On 17 Nov 2008, at 17:00, Jens Lehmann wrote:
Hello John,
John Goodwin wrote:
Thanks Chris and team for all your hard work getting this done. I do,
however, have a few comments regarding the OWL ontology. I think in
general the use of domain and range is perhaps a bit "dubious" in
that
for many things I think it is overly specified. I can imagine anyone
re-using the Dbpedia properties getting some unexpected inferences
from
the domain and range restrictions. Also the range restriction seem
to be
done as an OWL intersection so if, for example, something has a
publisher x then x will be inferred to be both a Company and a Person
which is probably not what you want. Personally, in all but a few
cases,
I'd be tempted to generalise or just remove the domain/range
restrictions. Any thoughts?
We specified the domains and ranges as disjunctions of classes (not
intersection). See the W3C specification of owl:unionOf [1].
John's comment relates to (at least) the axioms on "publisher":
[[
<owl:ObjectProperty rdf:about="http://dbpedia.org/ontology/publisher";>
<rdfs:label xml:lang="en">publisher</rdfs:label>
<rdfs:domain>
<owl:Class>
<owl:unionOf rdf:parseType="Collection">
<owl:Class rdf:about="Work"/>
<owl:Class rdf:about="Book"/>
<owl:Class rdf:about="Newspaper"/>
</owl:unionOf>
</owl:Class>
</rdfs:domain>
<rdfs:range rdf:resource="http://dbpedia.org/ontology/Person"/>
<rdfs:range rdf:resource="http://dbpedia.org/ontology/Company"/>
</owl:ObjectProperty>
]]
The semantics of range mean that you have essentially asserted that
the range of published is [Person and Company]. If you want the
union, you'll have to explicitly use the unionOf constructor here.
Cheers,
Sean
--
Sean Bechhofer
School of Computer Science
University of Manchester
[EMAIL PROTECTED]
http://www.cs.manchester.ac.uk/people/bechhofer
