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Applications of direct and inverse limits in analysis

Thesis (PhD (Mathematical Science))--University of Pretoria, 2022.

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Other Authors: Van der Walt, Jan Harm
Format: Thesis
Language:English
Published: University of Pretoria 2023
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access_status_str Open Access
author2 Van der Walt, Jan Harm
author_browse Van der Walt, Jan Harm
author_facet Van der Walt, Jan Harm
collection Thesis
dc_rights_str_mv © 2022 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 Thesis (PhD (Mathematical Science))--University of Pretoria, 2022.
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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 2023
publishDateRange 2023
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publisher University of Pretoria
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spelling oai:repository.up.ac.za:2263/88986 Applications of direct and inverse limits in analysis Van der Walt, Jan Harm sjvdwvanamstel@gmail.com De Jeu, Marcel Van Amstel, Walt UCTD Direct limit Inverse limit Vector lattice Free object Duality Sustainable Development Goals (SDGs) SDG-04: Quality education Natural and agricultural sciences theses SDG-04 SDG-09: Industry, innovation and infrastructure Natural and agricultural sciences theses SDG-09 Thesis (PhD (Mathematical Science))--University of Pretoria, 2022. In this dissertation, we use the categorical notions of direct and inverse limits to solve certain problems in analysis; in particular, in the field of vector lattices. Chapter 1 provides a general overview and motivation of the problems we will focus on. Specifically, these are a decomposition theorem for C(X) spaces that are order dual spaces, and the problem of existence of free objects in certain categories of locally convex structures. The connecting thread between these two disparate problems will be our extensive and fundamental use of direct and inverse limits in their solutions. Chapter 2 deals with the first of these two problems. After settling some preliminaries, the first few sections of Chapter 2 develops the basic theory of direct and inverse limits in categories of vector lattices. This includes results on existence, permanence properties, as well as some examples. After this, we give some results on the duality between direct and inverse limits. In particular, we will show that the order (continuous) dual of a direct limit of vector lattices is an inverse limit of order (continuous) duals, and (under more strict conditions) the order (continuous) dual of an inverse limit of vector lattices is a direct limit of order (continuous) duals. The rest of Chapter 2 deals with applications of this duality theory in various contexts, among these will be our desired decomposition result for certain C(X) spaces, which is formulated in terms of an inverse limit. Chapter 3 starts with some further preliminaries we need in order to define certain categories of algebraic structures, normed structures, and locally convex structures forming the setting of this chapter. After this, we cover some material from universal algebra to prove the existence of free objects in these algebraic categories. We use the existence of these algebraic free objects to expand upon the existing literature regarding certain `free objects' in categories of normed structures. As we shall detail below, these are not bona fide free objects in our sense of the term. Inverse limits re-enter the picture at this point: We will prove a general categorical result involving inverse limits that allows us to use our results for categories of normed structures to obtain genuine free objects in categories of locally convex structures. The abstract material in Chapter 3 will be interspersed with some concrete examples chosen from two particular cases. We conclude Chapter 3 by giving concrete descriptions of two free objects in certain categories of locally convex structures whose existence was proven using our general abstract methods. The author was supported by a grant from the DSI-NRF Centre of Excellence in Mathematical and Statistical Sciences (CoE-MaSS), South Africa. Opinions expressed and conclusions arrived at are those of the author and are not necessarily to be attributed to the CoE-MaSS. The results in this thesis were obtained, in part, while the author visited Leiden University from September 2021 to January 2022. This visit was funded through the European Union Erasmus+ ICM programme. Mathematics and Applied Mathematics PhD (Mathematical Science) Unrestricted 2023-01-26T13:59:17Z 2023-01-26T13:59:17Z 2023-04-01 2022-11-28 Thesis * A2024 https://repository.up.ac.za/handle/2263/88986 https://arxiv.org/abs/2207.05459 en © 2022 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
Direct limit
Inverse limit
Vector lattice
Free object
Duality
Sustainable Development Goals (SDGs)
SDG-04: Quality education
Natural and agricultural sciences theses SDG-04
SDG-09: Industry, innovation and infrastructure
Natural and agricultural sciences theses SDG-09
Applications of direct and inverse limits in analysis
title Applications of direct and inverse limits in analysis
title_full Applications of direct and inverse limits in analysis
title_fullStr Applications of direct and inverse limits in analysis
title_full_unstemmed Applications of direct and inverse limits in analysis
title_short Applications of direct and inverse limits in analysis
title_sort applications of direct and inverse limits in analysis
topic UCTD
Direct limit
Inverse limit
Vector lattice
Free object
Duality
Sustainable Development Goals (SDGs)
SDG-04: Quality education
Natural and agricultural sciences theses SDG-04
SDG-09: Industry, innovation and infrastructure
Natural and agricultural sciences theses SDG-09
url https://repository.up.ac.za/handle/2263/88986
https://arxiv.org/abs/2207.05459