sub-/superscripts that can span more than one
  2133   character. Text between \<^bsub> and \<^esub> is set in subscript in
  2134   ProofGeneral and LaTeX, text between \<^bsup> and \<^esup> in
  2135   superscript. The new control characters are not identifier parts.
  2136 
  2137 * Pure: Control-symbols of the form \<^raw:...> will literally print the
  2138   content of "..." to the latex file instead of \isacntrl... . The "..."
  2139   may consist of any printable characters excluding the end bracket >.
  2140 
  2141 * Pure: Using new Isar command "finalconsts" (or the ML functions
  2142   Theory.add_finals or Theory.add_finals_i) it is now possible to
  2143   declare constants "final", which prevents their being given a definition
  2144   later.  It is useful for constants whose behaviour is fixed axiomatically
  2145   rather than definitionally, such as the meta-logic connectives.
  2146 
  2147 * Pure: 'instance' now handles general arities with general sorts
  2148   (i.e. intersections of classes),
  2149 
  2150 * Presentation: generated HTML now uses a CSS style sheet to make layout
  2151   (somewhat) independent of content. It is copied from lib/html/isabelle.css.
  2152   It can be changed to alter the colors/layout of generated pages.
  2153 
  2154 
  2155 *** Isar ***
  2156 
  2157 * Tactic emulation methods rule_tac, erule_tac, drule_tac, frule_tac,
  2158   cut_tac, subgoal_tac and thin_tac:
  2159   - Now understand static (Isar) contexts.  As a consequence, users of Isar
  2160     locales are no longer forced to write Isar proof scripts.
  2161     For details see Isar Reference Manual, paragraph 4.3.2: Further tactic
  2162     emulations.
  2163   - INCOMPATIBILITY: names of variables to be instantiated may no
  2164     longer be enclosed in quotes.  Instead, precede variable name with `?'.
  2165     This is consistent with the instantiation attribute "where".
  2166 
  2167 * Attributes "where" and "of":
  2168   - Now take type variables of instantiated theorem into account when reading
  2169     the instantiation string.  This fixes a bug that caused instantiated
  2170     theorems to have too special types in some circumstances.
  2171   - "where" permits explicit instantiations of type variables.
  2172 
  2173 * Calculation commands "moreover" and "also" no longer interfere with
  2174   current facts ("this"), admitting arbitrary combinations with "then"
  2175   and derived forms.
  2176 
  2177 * Locales:
  2178   - Goal statements involving the context element "includes" no longer
  2179     generate theorems with internal delta predicates (those ending on
  2180     "_axioms") in the premise.
  2181     Resolve particular premise with <locale>.intro to obtain old form.
  2182   - Fixed bug in type inference ("unify_frozen") that prevented mix of target
  2183     specification and "includes" elements in goal statement.
  2184   - Rule sets <locale>.intro and <locale>.axioms no longer declared as
  2185     [intro?] and [elim?] (respectively) by default.
  2186   - Experimental command for instantiation of locales in proof contexts:
  2187         instantiate <label>[<attrs>]: <loc>
  2188     Instantiates locale <loc> and adds all its theorems to the current context
  2189     taking into account their attributes.  Label and attrs are optional
  2190     modifiers, like in theorem declarations.  If present, names of
  2191     instantiated theorems are qualified with <label>, and the attributes
  2192     <attrs> are applied after any attributes these theorems might have already.
  2193       If the locale has assumptions, a chained fact of the form
  2194     "<loc> t1 ... tn" is expected from which instantiations of the parameters
  2195     are derived.  The command does not support old-style locales declared
  2196     with "locale (open)".
  2197       A few (very simple) examples can be found in FOL/ex/LocaleInst.thy.
  2198 
  2199 * HOL: Tactic emulation methods induct_tac and case_tac understand static
  2200   (Isar) contexts.
  2201 
  2202 
  2203 *** HOL ***
  2204 
  2205 * Proof import: new image HOL4 contains the imported library from
  2206   the HOL4 system with about 2500 theorems. It is imported by
  2207   replaying proof terms produced by HOL4 in Isabelle. The HOL4 image
  2208   can be used like any other Isabelle image.  See
  2209   HOL/Import/HOL/README for more information.
  2210 
  2211 * Simplifier:
  2212   - Much improved handling of linear and partial orders.
  2213     Reasoners for linear and partial orders are set up for type classes
  2214     "linorder" and "order" respectively, and are added to the default simpset
  2215     as solvers.  This means that the simplifier can build transitivity chains
  2216     to solve goals from the assumptions.
  2217   - INCOMPATIBILITY: old proofs break occasionally.  Typically, applications
  2218     of blast or auto after simplification become unnecessary because the goal
  2219     is solved by simplification already.
  2220 
  2221 * Numerics: new theory Ring_and_Field contains over 250 basic numerical laws,
  2222     all proved in axiomatic type classes for semirings, rings and fields.
  2223 
  2224 * Numerics:
  2225   - Numeric types (nat, int, and in HOL-Complex rat, real, complex, etc.) are
  2226     now formalized using the Ring_and_Field theory mentioned above.
  2227   - INCOMPATIBILITY: simplification and arithmetic behaves somewhat differently
  2228     than before, because now they are set up once in a generic manner.
  2229   - INCOMPATIBILITY: many type-specific arithmetic laws have gone.
  2230     Look for the general versions in Ring_and_Field (and Power if they concern
  2231     exponentiation).
  2232 
  2233 * Type "rat" of the rational numbers is now available in HOL-Complex.
  2234 
  2235 * Records:
  2236   - Record types are now by default printed with their type abbreviation
  2237     instead of the list of all field types. This can be configured via
  2238     the reference "print_record_type_abbr".
  2239   - Simproc "record_upd_simproc" for simplification of multiple updates added
  2240     (not enabled by default).
  2241   - Simproc "record_ex_sel_eq_simproc" to simplify EX x. sel r = x resp.
  2242     EX x. x = sel r to True (not enabled by default).
  2243   - Tactic "record_split_simp_tac" to split and simplify records added.
  2244 
  2245 * 'specification' command added, allowing for definition by
  2246   specification.  There is also an 'ax_specification' command that
  2247   introduces the new constants axiomatically.
  2248 
  2249 * arith(_tac) is now able to generate counterexamples for reals as well.
  2250 
  2251 * HOL-Algebra: new locale "ring" for non-commutative rings.
  2252 
  2253 * HOL-ex: InductiveInvariant_examples illustrates advanced recursive function
  2254   definitions, thanks to Sava Krsti\'{c} and John Matthews.
  2255 
  2256 * HOL-Matrix: a first theory for matrices in HOL with an application of
  2257   matrix theory to linear programming.
  2258 
  2259 * Unions and Intersections:
  2260   The latex output syntax of UN and INT has been changed
  2261   from "\Union x \in A. B" to "\Union_{x \in A} B"
  2262   i.e. the index formulae has become a subscript.
  2263   Similarly for "\Union x. B", and for \Inter instead of \Union.
  2264 
  2265 * Unions and Intersections over Intervals:
  2266   There is new short syntax "UN i<=n. A" for "UN i:{0..n}. A". There is
  2267   also an x-symbol version with subscripts "\<Union>\<^bsub>i <= n\<^esub>. A"
  2268   like in normal math, and corresponding versions for < and for intersection.
  2269 
  2270 * HOL/List: Ordering "lexico" is renamed "lenlex" and the standard
  2271   lexicographic dictonary ordering has been added as "lexord".
  2272 
  2273 * ML: the legacy theory structures Int and List have been removed. They had
  2274   conflicted with ML Basis Library structures having the same names.
  2275 
  2276 * 'refute' command added to search for (finite) countermodels.  Only works
  2277   for a fragment of HOL.  The installation of an external SAT solver is
  2278   highly recommended.  See "HOL/Refute.thy" for details.
  2279 
  2280 * 'quickcheck' command: Allows to find counterexamples by evaluating
  2281   formulae under an assignment of free variables to random values.
  2282   In contrast to 'refute', it can deal with inductive datatypes,
  2283   but cannot handle quantifiers. See "HOL/ex/Quickcheck_Examples.thy"
  2284   for examples.
  2285 
  2286 
  2287 *** HOLCF ***
  2288 
  2289 * Streams now come with concatenation and are part of the HOLCF image
  2290 
  2291 
  2292 
  2293 New in Isabelle2003 (May 2003)
  2294 ------------------------------
  2295 
  2296 *** General ***
  2297 
  2298 * Provers/simplifier:
  2299 
  2300   - Completely reimplemented method simp (ML: Asm_full_simp_tac):
  2301     Assumptions are now subject to complete mutual simplification,
  2302     not just from left to right. The simplifier now preserves
  2303     the order of assumptions.
  2304 
  2305     Potential INCOMPATIBILITY:
  2306 
  2307     -- simp sometimes diverges where the old version did
  2308        not, e.g. invoking simp on the goal
  2309 
  2310         [| P (f x); y = x; f x = f y |] ==> Q
  2311 
  2312        now gives rise to the infinite reduction sequence
  2313 
  2314         P(f x) --(f x = f y)--> P(f y) --(y = x)--> P(f x) --(f x = f y)--> ...
  2315 
  2316        Using "simp (asm_lr)" (ML: Asm_lr_simp_tac) instead often solves this
  2317        kind of problem.
  2318 
  2319     -- Tactics combining classical reasoner and simplification (such as auto)
  2320        are also affected by this change, because many of them rely on
  2321        simp. They may sometimes diverge as well or yield a different numbers
  2322        of subgoals. Try to use e.g. force, fastsimp, or safe instead of auto
  2323        in case of problems. Sometimes subsequent calls to the classical
  2324        reasoner will fail because a preceeding call to the simplifier too
  2325        eagerly simplified the goal, e.g. deleted redundant premises.
  2326 
  2327   - The simplifier trace now shows the names of the applied rewrite rules
  2328 
  2329   - You can limit the number of recursive invocations of the simplifier
  2330     during conditional rewriting (where the simplifie tries to solve the
  2331     conditions before applying the rewrite rule):
  2332     ML "simp_depth_limit := n"
  2333     where n is an integer. Thus you can force termination where previously
  2334     the simplifier would diverge.
  2335 
  2336   - Accepts free variables as head terms in congruence rules.  Useful in Isar.
  2337 
  2338   - No longer aborts on failed congruence proof.  Instead, the
  2339     congruence is ignored.
  2340 
  2341 * Pure: New generic framework for extracting programs from constructive
  2342   proofs. See HOL/Extraction.thy for an example instantiation, as well
  2343   as HOL/Extraction for some case studies.
  2344 
  2345 * Pure: The main goal of the proof state is no longer shown by default, only
  2346 the subgoals. This behaviour is controlled by a new flag.
  2347    PG menu: Isabelle/Isar -> Settings -> Show Main Goal
  2348 (ML: Proof.show_main_goal).
  2349 
  2350 * Pure: You can find all matching introduction rules for subgoal 1, i.e. all
  2351 rules whose conclusion matches subgoal 1:
  2352       PG menu: Isabelle/Isar -> Show me -> matching rules
  2353 The rules are ordered by how closely they match the subgoal.
  2354 In particular, rules that solve a subgoal outright are displayed first
  2355 (or rather last, the way they are printed).
  2356 (ML: ProofGeneral.print_intros())
  2357 
  2358 * Pure: New flag trace_unify_fail causes unification to print
  2359 diagnostic information (PG: in trace buffer) when it fails. This is
  2360 useful for figuring out why single step proofs like rule, erule or
  2361 assumption failed.
  2362 
  2363 * Pure: Locale specifications now produce predicate definitions
  2364 according to the body of text (covering assumptions modulo local
  2365 definitions); predicate "loc_axioms" covers newly introduced text,
  2366 while "loc" is cumulative wrt. all included locale expressions; the
  2367 latter view is presented only on export into the global theory
  2368 context; potential INCOMPATIBILITY, use "(open)" option to fall back
  2369 on the old view without predicates;
  2370 
  2371 * Pure: predefined locales "var" and "struct" are useful for sharing
  2372 parameters (as in CASL, for example); just specify something like
  2373 ``var x + var y + struct M'' as import;
  2374 
  2375 * Pure: improved thms_containing: proper indexing of facts instead of
  2376 raw theorems; check validity of results wrt. current name space;
  2377 include local facts of proof configuration (also covers active
  2378 locales), cover fixed variables in index; may use "_" in term
  2379 specification; an optional limit for the number of printed facts may
  2380 be given (the default is 40);
  2381 
  2382 * Pure: disallow duplicate fact bindings within new-style theory files
  2383 (batch-mode only);
  2384 
  2385 * Provers: improved induct method: assumptions introduced by case
  2386 "foo" are split into "foo.hyps" (from the rule) and "foo.prems" (from
  2387 the goal statement); "foo" still refers to all facts collectively;
  2388 
  2389 * Provers: the function blast.overloaded has been removed: all constants
  2390 are regarded as potentially overloaded, which improves robustness in exchange
  2391 for slight decrease in efficiency;
  2392 
  2393 * Provers/linorder: New generic prover for transitivity reasoning over
  2394 linear orders.  Note: this prover is not efficient!
  2395 
  2396 * Isar: preview of problems to finish 'show' now produce an error
  2397 rather than just a warning (in interactive mode);
  2398 
  2399 
  2400 *** HOL ***
  2401 
  2402 * arith(_tac)
  2403 
  2404  - Produces a counter example if it cannot prove a goal.
  2405    Note that the counter example may be spurious if the goal is not a formula
  2406    of quantifier-free linear arithmetic.
  2407    In ProofGeneral the counter example appears in the trace buffer.
  2408 
  2409  - Knows about div k and mod k where k is a numeral of type nat or int.
  2410 
  2411  - Calls full Presburger arithmetic (by Amine Chaieb) if quantifier-free
  2412    linear arithmetic fails. This takes account of quantifiers and divisibility.
  2413    Presburger arithmetic can also be called explicitly via presburger(_tac).
  2414 
  2415 * simp's arithmetic capabilities have been enhanced a bit: it now
  2416 takes ~= in premises into account (by performing a case split);
  2417 
  2418 * simp reduces "m*(n div m) + n mod m" to n, even if the two summands
  2419 are distributed over a sum of terms;
  2420 
  2421 * New tactic "trans_tac" and method "trans" instantiate
  2422 Provers/linorder.ML for axclasses "order" and "linorder" (predicates
  2423 "<=", "<" and "=").
  2424 
  2425 * function INCOMPATIBILITIES: Pi-sets have been redefined and moved from main
  2426 HOL to Library/FuncSet; constant "Fun.op o" is now called "Fun.comp";
  2427 
  2428 * 'typedef' command has new option "open" to suppress the set
  2429 definition;
  2430 
  2431 * functions Min and Max on finite sets have been introduced (theory
  2432 Finite_Set);
  2433 
  2434 * attribute [symmetric] now works for relations as well; it turns
  2435 (x,y) : R^-1 into (y,x) : R, and vice versa;
  2436 
  2437 * induct over a !!-quantified statement (say !!x1..xn):
  2438   each "case" automatically performs "fix x1 .. xn" with exactly those names.
