Automorphisms with annihilator condition in prime rings

Abstract

Let R be a prime ring, I a nonzero ideal of R, and a ∈ R. Suppose that σ is a nontrivial automorphism of R such that a{(σ(x ∘ y))ⁿ − (x ∘ y)^m} = 0 or a{(σ([x,y]))ⁿ − ([x,y])^m} = 0 for all x,y ∈ I, where n and m are fixed positive integers. We prove that if char(R) > n + 1 or char(R) = 0, then either a = 0 or R is commutative.