Updated XML Schema

Hi folks,

I've completely my update to the XML Schema for OWL/XML which adds  
type information through out the schema. This involved *no change* to  
any content model (though I did put some parts of some content models  
in superclasses for clarity's sake).

Thus every legal OWL/XML file according to the prior schema is a legal  
OWL/XML according to the attached schema (pace any typos...which I've  
been correcting).

We can add some further refinements. It'd be nice to have a common  
supertype for the Object and Data cardinality expressions. Some of the  
global constraints can be easily added.

Here's a proposed prose change for the XML serialization spec:

""""• Each UML class that is intended to be instantiated is mapped to  
a global element, whose elements and attributes correspond to the  
components of the UML class.
• Each UML class that is not intended to be instantiated directly, but  
instead gathers together commonalities, is mapped to a global element  
group, whose choice members correspond to the children of the UML  
class. For all except a select few, the type corresponding to global  
element group is a global (abstract) XML Schema type. The contents of  
the group are mapped into the corresponding subtypes of the group type.

Since XML Schema's type system does not support multiple inheritance,  
some abstract UML classes cannot be directly mapped into an XML Schema  
type hierarchy with the intended result. In the case where there are  
multiple parent classes, only the most useful parents are mapped into  
the active type hierarchy. The excluded groups are:
	Entity
	AnnotationSubject
	AnnotationValue

Additionally, there were some groups which just didn't make sense as  
types:
	axiomAnnotations
	ontologyAnnotations
	annotationAnnotations""""

I'll have some demos up shortly.

Cheers,
Bijan.