Method of similar operators in harmonious Banach spaces

Fuente: arXiv
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Autores principales: Baskakov, Anatoly G., Krishtal, Ilya A., Uskova, Natalia B.
Formato: Preprint
Publicado: 2024
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author Baskakov, Anatoly G.
Krishtal, Ilya A.
Uskova, Natalia B.
author_facet Baskakov, Anatoly G.
Krishtal, Ilya A.
Uskova, Natalia B.
contents We consider similarity transformations of a perturbed linear operator $A-B$ in a complex Banach space $\mathcal{X}$, where the unperturbed operator $A$ is a generator of a Banach $L_1(\mathbb{R})$-module and the perturbation operator $B$ is a bounded linear operator. The result of the transformation is a simpler operator $A-B_0$. For example, if $A$ is a differentiation operator and $B$ is an operator of multiplication by an operator-valued function, then $B_0$ is an operator of multiplication by a function that is a restriction of an entire function of exponential type and could be $0$ in some cases. As a consequence, we derive the spectral invariance of the operator $A-B$ in a large class of spaces. The study is based on a widely applicable modification of the method of similar operators that is also presented in the paper. This non-traditional modification is rooted in the spectral theory of Banach $L_1(\mathbb{R})$-modules.
format Preprint
id arxiv_https___arxiv_org_abs_2404_01227
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Method of similar operators in harmonious Banach spaces
Baskakov, Anatoly G.
Krishtal, Ilya A.
Uskova, Natalia B.
Functional Analysis
Spectral Theory
We consider similarity transformations of a perturbed linear operator $A-B$ in a complex Banach space $\mathcal{X}$, where the unperturbed operator $A$ is a generator of a Banach $L_1(\mathbb{R})$-module and the perturbation operator $B$ is a bounded linear operator. The result of the transformation is a simpler operator $A-B_0$. For example, if $A$ is a differentiation operator and $B$ is an operator of multiplication by an operator-valued function, then $B_0$ is an operator of multiplication by a function that is a restriction of an entire function of exponential type and could be $0$ in some cases. As a consequence, we derive the spectral invariance of the operator $A-B$ in a large class of spaces. The study is based on a widely applicable modification of the method of similar operators that is also presented in the paper. This non-traditional modification is rooted in the spectral theory of Banach $L_1(\mathbb{R})$-modules.
title Method of similar operators in harmonious Banach spaces
topic Functional Analysis
Spectral Theory
url https://arxiv.org/abs/2404.01227