On Sylvester equations in Banach subalgebras

Fuente: arXiv
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Hauptverfasser: Fang, Qiquan, Shin, Chang Eon, Sun, Qiyu
Format: Preprint
Veröffentlicht: 2024
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author Fang, Qiquan
Shin, Chang Eon
Sun, Qiyu
author_facet Fang, Qiquan
Shin, Chang Eon
Sun, Qiyu
contents Let ${\mathcal B}$ be a Banach algebra and ${\mathcal A}$ be a Banach subalgebra that admits norm-controlled inversion in ${\mathcal B}$. In this work, we take $A, B$ in the Banach subalgebra ${\mathcal A}$ with their spectra in the Banach algebra ${\mathcal B}$ being disjoint, and show that the operator Sylvester equation $ BX-XA=Q$ has a unique solution $X\in {\mathcal A}$ for every $Q\in {\mathcal A}$. Under the additional assumptions that ${\mathcal B}$ is the operator algebra ${\mathcal B}(H)$ on a Hilbert space $H$ and that $A$ and $B$ are normal in ${\mathcal B}(H)$, an explicit norm estimate for the solution $X$ of the above operator Sylvester equation is provided in this work. In addition, the above conclusion on norm control is applied to Banach subalgebras of localized infinite matrices and integral operators.
format Preprint
id arxiv_https___arxiv_org_abs_2407_09752
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle On Sylvester equations in Banach subalgebras
Fang, Qiquan
Shin, Chang Eon
Sun, Qiyu
Functional Analysis
47G10, 47B38, 47A10, 47B49
Let ${\mathcal B}$ be a Banach algebra and ${\mathcal A}$ be a Banach subalgebra that admits norm-controlled inversion in ${\mathcal B}$. In this work, we take $A, B$ in the Banach subalgebra ${\mathcal A}$ with their spectra in the Banach algebra ${\mathcal B}$ being disjoint, and show that the operator Sylvester equation $ BX-XA=Q$ has a unique solution $X\in {\mathcal A}$ for every $Q\in {\mathcal A}$. Under the additional assumptions that ${\mathcal B}$ is the operator algebra ${\mathcal B}(H)$ on a Hilbert space $H$ and that $A$ and $B$ are normal in ${\mathcal B}(H)$, an explicit norm estimate for the solution $X$ of the above operator Sylvester equation is provided in this work. In addition, the above conclusion on norm control is applied to Banach subalgebras of localized infinite matrices and integral operators.
title On Sylvester equations in Banach subalgebras
topic Functional Analysis
47G10, 47B38, 47A10, 47B49
url https://arxiv.org/abs/2407.09752