Derivation-like mappings for normal elements in prime rings with involution.
Let be a prime ring, a nonzero ideal of , a derivation of and fixed positive integers. (i) If for all , then is commutative. (ii) If and for all , then is commutative. Moreover, we also examine the case when is a semiprime ring.
Let be a prime ring of char with a nonzero derivation and let be its noncentral Lie ideal. If for some fixed integers , for all , then satisfies , the standard identity in four variables.