--- a/ontology/ProvenanceOntology.owl	Thu Feb 23 22:43:54 2012 -0500
+++ b/ontology/ProvenanceOntology.owl	Thu Feb 23 22:49:26 2012 -0500
@@ -262,6 +262,7 @@
     <!-- http://www.w3.org/ns/prov#occurredAt -->
 
     <owl:ObjectProperty rdf:about="&prov;occurredAt">
+        <rdf:type rdf:resource="&owl;FunctionalProperty"/>
         <rdf:type rdf:resource="&owl;IrreflexiveProperty"/>
         <rdfs:label xml:lang="en">had temporal extent</rdfs:label>
         <rdfs:seeAlso rdf:resource="http://www.w3.org/2011/prov/wiki/ProvRDF#Usage"/>