Re: Declarative limitations of OWL/DAML

Ian Horrocks wrote:
> 
> A couple of points. DLs certainly CAN represent predicates involving
> multiple variables and predicate chains, it just happens that the
> particular DL on which DAML/OWL are based does not include these
> features 

Apologies for my imprecise language - I should indeed have said "the DLs behind
DAML/OWL".

> (there are a variety of reasons for this, not the least of
> which is the fact that the RDF and XML type systems do not specify
> n-ary predicates). 

I assume there are also complexity arguments. Predicate chains would be
compatible with the RDF substrate but I assumed that the combination of role
composition with the other operators in OWL would have pushed up the
computational complexity further. Is that correct?

> See [2,3] for details about DL support for datatypes
> (called concrete domains in DLs).

Thanks for the references.

Dave