classification inferences based on owl:disjointWith

I'm using Jena with Racer as the DIG reasoner, using a test program 
based on the "Extended example" at 
http://jena.sourceforge.net/how-to/dig-reasoner.html.

I have an ontology that imports foaf. After I load the ontology, I list 
the OWL classes using OntModel.listClasses. The foaf classes don't show 
up on the list, although they do appear when I list all the statements 
with predicate "rdf:type" and object "rdfs:Class." It looks like Racer 
is not inferring that the foaf classes are OWL classes, even though they 
are defined like this:

   <rdfs:Class rdf:about="http://xmlns.com/foaf/0.1/Document" 
rdfs:label="Document" rdfs:comment="A document.">
     <rdfs:subClassOf rdf:resource="http://xmlns.com/wordnet/1.6/Document"/>
     <rdfs:isDefinedBy rdf:resource="http://xmlns.com/foaf/0.1/"/>
     <owl:disjointWith 
rdf:resource="http://xmlns.com/foaf/0.1/Organization"/>
     <owl:disjointWith rdf:resource="http://xmlns.com/foaf/0.1/Person"/>
     <owl:disjointWith rdf:resource="http://xmlns.com/foaf/0.1/Project"/>
   </rdfs:Class>

Since the domain and range of owl:disjointWith is owl:Class, I would 
expect that an inference engine would classify foaf:Document as an 
owl:Class even though the ontology states that foaf:Document is an 
rdfs:Class.

Am I wrong about that?

Steven Gollery
sgollery@cadrc.calpoly.edu

Received on Tuesday, 11 January 2005 20:54:23 UTC