Geodesic neighborhoods in unitary orbits of self-adjoint operators of K + C
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Acceso en línea: | http://repositorio.ungs.edu.ar:8080/xmlui/handle/UNGS/2136 |
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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 |
_version_ |
1826997429282537472 |