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JOURNALS // Russian Universities Reports. Mathematics // Archive

Russian Universities Reports. Mathematics, 2024 Volume 29, Issue 148, Pages 494–516 (Mi vtamu342)

Scientific articles

On $\lambda$-commuting and left (right) pseudospectrum and left (right) condition pseudospectrum of continuous linear operators on ultrametric Banach spaces

J. Ettayb

Regional Academy of Education and Training Casablanca Settat, Hamman Al–Fatawaki collegiate High School

Abstract: In this paper, we demonstrate some spectral properties of the $\lambda$-commuting of continuous linear operators on ultrametric Banach spaces and we introduce and study the operator equations $ASB=S$ and $AS=SB.$ We give some properties of these operator equations. Some illustrative examples are provided. On the other hand, we introduce and study the left (right) pseudospectrum and the left (right) condition pseudospectrum of continuous linear operators on ultrametric Banach spaces. We prove that the left pseudospectra associated with various $\varepsilon>0$ are nested sets and the intersection of all the left pseudospectra is the left spectrum. We give a relationship between the left (right) pseudospectrum and the left (right) condition pseudospectrum. Moreover, many results are proved concerning the left (right) pseudospectrum and the left (right) condition pseudospectrum of continuous linear operators on ultrametric Banach spaces.

Keywords: ultrametric Banach spaces, bounded linear operators, spectrum, left and right pseudospectrum

UDC: 517.983, 517.984

MSC: 47A10, 47S10

Received: 03.10.2024
Accepted: 22.11.2024

Language: English

DOI: 10.20310/2686-9667-2024-29-148-494-516



© Steklov Math. Inst. of RAS, 2025