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Closed two-sided ideals in a von Neumann algebra and applications

Dissertation (MSc)--University of Pretoria, 1989.

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Other Authors: Swart, Johan
Format: Thesis
Language:English
Published: University of Pretoria 2022
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access_status_str Open Access
author2 Swart, Johan
author_browse Swart, Johan
author_facet Swart, Johan
collection Thesis
dc_rights_str_mv © 2020 University of Pretoria. All rights reserved. The copyright in this work vests in the University of Pretoria. No part of this work may be reproduced or transmitted in any form or by any means, without the prior written permission of the University of Pretoria.
description Dissertation (MSc)--University of Pretoria, 1989.
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institution University of Pretoria (South Africa)
language English
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license_str Other — see source repository
provenance_str_mv Harvested via OAI-PMH from UPSpace — University of Pretoria Institutional Repository
publishDate 2022
publishDateRange 2022
publishDateSort 2022
publisher University of Pretoria
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source_str UPSpace — University of Pretoria Institutional Repository
spelling oai:repository.up.ac.za:2263/85429 Closed two-sided ideals in a von Neumann algebra and applications Swart, Johan Stroh, Anton UCTD Closed two-sided ideals von Neumann algebra Dissertation (MSc)--University of Pretoria, 1989. The aim of this thesis is to study closed two-sided ideals in a von Neumann algebra A, not only by looking into the structure of these ideals, but by using them in several applications on the theory of von Neumann algebras. For example, one of the main objects of this thesis is to develop a Riesz theory relative to any closed ideal in a von Neumann algebra by proving some characterization theorems of relatively Riesz operators and then to use this to prove a Riesz decomposition theorem. Section 1 contains the definitions of some basic facts concerning von Neumann algebras used throughout this work. The main issue of section 2 is to consider three specific examples of closed two-sided ideals in a semifinite algebra with a non-zero type I direct summand, namely the ideals of operators compact relative to the von Neumann algebra, the ideal of compact operators contained rn A and the ideal of the so called Rosenthal operators relative to A. These ideals are used to obtain factorization results as well as a duality theorem. In the third section we deduce geometrical characterizations as well as a spectral characterization for the quotient norm on A/1, where 1 is any closed ideal in A. We then prove some characterization theorems on the semi-Fredholm elements relative to 1. In section 4 Riesz operators relative to a closed two-sided ideal are defined. The results in this section are similar to those known for the classical case and they are used in the sequel to prove characterization theorems for relatively Riesz operators as well as a Riesz decomposition theorem. In section 5 a geometrical characterization of Riesz operators relative to any closed ideal is proved. This geometrical characterization is used in section 6 to obtain a Riesz decomposition theorem for Riesz operators relative to specific closed ideals in a semifinite van Neumann algebra. Mathematics and Applied Mathematics MSc Unrestricted 2022-05-17T11:21:12Z 2022-05-17T11:21:12Z 2021/10/28 1989 Dissertation * https://repository.up.ac.za/handle/2263/85429 en © 2020 University of Pretoria. All rights reserved. The copyright in this work vests in the University of Pretoria. No part of this work may be reproduced or transmitted in any form or by any means, without the prior written permission of the University of Pretoria. application/pdf University of Pretoria
spellingShingle UCTD
Closed two-sided ideals
von Neumann algebra
Closed two-sided ideals in a von Neumann algebra and applications
title Closed two-sided ideals in a von Neumann algebra and applications
title_full Closed two-sided ideals in a von Neumann algebra and applications
title_fullStr Closed two-sided ideals in a von Neumann algebra and applications
title_full_unstemmed Closed two-sided ideals in a von Neumann algebra and applications
title_short Closed two-sided ideals in a von Neumann algebra and applications
title_sort closed two sided ideals in a von neumann algebra and applications
topic UCTD
Closed two-sided ideals
von Neumann algebra
url https://repository.up.ac.za/handle/2263/85429