  2439 
  2440 * Map: `empty' is no longer a constant but a syntactic abbreviation for
  2441 %x. None. Warning: empty_def now refers to the previously hidden definition
  2442 of the empty set.
  2443 
  2444 * Algebra: formalization of classical algebra.  Intended as base for
  2445 any algebraic development in Isabelle.  Currently covers group theory
  2446 (up to Sylow's theorem) and ring theory (Universal Property of
  2447 Univariate Polynomials).  Contributions welcome;
  2448 
  2449 * GroupTheory: deleted, since its material has been moved to Algebra;
  2450 
  2451 * Complex: new directory of the complex numbers with numeric constants,
  2452 nonstandard complex numbers, and some complex analysis, standard and
  2453 nonstandard (Jacques Fleuriot);
  2454 
  2455 * HOL-Complex: new image for analysis, replacing HOL-Real and HOL-Hyperreal;
  2456 
  2457 * Hyperreal: introduced Gauge integration and hyperreal logarithms (Jacques
  2458 Fleuriot);
  2459 
  2460 * Real/HahnBanach: updated and adapted to locales;
  2461 
  2462 * NumberTheory: added Gauss's law of quadratic reciprocity (by Avigad,
  2463 Gray and Kramer);
  2464 
  2465 * UNITY: added the Meier-Sanders theory of progress sets;
  2466 
  2467 * MicroJava: bytecode verifier and lightweight bytecode verifier
  2468 as abstract algorithms, instantiated to the JVM;
  2469 
  2470 * Bali: Java source language formalization. Type system, operational
  2471 semantics, axiomatic semantics. Supported language features:
  2472 classes, interfaces, objects,virtual methods, static methods,
  2473 static/instance fields, arrays, access modifiers, definite
  2474 assignment, exceptions.
  2475 
  2476 
  2477 *** ZF ***
  2478 
  2479 * ZF/Constructible: consistency proof for AC (Gdel's constructible
  2480 universe, etc.);
  2481 
  2482 * Main ZF: virtually all theories converted to new-style format;
  2483 
  2484 
  2485 *** ML ***
  2486 
  2487 * Pure: Tactic.prove provides sane interface for internal proofs;
  2488 omits the infamous "standard" operation, so this is more appropriate
  2489 than prove_goalw_cterm in many situations (e.g. in simprocs);
  2490 
  2491 * Pure: improved error reporting of simprocs;
  2492 
  2493 * Provers: Simplifier.simproc(_i) provides sane interface for setting
  2494 up simprocs;
  2495 
  2496 
  2497 *** Document preparation ***
  2498 
  2499 * uses \par instead of \\ for line breaks in theory text. This may
  2500 shift some page breaks in large documents. To get the old behaviour
  2501 use \renewcommand{\isanewline}{\mbox{}\\\mbox{}} in root.tex.
  2502 
  2503 * minimized dependencies of isabelle.sty and isabellesym.sty on
  2504 other packages
  2505 
  2506 * \<euro> now needs package babel/greek instead of marvosym (which
  2507 broke \Rightarrow)
  2508 
  2509 * normal size for \<zero>...\<nine> (uses \mathbf instead of
  2510 textcomp package)
  2511 
  2512 
  2513 
  2514 New in Isabelle2002 (March 2002)
  2515 --------------------------------
  2516 
  2517 *** Document preparation ***
  2518 
  2519 * greatly simplified document preparation setup, including more
  2520 graceful interpretation of isatool usedir -i/-d/-D options, and more
  2521 instructive isatool mkdir; users should basically be able to get
  2522 started with "isatool mkdir HOL Test && isatool make"; alternatively,
  2523 users may run a separate document processing stage manually like this:
  2524 "isatool usedir -D output HOL Test && isatool document Test/output";
  2525 
  2526 * theory dependency graph may now be incorporated into documents;
  2527 isatool usedir -g true will produce session_graph.eps/.pdf for use
  2528 with \includegraphics of LaTeX;
  2529 
  2530 * proper spacing of consecutive markup elements, especially text
  2531 blocks after section headings;
  2532 
  2533 * support bold style (for single symbols only), input syntax is like
  2534 this: "\<^bold>\<alpha>" or "\<^bold>A";
  2535 
  2536 * \<bullet> is now output as bold \cdot by default, which looks much
  2537 better in printed text;
  2538 
  2539 * added default LaTeX bindings for \<tturnstile> and \<TTurnstile>;
  2540 note that these symbols are currently unavailable in Proof General /
  2541 X-Symbol; new symbols \<zero>, \<one>, ..., \<nine>, and \<euro>;
  2542 
  2543 * isatool latex no longer depends on changed TEXINPUTS, instead
  2544 isatool document copies the Isabelle style files to the target
  2545 location;
  2546 
  2547 
  2548 *** Isar ***
  2549 
  2550 * Pure/Provers: improved proof by cases and induction;
  2551   - 'case' command admits impromptu naming of parameters (such as
  2552     "case (Suc n)");
  2553   - 'induct' method divinates rule instantiation from the inductive
  2554     claim; no longer requires excessive ?P bindings for proper
  2555     instantiation of cases;
  2556   - 'induct' method properly enumerates all possibilities of set/type
  2557     rules; as a consequence facts may be also passed through *type*
  2558     rules without further ado;
  2559   - 'induct' method now derives symbolic cases from the *rulified*
  2560     rule (before it used to rulify cases stemming from the internal
  2561     atomized version); this means that the context of a non-atomic
  2562     statement becomes is included in the hypothesis, avoiding the
  2563     slightly cumbersome show "PROP ?case" form;
  2564   - 'induct' may now use elim-style induction rules without chaining
  2565     facts, using ``missing'' premises from the goal state; this allows
  2566     rules stemming from inductive sets to be applied in unstructured
  2567     scripts, while still benefitting from proper handling of non-atomic
  2568     statements; NB: major inductive premises need to be put first, all
  2569     the rest of the goal is passed through the induction;
  2570   - 'induct' proper support for mutual induction involving non-atomic
  2571     rule statements (uses the new concept of simultaneous goals, see
  2572     below);
  2573   - append all possible rule selections, but only use the first
  2574     success (no backtracking);
  2575   - removed obsolete "(simplified)" and "(stripped)" options of methods;
  2576   - undeclared rule case names default to numbers 1, 2, 3, ...;
  2577   - added 'print_induct_rules' (covered by help item in recent Proof
  2578     General versions);
  2579   - moved induct/cases attributes to Pure, methods to Provers;
  2580   - generic method setup instantiated for FOL and HOL;
  2581 
  2582 * Pure: support multiple simultaneous goal statements, for example
  2583 "have a: A and b: B" (same for 'theorem' etc.); being a pure
  2584 meta-level mechanism, this acts as if several individual goals had
  2585 been stated separately; in particular common proof methods need to be
  2586 repeated in order to cover all claims; note that a single elimination
  2587 step is *not* sufficient to establish the two conjunctions, so this
  2588 fails:
  2589 
  2590   assume "A & B" then have A and B ..   (*".." fails*)
  2591 
  2592 better use "obtain" in situations as above; alternative refer to
  2593 multi-step methods like 'auto', 'simp_all', 'blast+' etc.;
  2594 
  2595 * Pure: proper integration with ``locales''; unlike the original
  2596 version by Florian Kammller, Isar locales package high-level proof
  2597 contexts rather than raw logical ones (e.g. we admit to include
  2598 attributes everywhere); operations on locales include merge and
  2599 rename; support for implicit arguments (``structures''); simultaneous
  2600 type-inference over imports and text; see also HOL/ex/Locales.thy for
  2601 some examples;
  2602 
  2603 * Pure: the following commands have been ``localized'', supporting a
  2604 target locale specification "(in name)": 'lemma', 'theorem',
  2605 'corollary', 'lemmas', 'theorems', 'declare'; the results will be
  2606 stored both within the locale and at the theory level (exported and
  2607 qualified by the locale name);
  2608 
  2609 * Pure: theory goals may now be specified in ``long'' form, with
  2610 ad-hoc contexts consisting of arbitrary locale elements. for example
  2611 ``lemma foo: fixes x assumes "A x" shows "B x"'' (local syntax and
  2612 definitions may be given, too); the result is a meta-level rule with
  2613 the context elements being discharged in the obvious way;
  2614 
  2615 * Pure: new proof command 'using' allows to augment currently used
  2616 facts after a goal statement ('using' is syntactically analogous to
  2617 'apply', but acts on the goal's facts only); this allows chained facts
  2618 to be separated into parts given before and after a claim, as in
  2619 ``from a and b have C using d and e <proof>'';
  2620 
  2621 * Pure: renamed "antecedent" case to "rule_context";
  2622 
  2623 * Pure: new 'judgment' command records explicit information about the
  2624 object-logic embedding (used by several tools internally); no longer
  2625 use hard-wired "Trueprop";
  2626 
  2627 * Pure: added 'corollary' command;
  2628 
  2629 * Pure: fixed 'token_translation' command;
  2630 
  2631 * Pure: removed obsolete 'exported' attribute;
  2632 
  2633 * Pure: dummy pattern "_" in is/let is now automatically lifted over
  2634 bound variables: "ALL x. P x --> Q x" (is "ALL x. _ --> ?C x")
  2635 supersedes more cumbersome ... (is "ALL x. _ x --> ?C x");
  2636 
  2637 * Pure: method 'atomize' presents local goal premises as object-level
  2638 statements (atomic meta-level propositions); setup controlled via
  2639 rewrite rules declarations of 'atomize' attribute; example
  2640 application: 'induct' method with proper rule statements in improper
  2641 proof *scripts*;
  2642 
  2643 * Pure: emulation of instantiation tactics (rule_tac, cut_tac, etc.)
  2644 now consider the syntactic context of assumptions, giving a better
  2645 chance to get type-inference of the arguments right (this is
  2646 especially important for locales);
  2647 
  2648 * Pure: "sorry" no longer requires quick_and_dirty in interactive
  2649 mode;
  2650 
  2651 * Pure/obtain: the formal conclusion "thesis", being marked as
  2652 ``internal'', may no longer be reference directly in the text;
  2653 potential INCOMPATIBILITY, may need to use "?thesis" in rare
  2654 situations;
  2655 
  2656 * Pure: generic 'sym' attribute which declares a rule both as pure
  2657 'elim?' and for the 'symmetric' operation;
  2658 
  2659 * Pure: marginal comments ``--'' may now occur just anywhere in the
  2660 text; the fixed correlation with particular command syntax has been
  2661 discontinued;
  2662 
  2663 * Pure: new method 'rules' is particularly well-suited for proof
  2664 search in intuitionistic logic; a bit slower than 'blast' or 'fast',
  2665 but often produces more compact proof terms with less detours;
  2666 
  2667 * Pure/Provers/classical: simplified integration with pure rule
  2668 attributes and methods; the classical "intro?/elim?/dest?"
  2669 declarations coincide with the pure ones; the "rule" method no longer
  2670 includes classically swapped intros; "intro" and "elim" methods no
  2671 longer pick rules from the context; also got rid of ML declarations
  2672 AddXIs/AddXEs/AddXDs; all of this has some potential for
  2673 INCOMPATIBILITY;
  2674 
  2675 * Provers/classical: attribute 'swapped' produces classical inversions
  2676 of introduction rules;
  2677 
  2678 * Provers/simplifier: 'simplified' attribute may refer to explicit
  2679 rules instead of full simplifier context; 'iff' attribute handles
  2680 conditional rules;
  2681 
  2682 * HOL: 'typedef' now allows alternative names for Rep/Abs morphisms;
  2683 
  2684 * HOL: 'recdef' now fails on unfinished automated proofs, use
  2685 "(permissive)" option to recover old behavior;
  2686 
  2687 * HOL: 'inductive' no longer features separate (collective) attributes
  2688 for 'intros' (was found too confusing);
  2689 
  2690 * HOL: properly declared induction rules less_induct and
  2691 wf_induct_rule;
  2692 
  2693 
  2694 *** HOL ***
  2695 
  2696 * HOL: moved over to sane numeral syntax; the new policy is as
  2697 follows:
  2698 
  2699   - 0 and 1 are polymorphic constants, which are defined on any
  2700   numeric type (nat, int, real etc.);
  2701 
  2702   - 2, 3, 4, ... and -1, -2, -3, ... are polymorphic numerals, based
  2703   binary representation internally;
  2704 
  2705   - type nat has special constructor Suc, and generally prefers Suc 0
  2706   over 1::nat and Suc (Suc 0) over 2::nat;
  2707 
  2708 This change may cause significant problems of INCOMPATIBILITY; here
  2709 are some hints on converting existing sources:
  2710 
  2711   - due to the new "num" token, "-0" and "-1" etc. are now atomic
  2712   entities, so expressions involving "-" (unary or binary minus) need
  2713   to be spaced properly;
  2714 
  2715   - existing occurrences of "1" may need to be constraint "1::nat" or
  2716   even replaced by Suc 0; similar for old "2";
  2717 
  2718   - replace "#nnn" by "nnn", and "#-nnn" by "-nnn";
  2719 
  2720   - remove all special provisions on numerals in proofs;
  2721 
  2722 * HOL: simp rules nat_number expand numerals on nat to Suc/0
  2723 representation (depends on bin_arith_simps in the default context);
  2724 
  2725 * HOL: symbolic syntax for x^2 (numeral 2);
  2726 
  2727 * HOL: the class of all HOL types is now called "type" rather than
  2728 "term"; INCOMPATIBILITY, need to adapt references to this type class
  2729 in axclass/classes, instance/arities, and (usually rare) occurrences
  2730 in typings (of consts etc.); internally the class is called
  2731 "HOL.type", ML programs should refer to HOLogic.typeS;
  2732 
  2733 * HOL/record package improvements:
  2734   - new derived operations "fields" to build a partial record section,
  2735     "extend" to promote a fixed record to a record scheme, and
  2736     "truncate" for the reverse; cf. theorems "xxx.defs", which are *not*
  2737     declared as simp by default;
  2738   - shared operations ("more", "fields", etc.) now need to be always
  2739     qualified) --- potential INCOMPATIBILITY;
  2740   - removed "make_scheme" operations (use "make" with "extend") --
  2741     INCOMPATIBILITY;
  2742   - removed "more" class (simply use "term") -- INCOMPATIBILITY;
  2743   - provides cases/induct rules for use with corresponding Isar
  2744     methods (for concrete records, record schemes, concrete more
  2745     parts, and schematic more parts -- in that order);
  2746   - internal definitions directly based on a light-weight abstract
  2747     theory of product types over typedef rather than datatype;
  2748 
  2749 * HOL: generic code generator for generating executable ML code from
  2750 specifications; specific support for HOL constructs such as inductive
  2751 datatypes and sets, as well as recursive functions; can be invoked
  2752 via 'generate_code' theory section;
  2753 
  2754 * HOL: canonical cases/induct rules for n-tuples (n = 3..7);
  2755 
  2756 * HOL: consolidated and renamed several theories.  In particular:
  2757         Ord.thy has been absorbed into HOL.thy
  2758         String.thy has been absorbed into List.thy
  2759 
  2760 * HOL: concrete setsum syntax "\<Sum>i:A. b" == "setsum (%i. b) A"
  2761 (beware of argument permutation!);
  2762 
  2763 * HOL: linorder_less_split superseded by linorder_cases;
  2764 
  2765 * HOL/List: "nodups" renamed to "distinct";
  2766 
  2767 * HOL: added "The" definite description operator; move Hilbert's "Eps"
  2768 to peripheral theory "Hilbert_Choice"; some INCOMPATIBILITIES:
  2769   - Ex_def has changed, now need to use some_eq_ex
  2770 
  2771 * HOL: made split_all_tac safe; EXISTING PROOFS MAY FAIL OR LOOP, so
  2772 in this (rare) case use:
  2773 
  2774   delSWrapper "split_all_tac"
  2775   addSbefore ("unsafe_split_all_tac", unsafe_split_all_tac)
  2776 
  2777 * HOL: added safe wrapper "split_conv_tac" to claset; EXISTING PROOFS
  2778 MAY FAIL;
  2779 
  2780 * HOL: introduced f^n = f o ... o f; warning: due to the limits of
  2781 Isabelle's type classes, ^ on functions and relations has too general
  2782 a domain, namely ('a * 'b) set and 'a => 'b; this means that it may be
  2783 necessary to attach explicit type constraints;
  2784 
  2785 * HOL/Relation: the prefix name of the infix "O" has been changed from
  2786 "comp" to "rel_comp"; INCOMPATIBILITY: a few theorems have been
  2787 renamed accordingly (eg "compI" -> "rel_compI").
