A formula for the numerical range of an elementary operator on C*-algebra

Mohamed Barraa

Let $\A$ be a $C^{\ast }-$algebra with unit element $1$ and unitary group $U.$ Let $a=(a_1,...,a_k)$ and $b=(b_1,...,b_k)$ two $k-$tuples of elements in $\A.$ The elementary operator…