Class with symmetric object property. 

Ontology(<http://example.com/ontology/Unnamed1>
Annotation(rdfs:label "Symmetric"^^xsd:string)

Declaration(Class(:Person))
Declaration(Class(:Spouse))
Declaration(ObjectProperty(:hasSpouse))

############################
#   Object Properties
############################

# Object Property: :hasSpouse (has spouse)

AnnotationAssertion(rdfs:label :hasSpouse "has spouse"^^xsd:string)
SymmetricObjectProperty(:hasSpouse)
ObjectPropertyDomain(:hasSpouse :Person)
ObjectPropertyRange(:hasSpouse :Spouse)




)