Geodesic neighborhoods in unitary orbits of self-adjoint operators of K + C

Revista con referato

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Autores principales: Bottazzi, Tamara Paula, Varela, Alejandro
Formato: Artículo publishedVersion
Lenguaje:Inglés
Publicado: Elsevier Science BV 2025
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Acceso en línea:http://repositorio.ungs.edu.ar:8080/xmlui/handle/UNGS/2136
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id I71-R177-UNGS-2136
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spelling I71-R177-UNGS-21362025-03-13T17:23:45Z Geodesic neighborhoods in unitary orbits of self-adjoint operators of K + C Bottazzi, Tamara Paula Varela, Alejandro Unitary orbits Geodesic curves Minimality Finsler metric 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. En el presente artículo, estudiamos la órbita unitaria de un operador diagonal hermitiano compacto con multiplicidad espectral uno bajo la acción del grupo unitario U(K+C) de la unitarización de los operadores compactos K(H) + C, o equivalentemente, el cociente U(K+C) /U(D(K+C)) . Relacionamos esto y la acción de diferentes subgrupos unitarios para describir geodésicas métricas (usando una distancia natural) que unen puntos finales. Como consecuencia obtenemos un teorema local de Hopf-Rinow. También exploramos casos sobre la unicidad de curvas cortas y demostramos que existen algunas de ellas que no pueden parametrizarse utilizando operadores antihermitianos mínimos de K(H) + C. In the present paper, we study the unitary orbit of a compact Hermitian diagonal operator with spectral multiplicity one under the action of the unitary group U(K+C) of the unitization of the compact operators K(H) + C, or equivalently, the quotient U(K+C) /U(D(K+C)) . We relate this and the action of different unitary subgroups to describe metric geodesics (using a natural distance) which join end points. As a consequence we obtain a local Hopf-Rinow theorem. We also explore cases about the uniqueness of short curves and prove that there exist some of these that cannot be parameterized using minimal anti-Hermitian operators of K(H) + C. No presente artigo, estudamos a órbita unitária de um operador diagonal Hermitiano compacto com multiplicidade espectral um sob a ação do grupo unitário U(K+C) da unitização dos operadores compactos K(H) + C, ou equivalentemente, o quociente U(K+C) /U(D(K+C)) . Relacionamos isso e a ação de diferentes subgrupos unitários para descrever geodésicas métricas (usando uma distância natural) que unem pontos finais. Como consequência obtemos um teorema local de Hopf-Rinow. Também exploramos casos sobre a unicidade de curvas curtas e provamos que existem algumas delas que não podem ser parametrizadas usando operadores mínimos anti-Hermitianos de K(H) + C. 2025-03-13T17:23:45Z 2025-03-13T17:23:45Z 2021 info:eu-repo/semantics/article info:ar-repo/semantics/artículo info:eu-repo/semantics/publishedVersion Bottazzi, T. P. y Varela, A. (2021). Geodesic neighborhoods in unitary orbits of self-adjoint operators of K + C. Differential Geometry and its Applications, 77, 1-15. 0926-2245 http://repositorio.ungs.edu.ar:8080/xmlui/handle/UNGS/2136 eng https://doi.org/10.1016/j.difgeo.2021.101778 info:eu-repo/semantics/openAccess https://creativecommons.org/licenses/by-nc-nd/4.0/ application/pdf application/pdf Elsevier Science BV Differential Geometry and its Applications. Ago. 2021; 77: 1-15 https://www.sciencedirect.com/journal/differential-geometry-and-its-applications/vol/77/suppl/C
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 Unitary orbits
Geodesic curves
Minimality
Finsler metric
Matemáticas
Matemática Pura
spellingShingle Unitary orbits
Geodesic curves
Minimality
Finsler metric
Matemáticas
Matemática Pura
Bottazzi, Tamara Paula
Varela, Alejandro
Geodesic neighborhoods in unitary orbits of self-adjoint operators of K + C
topic_facet Unitary orbits
Geodesic curves
Minimality
Finsler metric
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 Geodesic neighborhoods in unitary orbits of self-adjoint operators of K + C
title_short Geodesic neighborhoods in unitary orbits of self-adjoint operators of K + C
title_full Geodesic neighborhoods in unitary orbits of self-adjoint operators of K + C
title_fullStr Geodesic neighborhoods in unitary orbits of self-adjoint operators of K + C
title_full_unstemmed Geodesic neighborhoods in unitary orbits of self-adjoint operators of K + C
title_sort geodesic neighborhoods in unitary orbits of self-adjoint operators of k + c
publisher Elsevier Science BV
publishDate 2025
url http://repositorio.ungs.edu.ar:8080/xmlui/handle/UNGS/2136
work_keys_str_mv AT bottazzitamarapaula geodesicneighborhoodsinunitaryorbitsofselfadjointoperatorsofkc
AT varelaalejandro geodesicneighborhoodsinunitaryorbitsofselfadjointoperatorsofkc
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