Hi,

Can someone please clarify this for me.

In Section 3.2.1 of OWL Web Ontology Lang Ref, it mentioned that
The rdfs:subClassOf construct is defined as part of RDF Schema. Its
meaning in OWL is *exactly the same* .....
However, RDFS semantic conditions table in Section 4.1 of RDF Semantics
defines rdfs:subClassOf to be an "if ... then ... " relationship,
whereas the If-and-only-if conditions table in Section 5.2 of OWL Semantics
and Abstract Syntax defines rdfs:subClassOf to be "iff"

>From the definition, it seems that OWL defines subclass relationship
stronger than RDFS does. My intuitive understanding (please correct me if I am wrong)
is that, in OWL, if the class extension of c1 is a subset of class extension
of c2, then c1 is subClassOf c2.

I am not trying to be picky about the wording here. Just try to understand
this better.

Thanks,

Zhe (Alan) Wu
Oracle