A New Proof that the Numerical Range is a Complete 2-Spectral Set for Weighted Shift Matrices

Fuente: arXiv
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Main Authors: Crouzeix, Michel, Greenbaum, Anne
Format: Preprint
Published: 2025
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author Crouzeix, Michel
Greenbaum, Anne
author_facet Crouzeix, Michel
Greenbaum, Anne
contents In this paper we give an alternative proof that the family of matrices studied by Daeshik Choi in A proof of Crouzeix's conjecture for a class of matrices, Linear Algebra and its Applications, 438, no. 8 (2013), pp. 3247-3257, satisfy Crouzeix's conjecture. We also show that they satisfy the completely bounded version of the conjecture.
format Preprint
id arxiv_https___arxiv_org_abs_2508_12768
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle A New Proof that the Numerical Range is a Complete 2-Spectral Set for Weighted Shift Matrices
Crouzeix, Michel
Greenbaum, Anne
Functional Analysis
Numerical Analysis
In this paper we give an alternative proof that the family of matrices studied by Daeshik Choi in A proof of Crouzeix's conjecture for a class of matrices, Linear Algebra and its Applications, 438, no. 8 (2013), pp. 3247-3257, satisfy Crouzeix's conjecture. We also show that they satisfy the completely bounded version of the conjecture.
title A New Proof that the Numerical Range is a Complete 2-Spectral Set for Weighted Shift Matrices
topic Functional Analysis
Numerical Analysis
url https://arxiv.org/abs/2508.12768