The Weyl group and the normalizer of a conditional expectation

We define a discrete group W(E) associated to a faithful normal conditional expectation E : M → N for N ⊆ M von Neuman algebras. This group shows the relation between the unitary group U<sub>N</sub> and the normalizer N<sub>E</sub> of E, which can be also considered as the is...

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Detalles Bibliográficos
Autores principales: Argerami, Martín, Stojanoff, Demetrio
Formato: Articulo
Lenguaje:Inglés
Publicado: 1999
Materias:
Ciencias Exactas
Matemática
Física
Weyl group
Algebra
Normalizer
Conditional expectation
Acceso en línea:http://sedici.unlp.edu.ar/handle/10915/123300
Aporte de:
SEDICI (UNLP) de Universidad Nacional de La Plata
id I19-R120-10915-123300
record_format dspace
institution Universidad Nacional de La Plata
institution_str I-19
repository_str R-120
collection SEDICI (UNLP)
language Inglés
topic Ciencias Exactas
Matemática
Física
Weyl group
Algebra
Normalizer
Conditional expectation
spellingShingle Ciencias Exactas
Matemática
Física
Weyl group
Algebra
Normalizer
Conditional expectation
Argerami, Martín
Stojanoff, Demetrio
The Weyl group and the normalizer of a conditional expectation
topic_facet Ciencias Exactas
Matemática
Física
Weyl group
Algebra
Normalizer
Conditional expectation
description We define a discrete group W(E) associated to a faithful normal conditional expectation E : M → N for N ⊆ M von Neuman algebras. This group shows the relation between the unitary group U<sub>N</sub> and the normalizer N<sub>E</sub> of E, which can be also considered as the isotropy of the action of the unitary group U<sub>M</sub> of M on E. It is shown that W(E) is finite if dim Z(N) < ∞ and bounded by the index in the factor case. Also sharp bounds of the order of W(E) are founded. W(E) appears as the fibre of a covering space defined on the orbit of E by the natural action of the unitary group of M. W(E) is computed in some basic examples.
format Articulo
Articulo
author Argerami, Martín
Stojanoff, Demetrio
author_facet Argerami, Martín
Stojanoff, Demetrio
author_sort Argerami, Martín
title The Weyl group and the normalizer of a conditional expectation
title_short The Weyl group and the normalizer of a conditional expectation
title_full The Weyl group and the normalizer of a conditional expectation
title_fullStr The Weyl group and the normalizer of a conditional expectation
title_full_unstemmed The Weyl group and the normalizer of a conditional expectation
title_sort weyl group and the normalizer of a conditional expectation
publishDate 1999
url http://sedici.unlp.edu.ar/handle/10915/123300
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