Computing Spectral Value Sets Using the Subharmonicity of the Norm of Rational Matrices

Spectral value sets (SVS) are structured versions of pseudospectra, a tool of matrix analysis that has been popularized by Trefethen and Godunov in recent years. The main result contained in this note is a new algorithm for calculating complex SVS which, using the subharmonicity of the norm of rational matrices, is able to save large amounts of computation… (More)