The cone of nonnegative c-numerical range and its preservers Original Research Article

Let Mn be the vector space of n×n complex martices and let image. For each Aset membership, variantMn, the c-numerical range of A is given byLet image be the cone of all matrices with nonnegative c-numerical range, i.e.,In this paper, we study extremal properties of image and give a characterization for linear mappings T for which image.