Geodesics of projections in von Neumann algebras

Fil: Andruchow, Esteban. Universidad Nacional de General Sarmiento. Instituto de Ciencias; Argentina.

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Autor principal: Andruchow, Esteban
Formato: Artículo publishedVersion
Lenguaje:Inglés
Publicado: American Mathematical Society 2024
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Acceso en línea:http://repositorio.ungs.edu.ar:8080/xmlui/handle/UNGS/1801
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spelling I71-R177-UNGS-18012024-12-23T13:21:45Z Geodesics of projections in von Neumann algebras Andruchow, Esteban Projections Geodesics of projections Von Neumann algebras Index for subfactors Fil: Andruchow, Esteban. Universidad Nacional de General Sarmiento. Instituto de Ciencias; Argentina. Fil: Andruchow, Esteban. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto Argentino de Matemática "Alberto P. Calderón"; Argentina. Let A be a von Neumann algebra and PA the manifold of projections in A. There is a natural linear connection in PA, which in the finite dimensional case coincides with the the Levi-Civita connection of the Grassmann manifold of Cn. In this paper we show that two projections p, q can be joined by a geodesic, which has minimal length (with respect to the metric given by the usual norm of A), if and only if p ? q? ? p? ? q, where ? stands for the Murray-von Neumann equivalence of projections. It is shown that the minimal geodesic is unique if and only if p ? q? = p? ? q = 0. If A is a finite factor, any pair of projections in the same connected component of PA (i.e., with the same trace) can be joined by a minimal geodesic. We explore certain relations with Jones’ index theory for subfactors. For instance, it is shown that if N ?M are II1 factors with finite index [M : N ] = t?1, then the geodesic distance d(eN , eM) between the induced projections eN and eM is d(eN , eM) = arccos(t1/2). 2024-12-23T13:21:44Z 2024-12-23T13:21:44Z 2021 info:eu-repo/semantics/article info:ar-repo/semantics/artículo info:eu-repo/semantics/publishedVersion Andruchow, E. (7-2021). Geodesics of projections in von Neumann algebras. Proceedings of the American Mathematical Society, 149(10), 4501-4513. 0002-9939 http://repositorio.ungs.edu.ar:8080/xmlui/handle/UNGS/1801 eng http://dx.doi.org/10.1090/proc/15568 info:eu-repo/semantics/restrictedAccess https://creativecommons.org/licenses/by-nc-nd/4.0/ application/pdf American Mathematical Society Proceedings of the American Mathematical Society. (Jul. 2021); 149(10): 4501-4513 https://www.ams.org/proc/2021-149-10/S0002-9939-2021-15568-8/
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 Projections
Geodesics of projections
Von Neumann algebras
Index for subfactors
spellingShingle Projections
Geodesics of projections
Von Neumann algebras
Index for subfactors
Andruchow, Esteban
Geodesics of projections in von Neumann algebras
topic_facet Projections
Geodesics of projections
Von Neumann algebras
Index for subfactors
description Fil: Andruchow, Esteban. Universidad Nacional de General Sarmiento. Instituto de Ciencias; Argentina.
format Artículo
Artículo
publishedVersion
author Andruchow, Esteban
author_facet Andruchow, Esteban
author_sort Andruchow, Esteban
title Geodesics of projections in von Neumann algebras
title_short Geodesics of projections in von Neumann algebras
title_full Geodesics of projections in von Neumann algebras
title_fullStr Geodesics of projections in von Neumann algebras
title_full_unstemmed Geodesics of projections in von Neumann algebras
title_sort geodesics of projections in von neumann algebras
publisher American Mathematical Society
publishDate 2024
url http://repositorio.ungs.edu.ar:8080/xmlui/handle/UNGS/1801
work_keys_str_mv AT andruchowesteban geodesicsofprojectionsinvonneumannalgebras
_version_ 1824528619475566592