how about ... Re: SEM: Light review of semantics document

We might just give a disclaimer something along the lines of:

[[
Generally an OWL ontology will contain definitions of OWL classes and
properties, and an RDF document will contain descriptions of individual
resources. There is no absolute distinction between an OWL ontology and an
RDF document. This distinction is explicit in OWL DL and hence an OWL DL
document may be syntactically distinguished by ... however for OWL Full,
since indivuals might also be classes an absolute distinction cannot be made
...
]]

Jonathan