On the spectrum and energy of singular graphs
Energy of a graph is defined as the sum of the absolute values of the eigenvalues of the adjacency matrix A(G)of a graph Gand is denoted by E(G). The graph G with n vertices is called nonhypoenergetic if E(G)≥nand hypoenergetic if E(G)<n. Singular graphs are graphs with nullity η(G)>0. In this...
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doaj-77595b4920a84362af8fa23252af94672020-11-25T02:58:17ZengTaylor & Francis GroupAKCE International Journal of Graphs and Combinatorics0972-86002019-12-01163265271On the spectrum and energy of singular graphsT.K. Mathew Varkey0John K. Rajan1Department of Mathematics, TKM College of Engineering, Kollam, Kerala, India; Corresponding author.Department of Mathematics, University College, Thiruvananthapuram, Kerala, IndiaEnergy of a graph is defined as the sum of the absolute values of the eigenvalues of the adjacency matrix A(G)of a graph Gand is denoted by E(G). The graph G with n vertices is called nonhypoenergetic if E(G)≥nand hypoenergetic if E(G)<n. Singular graphs are graphs with nullity η(G)>0. In this paper we study about nonhypoenergetic and hypoenergetic graphs among singular graphs. We also construct singular graphs of larger nullity using coalescence. Keywords: Singular graphs, Coalescence, Core vertices, Energy of graph, Nonhypoenergetic graphhttp://www.sciencedirect.com/science/article/pii/S0972860016301608 |
collection |
DOAJ |
language |
English |
format |
Article |
sources |
DOAJ |
author |
T.K. Mathew Varkey John K. Rajan |
spellingShingle |
T.K. Mathew Varkey John K. Rajan On the spectrum and energy of singular graphs AKCE International Journal of Graphs and Combinatorics |
author_facet |
T.K. Mathew Varkey John K. Rajan |
author_sort |
T.K. Mathew Varkey |
title |
On the spectrum and energy of singular graphs |
title_short |
On the spectrum and energy of singular graphs |
title_full |
On the spectrum and energy of singular graphs |
title_fullStr |
On the spectrum and energy of singular graphs |
title_full_unstemmed |
On the spectrum and energy of singular graphs |
title_sort |
on the spectrum and energy of singular graphs |
publisher |
Taylor & Francis Group |
series |
AKCE International Journal of Graphs and Combinatorics |
issn |
0972-8600 |
publishDate |
2019-12-01 |
description |
Energy of a graph is defined as the sum of the absolute values of the eigenvalues of the adjacency matrix A(G)of a graph Gand is denoted by E(G). The graph G with n vertices is called nonhypoenergetic if E(G)≥nand hypoenergetic if E(G)<n. Singular graphs are graphs with nullity η(G)>0. In this paper we study about nonhypoenergetic and hypoenergetic graphs among singular graphs. We also construct singular graphs of larger nullity using coalescence. Keywords: Singular graphs, Coalescence, Core vertices, Energy of graph, Nonhypoenergetic graph |
url |
http://www.sciencedirect.com/science/article/pii/S0972860016301608 |
work_keys_str_mv |
AT tkmathewvarkey onthespectrumandenergyofsingulargraphs AT johnkrajan onthespectrumandenergyofsingulargraphs |
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1724707289244368896 |