  2788 
  2789 * HOL: syntax translations now work properly with numerals and records
  2790 expressions;
  2791 
  2792 * HOL: bounded abstraction now uses syntax "%" / "\<lambda>" instead
  2793 of "lam" -- INCOMPATIBILITY;
  2794 
  2795 * HOL: got rid of some global declarations (potential INCOMPATIBILITY
  2796 for ML tools): const "()" renamed "Product_Type.Unity", type "unit"
  2797 renamed "Product_Type.unit";
  2798 
  2799 * HOL: renamed rtrancl_into_rtrancl2 to converse_rtrancl_into_rtrancl
  2800 
  2801 * HOL: removed obsolete theorem "optionE" (use "option.exhaust", or
  2802 the "cases" method);
  2803 
  2804 * HOL/GroupTheory: group theory examples including Sylow's theorem (by
  2805 Florian Kammller);
  2806 
  2807 * HOL/IMP: updated and converted to new-style theory format; several
  2808 parts turned into readable document, with proper Isar proof texts and
  2809 some explanations (by Gerwin Klein);
  2810 
  2811 * HOL-Real: added Complex_Numbers (by Gertrud Bauer);
  2812 
  2813 * HOL-Hyperreal is now a logic image;
  2814 
  2815 
  2816 *** HOLCF ***
  2817 
  2818 * Isar: consts/constdefs supports mixfix syntax for continuous
  2819 operations;
  2820 
  2821 * Isar: domain package adapted to new-style theory format, e.g. see
  2822 HOLCF/ex/Dnat.thy;
  2823 
  2824 * theory Lift: proper use of rep_datatype lift instead of ML hacks --
  2825 potential INCOMPATIBILITY; now use plain induct_tac instead of former
  2826 lift.induct_tac, always use UU instead of Undef;
  2827 
  2828 * HOLCF/IMP: updated and converted to new-style theory;
  2829 
  2830 
  2831 *** ZF ***
  2832 
  2833 * Isar: proper integration of logic-specific tools and packages,
  2834 including theory commands '(co)inductive', '(co)datatype',
  2835 'rep_datatype', 'inductive_cases', as well as methods 'ind_cases',
  2836 'induct_tac', 'case_tac', and 'typecheck' (with attribute 'TC');
  2837 
  2838 * theory Main no longer includes AC; for the Axiom of Choice, base
  2839 your theory on Main_ZFC;
  2840 
  2841 * the integer library now covers quotients and remainders, with many
  2842 laws relating division to addition, multiplication, etc.;
  2843 
  2844 * ZF/UNITY: Chandy and Misra's UNITY is now available in ZF, giving a
  2845 typeless version of the formalism;
  2846 
  2847 * ZF/AC, Coind, IMP, Resid: updated and converted to new-style theory
  2848 format;
  2849 
  2850 * ZF/Induct: new directory for examples of inductive definitions,
  2851 including theory Multiset for multiset orderings; converted to
  2852 new-style theory format;
  2853 
  2854 * ZF: many new theorems about lists, ordinals, etc.;
  2855 
  2856 
  2857 *** General ***
  2858 
  2859 * Pure/kernel: meta-level proof terms (by Stefan Berghofer); reference
  2860 variable proof controls level of detail: 0 = no proofs (only oracle
  2861 dependencies), 1 = lemma dependencies, 2 = compact proof terms; see
  2862 also ref manual for further ML interfaces;
  2863 
  2864 * Pure/axclass: removed obsolete ML interface
  2865 goal_subclass/goal_arity;
  2866 
  2867 * Pure/syntax: new token syntax "num" for plain numerals (without "#"
  2868 of "xnum"); potential INCOMPATIBILITY, since -0, -1 etc. are now
  2869 separate tokens, so expressions involving minus need to be spaced
  2870 properly;
  2871 
  2872 * Pure/syntax: support non-oriented infixes, using keyword "infix"
  2873 rather than "infixl" or "infixr";
  2874 
  2875 * Pure/syntax: concrete syntax for dummy type variables admits genuine
  2876 sort constraint specifications in type inference; e.g. "x::_::foo"
  2877 ensures that the type of "x" is of sort "foo" (but not necessarily a
  2878 type variable);
  2879 
  2880 * Pure/syntax: print modes "type_brackets" and "no_type_brackets"
  2881 control output of nested => (types); the default behavior is
  2882 "type_brackets";
  2883 
  2884 * Pure/syntax: builtin parse translation for "_constify" turns valued
  2885 tokens into AST constants;
  2886 
  2887 * Pure/syntax: prefer later declarations of translations and print
  2888 translation functions; potential INCOMPATIBILITY: need to reverse
  2889 multiple declarations for same syntax element constant;
  2890 
  2891 * Pure/show_hyps reset by default (in accordance to existing Isar
  2892 practice);
  2893 
  2894 * Provers/classical: renamed addaltern to addafter, addSaltern to
  2895 addSafter;
  2896 
  2897 * Provers/clasimp: ``iff'' declarations now handle conditional rules
  2898 as well;
  2899 
  2900 * system: tested support for MacOS X; should be able to get Isabelle +
  2901 Proof General to work in a plain Terminal after installing Poly/ML
  2902 (e.g. from the Isabelle distribution area) and GNU bash alone
  2903 (e.g. from http://www.apple.com); full X11, XEmacs and X-Symbol
  2904 support requires further installations, e.g. from
  2905 http://fink.sourceforge.net/);
  2906 
  2907 * system: support Poly/ML 4.1.1 (able to manage larger heaps);
  2908 
  2909 * system: reduced base memory usage by Poly/ML (approx. 20 MB instead
  2910 of 40 MB), cf. ML_OPTIONS;
  2911 
  2912 * system: Proof General keywords specification is now part of the
  2913 Isabelle distribution (see etc/isar-keywords.el);
  2914 
  2915 * system: support for persistent Proof General sessions (refrain from
  2916 outdating all loaded theories on startup); user may create writable
  2917 logic images like this: ``isabelle -q HOL Test'';
  2918 
  2919 * system: smart selection of Isabelle process versus Isabelle
  2920 interface, accommodates case-insensitive file systems (e.g. HFS+); may
  2921 run both "isabelle" and "Isabelle" even if file names are badly
  2922 damaged (executable inspects the case of the first letter of its own
  2923 name); added separate "isabelle-process" and "isabelle-interface";
  2924 
  2925 * system: refrain from any attempt at filtering input streams; no
  2926 longer support ``8bit'' encoding of old isabelle font, instead proper
  2927 iso-latin characters may now be used; the related isatools
  2928 "symbolinput" and "nonascii" have disappeared as well;
  2929 
  2930 * system: removed old "xterm" interface (the print modes "xterm" and
  2931 "xterm_color" are still available for direct use in a suitable
  2932 terminal);
  2933 
  2934 
  2935 
  2936 New in Isabelle99-2 (February 2001)
  2937 -----------------------------------
  2938 
  2939 *** Overview of INCOMPATIBILITIES ***
  2940 
  2941 * HOL: please note that theories in the Library and elsewhere often use the
  2942 new-style (Isar) format; to refer to their theorems in an ML script you must
  2943 bind them to ML identifers by e.g.      val thm_name = thm "thm_name";
  2944 
  2945 * HOL: inductive package no longer splits induction rule aggressively,
  2946 but only as far as specified by the introductions given; the old
  2947 format may be recovered via ML function complete_split_rule or attribute
  2948 'split_rule (complete)';
  2949 
  2950 * HOL: induct renamed to lfp_induct, lfp_Tarski to lfp_unfold,
  2951 gfp_Tarski to gfp_unfold;
  2952 
  2953 * HOL: contrapos, contrapos2 renamed to contrapos_nn, contrapos_pp;
  2954 
  2955 * HOL: infix "dvd" now has priority 50 rather than 70 (because it is a
  2956 relation); infix "^^" has been renamed "``"; infix "``" has been
  2957 renamed "`"; "univalent" has been renamed "single_valued";
  2958 
  2959 * HOL/Real: "rinv" and "hrinv" replaced by overloaded "inverse"
  2960 operation;
  2961 
  2962 * HOLCF: infix "`" has been renamed "$"; the symbol syntax is \<cdot>;
  2963 
  2964 * Isar: 'obtain' no longer declares "that" fact as simp/intro;
  2965 
  2966 * Isar/HOL: method 'induct' now handles non-atomic goals; as a
  2967 consequence, it is no longer monotonic wrt. the local goal context
  2968 (which is now passed through the inductive cases);
  2969 
  2970 * Document preparation: renamed standard symbols \<ll> to \<lless> and
  2971 \<gg> to \<ggreater>;
  2972 
  2973 
  2974 *** Document preparation ***
  2975 
  2976 * \isabellestyle{NAME} selects version of Isabelle output (currently
  2977 available: are "it" for near math-mode best-style output, "sl" for
  2978 slanted text style, and "tt" for plain type-writer; if no
  2979 \isabellestyle command is given, output is according to slanted
  2980 type-writer);
  2981 
  2982 * support sub/super scripts (for single symbols only), input syntax is
  2983 like this: "A\<^sup>*" or "A\<^sup>\<star>";
  2984 
  2985 * some more standard symbols; see Appendix A of the system manual for
  2986 the complete list of symbols defined in isabellesym.sty;
  2987 
  2988 * improved isabelle style files; more abstract symbol implementation
  2989 (should now use \isamath{...} and \isatext{...} in custom symbol
  2990 definitions);
  2991 
  2992 * antiquotation @{goals} and @{subgoals} for output of *dynamic* goals
  2993 state; Note that presentation of goal states does not conform to
  2994 actual human-readable proof documents.  Please do not include goal
  2995 states into document output unless you really know what you are doing!
  2996 
  2997 * proper indentation of antiquoted output with proportional LaTeX
  2998 fonts;
  2999 
  3000 * no_document ML operator temporarily disables LaTeX document
  3001 generation;
  3002 
  3003 * isatool unsymbolize tunes sources for plain ASCII communication;
  3004 
  3005 
  3006 *** Isar ***
  3007 
  3008 * Pure: Isar now suffers initial goal statements to contain unbound
  3009 schematic variables (this does not conform to actual readable proof
  3010 documents, due to unpredictable outcome and non-compositional proof
  3011 checking); users who know what they are doing may use schematic goals
  3012 for Prolog-style synthesis of proven results;
  3013 
  3014 * Pure: assumption method (an implicit finishing) now handles actual
  3015 rules as well;
  3016 
  3017 * Pure: improved 'obtain' --- moved to Pure, insert "that" into
  3018 initial goal, declare "that" only as Pure intro (only for single
  3019 steps); the "that" rule assumption may now be involved in implicit
  3020 finishing, thus ".." becomes a feasible for trivial obtains;
  3021 
  3022 * Pure: default proof step now includes 'intro_classes'; thus trivial
  3023 instance proofs may be performed by "..";
  3024 
  3025 * Pure: ?thesis / ?this / "..." now work for pure meta-level
  3026 statements as well;
  3027 
  3028 * Pure: more robust selection of calculational rules;
  3029 
  3030 * Pure: the builtin notion of 'finished' goal now includes the ==-refl
  3031 rule (as well as the assumption rule);
  3032 
  3033 * Pure: 'thm_deps' command visualizes dependencies of theorems and
  3034 lemmas, using the graph browser tool;
  3035 
  3036 * Pure: predict failure of "show" in interactive mode;
  3037 
  3038 * Pure: 'thms_containing' now takes actual terms as arguments;
  3039 
  3040 * HOL: improved method 'induct' --- now handles non-atomic goals
  3041 (potential INCOMPATIBILITY); tuned error handling;
  3042 
  3043 * HOL: cases and induct rules now provide explicit hints about the
  3044 number of facts to be consumed (0 for "type" and 1 for "set" rules);
  3045 any remaining facts are inserted into the goal verbatim;
  3046 
  3047 * HOL: local contexts (aka cases) may now contain term bindings as
  3048 well; the 'cases' and 'induct' methods new provide a ?case binding for
  3049 the result to be shown in each case;
  3050 
  3051 * HOL: added 'recdef_tc' command;
  3052 
  3053 * isatool convert assists in eliminating legacy ML scripts;
  3054 
  3055 
  3056 *** HOL ***
  3057 
  3058 * HOL/Library: a collection of generic theories to be used together
  3059 with main HOL; the theory loader path already includes this directory
  3060 by default; the following existing theories have been moved here:
  3061 HOL/Induct/Multiset, HOL/Induct/Acc (as Accessible_Part), HOL/While
  3062 (as While_Combinator), HOL/Lex/Prefix (as List_Prefix);
