Prime rings having nontrivial centralizers of (skew) traces of Lie ideals

Abstract

Let $R$ be a prime ring with center $Z(R)$ and with involution $\ast$. Given an additive subgroup $A$ of $R$, let $T(A):=\{x+x^{\ast }\mid x\in A\}$ and $K_0(A):=\{x-x^{\ast }\mid x\in A\}$. Let $L$ be a non-abelian Lie ideal of $R$. It is proved that if $d$ is a nonzero derivation of $R$ satisfying $d(T(L))=0$ (resp. $d(K_0(L))=0$), then $T(R{)}^2\subseteq Z(R)$ (resp. $K_0(R{)}^2\subseteq Z(R)$). These results are applied to the study of $d(T(M))=0$ and $d(K_0(M))=0$ for noncentral $\ast$-subrings $M$ of a division ring $R$ such that $M$ is invariant under all inner automorphisms of $R$, and for noncentral additive subgroups $M$ of a prime ring $R$ containing a nontrivial idempotent such that $M$ is invariant under all special inner automorphisms of $R$. The obtained theorems also generalize some recent results on simple artinian rings with involution due to M. Chacron.