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Graph Theory: A Lost Component For Development in Nigeria

Journal of Nigerian Society of Physical Sciences, 2022
Graph theory is one of the neglected branches of mathematics in Nigeria but with the most applications in other fields of research. This article shows the paucity, importance, and necessity of graph theory in the development of Nigeria.
Olayiwola Babarinsa
doaj   +1 more source

Estimating the total π-electron energy [PDF]

Journal of the Serbian Chemical Society, 2013
The paper gives a short survey of the most important lower and upper bounds for total π-electron energy, i.e., graph energy (E). In addition, a new lower and a new upper bound for E are deduced, valid for general molecular graphs.
Gutman Ivan, Das Kinkar Ch.
doaj   +1 more source

Randić Incidence Energy of Graphs [PDF]

Transactions on Combinatorics, 2014
Let $G$ be a simple graph with vertex set $V(G) = \{v_1, v_2,\ldots, v_n\}$ and edge set $E(G) = \{e_1, e_2,\ldots, e_m\}$. Similar to the Randić matrix, here we introduce the Randić incidence matrix of a graph $G$, denoted by $I_R(G)$, which is defined as the $n\times m$ matrix whose $(i, j)$-entry is $(d_i)^{-\frac{1}{2}}$ if $v_i$ is incident to ...
Gu, Ran, Huang, Fei, Li, Xueliang
openaire   +6 more sources

Energy of a digraph with respect to a VDB topological index

Special Matrices, 2022
Let DD be a digraph with vertex set VV and arc set EE. For a vertex uu, the out-degree and in-degree of uu are denoted by du+{d}_{u}^{+} and du−{d}_{u}^{-}, respectively.
Monsalve Juan, Rada Juan
doaj   +1 more source

Research and Application of Hypernetwork Energy

Jisuanji kexue yu tansuo, 2021
Graph energy plays an important role in research of graph theory. Graph energy and many other similar variants have been applied in many other types of graphs, e.g., undirected graphs, oriented graphs, mixed graphs, and so on.
LIU Shengjiu, LI Tianrui, LIU Jia, XIE Peng
doaj   +1 more source

ON SPECTRA OF HERMITIAN RANDIĆ MATRIX OF SECOND KIND [PDF]

Journal of Algebraic Systems
Let $X$ be a mixed graph and $\omega=\frac{1+\i \sqrt{3}}{2}$. We write $i\rightarrow j$, if there is an oriented edge from a vertex $v_i$ to another vertex $v_j$, and $i\sim j$ for an un-oriented edge between the vertices $v_i$ and $v_j$.
A Bharali, Bikash Bhattacharjya, Sumanta Borah, Idweep Gogoi   +3 more
doaj   +1 more source

Bounds on Energy and Laplacian Energy of Graphs [PDF]

Journal of the Indonesian Mathematical Society, 2017
Let G be simple graph with n vertices and m edges. The energy E(G) of G, denotedby E(G), is dened to be the sum of the absolute values of the eigenvalues of G. Inthis paper, we present two new upper bounds for energy of a graph, one in terms ofm,n and another in terms of largest absolute eigenvalue and the smallest absoluteeigenvalue.
Sridhara, G., Kanna, Rajesh M. R.
openaire   +2 more sources

Bounds for the Energy of Graphs

Hacettepe Journal of Mathematics and Statistics, 2016
© 2016, Hacettepe University. All rights reserved. The energy of a graph G, denoted by E(G), is the sum of the absolute values of all eigenvalues of G. In this paper we present some lower and upper bounds for E(G) in terms of number of vertices, number of edges, and determinant of the adjacency matrix.
DAS, Kinkar Ch., GUTMAN, İvan
openaire   +3 more sources

Construction of L-equienergetic graphs using some graph operations

AKCE International Journal of Graphs and Combinatorics, 2020
For a graph G with n vertices and m edges, the eigenvalues of its adjacency matrix A(G) are known as eigenvalues of G. The sum of absolute values of eigenvalues of G is called the energy of G.
S. K. Vaidya, Kalpesh M. Popat
doaj   +1 more source

On Laplacian energy of graphs

Discrete Mathematics, 2014
zbMATH Open Web Interface contents unavailable due to conflicting licenses.
Kinkar Chandra Das, Seyed Ahmad Mojallal
openaire   +1 more source