a Relationship between a Vendor and a Name (i.e. a text string) whereby
the Name is identifiable by Customer s
the Name is associated with one or more Product s of the Vendor.
(=> (Brand ?Brand) (Exists (?Vendor) (Brand-Of ?Brand ?Vendor)))
(<=> (Brand ?Brand) (And (String ?Brand) (Qua-Entity ?Brand) (Exists (?Vendor) (Brand-Of ?Brand ?Vendor))))