  3063 
  3064 * HOL/Unix: "Some aspects of Unix file-system security", a typical
  3065 modelling and verification task performed in Isabelle/HOL +
  3066 Isabelle/Isar + Isabelle document preparation (by Markus Wenzel).
  3067 
  3068 * HOL/Algebra: special summation operator SUM no longer exists, it has
  3069 been replaced by setsum; infix 'assoc' now has priority 50 (like
  3070 'dvd'); axiom 'one_not_zero' has been moved from axclass 'ring' to
  3071 'domain', this makes the theory consistent with mathematical
  3072 literature;
  3073 
  3074 * HOL basics: added overloaded operations "inverse" and "divide"
  3075 (infix "/"), syntax for generic "abs" operation, generic summation
  3076 operator \<Sum>;
  3077 
  3078 * HOL/typedef: simplified package, provide more useful rules (see also
  3079 HOL/subset.thy);
  3080 
  3081 * HOL/datatype: induction rule for arbitrarily branching datatypes is
  3082 now expressed as a proper nested rule (old-style tactic scripts may
  3083 require atomize_strip_tac to cope with non-atomic premises);
  3084 
  3085 * HOL: renamed theory "Prod" to "Product_Type", renamed "split" rule
  3086 to "split_conv" (old name still available for compatibility);
  3087 
  3088 * HOL: improved concrete syntax for strings (e.g. allows translation
  3089 rules with string literals);
  3090 
  3091 * HOL-Real-Hyperreal: this extends HOL-Real with the hyperreals
  3092  and Fleuriot's mechanization of analysis, including the transcendental
  3093  functions for the reals;
  3094 
  3095 * HOL/Real, HOL/Hyperreal: improved arithmetic simplification;
  3096 
  3097 
  3098 *** CTT ***
  3099 
  3100 * CTT: x-symbol support for Pi, Sigma, -->, : (membership); note that
  3101 "lam" is displayed as TWO lambda-symbols
  3102 
  3103 * CTT: theory Main now available, containing everything (that is, Bool
  3104 and Arith);
  3105 
  3106 
  3107 *** General ***
  3108 
  3109 * Pure: the Simplifier has been implemented properly as a derived rule
  3110 outside of the actual kernel (at last!); the overall performance
  3111 penalty in practical applications is about 50%, while reliability of
  3112 the Isabelle inference kernel has been greatly improved;
  3113 
  3114 * print modes "brackets" and "no_brackets" control output of nested =>
  3115 (types) and ==> (props); the default behaviour is "brackets";
  3116 
  3117 * Provers: fast_tac (and friends) now handle actual object-logic rules
  3118 as assumptions as well;
  3119 
  3120 * system: support Poly/ML 4.0;
  3121 
  3122 * system: isatool install handles KDE version 1 or 2;
  3123 
  3124 
  3125 
  3126 New in Isabelle99-1 (October 2000)
  3127 ----------------------------------
  3128 
  3129 *** Overview of INCOMPATIBILITIES ***
  3130 
  3131 * HOL: simplification of natural numbers is much changed; to partly
  3132 recover the old behaviour (e.g. to prevent n+n rewriting to #2*n)
  3133 issue the following ML commands:
  3134 
  3135   Delsimprocs Nat_Numeral_Simprocs.cancel_numerals;
  3136   Delsimprocs [Nat_Numeral_Simprocs.combine_numerals];
  3137 
  3138 * HOL: simplification no longer dives into case-expressions; this is
  3139 controlled by "t.weak_case_cong" for each datatype t;
  3140 
  3141 * HOL: nat_less_induct renamed to less_induct;
  3142 
  3143 * HOL: systematic renaming of the SOME (Eps) rules, may use isatool
  3144 fixsome to patch .thy and .ML sources automatically;
  3145 
  3146   select_equality  -> some_equality
  3147   select_eq_Ex     -> some_eq_ex
  3148   selectI2EX       -> someI2_ex
  3149   selectI2         -> someI2
  3150   selectI          -> someI
  3151   select1_equality -> some1_equality
  3152   Eps_sym_eq       -> some_sym_eq_trivial
  3153   Eps_eq           -> some_eq_trivial
  3154 
  3155 * HOL: exhaust_tac on datatypes superceded by new generic case_tac;
  3156 
  3157 * HOL: removed obsolete theorem binding expand_if (refer to split_if
  3158 instead);
  3159 
  3160 * HOL: the recursion equations generated by 'recdef' are now called
  3161 f.simps instead of f.rules;
  3162 
  3163 * HOL: qed_spec_mp now also handles bounded ALL as well;
  3164 
  3165 * HOL: 0 is now overloaded, so the type constraint ":: nat" may
  3166 sometimes be needed;
  3167 
  3168 * HOL: the constant for "f``x" is now "image" rather than "op ``";
  3169 
  3170 * HOL: the constant for "f-``x" is now "vimage" rather than "op -``";
  3171 
  3172 * HOL: the disjoint sum is now "<+>" instead of "Plus"; the cartesian
  3173 product is now "<*>" instead of "Times"; the lexicographic product is
  3174 now "<*lex*>" instead of "**";
  3175 
  3176 * HOL: theory Sexp is now in HOL/Induct examples (it used to be part
  3177 of main HOL, but was unused); better use HOL's datatype package;
  3178 
  3179 * HOL: removed "symbols" syntax for constant "override" of theory Map;
  3180 the old syntax may be recovered as follows:
  3181 
  3182   syntax (symbols)
  3183     override  :: "('a ~=> 'b) => ('a ~=> 'b) => ('a ~=> 'b)"
  3184       (infixl "\\<oplus>" 100)
  3185 
  3186 * HOL/Real: "rabs" replaced by overloaded "abs" function;
  3187 
  3188 * HOL/ML: even fewer consts are declared as global (see theories Ord,
  3189 Lfp, Gfp, WF); this only affects ML packages that refer to const names
  3190 internally;
  3191 
  3192 * HOL and ZF: syntax for quotienting wrt an equivalence relation
  3193 changed from A/r to A//r;
  3194 
  3195 * ZF: new treatment of arithmetic (nat & int) may break some old
  3196 proofs;
  3197 
  3198 * Isar: renamed some attributes (RS -> THEN, simplify -> simplified,
  3199 rulify -> rule_format, elimify -> elim_format, ...);
  3200 
  3201 * Isar/Provers: intro/elim/dest attributes changed; renamed
  3202 intro/intro!/intro!! flags to intro!/intro/intro? (in most cases, one
  3203 should have to change intro!! to intro? only); replaced "delrule" by
  3204 "rule del";
  3205 
  3206 * Isar/HOL: renamed "intrs" to "intros" in inductive definitions;
  3207 
  3208 * Provers: strengthened force_tac by using new first_best_tac;
  3209 
  3210 * LaTeX document preparation: several changes of isabelle.sty (see
  3211 lib/texinputs);
  3212 
  3213 
  3214 *** Document preparation ***
  3215 
  3216 * formal comments (text blocks etc.) in new-style theories may now
  3217 contain antiquotations of thm/prop/term/typ/text to be presented
  3218 according to latex print mode; concrete syntax is like this:
  3219 @{term[show_types] "f(x) = a + x"};
  3220 
  3221 * isatool mkdir provides easy setup of Isabelle session directories,
  3222 including proper document sources;
  3223 
  3224 * generated LaTeX sources are now deleted after successful run
  3225 (isatool document -c); may retain a copy somewhere else via -D option
  3226 of isatool usedir;
  3227 
  3228 * isatool usedir -D now lets isatool latex -o sty update the Isabelle
  3229 style files, achieving self-contained LaTeX sources and simplifying
  3230 LaTeX debugging;
  3231 
  3232 * old-style theories now produce (crude) LaTeX output as well;
  3233 
  3234 * browser info session directories are now self-contained (may be put
  3235 on WWW server seperately); improved graphs of nested sessions; removed
  3236 graph for 'all sessions';
  3237 
  3238 * several improvements in isabelle style files; \isabellestyle{it}
  3239 produces fake math mode output; \isamarkupheader is now \section by
  3240 default; see lib/texinputs/isabelle.sty etc.;
  3241 
  3242 
  3243 *** Isar ***
  3244 
  3245 * Isar/Pure: local results and corresponding term bindings are now
  3246 subject to Hindley-Milner polymorphism (similar to ML); this
  3247 accommodates incremental type-inference very nicely;
  3248 
  3249 * Isar/Pure: new derived language element 'obtain' supports
  3250 generalized existence reasoning;
  3251 
  3252 * Isar/Pure: new calculational elements 'moreover' and 'ultimately'
  3253 support accumulation of results, without applying any rules yet;
  3254 useful to collect intermediate results without explicit name
  3255 references, and for use with transitivity rules with more than 2
  3256 premises;
  3257 
  3258 * Isar/Pure: scalable support for case-analysis type proofs: new
  3259 'case' language element refers to local contexts symbolically, as
  3260 produced by certain proof methods; internally, case names are attached
  3261 to theorems as "tags";
  3262 
  3263 * Isar/Pure: theory command 'hide' removes declarations from
  3264 class/type/const name spaces;
  3265 
  3266 * Isar/Pure: theory command 'defs' supports option "(overloaded)" to
  3267 indicate potential overloading;
  3268 
  3269 * Isar/Pure: changed syntax of local blocks from {{ }} to { };
  3270 
  3271 * Isar/Pure: syntax of sorts made 'inner', i.e. have to write
  3272 "{a,b,c}" instead of {a,b,c};
  3273 
  3274 * Isar/Pure now provides its own version of intro/elim/dest
  3275 attributes; useful for building new logics, but beware of confusion
  3276 with the version in Provers/classical;
  3277 
  3278 * Isar/Pure: the local context of (non-atomic) goals is provided via
  3279 case name 'antecedent';
  3280 
  3281 * Isar/Pure: removed obsolete 'transfer' attribute (transfer of thms
  3282 to the current context is now done automatically);
  3283 
  3284 * Isar/Pure: theory command 'method_setup' provides a simple interface
  3285 for definining proof methods in ML;
  3286 
  3287 * Isar/Provers: intro/elim/dest attributes changed; renamed
  3288 intro/intro!/intro!! flags to intro!/intro/intro? (INCOMPATIBILITY, in
  3289 most cases, one should have to change intro!! to intro? only);
  3290 replaced "delrule" by "rule del";
  3291 
  3292 * Isar/Provers: new 'hypsubst' method, plain 'subst' method and
  3293 'symmetric' attribute (the latter supercedes [RS sym]);
  3294 
  3295 * Isar/Provers: splitter support (via 'split' attribute and 'simp'
  3296 method modifier); 'simp' method: 'only:' modifier removes loopers as
  3297 well (including splits);
  3298 
  3299 * Isar/Provers: Simplifier and Classical methods now support all kind
  3300 of modifiers used in the past, including 'cong', 'iff', etc.
  3301 
  3302 * Isar/Provers: added 'fastsimp' and 'clarsimp' methods (combination
  3303 of Simplifier and Classical reasoner);
  3304 
  3305 * Isar/HOL: new proof method 'cases' and improved version of 'induct'
  3306 now support named cases; major packages (inductive, datatype, primrec,
  3307 recdef) support case names and properly name parameters;
  3308 
  3309 * Isar/HOL: new transitivity rules for substitution in inequalities --
  3310 monotonicity conditions are extracted to be proven at end of
  3311 calculations;
  3312 
  3313 * Isar/HOL: removed 'case_split' thm binding, should use 'cases' proof
  3314 method anyway;
  3315 
  3316 * Isar/HOL: removed old expand_if = split_if; theorems if_splits =
  3317 split_if split_if_asm; datatype package provides theorems foo.splits =
  3318 foo.split foo.split_asm for each datatype;
  3319 
  3320 * Isar/HOL: tuned inductive package, rename "intrs" to "intros"
  3321 (potential INCOMPATIBILITY), emulation of mk_cases feature for proof
  3322 scripts: new 'inductive_cases' command and 'ind_cases' method; (Note:
  3323 use "(cases (simplified))" method in proper proof texts);
  3324 
  3325 * Isar/HOL: added global 'arith_split' attribute for 'arith' method;
  3326 
  3327 * Isar: names of theorems etc. may be natural numbers as well;
  3328 
  3329 * Isar: 'pr' command: optional arguments for goals_limit and
  3330 ProofContext.prems_limit; no longer prints theory contexts, but only
  3331 proof states;
  3332 
  3333 * Isar: diagnostic commands 'pr', 'thm', 'prop', 'term', 'typ' admit
  3334 additional print modes to be specified; e.g. "pr(latex)" will print
  3335 proof state according to the Isabelle LaTeX style;
  3336 
  3337 * Isar: improved support for emulating tactic scripts, including proof
  3338 methods 'rule_tac' etc., 'cut_tac', 'thin_tac', 'subgoal_tac',
  3339 'rename_tac', 'rotate_tac', 'tactic', and 'case_tac' / 'induct_tac'
  3340 (for HOL datatypes);
  3341 
  3342 * Isar: simplified (more robust) goal selection of proof methods: 1st
  3343 goal, all goals, or explicit goal specifier (tactic emulation); thus
  3344 'proof method scripts' have to be in depth-first order;
  3345 
  3346 * Isar: tuned 'let' syntax: replaced 'as' keyword by 'and';
  3347 
  3348 * Isar: removed 'help' command, which hasn't been too helpful anyway;
  3349 should instead use individual commands for printing items
  3350 (print_commands, print_methods etc.);
  3351 
  3352 * Isar: added 'nothing' --- the empty list of theorems;
  3353 
  3354 
  3355 *** HOL ***
  3356 
  3357 * HOL/MicroJava: formalization of a fragment of Java, together with a
  3358 corresponding virtual machine and a specification of its bytecode
  3359 verifier and a lightweight bytecode verifier, including proofs of
  3360 type-safety; by Gerwin Klein, Tobias Nipkow, David von Oheimb, and
  3361 Cornelia Pusch (see also the homepage of project Bali at
  3362 http://isabelle.in.tum.de/Bali/);
  3363 
  3364 * HOL/Algebra: new theory of rings and univariate polynomials, by
  3365 Clemens Ballarin;
  3366 
  3367 * HOL/NumberTheory: fundamental Theorem of Arithmetic, Chinese
  3368 Remainder Theorem, Fermat/Euler Theorem, Wilson's Theorem, by Thomas M
  3369 Rasmussen;
  3370 
  3371 * HOL/Lattice: fundamental concepts of lattice theory and order
  3372 structures, including duals, properties of bounds versus algebraic
  3373 laws, lattice operations versus set-theoretic ones, the Knaster-Tarski
  3374 Theorem for complete lattices etc.; may also serve as a demonstration
  3375 for abstract algebraic reasoning using axiomatic type classes, and
  3376 mathematics-style proof in Isabelle/Isar; by Markus Wenzel;
  3377 
  3378 * HOL/Prolog: a (bare-bones) implementation of Lambda-Prolog, by David
  3379 von Oheimb;
  3380 
  3381 * HOL/IMPP: extension of IMP with local variables and mutually
  3382 recursive procedures, by David von Oheimb;
  3383 
  3384 * HOL/Lambda: converted into new-style theory and document;
  3385 
  3386 * HOL/ex/Multiquote: example of multiple nested quotations and
  3387 anti-quotations -- basically a generalized version of de-Bruijn
  3388 representation; very useful in avoiding lifting of operations;
  3389 
  3390 * HOL/record: added general record equality rule to simpset; fixed
  3391 select-update simplification procedure to handle extended records as
  3392 well; admit "r" as field name;
  3393 
  3394 * HOL: 0 is now overloaded over the new sort "zero", allowing its use with
  3395 other numeric types and also as the identity of groups, rings, etc.;
  3396 
  3397 * HOL: new axclass plus_ac0 for addition with the AC-laws and 0 as identity.
