Determination of the distance from a projection to nilpotents

Fuente: arXiv
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Main Authors: Izumi, Masaki, Mori, Michiya
Format: Preprint
Published: 2024
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author Izumi, Masaki
Mori, Michiya
author_facet Izumi, Masaki
Mori, Michiya
contents In this note, we study the distance from an arbitrary nonzero projection $P$ to the set of nilpotents in a factor $\mathcal{M}$ equipped with a normal faithful tracial state $τ$. We prove that the distance equals $(2\cos \frac{τ(P)π}{1+2τ(P)})^{-1}$. This is new even in the case where $\mathcal{M}$ is the matrix algebra. The special case settles a conjecture posed by Z. Cramer.
format Preprint
id arxiv_https___arxiv_org_abs_2406_09234
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Determination of the distance from a projection to nilpotents
Izumi, Masaki
Mori, Michiya
Operator Algebras
Functional Analysis
In this note, we study the distance from an arbitrary nonzero projection $P$ to the set of nilpotents in a factor $\mathcal{M}$ equipped with a normal faithful tracial state $τ$. We prove that the distance equals $(2\cos \frac{τ(P)π}{1+2τ(P)})^{-1}$. This is new even in the case where $\mathcal{M}$ is the matrix algebra. The special case settles a conjecture posed by Z. Cramer.
title Determination of the distance from a projection to nilpotents
topic Operator Algebras
Functional Analysis
url https://arxiv.org/abs/2406.09234