Geometric Characterization of the Numerical Range of Parallel Sum of Two Orthogonal Projections

Let H be a complex separable Hilbert space and BH be the algebra of all bounded linear operators from H to H. Our goal in this article is to describe the closure of numerical range of parallel sum operator P:PQ for two orthogonal projections P and Q in BH as a closed convex hull of some explicit ell...

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Main Authors: Weiyan Yu, Ran Wang, Chen Zhang
Format: Article
Language:English
Published: Wiley 2024-01-01
Series:Journal of Mathematics
Online Access:http://dx.doi.org/10.1155/2024/1448498
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author Weiyan Yu
Ran Wang
Chen Zhang
author_facet Weiyan Yu
Ran Wang
Chen Zhang
author_sort Weiyan Yu
collection DOAJ
description Let H be a complex separable Hilbert space and BH be the algebra of all bounded linear operators from H to H. Our goal in this article is to describe the closure of numerical range of parallel sum operator P:PQ for two orthogonal projections P and Q in BH as a closed convex hull of some explicit ellipses parameterized by points in the spectrum.
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institution Kabale University
issn 2314-4785
language English
publishDate 2024-01-01
publisher Wiley
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series Journal of Mathematics
spelling doaj-art-92024ed6652b49489013f7843d4ba3162025-02-03T01:32:21ZengWileyJournal of Mathematics2314-47852024-01-01202410.1155/2024/1448498Geometric Characterization of the Numerical Range of Parallel Sum of Two Orthogonal ProjectionsWeiyan Yu0Ran Wang1Chen Zhang2College of Mathematics and StatisticsCollege of Mathematics and StatisticsCollege of Mathematics and StatisticsLet H be a complex separable Hilbert space and BH be the algebra of all bounded linear operators from H to H. Our goal in this article is to describe the closure of numerical range of parallel sum operator P:PQ for two orthogonal projections P and Q in BH as a closed convex hull of some explicit ellipses parameterized by points in the spectrum.http://dx.doi.org/10.1155/2024/1448498
spellingShingle Weiyan Yu
Ran Wang
Chen Zhang
Geometric Characterization of the Numerical Range of Parallel Sum of Two Orthogonal Projections
Journal of Mathematics
title Geometric Characterization of the Numerical Range of Parallel Sum of Two Orthogonal Projections
title_full Geometric Characterization of the Numerical Range of Parallel Sum of Two Orthogonal Projections
title_fullStr Geometric Characterization of the Numerical Range of Parallel Sum of Two Orthogonal Projections
title_full_unstemmed Geometric Characterization of the Numerical Range of Parallel Sum of Two Orthogonal Projections
title_short Geometric Characterization of the Numerical Range of Parallel Sum of Two Orthogonal Projections
title_sort geometric characterization of the numerical range of parallel sum of two orthogonal projections
url http://dx.doi.org/10.1155/2024/1448498
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AT ranwang geometriccharacterizationofthenumericalrangeofparallelsumoftwoorthogonalprojections
AT chenzhang geometriccharacterizationofthenumericalrangeofparallelsumoftwoorthogonalprojections