A note on the distance bound for pseudospectra of matrix polynomials

Abstract: Recently, Psarrakos obtained a lower bound, which depends on a real parameter , for the distance between the pseudospectrum of a matrix polynomial and a given point that lies out of it. In this note, we study the best choice of the parameter. As a consequence, the best lower bound among those given by Psarrakos is obtained. [Copyright &y& Elsevier]