  3398 Types nat and int belong to this axclass;
  3399 
  3400 * HOL: greatly improved simplification involving numerals of type nat, int, real:
  3401    (i + #8 + j) = Suc k simplifies to  #7 + (i + j) = k
  3402    i*j + k + j*#3*i     simplifies to  #4*(i*j) + k
  3403   two terms #m*u and #n*u are replaced by #(m+n)*u
  3404     (where #m, #n and u can implicitly be 1; this is simproc combine_numerals)
  3405   and the term/formula #m*u+x ~~ #n*u+y simplifies simplifies to #(m-n)+x ~~ y
  3406     or x ~~ #(n-m)+y, where ~~ is one of = < <= or - (simproc cancel_numerals);
  3407 
  3408 * HOL: meson_tac is available (previously in ex/meson.ML); it is a
  3409 powerful prover for predicate logic but knows nothing of clasets; see
  3410 ex/mesontest.ML and ex/mesontest2.ML for example applications;
  3411 
  3412 * HOL: new version of "case_tac" subsumes both boolean case split and
  3413 "exhaust_tac" on datatypes; INCOMPATIBILITY: exhaust_tac no longer
  3414 exists, may define val exhaust_tac = case_tac for ad-hoc portability;
  3415 
  3416 * HOL: simplification no longer dives into case-expressions: only the
  3417 selector expression is simplified, but not the remaining arms; to
  3418 enable full simplification of case-expressions for datatype t, you may
  3419 remove t.weak_case_cong from the simpset, either globally (Delcongs
  3420 [thm"t.weak_case_cong"];) or locally (delcongs [...]).
  3421 
  3422 * HOL/recdef: the recursion equations generated by 'recdef' for
  3423 function 'f' are now called f.simps instead of f.rules; if all
  3424 termination conditions are proved automatically, these simplification
  3425 rules are added to the simpset, as in primrec; rules may be named
  3426 individually as well, resulting in a separate list of theorems for
  3427 each equation;
  3428 
  3429 * HOL/While is a new theory that provides a while-combinator. It
  3430 permits the definition of tail-recursive functions without the
  3431 provision of a termination measure. The latter is necessary once the
  3432 invariant proof rule for while is applied.
  3433 
  3434 * HOL: new (overloaded) notation for the set of elements below/above
  3435 some element: {..u}, {..u(}, {l..}, {)l..}. See theory SetInterval.
  3436 
  3437 * HOL: theorems impI, allI, ballI bound as "strip";
  3438 
  3439 * HOL: new tactic induct_thm_tac: thm -> string -> int -> tactic
  3440 induct_tac th "x1 ... xn" expects th to have a conclusion of the form
  3441 P v1 ... vn and abbreviates res_inst_tac [("v1","x1"),...,("vn","xn")] th;
  3442 
  3443 * HOL/Real: "rabs" replaced by overloaded "abs" function;
  3444 
  3445 * HOL: theory Sexp now in HOL/Induct examples (it used to be part of
  3446 main HOL, but was unused);
  3447 
  3448 * HOL: fewer consts declared as global (e.g. have to refer to
  3449 "Lfp.lfp" instead of "lfp" internally; affects ML packages only);
  3450 
  3451 * HOL: tuned AST representation of nested pairs, avoiding bogus output
  3452 in case of overlap with user translations (e.g. judgements over
  3453 tuples); (note that the underlying logical represenation is still
  3454 bogus);
  3455 
  3456 
  3457 *** ZF ***
  3458 
  3459 * ZF: simplification automatically cancels common terms in arithmetic
  3460 expressions over nat and int;
  3461 
  3462 * ZF: new treatment of nat to minimize type-checking: all operators
  3463 coerce their operands to a natural number using the function natify,
  3464 making the algebraic laws unconditional;
  3465 
  3466 * ZF: as above, for int: operators coerce their operands to an integer
  3467 using the function intify;
  3468 
  3469 * ZF: the integer library now contains many of the usual laws for the
  3470 orderings, including $<=, and monotonicity laws for $+ and $*;
  3471 
  3472 * ZF: new example ZF/ex/NatSum to demonstrate integer arithmetic
  3473 simplification;
  3474 
  3475 * FOL and ZF: AddIffs now available, giving theorems of the form P<->Q
  3476 to the simplifier and classical reasoner simultaneously;
  3477 
  3478 
  3479 *** General ***
  3480 
  3481 * Provers: blast_tac now handles actual object-logic rules as
  3482 assumptions; note that auto_tac uses blast_tac internally as well;
  3483 
  3484 * Provers: new functions rulify/rulify_no_asm: thm -> thm for turning
  3485 outer -->/All/Ball into ==>/!!; qed_spec_mp now uses rulify_no_asm;
  3486 
  3487 * Provers: delrules now handles destruct rules as well (no longer need
  3488 explicit make_elim);
  3489 
  3490 * Provers: Blast_tac now warns of and ignores "weak elimination rules" e.g.
  3491   [| inj ?f;          ?f ?x = ?f ?y; ?x = ?y ==> ?W |] ==> ?W
  3492 use instead the strong form,
  3493   [| inj ?f; ~ ?W ==> ?f ?x = ?f ?y; ?x = ?y ==> ?W |] ==> ?W
  3494 in HOL, FOL and ZF the function cla_make_elim will create such rules
  3495 from destruct-rules;
  3496 
  3497 * Provers: Simplifier.easy_setup provides a fast path to basic
  3498 Simplifier setup for new object-logics;
  3499 
  3500 * Pure: AST translation rules no longer require constant head on LHS;
  3501 
  3502 * Pure: improved name spaces: ambiguous output is qualified; support
  3503 for hiding of names;
  3504 
  3505 * system: smart setup of canonical ML_HOME, ISABELLE_INTERFACE, and
  3506 XSYMBOL_HOME; no longer need to do manual configuration in most
  3507 situations;
  3508 
  3509 * system: compression of ML heaps images may now be controlled via -c
  3510 option of isabelle and isatool usedir (currently only observed by
  3511 Poly/ML);
  3512 
  3513 * system: isatool installfonts may handle X-Symbol fonts as well (very
  3514 useful for remote X11);
  3515 
  3516 * system: provide TAGS file for Isabelle sources;
  3517 
  3518 * ML: infix 'OF' is a version of 'MRS' with more appropriate argument
  3519 order;
  3520 
  3521 * ML: renamed flags Syntax.trace_norm_ast to Syntax.trace_ast; global
  3522 timing flag supersedes proof_timing and Toplevel.trace;
  3523 
  3524 * ML: new combinators |>> and |>>> for incremental transformations
  3525 with secondary results (e.g. certain theory extensions):
  3526 
  3527 * ML: PureThy.add_defs gets additional argument to indicate potential
  3528 overloading (usually false);
  3529 
  3530 * ML: PureThy.add_thms/add_axioms/add_defs now return theorems as
  3531 results;
  3532 
  3533 
  3534 
  3535 New in Isabelle99 (October 1999)
  3536 --------------------------------
  3537 
  3538 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  3539 
  3540 * HOL: The THEN and ELSE parts of conditional expressions (if P then x else y)
  3541 are no longer simplified.  (This allows the simplifier to unfold recursive
  3542 functional programs.)  To restore the old behaviour, declare
  3543 
  3544     Delcongs [if_weak_cong];
  3545 
  3546 * HOL: Removed the obsolete syntax "Compl A"; use -A for set
  3547 complement;
  3548 
  3549 * HOL: the predicate "inj" is now defined by translation to "inj_on";
  3550 
  3551 * HOL/datatype: mutual_induct_tac no longer exists --
  3552   use induct_tac "x_1 ... x_n" instead of mutual_induct_tac ["x_1", ..., "x_n"]
  3553 
  3554 * HOL/typedef: fixed type inference for representing set; type
  3555 arguments now have to occur explicitly on the rhs as type constraints;
  3556 
  3557 * ZF: The con_defs part of an inductive definition may no longer refer
  3558 to constants declared in the same theory;
  3559 
  3560 * HOL, ZF: the function mk_cases, generated by the inductive
  3561 definition package, has lost an argument.  To simplify its result, it
  3562 uses the default simpset instead of a supplied list of theorems.
  3563 
  3564 * HOL/List: the constructors of type list are now Nil and Cons;
  3565 
  3566 * Simplifier: the type of the infix ML functions
  3567         setSSolver addSSolver setSolver addSolver
  3568 is now  simpset * solver -> simpset  where `solver' is a new abstract type
  3569 for packaging solvers. A solver is created via
  3570         mk_solver: string -> (thm list -> int -> tactic) -> solver
  3571 where the string argument is only a comment.
  3572 
  3573 
  3574 *** Proof tools ***
  3575 
  3576 * Provers/Arith/fast_lin_arith.ML contains a functor for creating a
  3577 decision procedure for linear arithmetic. Currently it is used for
  3578 types `nat', `int', and `real' in HOL (see below); it can, should and
  3579 will be instantiated for other types and logics as well.
  3580 
  3581 * The simplifier now accepts rewrite rules with flexible heads, eg
  3582      hom ?f ==> ?f(?x+?y) = ?f ?x + ?f ?y
  3583   They are applied like any rule with a non-pattern lhs, i.e. by first-order
  3584   matching.
  3585 
  3586 
  3587 *** General ***
  3588 
  3589 * New Isabelle/Isar subsystem provides an alternative to traditional
  3590 tactical theorem proving; together with the ProofGeneral/isar user
  3591 interface it offers an interactive environment for developing human
  3592 readable proof documents (Isar == Intelligible semi-automated
  3593 reasoning); for further information see isatool doc isar-ref,
  3594 src/HOL/Isar_examples and http://isabelle.in.tum.de/Isar/
  3595 
  3596 * improved and simplified presentation of theories: better HTML markup
  3597 (including colors), graph views in several sizes; isatool usedir now
  3598 provides a proper interface for user theories (via -P option); actual
  3599 document preparation based on (PDF)LaTeX is available as well (for
  3600 new-style theories only); see isatool doc system for more information;
  3601 
  3602 * native support for Proof General, both for classic Isabelle and
  3603 Isabelle/Isar;
  3604 
  3605 * ML function thm_deps visualizes dependencies of theorems and lemmas,
  3606 using the graph browser tool;
  3607 
  3608 * Isabelle manuals now also available as PDF;
  3609 
  3610 * theory loader rewritten from scratch (may not be fully
  3611 bug-compatible); old loadpath variable has been replaced by show_path,
  3612 add_path, del_path, reset_path functions; new operations such as
  3613 update_thy, touch_thy, remove_thy, use/update_thy_only (see also
  3614 isatool doc ref);
  3615 
  3616 * improved isatool install: option -k creates KDE application icon,
  3617 option -p DIR installs standalone binaries;
  3618 
  3619 * added ML_PLATFORM setting (useful for cross-platform installations);
  3620 more robust handling of platform specific ML images for SML/NJ;
  3621 
  3622 * the settings environment is now statically scoped, i.e. it is never
  3623 created again in sub-processes invoked from isabelle, isatool, or
  3624 Isabelle;
  3625 
  3626 * path element specification '~~' refers to '$ISABELLE_HOME';
  3627 
  3628 * in locales, the "assumes" and "defines" parts may be omitted if
  3629 empty;
  3630 
  3631 * new print_mode "xsymbols" for extended symbol support (e.g. genuine
  3632 long arrows);
  3633 
  3634 * new print_mode "HTML";
  3635 
  3636 * new flag show_tags controls display of tags of theorems (which are
  3637 basically just comments that may be attached by some tools);
  3638 
  3639 * Isamode 2.6 requires patch to accomodate change of Isabelle font
  3640 mode and goal output format:
  3641 
  3642 diff -r Isamode-2.6/elisp/isa-load.el Isamode/elisp/isa-load.el
  3643 244c244
  3644 <       (list (isa-getenv "ISABELLE") "-msymbols" logic-name)
  3645 ---
  3646 >       (list (isa-getenv "ISABELLE") "-misabelle_font" "-msymbols" logic-name)
  3647 diff -r Isabelle-2.6/elisp/isa-proofstate.el Isamode/elisp/isa-proofstate.el
  3648 181c181
  3649 < (defconst proofstate-proofstart-regexp "^Level [0-9]+$"
  3650 ---
  3651 > (defconst proofstate-proofstart-regexp "^Level [0-9]+"
  3652 
  3653 * function bind_thms stores lists of theorems (cf. bind_thm);
  3654 
  3655 * new shorthand tactics ftac, eatac, datac, fatac;
  3656 
  3657 * qed (and friends) now accept "" as result name; in that case the
  3658 theorem is not stored, but proper checks and presentation of the
  3659 result still apply;
  3660 
  3661 * theorem database now also indexes constants "Trueprop", "all",
  3662 "==>", "=="; thus thms_containing, findI etc. may retrieve more rules;
  3663 
  3664 
  3665 *** HOL ***
  3666 
  3667 ** HOL arithmetic **
  3668 
  3669 * There are now decision procedures for linear arithmetic over nat and
  3670 int:
  3671 
  3672 1. arith_tac copes with arbitrary formulae involving `=', `<', `<=',
  3673 `+', `-', `Suc', `min', `max' and numerical constants; other subterms
  3674 are treated as atomic; subformulae not involving type `nat' or `int'
  3675 are ignored; quantified subformulae are ignored unless they are
  3676 positive universal or negative existential. The tactic has to be
  3677 invoked by hand and can be a little bit slow. In particular, the
  3678 running time is exponential in the number of occurrences of `min' and
  3679 `max', and `-' on `nat'.
  3680 
  3681 2. fast_arith_tac is a cut-down version of arith_tac: it only takes
  3682 (negated) (in)equalities among the premises and the conclusion into
  3683 account (i.e. no compound formulae) and does not know about `min' and
  3684 `max', and `-' on `nat'. It is fast and is used automatically by the
  3685 simplifier.
  3686 
  3687 NB: At the moment, these decision procedures do not cope with mixed
  3688 nat/int formulae where the two parts interact, such as `m < n ==>
  3689 int(m) < int(n)'.
