{tt nth} returns the item in the list specified as its first
argument in the position specified as its second argument.
(Nth-Domain@Frame-Ontology Nth 2 Natural) (Nth-Domain@Frame-Ontology Nth 1 List)
(=> (= (Projection@Frame-Ontology ?Relation ?Column)
?Projection-Relation)
(Forall (?Projection-Instance)
(<=> (Instance-Of@Frame-Ontology ?Instance
?Projection-Relation)
(Exists (?Tuple)
(And (Member@Ol-User%Kif-Sets ?Tuple
?Relation)
(= (Nth ?Tuple ?Column) ?Instance))))))
(=> (Nth-Domain@Frame-Ontology ?Relation ?N ?Type)
(Forall (?Tuple)
(=> (Member@Ol-User%Kif-Sets ?Tuple ?Relation)
(And (>= (Length ?Tuple) ?N)
(Instance-Of@Frame-Ontology (Nth ?Tuple ?N)
?Type)))))
(<=> (Projection@Frame-Ontology ?Relation ?Column)
(And (Defined@Ol-User%Kif-Extensions
(Arity@Frame-Ontology ?Relation))
(Positive-Integer@Ol-User%Kif-Extensions ?Column)
(=< ?Column (Arity@Frame-Ontology ?Relation))
(Class@Frame-Ontology ?Projection-Relation)
(Forall (?Projection-Instance)
(<=> (Instance-Of@Frame-Ontology
?Instance
?Projection-Relation)
(Exists (?Tuple)
(And (Member@Ol-User%Kif-Sets ?Tuple
?Relation)
(= (Nth ?Tuple ?Column)
?Instance)))))))
(<=> (Nth-Domain@Frame-Ontology ?Relation ?N ?Type)
(And (Defined@Ol-User%Kif-Extensions
(Arity@Frame-Ontology ?Relation))
(Positive-Integer@Ol-User%Kif-Extensions ?N)
(Class@Frame-Ontology ?Type)
(Forall (?Tuple)
(=> (Member@Ol-User%Kif-Sets ?Tuple ?Relation)
(And (>= (Length ?Tuple) ?N)
(Instance-Of@Frame-Ontology (Nth ?Tuple ?N)
?Type))))))