Is there any nontrivial compact generalized shift operator on Hilbert spaces?

Fuente: arXiv
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Main Authors: Shirazi, Fatemah Ayatollah Zadeh, Ebrahimifar, Fatemeh
Format: Preprint
Published: 2018
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author Shirazi, Fatemah Ayatollah Zadeh
Ebrahimifar, Fatemeh
author_facet Shirazi, Fatemah Ayatollah Zadeh
Ebrahimifar, Fatemeh
contents In the following text for cardinal number $τ>0$, and self--map $φ:τ\toτ$ we show the generalized shift operator $σ_φ(\ell^2(τ))\subseteq\ell^2(τ)$ (where $σ_φ((x_α)_{α<τ})=(x_{φ(α)})_{α<τ}$ for $(x_α)_{α<τ}\in{\mathbb C}^τ$) if and only if $φ:τ\toτ$ is bounded and in this case $σ_φ\restriction_{\ell^2(τ)}:\ell^2(τ)\to\ell^2(τ)$ is continuous, consequently $σ_φ\restriction_{\ell^2(τ)}:\ell^2(τ)\to\ell^2(τ)$ is a compact operator if and only if $τ$ is finite.
format Preprint
id arxiv_https___arxiv_org_abs_1804_07921
institution arXiv
publishDate 2018
record_format arxiv
spellingShingle Is there any nontrivial compact generalized shift operator on Hilbert spaces?
Shirazi, Fatemah Ayatollah Zadeh
Ebrahimifar, Fatemeh
Functional Analysis
46C99
In the following text for cardinal number $τ>0$, and self--map $φ:τ\toτ$ we show the generalized shift operator $σ_φ(\ell^2(τ))\subseteq\ell^2(τ)$ (where $σ_φ((x_α)_{α<τ})=(x_{φ(α)})_{α<τ}$ for $(x_α)_{α<τ}\in{\mathbb C}^τ$) if and only if $φ:τ\toτ$ is bounded and in this case $σ_φ\restriction_{\ell^2(τ)}:\ell^2(τ)\to\ell^2(τ)$ is continuous, consequently $σ_φ\restriction_{\ell^2(τ)}:\ell^2(τ)\to\ell^2(τ)$ is a compact operator if and only if $τ$ is finite.
title Is there any nontrivial compact generalized shift operator on Hilbert spaces?
topic Functional Analysis
46C99
url https://arxiv.org/abs/1804.07921