Superclass-of is the inverse of the subclass-of relation. It is useful to create an explicit inverse because there are efficient ways to assert and query superclass and subclass relationships separately.In Cyc, superclass-of is called #%allSpecs because it is a slot from a collection to all of its specializations (subclasses).
(<=> (Superclass-Of $Arg1 $Arg2) (Subclass-Of $Arg2 $Arg1))