On the structure of compact graphs

A simple graph \(G\) is called a compact graph if \(G\) contains no isolated vertices and for each pair \(x\), \(y\) of non-adjacent vertices of \(G\), there is a vertex \(z\) with \(N(x)\cup N(y)\subseteq N(z)\), where \(N(v)\) is the neighborhood of \(v\), for every vertex \(v\) of \(G\). In this...

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Main Authors: Reza Nikandish, Farzad Shaveisi
Format: Article
Language:English
Published: AGH Univeristy of Science and Technology Press 2017-01-01
Series:Opuscula Mathematica
Subjects:
Online Access:http://www.opuscula.agh.edu.pl/vol37/6/art/opuscula_math_3747.pdf
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author Reza Nikandish
Farzad Shaveisi
author_facet Reza Nikandish
Farzad Shaveisi
author_sort Reza Nikandish
collection DOAJ
description A simple graph \(G\) is called a compact graph if \(G\) contains no isolated vertices and for each pair \(x\), \(y\) of non-adjacent vertices of \(G\), there is a vertex \(z\) with \(N(x)\cup N(y)\subseteq N(z)\), where \(N(v)\) is the neighborhood of \(v\), for every vertex \(v\) of \(G\). In this paper, compact graphs with sufficient number of edges are studied. Also, it is proved that every regular compact graph is strongly regular. Some results about cycles in compact graphs are proved, too. Among other results, it is proved that if the ascending chain condition holds for the set of neighbors of a compact graph \(G\), then the descending chain condition holds for the set of neighbors of \(G\).
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spelling doaj.art-6495c7d35f994eb1a850086b257b5eef2022-12-21T19:46:05ZengAGH Univeristy of Science and Technology PressOpuscula Mathematica1232-92742017-01-01376875886http://dx.doi.org/10.7494/OpMath.2017.37.6.8753747On the structure of compact graphsReza Nikandish0Farzad Shaveisi1Department of Basic Sciences, Jundi-Shapur University of Technology, P.O. Box 64615-334, Dezful, IranDepartment of Mathematics, Faculty of Sciences, Razi University, P.O. Box 67149-67346, Kermanshah, IranA simple graph \(G\) is called a compact graph if \(G\) contains no isolated vertices and for each pair \(x\), \(y\) of non-adjacent vertices of \(G\), there is a vertex \(z\) with \(N(x)\cup N(y)\subseteq N(z)\), where \(N(v)\) is the neighborhood of \(v\), for every vertex \(v\) of \(G\). In this paper, compact graphs with sufficient number of edges are studied. Also, it is proved that every regular compact graph is strongly regular. Some results about cycles in compact graphs are proved, too. Among other results, it is proved that if the ascending chain condition holds for the set of neighbors of a compact graph \(G\), then the descending chain condition holds for the set of neighbors of \(G\).http://www.opuscula.agh.edu.pl/vol37/6/art/opuscula_math_3747.pdfcompact graphvertex degreecycleneighborhood
spellingShingle Reza Nikandish
Farzad Shaveisi
On the structure of compact graphs
Opuscula Mathematica
compact graph
vertex degree
cycle
neighborhood
title On the structure of compact graphs
title_full On the structure of compact graphs
title_fullStr On the structure of compact graphs
title_full_unstemmed On the structure of compact graphs
title_short On the structure of compact graphs
title_sort on the structure of compact graphs
topic compact graph
vertex degree
cycle
neighborhood
url http://www.opuscula.agh.edu.pl/vol37/6/art/opuscula_math_3747.pdf
work_keys_str_mv AT rezanikandish onthestructureofcompactgraphs
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