On Fri, Apr 18, 2014 at 8:03 AM, Dave Reynolds <[email protected]> wrote: >> 2 – question : I try to >> link two persons with an “FOAF:knows” object property and not with an >> annotation. How can I infer and use object properties ? > > > Don't understand the question. What do you mean by "annotation" here? Your > rule has asserted some foaf:knows triples, foaf:knows is an object property, > so you have inferred some object properties. What else is there? > > From the point of view of RDF and generic RDF rules there's just triples and > it makes no difference whether the property in a triple is a > owl:DatatypeProperty, owl:ObjectProperty, owl:AnnotationProperty, > rdf:Property or just some resource whose type you don't know.
OWL puts more restrictions on things than RDF alone does. In an OWL2 ontology, it's required that (almost) everything have declarations. I think that the default behavior of Protege, when it sees an assertion using a property that hasn't been declared as an object, datatype, or annotation property, is to assume that it's an annotation property (since those won't affect OWL reasoning, this is sort of the "safest" option). Are you loading the resulting inferences in Protege? Is that where you're seeing foaf:knows as an annotation property? //JT -- Joshua Taylor, http://www.cs.rpi.edu/~tayloj/
