Essentially Commuting with a Unitary

Fuente: arXiv
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Main Authors: Chung, Jui-Hui, Shapiro, Jacob
Format: Preprint
Published: 2025
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author Chung, Jui-Hui
Shapiro, Jacob
author_facet Chung, Jui-Hui
Shapiro, Jacob
contents Let $R$ be a unitary operator whose spectrum is the circle. We show that the set of unitaries $U$ which essentially commute with $R$ (i.e., $[U,R]\equiv UR-RU$ is compact) is path-connected. Moreover, we also calculate the set of path-connected components of the orthogonal projections which essentially commute with $R$ and obey a non-triviality condition, and prove it is bijective with $\mathbb{Z}$.
format Preprint
id arxiv_https___arxiv_org_abs_2501_03934
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Essentially Commuting with a Unitary
Chung, Jui-Hui
Shapiro, Jacob
Functional Analysis
Mathematical Physics
Operator Algebras
Let $R$ be a unitary operator whose spectrum is the circle. We show that the set of unitaries $U$ which essentially commute with $R$ (i.e., $[U,R]\equiv UR-RU$ is compact) is path-connected. Moreover, we also calculate the set of path-connected components of the orthogonal projections which essentially commute with $R$ and obey a non-triviality condition, and prove it is bijective with $\mathbb{Z}$.
title Essentially Commuting with a Unitary
topic Functional Analysis
Mathematical Physics
Operator Algebras
url https://arxiv.org/abs/2501.03934