Hi David,

Thanks for your question.

David Mott wrote: > 1) Please could you explain why condition 8 in section 3.2.1.2 uses "superset of" > leading to the comment "a rdfs:subClassOf b is true if a ## b is true". > > Why is this not "equal to", leading to "a rdfs:subClassOf b is true iff a ## b is true"?

RDFS semantics stipulates subclass to be reflexive, so for all a: a rdfs:subClassOf a. RIF subclass is not necessarily reflexive. You can assert that some class is a subclass of itself, but it isn't entailed for every class. Thus, every rif subclass relation is an rdfs one, but not the other way around.

> 2) for clarity, is the sentence "Since RIF frame formulas are interpreted using an extension function, as in RDF " in section 4 5th para, justified by the condition 4 in 3.2.1.2? If so, could you add a pointer?

No, those statements are justified by the RDF and RIF semantics. The "RDF&OWL" document just talks about combining them, and thus 3.2.1.2 is just about combinations of RIF and RDF.

Please let us know if this is satisfactory.

-The RIF WG