$\mathbf{S}$-pseudospectra and $\mathbf{S}$-essential pseudospectra


A. Ammar, H. Daoud, A. Jeribi




In the present paper, we introduce and study the $\mathcal{S}$-pseudospectra and the essential $\mathcal{S}$-pseudospectra of linear relations. We start by giving the definition and we investigate the characterization and some properties of these $\mathcal{S}$-pseudospectra.