(<=> (Ring ?Domain ?Plus-Op ?Zero-Id ?Mult-Op ?One-Id)
(And (Abelian-Group ?Domain ?Plus-Op ?Zero-Id)
(Semigroup ?Domain ?Mult-Op ?One-Id)
(Distributes ?Mult-Op ?Plus-Op ?Domain)))
(<=> (Ring ?Domain ?Plus-Op ?Zero-Id ?Mult-Op ?One-Id)
(And (Abelian-Group ?Domain ?Plus-Op ?Zero-Id)
(Semigroup ?Domain ?Mult-Op ?One-Id)
(Distributes ?Mult-Op ?Plus-Op ?Domain)))
(Subrelation-Of Division-Ring Ring)
(<=> (Division-Ring ?Domain ?Plus-Op ?Zero-Id ?Mult-Op ?One-Id)
(And (Ring ?Domain ?Plus-Op ?Zero-Id ?Mult-Op ?One-Id)
(Group (Kappa (?X)
(And (Instance-Of ?X ?Domain)
(/= ?X ?Zero-Id)))
?Mult-Op
?One-Id)))