The Weyl group and the normalizer of a conditional expectation

Autores
Argerami, Martín; Stojanoff, Demetrio
Año de publicación
1999
Idioma
inglés
Tipo de recurso
artículo
Estado
versión publicada
Descripción
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 UN and the normalizer NE of E, which can be also considered as the isotropy of the action of the unitary group UM 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.
Facultad de Ciencias Exactas
Materia
Ciencias Exactas
Matemática
Física
Weyl group
Algebra
Normalizer
Conditional expectation
Nivel de accesibilidad
acceso abierto
Condiciones de uso
http://creativecommons.org/licenses/by-nc-sa/4.0/
Repositorio
SEDICI (UNLP)
Institución
Universidad Nacional de La Plata
OAI Identificador
oai:sedici.unlp.edu.ar:10915/123300

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network_name_str SEDICI (UNLP)
spelling The Weyl group and the normalizer of a conditional expectationArgerami, MartínStojanoff, DemetrioCiencias ExactasMatemáticaFísicaWeyl groupAlgebraNormalizerConditional expectationWe 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.Facultad de Ciencias Exactas1999info:eu-repo/semantics/articleinfo:eu-repo/semantics/publishedVersionArticulohttp://purl.org/coar/resource_type/c_6501info:ar-repo/semantics/articuloapplication/pdf165-186http://sedici.unlp.edu.ar/handle/10915/123300enginfo:eu-repo/semantics/altIdentifier/issn/0378-620Xinfo:eu-repo/semantics/altIdentifier/issn/1420-8989info:eu-repo/semantics/altIdentifier/doi/10.1007/bf01236470info:eu-repo/semantics/openAccesshttp://creativecommons.org/licenses/by-nc-sa/4.0/Creative Commons Attribution-NonCommercial-ShareAlike 4.0 International (CC BY-NC-SA 4.0)reponame:SEDICI (UNLP)instname:Universidad Nacional de La Platainstacron:UNLP2025-09-03T11:01:22Zoai:sedici.unlp.edu.ar:10915/123300Institucionalhttp://sedici.unlp.edu.ar/Universidad públicaNo correspondehttp://sedici.unlp.edu.ar/oai/snrdalira@sedici.unlp.edu.arArgentinaNo correspondeNo correspondeNo correspondeopendoar:13292025-09-03 11:01:22.861SEDICI (UNLP) - Universidad Nacional de La Platafalse
dc.title.none.fl_str_mv The Weyl group and the normalizer of a conditional expectation
title The Weyl group and the normalizer of a conditional expectation
spellingShingle The Weyl group and the normalizer of a conditional expectation
Argerami, Martín
Ciencias Exactas
Matemática
Física
Weyl group
Algebra
Normalizer
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 The Weyl group and the normalizer of a conditional expectation
dc.creator.none.fl_str_mv Argerami, Martín
Stojanoff, Demetrio
author Argerami, Martín
author_facet Argerami, Martín
Stojanoff, Demetrio
author_role author
author2 Stojanoff, Demetrio
author2_role author
dc.subject.none.fl_str_mv Ciencias Exactas
Matemática
Física
Weyl group
Algebra
Normalizer
Conditional expectation
topic Ciencias Exactas
Matemática
Física
Weyl group
Algebra
Normalizer
Conditional expectation
dc.description.none.fl_txt_mv 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.
Facultad de Ciencias Exactas
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.
publishDate 1999
dc.date.none.fl_str_mv 1999
dc.type.none.fl_str_mv info:eu-repo/semantics/article
info:eu-repo/semantics/publishedVersion
Articulo
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format article
status_str publishedVersion
dc.identifier.none.fl_str_mv http://sedici.unlp.edu.ar/handle/10915/123300
url http://sedici.unlp.edu.ar/handle/10915/123300
dc.language.none.fl_str_mv eng
language eng
dc.relation.none.fl_str_mv info:eu-repo/semantics/altIdentifier/issn/0378-620X
info:eu-repo/semantics/altIdentifier/issn/1420-8989
info:eu-repo/semantics/altIdentifier/doi/10.1007/bf01236470
dc.rights.none.fl_str_mv info:eu-repo/semantics/openAccess
http://creativecommons.org/licenses/by-nc-sa/4.0/
Creative Commons Attribution-NonCommercial-ShareAlike 4.0 International (CC BY-NC-SA 4.0)
eu_rights_str_mv openAccess
rights_invalid_str_mv http://creativecommons.org/licenses/by-nc-sa/4.0/
Creative Commons Attribution-NonCommercial-ShareAlike 4.0 International (CC BY-NC-SA 4.0)
dc.format.none.fl_str_mv application/pdf
165-186
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instname:Universidad Nacional de La Plata
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repository.name.fl_str_mv SEDICI (UNLP) - Universidad Nacional de La Plata
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