For and a bounded linear operator acting on some Hilbert space, the -pseudospectrum of is and the -pseudospectral radius of is . In this article, we provide a characterization of those operators satisfying for all . Here denotes the spectral radius of .
"On pseudospectral radii of operators on Hilbert spaces." Ann. Funct. Anal. 9 (4) 474 - 484, November 2018. https://doi.org/10.1215/20088752-2017-0062