  3690 
  3691 * HOL/Numeral provides a generic theory of numerals (encoded
  3692 efficiently as bit strings); setup for types nat/int/real is in place;
  3693 INCOMPATIBILITY: since numeral syntax is now polymorphic, rather than
  3694 int, existing theories and proof scripts may require a few additional
  3695 type constraints;
  3696 
  3697 * integer division and remainder can now be performed on constant
  3698 arguments;
  3699 
  3700 * many properties of integer multiplication, division and remainder
  3701 are now available;
  3702 
  3703 * An interface to the Stanford Validity Checker (SVC) is available through the
  3704 tactic svc_tac.  Propositional tautologies and theorems of linear arithmetic
  3705 are proved automatically.  SVC must be installed separately, and its results
  3706 must be TAKEN ON TRUST (Isabelle does not check the proofs, but tags any
  3707 invocation of the underlying oracle).  For SVC see
  3708   http://verify.stanford.edu/SVC
  3709 
  3710 * IsaMakefile: the HOL-Real target now builds an actual image;
  3711 
  3712 
  3713 ** HOL misc **
  3714 
  3715 * HOL/Real/HahnBanach: the Hahn-Banach theorem for real vector spaces
  3716 (in Isabelle/Isar) -- by Gertrud Bauer;
  3717 
  3718 * HOL/BCV: generic model of bytecode verification, i.e. data-flow
  3719 analysis for assembly languages with subtypes;
  3720 
  3721 * HOL/TLA (Lamport's Temporal Logic of Actions): major reorganization
  3722 -- avoids syntactic ambiguities and treats state, transition, and
  3723 temporal levels more uniformly; introduces INCOMPATIBILITIES due to
  3724 changed syntax and (many) tactics;
  3725 
  3726 * HOL/inductive: Now also handles more general introduction rules such
  3727   as "ALL y. (y, x) : r --> y : acc r ==> x : acc r"; monotonicity
  3728   theorems are now maintained within the theory (maintained via the
  3729   "mono" attribute);
  3730 
  3731 * HOL/datatype: Now also handles arbitrarily branching datatypes
  3732   (using function types) such as
  3733 
  3734   datatype 'a tree = Atom 'a | Branch "nat => 'a tree"
  3735 
  3736 * HOL/record: record_simproc (part of the default simpset) takes care
  3737 of selectors applied to updated records; record_split_tac is no longer
  3738 part of the default claset; update_defs may now be removed from the
  3739 simpset in many cases; COMPATIBILITY: old behavior achieved by
  3740 
  3741   claset_ref () := claset() addSWrapper record_split_wrapper;
  3742   Delsimprocs [record_simproc]
  3743 
  3744 * HOL/typedef: fixed type inference for representing set; type
  3745 arguments now have to occur explicitly on the rhs as type constraints;
  3746 
  3747 * HOL/recdef (TFL): 'congs' syntax now expects comma separated list of theorem
  3748 names rather than an ML expression;
  3749 
  3750 * HOL/defer_recdef (TFL): like recdef but the well-founded relation can be
  3751 supplied later.  Program schemes can be defined, such as
  3752     "While B C s = (if B s then While B C (C s) else s)"
  3753 where the well-founded relation can be chosen after B and C have been given.
  3754 
  3755 * HOL/List: the constructors of type list are now Nil and Cons;
  3756 INCOMPATIBILITY: while [] and infix # syntax is still there, of
  3757 course, ML tools referring to List.list.op # etc. have to be adapted;
  3758 
  3759 * HOL_quantifiers flag superseded by "HOL" print mode, which is
  3760 disabled by default; run isabelle with option -m HOL to get back to
  3761 the original Gordon/HOL-style output;
  3762 
  3763 * HOL/Ord.thy: new bounded quantifier syntax (input only): ALL x<y. P,
  3764 ALL x<=y. P, EX x<y. P, EX x<=y. P;
  3765 
  3766 * HOL basic syntax simplified (more orthogonal): all variants of
  3767 All/Ex now support plain / symbolic / HOL notation; plain syntax for
  3768 Eps operator is provided as well: "SOME x. P[x]";
  3769 
  3770 * HOL/Sum.thy: sum_case has been moved to HOL/Datatype;
  3771 
  3772 * HOL/Univ.thy: infix syntax <*>, <+>, <**>, <+> eliminated and made
  3773 thus available for user theories;
  3774 
  3775 * HOLCF/IOA/Sequents: renamed 'Cons' to 'Consq' to avoid clash with
  3776 HOL/List; hardly an INCOMPATIBILITY since '>>' syntax is used all the
  3777 time;
  3778 
  3779 * HOL: new tactic smp_tac: int -> int -> tactic, which applies spec
  3780 several times and then mp;
  3781 
  3782 
  3783 *** LK ***
  3784 
  3785 * the notation <<...>> is now available as a notation for sequences of
  3786 formulas;
  3787 
  3788 * the simplifier is now installed
  3789 
  3790 * the axiom system has been generalized (thanks to Soren Heilmann)
  3791 
  3792 * the classical reasoner now has a default rule database
  3793 
  3794 
  3795 *** ZF ***
  3796 
  3797 * new primrec section allows primitive recursive functions to be given
  3798 directly (as in HOL) over datatypes and the natural numbers;
  3799 
  3800 * new tactics induct_tac and exhaust_tac for induction (or case
  3801 analysis) over datatypes and the natural numbers;
  3802 
  3803 * the datatype declaration of type T now defines the recursor T_rec;
  3804 
  3805 * simplification automatically does freeness reasoning for datatype
  3806 constructors;
  3807 
  3808 * automatic type-inference, with AddTCs command to insert new
  3809 type-checking rules;
  3810 
  3811 * datatype introduction rules are now added as Safe Introduction rules
  3812 to the claset;
  3813 
  3814 * the syntax "if P then x else y" is now available in addition to
  3815 if(P,x,y);
  3816 
  3817 
  3818 *** Internal programming interfaces ***
  3819 
  3820 * tuned simplifier trace output; new flag debug_simp;
  3821 
  3822 * structures Vartab / Termtab (instances of TableFun) offer efficient
  3823 tables indexed by indexname_ord / term_ord (compatible with aconv);
  3824 
  3825 * AxClass.axclass_tac lost the theory argument;
  3826 
  3827 * tuned current_goals_markers semantics: begin / end goal avoids
  3828 printing empty lines;
  3829 
  3830 * removed prs and prs_fn hook, which was broken because it did not
  3831 include \n in its semantics, forcing writeln to add one
  3832 uncoditionally; replaced prs_fn by writeln_fn; consider std_output:
  3833 string -> unit if you really want to output text without newline;
  3834 
  3835 * Symbol.output subject to print mode; INCOMPATIBILITY: defaults to
  3836 plain output, interface builders may have to enable 'isabelle_font'
  3837 mode to get Isabelle font glyphs as before;
  3838 
  3839 * refined token_translation interface; INCOMPATIBILITY: output length
  3840 now of type real instead of int;
  3841 
  3842 * theory loader actions may be traced via new ThyInfo.add_hook
  3843 interface (see src/Pure/Thy/thy_info.ML); example application: keep
  3844 your own database of information attached to *whole* theories -- as
  3845 opposed to intra-theory data slots offered via TheoryDataFun;
  3846 
  3847 * proper handling of dangling sort hypotheses (at last!);
  3848 Thm.strip_shyps and Drule.strip_shyps_warning take care of removing
  3849 extra sort hypotheses that can be witnessed from the type signature;
  3850 the force_strip_shyps flag is gone, any remaining shyps are simply
  3851 left in the theorem (with a warning issued by strip_shyps_warning);
  3852 
  3853 
  3854 
  3855 New in Isabelle98-1 (October 1998)
  3856 ----------------------------------
  3857 
  3858 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  3859 
  3860 * several changes of automated proof tools;
  3861 
  3862 * HOL: major changes to the inductive and datatype packages, including
  3863 some minor incompatibilities of theory syntax;
  3864 
  3865 * HOL: renamed r^-1 to 'converse' from 'inverse'; 'inj_onto' is now
  3866 called `inj_on';
  3867 
  3868 * HOL: removed duplicate thms in Arith:
  3869   less_imp_add_less  should be replaced by  trans_less_add1
  3870   le_imp_add_le      should be replaced by  trans_le_add1
  3871 
  3872 * HOL: unary minus is now overloaded (new type constraints may be
  3873 required);
  3874 
  3875 * HOL and ZF: unary minus for integers is now #- instead of #~.  In
  3876 ZF, expressions such as n#-1 must be changed to n#- 1, since #-1 is
  3877 now taken as an integer constant.
  3878 
  3879 * Pure: ML function 'theory_of' renamed to 'theory';
  3880 
  3881 
  3882 *** Proof tools ***
  3883 
  3884 * Simplifier:
  3885   1. Asm_full_simp_tac is now more aggressive.
  3886      1. It will sometimes reorient premises if that increases their power to
  3887         simplify.
  3888      2. It does no longer proceed strictly from left to right but may also
  3889         rotate premises to achieve further simplification.
  3890      For compatibility reasons there is now Asm_lr_simp_tac which is like the
  3891      old Asm_full_simp_tac in that it does not rotate premises.
  3892   2. The simplifier now knows a little bit about nat-arithmetic.
  3893 
  3894 * Classical reasoner: wrapper mechanism for the classical reasoner now
  3895 allows for selected deletion of wrappers, by introduction of names for
  3896 wrapper functionals.  This implies that addbefore, addSbefore,
  3897 addaltern, and addSaltern now take a pair (name, tactic) as argument,
  3898 and that adding two tactics with the same name overwrites the first
  3899 one (emitting a warning).
  3900   type wrapper = (int -> tactic) -> (int -> tactic)
  3901   setWrapper, setSWrapper, compWrapper and compSWrapper are replaced by
  3902   addWrapper, addSWrapper: claset * (string * wrapper) -> claset
  3903   delWrapper, delSWrapper: claset *  string            -> claset
  3904   getWrapper is renamed to appWrappers, getSWrapper to appSWrappers;
  3905 
  3906 * Classical reasoner: addbefore/addSbefore now have APPEND/ORELSE
  3907 semantics; addbefore now affects only the unsafe part of step_tac
  3908 etc.; this affects addss/auto_tac/force_tac, so EXISTING PROOFS MAY
  3909 FAIL, but proofs should be fixable easily, e.g. by replacing Auto_tac
  3910 by Force_tac;
  3911 
  3912 * Classical reasoner: setwrapper to setWrapper and compwrapper to
  3913 compWrapper; added safe wrapper (and access functions for it);
  3914 
  3915 * HOL/split_all_tac is now much faster and fails if there is nothing
  3916 to split.  Some EXISTING PROOFS MAY REQUIRE ADAPTION because the order
  3917 and the names of the automatically generated variables have changed.
  3918 split_all_tac has moved within claset() from unsafe wrappers to safe
  3919 wrappers, which means that !!-bound variables are split much more
  3920 aggressively, and safe_tac and clarify_tac now split such variables.
  3921 If this splitting is not appropriate, use delSWrapper "split_all_tac".
  3922 Note: the same holds for record_split_tac, which does the job of
  3923 split_all_tac for record fields.
  3924 
  3925 * HOL/Simplifier: Rewrite rules for case distinctions can now be added
  3926 permanently to the default simpset using Addsplits just like
  3927 Addsimps. They can be removed via Delsplits just like
  3928 Delsimps. Lower-case versions are also available.
  3929 
  3930 * HOL/Simplifier: The rule split_if is now part of the default
  3931 simpset. This means that the simplifier will eliminate all occurrences
  3932 of if-then-else in the conclusion of a goal. To prevent this, you can
  3933 either remove split_if completely from the default simpset by
  3934 `Delsplits [split_if]' or remove it in a specific call of the
  3935 simplifier using `... delsplits [split_if]'.  You can also add/delete
  3936 other case splitting rules to/from the default simpset: every datatype
  3937 generates suitable rules `split_t_case' and `split_t_case_asm' (where
  3938 t is the name of the datatype).
  3939 
  3940 * Classical reasoner / Simplifier combination: new force_tac (and
  3941 derivatives Force_tac, force) combines rewriting and classical
  3942 reasoning (and whatever other tools) similarly to auto_tac, but is
  3943 aimed to solve the given subgoal completely.
  3944 
  3945 
  3946 *** General ***
  3947 
  3948 * new top-level commands `Goal' and `Goalw' that improve upon `goal'
  3949 and `goalw': the theory is no longer needed as an explicit argument -
  3950 the current theory context is used; assumptions are no longer returned
  3951 at the ML-level unless one of them starts with ==> or !!; it is
  3952 recommended to convert to these new commands using isatool fixgoal
  3953 (backup your sources first!);
  3954 
  3955 * new top-level commands 'thm' and 'thms' for retrieving theorems from
  3956 the current theory context, and 'theory' to lookup stored theories;
  3957 
  3958 * new theory section 'locale' for declaring constants, assumptions and
  3959 definitions that have local scope;
  3960 
  3961 * new theory section 'nonterminals' for purely syntactic types;
  3962 
  3963 * new theory section 'setup' for generic ML setup functions
  3964 (e.g. package initialization);
  3965 
  3966 * the distribution now includes Isabelle icons: see
  3967 lib/logo/isabelle-{small,tiny}.xpm;
  3968 
  3969 * isatool install - install binaries with absolute references to
  3970 ISABELLE_HOME/bin;
  3971 
  3972 * isatool logo -- create instances of the Isabelle logo (as EPS);
  3973 
  3974 * print mode 'emacs' reserved for Isamode;
  3975 
  3976 * support multiple print (ast) translations per constant name;
  3977 
  3978 * theorems involving oracles are now printed with a suffixed [!];
  3979 
  3980 
  3981 *** HOL ***
  3982 
  3983 * there is now a tutorial on Isabelle/HOL (do 'isatool doc tutorial');
  3984 
  3985 * HOL/inductive package reorganized and improved: now supports mutual
  3986 definitions such as
  3987 
  3988   inductive EVEN ODD
  3989     intrs
  3990       null "0 : EVEN"
  3991       oddI "n : EVEN ==> Suc n : ODD"
  3992       evenI "n : ODD ==> Suc n : EVEN"
  3993 
  3994 new theorem list "elims" contains an elimination rule for each of the
  3995 recursive sets; inductive definitions now handle disjunctive premises
  3996 correctly (also ZF);
  3997 
  3998 INCOMPATIBILITIES: requires Inductive as an ancestor; component
  3999 "mutual_induct" no longer exists - the induction rule is always
  4000 contained in "induct";
  4001 
  4002 
  4003 * HOL/datatype package re-implemented and greatly improved: now
  4004 supports mutually recursive datatypes such as
  4005 
  4006   datatype
  4007     'a aexp = IF_THEN_ELSE ('a bexp) ('a aexp) ('a aexp)
  4008             | SUM ('a aexp) ('a aexp)
  4009             | DIFF ('a aexp) ('a aexp)
  4010             | NUM 'a
  4011   and
  4012     'a bexp = LESS ('a aexp) ('a aexp)
  4013             | AND ('a bexp) ('a bexp)
  4014             | OR ('a bexp) ('a bexp)
  4015 
  4016 as well as indirectly recursive datatypes such as
  4017 
  4018   datatype
  4019     ('a, 'b) term = Var 'a
  4020                   | App 'b ((('a, 'b) term) list)
  4021 
  4022 The new tactic  mutual_induct_tac [<var_1>, ..., <var_n>] i  performs
  4023 induction on mutually / indirectly recursive datatypes.
  4024 
  4025 Primrec equations are now stored in theory and can be accessed via
  4026 <function_name>.simps.
  4027 
  4028 INCOMPATIBILITIES:
  4029 
  4030   - Theories using datatypes must now have theory Datatype as an
  4031     ancestor.
  4032   - The specific <typename>.induct_tac no longer exists - use the
  4033     generic induct_tac instead.
  4034   - natE has been renamed to nat.exhaust - use exhaust_tac
  4035     instead of res_inst_tac ... natE. Note that the variable
  4036     names in nat.exhaust differ from the names in natE, this
  4037     may cause some "fragile" proofs to fail.
