An integer greater than zero, not including zero. A less ambiguous name for KIF's NATURAL.
(=> (Positive-Integer ?X) (> ?X 0))
(<=> (Positive-Integer ?X) (And (Integer ?X) (> ?X 0)))
(=> (= (Projection@Frame-Ontology ?Relation ?Column) ?Projection-Relation) (Positive-Integer ?Column))
(<=> (Projection@Frame-Ontology ?Relation ?Column) (And (Defined (Arity@Frame-Ontology ?Relation)) (Positive-Integer ?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 ?Tuple ?Relation) (= (Nth ?Tuple ?Column) ?Instance))))))) (<=> (Nth-Domain@Frame-Ontology ?Relation ?N ?Type) (And (Defined (Arity@Frame-Ontology ?Relation)) (Positive-Integer ?N) (Class@Frame-Ontology ?Type) (Forall (?Tuple) (=> (Member ?Tuple ?Relation) (And (>= (Length ?Tuple) ?N) (Instance-Of@Frame-Ontology (Nth ?Tuple ?N) ?Type))))))
(Nth-Domain@Frame-Ontology Projection@Frame-Ontology 2 Positive-Integer) (Nth-Domain@Frame-Ontology Nth-Domain@Frame-Ontology 2 Positive-Integer)