Irregularity Measure of Graphs

A simple graph G is said to be regular if its vertices have the same number of neighbors. Otherwise, G is nonregular. So far, various formulas, such as the Albertson index, total Albertson index, and degree deviation, have been introduced to quantify the irregularity of a graph. In this paper, we pr...

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Main Authors: Ali Ghalavand, Ivan Gutman, Mostafa Tavakoli
Format: Article
Language:English
Published: Wiley 2023-01-01
Series:Journal of Mathematics
Online Access:http://dx.doi.org/10.1155/2023/4891183
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author Ali Ghalavand
Ivan Gutman
Mostafa Tavakoli
author_facet Ali Ghalavand
Ivan Gutman
Mostafa Tavakoli
author_sort Ali Ghalavand
collection DOAJ
description A simple graph G is said to be regular if its vertices have the same number of neighbors. Otherwise, G is nonregular. So far, various formulas, such as the Albertson index, total Albertson index, and degree deviation, have been introduced to quantify the irregularity of a graph. In this paper, we present sharp lower bounds for these indices in terms of the order, size, maximum degree, minimum degree, and forgotten and Zagreb indices of the underlying graph. We also prove that if G has the minimum value of degree deviation, among all nonregular n,m-graphs, then ΔG−δG=1.
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spelling doaj-art-21b54c0d93224c89895b8300ca9a47492025-08-20T03:54:42ZengWileyJournal of Mathematics2314-47852023-01-01202310.1155/2023/4891183Irregularity Measure of GraphsAli Ghalavand0Ivan Gutman1Mostafa Tavakoli2Department of Applied MathematicsFaculty of ScienceDepartment of Applied MathematicsA simple graph G is said to be regular if its vertices have the same number of neighbors. Otherwise, G is nonregular. So far, various formulas, such as the Albertson index, total Albertson index, and degree deviation, have been introduced to quantify the irregularity of a graph. In this paper, we present sharp lower bounds for these indices in terms of the order, size, maximum degree, minimum degree, and forgotten and Zagreb indices of the underlying graph. We also prove that if G has the minimum value of degree deviation, among all nonregular n,m-graphs, then ΔG−δG=1.http://dx.doi.org/10.1155/2023/4891183
spellingShingle Ali Ghalavand
Ivan Gutman
Mostafa Tavakoli
Irregularity Measure of Graphs
Journal of Mathematics
title Irregularity Measure of Graphs
title_full Irregularity Measure of Graphs
title_fullStr Irregularity Measure of Graphs
title_full_unstemmed Irregularity Measure of Graphs
title_short Irregularity Measure of Graphs
title_sort irregularity measure of graphs
url http://dx.doi.org/10.1155/2023/4891183
work_keys_str_mv AT alighalavand irregularitymeasureofgraphs
AT ivangutman irregularitymeasureofgraphs
AT mostafatavakoli irregularitymeasureofgraphs