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

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Detalles Bibliográficos
Autores: Bottazzi, Tamara Paula, Varela, Alejandro
Tipo de recurso: artículo
Estado:Versión publicada
Fecha de publicación:2021
País:Argentina
Institución:Consejo Nacional de Investigaciones Científicas y Técnicas
Repositorio:CONICET Digital (CONICET)
Idioma:inglés
OAI Identifier:oai:ri.conicet.gov.ar:11336/157556
Acceso en línea:http://hdl.handle.net/11336/157556
Access Level:acceso abierto
Palabra clave:UNITARY ORBITS
GEODESIC CURVES
MINIMALITY
FINSLER METRICS
https://purl.org/becyt/ford/1.1
https://purl.org/becyt/ford/1
Descripción
Sumario: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.