The spectral radius of signless Laplacian matrix and sum-connectivity index of graphs

AbstractThe sum-connectivity index of a graph G is defined as the sum of weights [Formula: see text] over all edges uv of G, where du and dv are the degrees of the vertices u and v in G, respectively. The sum-connectivity index is one of the most important indices in chemical and mathematical fields...

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Main Authors: A. Jahanbani, S. M. Sheikholeslami
Format: Article
Language:English
Published: Taylor & Francis Group 2022-09-01
Series:AKCE International Journal of Graphs and Combinatorics
Subjects:
Online Access:https://www.tandfonline.com/doi/10.1080/09728600.2022.2093686
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author A. Jahanbani
S. M. Sheikholeslami
author_facet A. Jahanbani
S. M. Sheikholeslami
author_sort A. Jahanbani
collection DOAJ
description AbstractThe sum-connectivity index of a graph G is defined as the sum of weights [Formula: see text] over all edges uv of G, where du and dv are the degrees of the vertices u and v in G, respectively. The sum-connectivity index is one of the most important indices in chemical and mathematical fields. The spectral radius of a square matrix M is the maximum among the absolute values of the eigenvalues of M. Let q(G) be the spectral radius of the signless Laplacian matrix [Formula: see text] where D(G) is the diagonal matrix having degrees of the vertices on the main diagonal and A(G) is the (0, 1) adjacency matrix of G. The sum-connectivity index of a graph G and the spectral radius of the matrix Q(G) have been extensively studied. We investigate the relationship between the sum-connectivity index of a graph G and the spectral radius of the matrix Q(G). We prove that for some connected graphs with n vertices and m edges, [Graphic: see text]q(G)SCI(G)≤n(n+2mn−1−2)n(n−1)+2m−2n+2.
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spelling doaj.art-7c44388ceb794271b1248b8ea978271f2022-12-22T04:37:56ZengTaylor & Francis GroupAKCE International Journal of Graphs and Combinatorics0972-86002543-34742022-09-0119319119610.1080/09728600.2022.2093686The spectral radius of signless Laplacian matrix and sum-connectivity index of graphsA. Jahanbani0S. M. Sheikholeslami1Department of Mathematics, Azarbaijan Shahid Madani University, Tabriz, IranDepartment of Mathematics, Azarbaijan Shahid Madani University, Tabriz, IranAbstractThe sum-connectivity index of a graph G is defined as the sum of weights [Formula: see text] over all edges uv of G, where du and dv are the degrees of the vertices u and v in G, respectively. The sum-connectivity index is one of the most important indices in chemical and mathematical fields. The spectral radius of a square matrix M is the maximum among the absolute values of the eigenvalues of M. Let q(G) be the spectral radius of the signless Laplacian matrix [Formula: see text] where D(G) is the diagonal matrix having degrees of the vertices on the main diagonal and A(G) is the (0, 1) adjacency matrix of G. The sum-connectivity index of a graph G and the spectral radius of the matrix Q(G) have been extensively studied. We investigate the relationship between the sum-connectivity index of a graph G and the spectral radius of the matrix Q(G). We prove that for some connected graphs with n vertices and m edges, [Graphic: see text]q(G)SCI(G)≤n(n+2mn−1−2)n(n−1)+2m−2n+2.https://www.tandfonline.com/doi/10.1080/09728600.2022.2093686Sum-connectivity indexspectral radiussignless Laplacian matrix05C50
spellingShingle A. Jahanbani
S. M. Sheikholeslami
The spectral radius of signless Laplacian matrix and sum-connectivity index of graphs
AKCE International Journal of Graphs and Combinatorics
Sum-connectivity index
spectral radius
signless Laplacian matrix
05C50
title The spectral radius of signless Laplacian matrix and sum-connectivity index of graphs
title_full The spectral radius of signless Laplacian matrix and sum-connectivity index of graphs
title_fullStr The spectral radius of signless Laplacian matrix and sum-connectivity index of graphs
title_full_unstemmed The spectral radius of signless Laplacian matrix and sum-connectivity index of graphs
title_short The spectral radius of signless Laplacian matrix and sum-connectivity index of graphs
title_sort spectral radius of signless laplacian matrix and sum connectivity index of graphs
topic Sum-connectivity index
spectral radius
signless Laplacian matrix
05C50
url https://www.tandfonline.com/doi/10.1080/09728600.2022.2093686
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