> In actuality, defining things like owl:sameAs is indeed extending RDF. > Defining things in terms of OWL connectives also goes beyond RDF. This is > different from introducing domain predicates like foaf:friends. (Yes, it is > sometimes a bit hard to figure out which side of the line one is on.)
Thanks for clarifying, and this is indeed where we disagree. For me, such a line does not exist, nor was it ever defined. And even if there were, I don't see the need to draw it. RDF is the framework, the interpretation is semantics. All predicates have meaning associated with them, none has “more” meaning than the other; maybe some usually allow to infer more triples, but that doesn't change the framework at all. Cheers, Ruben
