A Legal-Entity who either 1) offers a Product For-Sale for an Asking-Price or 2) agrees to exchange a Product for a Sale-Price in a Sale.
(<=> (Vendor ?X) (Or (Exists (?Sale) (Sale-Vendor ?Sale ?X)) (Exists (?For-Sale) (For-Sale-Vendor ?For-Sale ?X)) (Exists (?Potential-Sale) (Potential-Vendor ?Potential-Sale ?X))))
(=> (Competitor ?Competitor) (Vendor ?Competitor)) (=> (Set-Of-Vendors ?Vendors) (Forall (?X) (=> (Member ?X ?Vendors) (Vendor ?X))))
(<=> (Competitor ?Competitor) (And (Vendor ?Competitor) (Qua-Entity ?Competitor) (Or (Exists (?Vendor2) (Competitor-Of ?Competitor ?Vendor2)) (Exists (?Vendor1) (Competitor-Of ?Vendor1 ?Competitor))))) (<=> (Set-Of-Vendors ?Vendors) (And (Eo-Set ?Vendors) (Set ?Vendors) (Forall (?X) (=> (Member ?X ?Vendors) (Vendor ?X)))))