The numerical range of elementary operators. II (Q5955659)

This article is a continuation of \textit{A. Seddik} [Integral Equations Oper. Theory 43, 248-252 (2002; Zbl 1016.47004)]. For two Hilbert space operators \(A\) and \(B\), the author proves that: (i) the generalized derivation \(\delta_{A,B}\) is convexoid if and only if \(A\) and \(B\) are convexoid; (ii) the operators \(\delta_{A,B}\) and \(\delta_{A,B}|\mathcal{C}_p\) have the same numerical range \(W_0(A)-W_0(B)\).