  4038   - The theorems split_<typename>_case and split_<typename>_case_asm
  4039     have been renamed to <typename>.split and <typename>.split_asm.
  4040   - Since default sorts of type variables are now handled correctly,
  4041     some datatype definitions may have to be annotated with explicit
  4042     sort constraints.
  4043   - Primrec definitions no longer require function name and type
  4044     of recursive argument.
  4045 
  4046 Consider using isatool fixdatatype to adapt your theories and proof
  4047 scripts to the new package (backup your sources first!).
  4048 
  4049 
  4050 * HOL/record package: considerably improved implementation; now
  4051 includes concrete syntax for record types, terms, updates; theorems
  4052 for surjective pairing and splitting !!-bound record variables; proof
  4053 support is as follows:
  4054 
  4055   1) standard conversions (selectors or updates applied to record
  4056 constructor terms) are part of the standard simpset;
  4057 
  4058   2) inject equations of the form ((x, y) = (x', y')) == x=x' & y=y' are
  4059 made part of standard simpset and claset via addIffs;
  4060 
  4061   3) a tactic for record field splitting (record_split_tac) is part of
  4062 the standard claset (addSWrapper);
  4063 
  4064 To get a better idea about these rules you may retrieve them via
  4065 something like 'thms "foo.simps"' or 'thms "foo.iffs"', where "foo" is
  4066 the name of your record type.
  4067 
  4068 The split tactic 3) conceptually simplifies by the following rule:
  4069 
  4070   "(!!x. PROP ?P x) == (!!a b. PROP ?P (a, b))"
  4071 
  4072 Thus any record variable that is bound by meta-all will automatically
  4073 blow up into some record constructor term, consequently the
  4074 simplifications of 1), 2) apply.  Thus force_tac, auto_tac etc. shall
  4075 solve record problems automatically.
  4076 
  4077 
  4078 * reorganized the main HOL image: HOL/Integ and String loaded by
  4079 default; theory Main includes everything;
  4080 
  4081 * automatic simplification of integer sums and comparisons, using cancellation;
  4082 
  4083 * added option_map_eq_Some and not_Some_eq to the default simpset and claset;
  4084 
  4085 * added disj_not1 = "(~P | Q) = (P --> Q)" to the default simpset;
  4086 
  4087 * many new identities for unions, intersections, set difference, etc.;
  4088 
  4089 * expand_if, expand_split, expand_sum_case and expand_nat_case are now
  4090 called split_if, split_split, split_sum_case and split_nat_case (to go
  4091 with add/delsplits);
  4092 
  4093 * HOL/Prod introduces simplification procedure unit_eq_proc rewriting
  4094 (?x::unit) = (); this is made part of the default simpset, which COULD
  4095 MAKE EXISTING PROOFS FAIL under rare circumstances (consider
  4096 'Delsimprocs [unit_eq_proc];' as last resort); also note that
  4097 unit_abs_eta_conv is added in order to counter the effect of
  4098 unit_eq_proc on (%u::unit. f u), replacing it by f rather than by
  4099 %u.f();
  4100 
  4101 * HOL/Fun INCOMPATIBILITY: `inj_onto' is now called `inj_on' (which
  4102 makes more sense);
  4103 
  4104 * HOL/Set INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
  4105   It and 'sym RS equals0D' are now in the default  claset, giving automatic
  4106   disjointness reasoning but breaking a few old proofs.
  4107 
  4108 * HOL/Relation INCOMPATIBILITY: renamed the relational operator r^-1
  4109 to 'converse' from 'inverse' (for compatibility with ZF and some
  4110 literature);
  4111 
  4112 * HOL/recdef can now declare non-recursive functions, with {} supplied as
  4113 the well-founded relation;
  4114 
  4115 * HOL/Set INCOMPATIBILITY: the complement of set A is now written -A instead of
  4116     Compl A.  The "Compl" syntax remains available as input syntax for this
  4117     release ONLY.
  4118 
  4119 * HOL/Update: new theory of function updates:
  4120     f(a:=b) == %x. if x=a then b else f x
  4121 may also be iterated as in f(a:=b,c:=d,...);
  4122 
  4123 * HOL/Vimage: new theory for inverse image of a function, syntax f-``B;
  4124 
  4125 * HOL/List:
  4126   - new function list_update written xs[i:=v] that updates the i-th
  4127     list position. May also be iterated as in xs[i:=a,j:=b,...].
  4128   - new function `upt' written [i..j(] which generates the list
  4129     [i,i+1,...,j-1], i.e. the upper bound is excluded. To include the upper
  4130     bound write [i..j], which is a shorthand for [i..j+1(].
  4131   - new lexicographic orderings and corresponding wellfoundedness theorems.
  4132 
  4133 * HOL/Arith:
  4134   - removed 'pred' (predecessor) function;
  4135   - generalized some theorems about n-1;
  4136   - many new laws about "div" and "mod";
  4137   - new laws about greatest common divisors (see theory ex/Primes);
  4138 
  4139 * HOL/Relation: renamed the relational operator r^-1 "converse"
  4140 instead of "inverse";
  4141 
  4142 * HOL/Induct/Multiset: a theory of multisets, including the wellfoundedness
  4143   of the multiset ordering;
  4144 
  4145 * directory HOL/Real: a construction of the reals using Dedekind cuts
  4146   (not included by default);
  4147 
  4148 * directory HOL/UNITY: Chandy and Misra's UNITY formalism;
  4149 
  4150 * directory HOL/Hoare: a new version of Hoare logic which permits many-sorted
  4151   programs, i.e. different program variables may have different types.
  4152 
  4153 * calling (stac rew i) now fails if "rew" has no effect on the goal
  4154   [previously, this check worked only if the rewrite rule was unconditional]
  4155   Now rew can involve either definitions or equalities (either == or =).
  4156 
  4157 
  4158 *** ZF ***
  4159 
  4160 * theory Main includes everything; INCOMPATIBILITY: theory ZF.thy contains
  4161   only the theorems proved on ZF.ML;
  4162 
  4163 * ZF INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
  4164   It and 'sym RS equals0D' are now in the default  claset, giving automatic
  4165   disjointness reasoning but breaking a few old proofs.
  4166 
  4167 * ZF/Update: new theory of function updates
  4168     with default rewrite rule  f(x:=y) ` z = if(z=x, y, f`z)
  4169   may also be iterated as in f(a:=b,c:=d,...);
  4170 
  4171 * in  let x=t in u(x), neither t nor u(x) has to be an FOL term.
  4172 
  4173 * calling (stac rew i) now fails if "rew" has no effect on the goal
  4174   [previously, this check worked only if the rewrite rule was unconditional]
  4175   Now rew can involve either definitions or equalities (either == or =).
  4176 
  4177 * case_tac provided for compatibility with HOL
  4178     (like the old excluded_middle_tac, but with subgoals swapped)
  4179 
  4180 
  4181 *** Internal programming interfaces ***
  4182 
  4183 * Pure: several new basic modules made available for general use, see
  4184 also src/Pure/README;
  4185 
  4186 * improved the theory data mechanism to support encapsulation (data
  4187 kind name replaced by private Object.kind, acting as authorization
  4188 key); new type-safe user interface via functor TheoryDataFun; generic
  4189 print_data function becomes basically useless;
  4190 
  4191 * removed global_names compatibility flag -- all theory declarations
  4192 are qualified by default;
  4193 
  4194 * module Pure/Syntax now offers quote / antiquote translation
  4195 functions (useful for Hoare logic etc. with implicit dependencies);
  4196 see HOL/ex/Antiquote for an example use;
  4197 
  4198 * Simplifier now offers conversions (asm_)(full_)rewrite: simpset ->
  4199 cterm -> thm;
  4200 
  4201 * new tactical CHANGED_GOAL for checking that a tactic modifies a
  4202 subgoal;
  4203 
  4204 * Display.print_goals function moved to Locale.print_goals;
  4205 
  4206 * standard print function for goals supports current_goals_markers
  4207 variable for marking begin of proof, end of proof, start of goal; the
  4208 default is ("", "", ""); setting current_goals_markers := ("<proof>",
  4209 "</proof>", "<goal>") causes SGML like tagged proof state printing,
  4210 for example;
  4211 
  4212 
  4213 
  4214 New in Isabelle98 (January 1998)
  4215 --------------------------------
  4216 
  4217 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  4218 
  4219 * changed lexical syntax of terms / types: dots made part of long
  4220 identifiers, e.g. "%x.x" no longer possible, should be "%x. x";
  4221 
  4222 * simpset (and claset) reference variable replaced by functions
  4223 simpset / simpset_ref;
  4224 
  4225 * no longer supports theory aliases (via merge) and non-trivial
  4226 implicit merge of thms' signatures;
  4227 
  4228 * most internal names of constants changed due to qualified names;
  4229 
  4230 * changed Pure/Sequence interface (see Pure/seq.ML);
  4231 
  4232 
  4233 *** General Changes ***
  4234 
  4235 * hierachically structured name spaces (for consts, types, axms, thms
  4236 etc.); new lexical class 'longid' (e.g. Foo.bar.x) may render much of
  4237 old input syntactically incorrect (e.g. "%x.x"); COMPATIBILITY:
  4238 isatool fixdots ensures space after dots (e.g. "%x. x"); set
  4239 long_names for fully qualified output names; NOTE: ML programs
  4240 (special tactics, packages etc.) referring to internal names may have
  4241 to be adapted to cope with fully qualified names; in case of severe
  4242 backward campatibility problems try setting 'global_names' at compile
  4243 time to have enrything declared within a flat name space; one may also
  4244 fine tune name declarations in theories via the 'global' and 'local'
  4245 section;
  4246 
  4247 * reimplemented the implicit simpset and claset using the new anytype
  4248 data filed in signatures; references simpset:simpset ref etc. are
  4249 replaced by functions simpset:unit->simpset and
  4250 simpset_ref:unit->simpset ref; COMPATIBILITY: use isatool fixclasimp
  4251 to patch your ML files accordingly;
  4252 
  4253 * HTML output now includes theory graph data for display with Java
  4254 applet or isatool browser; data generated automatically via isatool
  4255 usedir (see -i option, ISABELLE_USEDIR_OPTIONS);
  4256 
  4257 * defs may now be conditional; improved rewrite_goals_tac to handle
  4258 conditional equations;
  4259 
  4260 * defs now admits additional type arguments, using TYPE('a) syntax;
  4261 
  4262 * theory aliases via merge (e.g. M=A+B+C) no longer supported, always
  4263 creates a new theory node; implicit merge of thms' signatures is
  4264 restricted to 'trivial' ones; COMPATIBILITY: one may have to use
  4265 transfer:theory->thm->thm in (rare) cases;
  4266 
  4267 * improved handling of draft signatures / theories; draft thms (and
  4268 ctyps, cterms) are automatically promoted to real ones;
  4269 
  4270 * slightly changed interfaces for oracles: admit many per theory, named
  4271 (e.g. oracle foo = mlfun), additional name argument for invoke_oracle;
  4272 
  4273 * print_goals: optional output of const types (set show_consts and
  4274 show_types);
  4275 
  4276 * improved output of warnings (###) and errors (***);
  4277 
  4278 * subgoal_tac displays a warning if the new subgoal has type variables;
  4279 
  4280 * removed old README and Makefiles;
  4281 
  4282 * replaced print_goals_ref hook by print_current_goals_fn and result_error_fn;
  4283 
  4284 * removed obsolete init_pps and init_database;
  4285 
  4286 * deleted the obsolete tactical STATE, which was declared by
  4287     fun STATE tacfun st = tacfun st st;
  4288 
  4289 * cd and use now support path variables, e.g. $ISABELLE_HOME, or ~
  4290 (which abbreviates $HOME);
  4291 
  4292 * changed Pure/Sequence interface (see Pure/seq.ML); COMPATIBILITY:
  4293 use isatool fixseq to adapt your ML programs (this works for fully
  4294 qualified references to the Sequence structure only!);
  4295 
  4296 * use_thy no longer requires writable current directory; it always
  4297 reloads .ML *and* .thy file, if either one is out of date;
  4298 
  4299 
  4300 *** Classical Reasoner ***
  4301 
  4302 * Clarify_tac, clarify_tac, clarify_step_tac, Clarify_step_tac: new
  4303 tactics that use classical reasoning to simplify a subgoal without
  4304 splitting it into several subgoals;
  4305 
  4306 * Safe_tac: like safe_tac but uses the default claset;
  4307 
  4308 
  4309 *** Simplifier ***
  4310 
  4311 * added simplification meta rules:
  4312     (asm_)(full_)simplify: simpset -> thm -> thm;
  4313 
  4314 * simplifier.ML no longer part of Pure -- has to be loaded by object
  4315 logics (again);
  4316 
  4317 * added prems argument to simplification procedures;
  4318 
  4319 * HOL, FOL, ZF: added infix function `addsplits':
  4320   instead of `<simpset> setloop (split_tac <thms>)'
  4321   you can simply write `<simpset> addsplits <thms>'
  4322 
  4323 
  4324 *** Syntax ***
  4325 
  4326 * TYPE('a) syntax for type reflection terms;
  4327 
  4328 * no longer handles consts with name "" -- declare as 'syntax' instead;
  4329 
  4330 * pretty printer: changed order of mixfix annotation preference (again!);
  4331 
  4332 * Pure: fixed idt/idts vs. pttrn/pttrns syntactic categories;
  4333 
  4334 
  4335 *** HOL ***
  4336 
  4337 * HOL: there is a new splitter `split_asm_tac' that can be used e.g.
  4338   with `addloop' of the simplifier to faciliate case splitting in premises.
  4339 
  4340 * HOL/TLA: Stephan Merz's formalization of Lamport's Temporal Logic of Actions;
  4341 
  4342 * HOL/Auth: new protocol proofs including some for the Internet
  4343   protocol TLS;
  4344 
  4345 * HOL/Map: new theory of `maps' a la VDM;
  4346 
  4347 * HOL/simplifier: simplification procedures nat_cancel_sums for
  4348 cancelling out common nat summands from =, <, <= (in)equalities, or
  4349 differences; simplification procedures nat_cancel_factor for
  4350 cancelling common factor from =, <, <= (in)equalities over natural
  4351 sums; nat_cancel contains both kinds of procedures, it is installed by
  4352 default in Arith.thy -- this COULD MAKE EXISTING PROOFS FAIL;
  4353 
  4354 * HOL/simplifier: terms of the form
  4355   `? x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x)'  (or t=x)
  4356   are rewritten to
  4357   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t)',
  4358   and those of the form
  4359   `! x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x) --> R(x)'  (or t=x)
  4360   are rewritten to
  4361   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t) --> R(t)',
  4362 
  4363 * HOL/datatype
  4364   Each datatype `t' now comes with a theorem `split_t_case' of the form
  4365 
  4366   P(t_case f1 ... fn x) =
  4367      ( (!y1 ... ym1. x = C1 y1 ... ym1 --> P(f1 y1 ... ym1)) &
  4368         ...
