Spectra and Pseudospectra of the Direct Sum Operators

İsmailov Z., İpek Al P.

SIGMA JOURNAL OF ENGINEERING AND NATURAL SCIENCES, vol.38, pp.1251-1259, 2020 (ESCI) identifier

  • Publication Type: Article / Article
  • Volume: 38
  • Publication Date: 2020
  • Journal Name: SIGMA JOURNAL OF ENGINEERING AND NATURAL SCIENCES
  • Journal Indexes: Emerging Sources Citation Index (ESCI), Academic Search Premier, Directory of Open Access Journals
  • Page Numbers: pp.1251-1259
  • Keywords: Direct sum of operators, spectrum, pseudospectrum, spectral radii
  • Karadeniz Technical University Affiliated: Yes

Abstract

In this paper, the relationships between spectrum and pseudospectrum of the direct sum of linear operators in the direct sum of Hilbert spaces and its coordinate operators have been researched. Also, the analogous relations of some numerical characteristics (spectral and pseudospectral radii) of such operators have been investigated.