RIGHT (σ,τ)-DERIVATIONS ON LEFT IDEALS

Let R be a prime ring and I a nonzero left Ideal of R which is a semi prime as a ring. For a right (σ,τ) – derivations ȣ:R → R, we prove the following results: (1) If δ acts as a homomorphism on I, then ȣ= 0 on R. (2) If δ acts as an anti- homomorphism on I, then either ȣ = 0 on R or I subseteq Z(R).