Nowhere dense sets and real-valued functions with closed graphs

Closed and nowhere dense subsets which coincide with the points of discontinuity of real-valued functions with a closed graph on spaces which are not necessarily perfectly normal are investigated. Certain Gδ subsets of completely regular and normal spaces are characterized. It is also shown that th...

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Main Author: Ivan Baggs
Format: Article
Language:English
Published: Wiley 1989-01-01
Series:International Journal of Mathematics and Mathematical Sciences
Online Access:http://dx.doi.org/10.1155/S0161171289000013
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author Ivan Baggs
author_facet Ivan Baggs
author_sort Ivan Baggs
collection DOAJ
description Closed and nowhere dense subsets which coincide with the points of discontinuity of real-valued functions with a closed graph on spaces which are not necessarily perfectly normal are investigated. Certain Gδ subsets of completely regular and normal spaces are characterized. It is also shown that there exists a countable connected Urysohn space X with the property that no closed and nowhere dense subset of X coincides with the points of discontinuity of a real-valued function on X with a closed graph.
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institution Kabale University
issn 0161-1712
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language English
publishDate 1989-01-01
publisher Wiley
record_format Article
series International Journal of Mathematics and Mathematical Sciences
spelling doaj-art-3b984d1c026b4bb0954e0f91bb336e032025-02-03T05:48:05ZengWileyInternational Journal of Mathematics and Mathematical Sciences0161-17121687-04251989-01-011211810.1155/S0161171289000013Nowhere dense sets and real-valued functions with closed graphsIvan Baggs0Department of Mathematics, University of Alberta, Edmonton T6G 2G1, Alberta, CanadaClosed and nowhere dense subsets which coincide with the points of discontinuity of real-valued functions with a closed graph on spaces which are not necessarily perfectly normal are investigated. Certain Gδ subsets of completely regular and normal spaces are characterized. It is also shown that there exists a countable connected Urysohn space X with the property that no closed and nowhere dense subset of X coincides with the points of discontinuity of a real-valued function on X with a closed graph.http://dx.doi.org/10.1155/S0161171289000013
spellingShingle Ivan Baggs
Nowhere dense sets and real-valued functions with closed graphs
International Journal of Mathematics and Mathematical Sciences
title Nowhere dense sets and real-valued functions with closed graphs
title_full Nowhere dense sets and real-valued functions with closed graphs
title_fullStr Nowhere dense sets and real-valued functions with closed graphs
title_full_unstemmed Nowhere dense sets and real-valued functions with closed graphs
title_short Nowhere dense sets and real-valued functions with closed graphs
title_sort nowhere dense sets and real valued functions with closed graphs
url http://dx.doi.org/10.1155/S0161171289000013
work_keys_str_mv AT ivanbaggs nowheredensesetsandrealvaluedfunctionswithclosedgraphs