  4369        (!y1 ... ymn. x = Cn y1 ... ymn --> P(f1 y1 ... ymn))
  4370      )
  4371 
  4372   and a theorem `split_t_case_asm' of the form
  4373 
  4374   P(t_case f1 ... fn x) =
  4375     ~( (? y1 ... ym1. x = C1 y1 ... ym1 & ~P(f1 y1 ... ym1)) |
  4376         ...
  4377        (? y1 ... ymn. x = Cn y1 ... ymn & ~P(f1 y1 ... ymn))
  4378      )
  4379   which can be added to a simpset via `addsplits'. The existing theorems
  4380   expand_list_case and expand_option_case have been renamed to
  4381   split_list_case and split_option_case.
  4382 
  4383 * HOL/Arithmetic:
  4384   - `pred n' is automatically converted to `n-1'.
  4385     Users are strongly encouraged not to use `pred' any longer,
  4386     because it will disappear altogether at some point.
  4387   - Users are strongly encouraged to write "0 < n" rather than
  4388     "n ~= 0". Theorems and proof tools have been modified towards this
  4389     `standard'.
  4390 
  4391 * HOL/Lists:
  4392   the function "set_of_list" has been renamed "set" (and its theorems too);
  4393   the function "nth" now takes its arguments in the reverse order and
  4394   has acquired the infix notation "!" as in "xs!n".
  4395 
  4396 * HOL/Set: UNIV is now a constant and is no longer translated to Compl{};
  4397 
  4398 * HOL/Set: The operator (UN x.B x) now abbreviates (UN x:UNIV. B x) and its
  4399   specialist theorems (like UN1_I) are gone.  Similarly for (INT x.B x);
  4400 
  4401 * HOL/record: extensible records with schematic structural subtyping
  4402 (single inheritance); EXPERIMENTAL version demonstrating the encoding,
  4403 still lacks various theorems and concrete record syntax;
  4404 
  4405 
  4406 *** HOLCF ***
  4407 
  4408 * removed "axioms" and "generated by" sections;
  4409 
  4410 * replaced "ops" section by extended "consts" section, which is capable of
  4411   handling the continuous function space "->" directly;
  4412 
  4413 * domain package:
  4414   . proves theorems immediately and stores them in the theory,
  4415   . creates hierachical name space,
  4416   . now uses normal mixfix annotations (instead of cinfix...),
  4417   . minor changes to some names and values (for consistency),
  4418   . e.g. cases -> casedist, dists_eq -> dist_eqs, [take_lemma] -> take_lemmas,
  4419   . separator between mutual domain defs: changed "," to "and",
  4420   . improved handling of sort constraints;  now they have to
  4421     appear on the left-hand side of the equations only;
  4422 
  4423 * fixed LAM <x,y,zs>.b syntax;
  4424 
  4425 * added extended adm_tac to simplifier in HOLCF -- can now discharge
  4426 adm (%x. P (t x)), where P is chainfinite and t continuous;
  4427 
  4428 
  4429 *** FOL and ZF ***
  4430 
  4431 * FOL: there is a new splitter `split_asm_tac' that can be used e.g.
  4432   with `addloop' of the simplifier to faciliate case splitting in premises.
  4433 
  4434 * qed_spec_mp, qed_goal_spec_mp, qed_goalw_spec_mp are available, as
  4435 in HOL, they strip ALL and --> from proved theorems;
  4436 
  4437 
  4438 
  4439 New in Isabelle94-8 (May 1997)
  4440 ------------------------------
  4441 
  4442 *** General Changes ***
  4443 
  4444 * new utilities to build / run / maintain Isabelle etc. (in parts
  4445 still somewhat experimental); old Makefiles etc. still functional;
  4446 
  4447 * new 'Isabelle System Manual';
  4448 
  4449 * INSTALL text, together with ./configure and ./build scripts;
  4450 
  4451 * reimplemented type inference for greater efficiency, better error
  4452 messages and clean internal interface;
  4453 
  4454 * prlim command for dealing with lots of subgoals (an easier way of
  4455 setting goals_limit);
  4456 
  4457 
  4458 *** Syntax ***
  4459 
  4460 * supports alternative (named) syntax tables (parser and pretty
  4461 printer); internal interface is provided by add_modesyntax(_i);
  4462 
  4463 * Pure, FOL, ZF, HOL, HOLCF now support symbolic input and output; to
  4464 be used in conjunction with the Isabelle symbol font; uses the
  4465 "symbols" syntax table;
  4466 
  4467 * added token_translation interface (may translate name tokens in
  4468 arbitrary ways, dependent on their type (free, bound, tfree, ...) and
  4469 the current print_mode); IMPORTANT: user print translation functions
  4470 are responsible for marking newly introduced bounds
  4471 (Syntax.mark_boundT);
  4472 
  4473 * token translations for modes "xterm" and "xterm_color" that display
  4474 names in bold, underline etc. or colors (which requires a color
  4475 version of xterm);
  4476 
  4477 * infixes may now be declared with names independent of their syntax;
  4478 
  4479 * added typed_print_translation (like print_translation, but may
  4480 access type of constant);
  4481 
  4482 
  4483 *** Classical Reasoner ***
  4484 
  4485 Blast_tac: a new tactic!  It is often more powerful than fast_tac, but has
  4486 some limitations.  Blast_tac...
  4487   + ignores addss, addbefore, addafter; this restriction is intrinsic
  4488   + ignores elimination rules that don't have the correct format
  4489         (the conclusion MUST be a formula variable)
  4490   + ignores types, which can make HOL proofs fail
  4491   + rules must not require higher-order unification, e.g. apply_type in ZF
  4492     [message "Function Var's argument not a bound variable" relates to this]
  4493   + its proof strategy is more general but can actually be slower
  4494 
  4495 * substitution with equality assumptions no longer permutes other
  4496 assumptions;
  4497 
  4498 * minor changes in semantics of addafter (now called addaltern); renamed
  4499 setwrapper to setWrapper and compwrapper to compWrapper; added safe wrapper
  4500 (and access functions for it);
  4501 
  4502 * improved combination of classical reasoner and simplifier:
  4503   + functions for handling clasimpsets
  4504   + improvement of addss: now the simplifier is called _after_ the
  4505     safe steps.
  4506   + safe variant of addss called addSss: uses safe simplifications
  4507     _during_ the safe steps. It is more complete as it allows multiple
  4508     instantiations of unknowns (e.g. with slow_tac).
  4509 
  4510 *** Simplifier ***
  4511 
  4512 * added interface for simplification procedures (functions that
  4513 produce *proven* rewrite rules on the fly, depending on current
  4514 redex);
  4515 
  4516 * ordering on terms as parameter (used for ordered rewriting);
  4517 
  4518 * new functions delcongs, deleqcongs, and Delcongs. richer rep_ss;
  4519 
  4520 * the solver is now split into a safe and an unsafe part.
  4521 This should be invisible for the normal user, except that the
  4522 functions setsolver and addsolver have been renamed to setSolver and
  4523 addSolver; added safe_asm_full_simp_tac;
  4524 
  4525 
  4526 *** HOL ***
  4527 
  4528 * a generic induction tactic `induct_tac' which works for all datatypes and
  4529 also for type `nat';
  4530 
  4531 * a generic case distinction tactic `exhaust_tac' which works for all
  4532 datatypes and also for type `nat';
  4533 
  4534 * each datatype comes with a function `size';
  4535 
  4536 * patterns in case expressions allow tuple patterns as arguments to
  4537 constructors, for example `case x of [] => ... | (x,y,z)#ps => ...';
  4538 
  4539 * primrec now also works with type nat;
  4540 
  4541 * recdef: a new declaration form, allows general recursive functions to be
  4542 defined in theory files.  See HOL/ex/Fib, HOL/ex/Primes, HOL/Subst/Unify.
  4543 
  4544 * the constant for negation has been renamed from "not" to "Not" to
  4545 harmonize with FOL, ZF, LK, etc.;
  4546 
  4547 * HOL/ex/LFilter theory of a corecursive "filter" functional for
  4548 infinite lists;
  4549 
  4550 * HOL/Modelcheck demonstrates invocation of model checker oracle;
  4551 
  4552 * HOL/ex/Ring.thy declares cring_simp, which solves equational
  4553 problems in commutative rings, using axiomatic type classes for + and *;
  4554 
  4555 * more examples in HOL/MiniML and HOL/Auth;
  4556 
  4557 * more default rewrite rules for quantifiers, union/intersection;
  4558 
  4559 * a new constant `arbitrary == @x.False';
  4560 
  4561 * HOLCF/IOA replaces old HOL/IOA;
  4562 
  4563 * HOLCF changes: derived all rules and arities
  4564   + axiomatic type classes instead of classes
  4565   + typedef instead of faking type definitions
  4566   + eliminated the internal constants less_fun, less_cfun, UU_fun, UU_cfun etc.
  4567   + new axclasses cpo, chfin, flat with flat < chfin < pcpo < cpo < po
  4568   + eliminated the types void, one, tr
  4569   + use unit lift and bool lift (with translations) instead of one and tr
  4570   + eliminated blift from Lift3.thy (use Def instead of blift)
  4571   all eliminated rules are derived as theorems --> no visible changes ;
  4572 
  4573 
  4574 *** ZF ***
  4575 
  4576 * ZF now has Fast_tac, Simp_tac and Auto_tac.  Union_iff is a now a default
  4577 rewrite rule; this may affect some proofs.  eq_cs is gone but can be put back
  4578 as ZF_cs addSIs [equalityI];
  4579 
  4580 
  4581 
  4582 New in Isabelle94-7 (November 96)
  4583 ---------------------------------
  4584 
  4585 * allowing negative levels (as offsets) in prlev and choplev;
  4586 
  4587 * super-linear speedup for large simplifications;
  4588 
  4589 * FOL, ZF and HOL now use miniscoping: rewriting pushes
  4590 quantifications in as far as possible (COULD MAKE EXISTING PROOFS
  4591 FAIL); can suppress it using the command Delsimps (ex_simps @
  4592 all_simps); De Morgan laws are also now included, by default;
  4593 
  4594 * improved printing of ==>  :  ~:
  4595 
  4596 * new object-logic "Sequents" adds linear logic, while replacing LK
  4597 and Modal (thanks to Sara Kalvala);
  4598 
  4599 * HOL/Auth: correctness proofs for authentication protocols;
  4600 
  4601 * HOL: new auto_tac combines rewriting and classical reasoning (many
  4602 examples on HOL/Auth);
  4603 
  4604 * HOL: new command AddIffs for declaring theorems of the form P=Q to
  4605 the rewriter and classical reasoner simultaneously;
  4606 
  4607 * function uresult no longer returns theorems in "standard" format;
  4608 regain previous version by: val uresult = standard o uresult;
  4609 
  4610 
  4611 
  4612 New in Isabelle94-6
  4613 -------------------
  4614 
  4615 * oracles -- these establish an interface between Isabelle and trusted
  4616 external reasoners, which may deliver results as theorems;
  4617 
  4618 * proof objects (in particular record all uses of oracles);
  4619 
  4620 * Simp_tac, Fast_tac, etc. that refer to implicit simpset / claset;
  4621 
  4622 * "constdefs" section in theory files;
  4623 
  4624 * "primrec" section (HOL) no longer requires names;
  4625 
  4626 * internal type "tactic" now simply "thm -> thm Sequence.seq";
  4627 
  4628 
  4629 
  4630 New in Isabelle94-5
  4631 -------------------
  4632 
  4633 * reduced space requirements;
  4634 
  4635 * automatic HTML generation from theories;
  4636 
  4637 * theory files no longer require "..." (quotes) around most types;
  4638 
  4639 * new examples, including two proofs of the Church-Rosser theorem;
  4640 
  4641 * non-curried (1994) version of HOL is no longer distributed;
  4642 
  4643 
  4644 
  4645 New in Isabelle94-4
  4646 -------------------
  4647 
  4648 * greatly reduced space requirements;
  4649 
  4650 * theory files (.thy) no longer require \...\ escapes at line breaks;
  4651 
  4652 * searchable theorem database (see the section "Retrieving theorems" on
  4653 page 8 of the Reference Manual);
  4654 
  4655 * new examples, including Grabczewski's monumental case study of the
  4656 Axiom of Choice;
  4657 
  4658 * The previous version of HOL renamed to Old_HOL;
  4659 
  4660 * The new version of HOL (previously called CHOL) uses a curried syntax
  4661 for functions.  Application looks like f a b instead of f(a,b);
  4662 
  4663 * Mutually recursive inductive definitions finally work in HOL;
  4664 
  4665 * In ZF, pattern-matching on tuples is now available in all abstractions and
  4666 translates to the operator "split";
  4667 
  4668 
  4669 
  4670 New in Isabelle94-3
  4671 -------------------
  4672 
  4673 * new infix operator, addss, allowing the classical reasoner to
  4674 perform simplification at each step of its search.  Example:
  4675         fast_tac (cs addss ss)
  4676 
  4677 * a new logic, CHOL, the same as HOL, but with a curried syntax
  4678 for functions.  Application looks like f a b instead of f(a,b).  Also pairs
  4679 look like (a,b) instead of <a,b>;
  4680 
  4681 * PLEASE NOTE: CHOL will eventually replace HOL!
  4682 
  4683 * In CHOL, pattern-matching on tuples is now available in all abstractions.
  4684 It translates to the operator "split".  A new theory of integers is available;
  4685 
  4686 * In ZF, integer numerals now denote two's-complement binary integers.
  4687 Arithmetic operations can be performed by rewriting.  See ZF/ex/Bin.ML;
  4688 
  4689 * Many new examples: I/O automata, Church-Rosser theorem, equivalents
  4690 of the Axiom of Choice;
  4691 
  4692 
  4693 
  4694 New in Isabelle94-2
  4695 -------------------
  4696 
  4697 * Significantly faster resolution;
  4698 
  4699 * the different sections in a .thy file can now be mixed and repeated
  4700 freely;
  4701 
  4702 * Database of theorems for FOL, HOL and ZF.  New
  4703 commands including qed, qed_goal and bind_thm store theorems in the database.
  4704 
  4705 * Simple database queries: return a named theorem (get_thm) or all theorems of
  4706 a given theory (thms_of), or find out what theory a theorem was proved in
  4707 (theory_of_thm);
  4708 
  4709 * Bugs fixed in the inductive definition and datatype packages;
  4710 
  4711 * The classical reasoner provides deepen_tac and depth_tac, making FOL_dup_cs
  4712 and HOL_dup_cs obsolete;
  4713 
  4714 * Syntactic ambiguities caused by the new treatment of syntax in Isabelle94-1
  4715 have been removed;
  4716 
  4717 * Simpler definition of function space in ZF;
  4718 
  4719 * new results about cardinal and ordinal arithmetic in ZF;
  4720 
  4721 * 'subtype' facility in HOL for introducing new types as subsets of existing
  4722 types;
  4723 
  4724 
  4725 $Id$