$S$-spectra and $S$-essential pseudospectra of the diagonal block operator matrices

Year 2021, Volume: 50 Issue: 2, 433 - 443, 11.04.2021

Pembe Ipek Al , Zameddin İsmailov

https://doi.org/10.15672/hujms.701108

Abstract

In this article, the relationships between the $S$-spectra, the $ S$-spectral radius, the $ \epsilon$-$S$-essential pseudospectra, and the $ \epsilon$-$S$-essential pseudospectral radius of the diagonal block operator matrices in the direct sum of Banach spaces and their block coordinate operators are studied. Then, the results are supported by applications.

Keywords

$ S$-spectrum, $ \epsilon$-$S$-essential pseudospectrum, $ S$-spectral radius, $ \epsilon$-$S$-essential pseudospectral radius

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