rdfs_subproperty_of(?SubProperty,
?Property)True if SubProperty is equal to Property or Property
can be reached from SubProperty following the
rdfs:subPropertyOf relation. It can be used to test as well
as generate sub-properties or super-properties. Note that the commonly
used semantics of this predicate is wired into rdf_has/[3,4].bugThe
current implementation cannot deal with cycles.bugThe
current implementation cannot deal with predicates that are an rdfs:subPropertyOf
of rdfs:subPropertyOf, such as owl:samePropertyAs.