Knowledge Systems Laboratory, Stanford University
7
Property Restrictions on Instances
Joe is a person.
John is a parent of Joe.
What is John?
A person.
u<Class ID = "Person">
u   <comment> Person is a subclass of resources whose parents are persons. </comment>
u   <rdfs:subClassOf>
u      <daml:Restriction>
u         <daml:onProperty rdf:resource = “#hasParent” />
u         <daml:toClass rdf:resource = “#Person” />
u      </daml:Restriction>
u   </rdfs:subClassOf>
u  
Joe is a person.
How many fathers does Joe have?
1.
u   <comment > Person is a subclass of resources that have one father. </comment>
u   <rdfs:subClassOf>
u       <daml:Restriction>
u          <daml:onProperty rdf:resource = “#hasFather” />
u          <daml:cardinality> 1 </daml:cardinality>
u       </daml:Restriction>
u   </rdfs:subClassOf>