union of anyAttribute namespace constraints

Hello,

In the schema specification 1.0 errata (2003/03/07) for
computing the intensional union of namespace
constraints for xs:anyAttribute item (5) states:

5. If either O1 or O2 is a pair of *not* and a namespace name
and the other is a set of (namespace names or *absent*)
(call this set S), then the appropriate case among the following
must be true:

5.1 If the set S includes both the negated namespace name and
*absent*, then *any* must be the value.

and similar points which appear to assume that S may contain
a negated namespace name.

My question is: if S contains "a set of namespace names or *absent*",
then is it possible for it to contain a negated namespace name ?  In
other words, does "having a namespace name" include the case of
"having a negated namespace name" or exclude it.

Previous language seems to imply that they are excluded since
Item (3) states:

3. If both O1 and O2 are sets of (namespace names or *absent*) then
the union of those sets must be the value.

If "namespace names" were to include negated namespace names
this would seem to be a circular definition.

Received on Wednesday, 2 April 2003 15:35:27 UTC