Re: Semantics of owl:unionOf vs subclass ...

On 8 Jul 2009, at 19:31, Ruth Dhanaraj wrote:

> Hi,
>
> I've been trying to figure out how I would write a property and say
> its domain can be of type A *or* B. The RDF primer says that
> specifying multiple domains is an AND, so that's out.

Correct.

> As far as I can tell, the semantics go something like this:
> A subclassof C
> B subclassof C
> = C is a superset of A u B
>
> C unionOf (A B)
> = C is A u B
>
> (then I can say that my property has domain C)

You don't need the first two axioms when the latter is an equivalence  
axiom.

> Is this correct? What's the recommended way to specify this?

You can do this without introducing a new term (C). I.e., (in no real  
syntax)

p domain unionOf(A B)

Some versions of the Protege 3 series would do that by default when  
you added multiple domains (or ranges).

Cheers,
Bijan.