However many "newbies" to RDF and ontologies are confused by this,
because the triple
foaf:Agent foaf:holdsAccount foaf:OnlineAccount .
is actually not contained in the ontology.
What needs to be communicated is that:
[ a foaf:Agent ] foaf:holdsAccount [ a foaf:OnlineAccount ] .
instead. Those triples are not actually in the ontology itself, but
will
be found (or at least implied) in any instance data that makes use of
the foaf:holdsAccount property.
Certainly true, although this approach mixes up ontology and instance
level, which might also lead to confusion. (Remember, I'm talking
about people who have never heard of those things ...)
Something like this might be a nice visualisation:
http://buzzword.org.uk/2009/domain-range-illustration.png
It would be even better to flip it so that the ontology level is on
top of the instance level, so to be in line with MOF.
Best,
Bernhard
