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Bibliographic Details
Main Author: Ogawa, Hiroyuki
Format: Preprint
Published: 2024
Subjects:
Online Access:https://arxiv.org/abs/2401.01612
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author Ogawa, Hiroyuki
author_facet Ogawa, Hiroyuki
contents We define a subset of the closure of the upper half plane associated with an endomorphism on a real inner product space, which is called the leaf. When the dimension of the space is at least 3, the leaf is a convex with respect to the Poincaré metric, and contains all eigenvalues with nonnegative imaginary part. Moreover, the leaf of a normal endomorphism is the minimum Poincaré convex domain containing all eigenvalues with nonnegative imaginary part. The most commonly studied convex domain containing eigenvalues is number range. Numerical range is convex with respect to the Euclidean metric on $\mathbb C$, so numerical range has less information than leaf about real eigenvalues. We provide a new visual approach to endomorphisms.
format Preprint
id arxiv_https___arxiv_org_abs_2401_01612
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Leaf as a Poincaré convex domain associated with an endomorphism on a real inner product space
Ogawa, Hiroyuki
Functional Analysis
15A60, 47A12
We define a subset of the closure of the upper half plane associated with an endomorphism on a real inner product space, which is called the leaf. When the dimension of the space is at least 3, the leaf is a convex with respect to the Poincaré metric, and contains all eigenvalues with nonnegative imaginary part. Moreover, the leaf of a normal endomorphism is the minimum Poincaré convex domain containing all eigenvalues with nonnegative imaginary part. The most commonly studied convex domain containing eigenvalues is number range. Numerical range is convex with respect to the Euclidean metric on $\mathbb C$, so numerical range has less information than leaf about real eigenvalues. We provide a new visual approach to endomorphisms.
title Leaf as a Poincaré convex domain associated with an endomorphism on a real inner product space
topic Functional Analysis
15A60, 47A12
url https://arxiv.org/abs/2401.01612