Minimal self-adjoint compact operators, moment of a subspace and joint numerical range

Revista con referato

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Autores principales: Bottazzi, Tamara Paula, Varela, Alejandro
Formato: Artículo publishedVersion
Lenguaje:Inglés
Publicado: Elsevier Science 2026
Materias:
Moment of Subspace
Self-Adjoint Compact Operators
Minimality
Joint Numerical Range
Matemáticas
Matemática Pura
Acceso en línea:http://repositorio.ungs.edu.ar:8080/xmlui/handle/UNGS/2699
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Repositorio Institucional Digital de Acceso Abierto (UNGS) de Universidad Nacional de General Sarmiento
id I71-R177-UNGS-2699
record_format dspace
spelling I71-R177-UNGS-26992026-01-14T11:47:52Z Minimal self-adjoint compact operators, moment of a subspace and joint numerical range Bottazzi, Tamara Paula Varela, Alejandro Moment of Subspace Self-Adjoint Compact Operators Minimality Joint Numerical Range Matemáticas Matemática Pura Revista con referato Fil: Bottazzi, Tamara Paula. Universidad Nacional de General Sarmiento. Instituto de Ciencias; Argentina. Fil: Bottazzi, Tamara Paula. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Patagonia Norte; Argentina. Fil: Varela, Alejandro. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto Argentino de Matemática Alberto Calderón; Argentina. Fil: Varela, Alejandro. Universidad Nacional de General Sarmiento. Instituto de Ciencias; Argentina. We define the (convex) joint numerical range for an infinite family of compact operators in a Hilbert space H. We use this set to determine whether a self-adjoint compact operator A with ±‖A‖ in its spectrum is minimal respect to the set of diagonals in a fixed basis E of H in the operator norm, that is ‖A‖≤‖A+D‖, for all diagonal D. We also describe the moment set mS=conv{|v|2:v∈S and ‖v‖=1} of a subspace S⊂H in terms of joint numerical ranges and obtain equivalences between the intersection of moments of two subspaces and of its two related joint numerical ranges. Moreover, we relate the condition of minimality of A or the intersection of the moments of the eigenspaces of ±‖A‖ to the intersection of the joint numerical ranges of two finite families of certain finite hermitian matrices. We also study geometric properties of the set mS such as extremal curves related with the basis E. All these conditions are directly related with the description of minimal self-adjoint compact operators. 2026-01-14T11:46:13Z 2026-01-14T11:46:13Z 2023 info:eu-repo/semantics/article info:ar-repo/semantics/artículo info:eu-repo/semantics/publishedVersion Bottazzi, T. P. y Varela, A. (2023). Minimal self-adjoint compact operators, moment of a subspace and joint numerical range. Journal of Mathematical Analysis and Applications, 528(2), 1-22. 0022-247X http://repositorio.ungs.edu.ar:8080/xmlui/handle/UNGS/2699 eng https://doi.org/10.1016/j.jmaa.2023.127552 info:eu-repo/semantics/restrictedAccess https://creativecommons.org/licenses/by-nc-nd/4.0/ application/pdf Elsevier Science Journal of Mathematical Analysis and Applications. Dic. 2023; 528(2): 1-22 https://www.sciencedirect.com/journal/journal-of-mathematical-analysis-and-applications/vol/528/issue/2
institution Universidad Nacional de General Sarmiento
institution_str I-71
repository_str R-177
collection Repositorio Institucional Digital de Acceso Abierto (UNGS)
language Inglés
orig_language_str_mv eng
topic Moment of Subspace
Self-Adjoint Compact Operators
Minimality
Joint Numerical Range
Matemáticas
Matemática Pura
spellingShingle Moment of Subspace
Self-Adjoint Compact Operators
Minimality
Joint Numerical Range
Matemáticas
Matemática Pura
Bottazzi, Tamara Paula
Varela, Alejandro
Minimal self-adjoint compact operators, moment of a subspace and joint numerical range
topic_facet Moment of Subspace
Self-Adjoint Compact Operators
Minimality
Joint Numerical Range
Matemáticas
Matemática Pura
description Revista con referato
format Artículo
Artículo
publishedVersion
author Bottazzi, Tamara Paula
Varela, Alejandro
author_facet Bottazzi, Tamara Paula
Varela, Alejandro
author_sort Bottazzi, Tamara Paula
title Minimal self-adjoint compact operators, moment of a subspace and joint numerical range
title_short Minimal self-adjoint compact operators, moment of a subspace and joint numerical range
title_full Minimal self-adjoint compact operators, moment of a subspace and joint numerical range
title_fullStr Minimal self-adjoint compact operators, moment of a subspace and joint numerical range
title_full_unstemmed Minimal self-adjoint compact operators, moment of a subspace and joint numerical range
title_sort minimal self-adjoint compact operators, moment of a subspace and joint numerical range
publisher Elsevier Science
publishDate 2026
url http://repositorio.ungs.edu.ar:8080/xmlui/handle/UNGS/2699
work_keys_str_mv AT bottazzitamarapaula minimalselfadjointcompactoperatorsmomentofasubspaceandjointnumericalrange
AT varelaalejandro minimalselfadjointcompactoperatorsmomentofasubspaceandjointnumericalrange
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