On commutators of square-zero Hilbert space operators

Fuente: arXiv
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Autori principali: Marcoux, Laurent W., Radjavi, Heydar, Zhang, Yuanhang
Natura: Preprint
Pubblicazione: 2024
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_version_ 1866913696546029568
author Marcoux, Laurent W.
Radjavi, Heydar
Zhang, Yuanhang
author_facet Marcoux, Laurent W.
Radjavi, Heydar
Zhang, Yuanhang
contents Let $\mathcal{H}$ be a complex, separable Hilbert space, and set $\mathfrak{c}($NIL$_2)=\{ MN - NM : N, M \in \mathcal{B}(\mathcal{H}), M^2 = 0 = N^2 \}$. When $\dim\, \mathcal{H}$ is finite, we characterise the set $\mathfrak{c}($NIL$_2)$ and its norm-closure CLOS$(\mathfrak{c}($NIL$_2))$. In the infinite-dimensional setting, we characterise the intersection of CLOS$(\mathfrak{c}($NIL$_2))$ with the set of biquasitriangular operators, and we exhibit an index obstruction to belonging to CLOS$(\mathfrak{c}($NIL$_2))$.
format Preprint
id arxiv_https___arxiv_org_abs_2402_15676
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle On commutators of square-zero Hilbert space operators
Marcoux, Laurent W.
Radjavi, Heydar
Zhang, Yuanhang
Functional Analysis
Primary: 47B47, Secondary: 47A58
Let $\mathcal{H}$ be a complex, separable Hilbert space, and set $\mathfrak{c}($NIL$_2)=\{ MN - NM : N, M \in \mathcal{B}(\mathcal{H}), M^2 = 0 = N^2 \}$. When $\dim\, \mathcal{H}$ is finite, we characterise the set $\mathfrak{c}($NIL$_2)$ and its norm-closure CLOS$(\mathfrak{c}($NIL$_2))$. In the infinite-dimensional setting, we characterise the intersection of CLOS$(\mathfrak{c}($NIL$_2))$ with the set of biquasitriangular operators, and we exhibit an index obstruction to belonging to CLOS$(\mathfrak{c}($NIL$_2))$.
title On commutators of square-zero Hilbert space operators
topic Functional Analysis
Primary: 47B47, Secondary: 47A58
url https://arxiv.org/abs/2402.15676