Results 31 to 40 of about 132 (84)

Brouwer's conjecture for the sum of the k largest Laplacian eigenvalues of some graphs

Open Mathematics
Let GG be a graph with n(G)n\left(G) vertices and e(G)e\left(G) edges, and Sk(G){S}_{k}\left(G) be the sum of the kk largest Laplacian eigenvalues of GG. Brouwer conjectured that Sk(G)≤e(G)+k+12{S}_{k}\left(G)\le e\left(G)+\left(\phantom{\rule[-0.75em]{}{
Wang Ke, Lin Zhen, Zhang Shumin, Ye Chengfu   +3 more
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On the Harary Estrada index of graphs

Special Matrices
Let GG be a connected graph with nn vertices v1,…,vn{v}_{1},\ldots ,{v}_{n}. The Harary matrix of GG, denoted by H(G)H\left(G), is an n×nn\times n matrix with a zero main diagonal, where the (i,j)\left(i,j)-entry is 1d(vi,vj)\frac{1}{d\left({v}_{i},{v}_ ...
Oboudi Mohammad Reza
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Indices analysis of hexa organic molecular structures together with fundamental insights of a novel connectivity index

Main Group Metal Chemistry
Topological indices play a central role in mathematical chemistry for correlating structural features of molecular graphs with physicochemical properties.
Noreen Tahira, Salman Muhammad
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Irregularity of expansions and Pell graphs

, 2021
For a graph $G$ the imbalance of an edge $uv$ of $G$ is $|deg_G(u)-deg_G(v)|$. Irregularity of a graph $G$ is defined as the sum of imbalances over all edges of $G$. In this paper we consider expansions and Pell graphs. If $H$ is an expansion of $G$ with
Taranenko, Andrej
core  

Study on (r, s)-generalised transformation graphs, a novel perspective based on transformation graphs

Main Group Metal Chemistry
For a graph Q=(V,E){\mathbb{Q}}=\left({\mathbb{V}},{\mathbb{E}}), the transformation graph are defined as graphs with vertex set being V(Q)∪E(Q){\mathbb{V}}\left({\mathbb{Q}})\cup {\mathbb{E}}\left({\mathbb{Q}}) and edge set is described following ...
Ali Parvez, Baby Annmaria, Xavier D. Antony, Theertha Nair A., Ali Haidar, Kirmani Syed Ajaz K.   +5 more
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Indeks Padmakar-Ivan dan indeks Randic pada graf non-koprima dari grup bilangan bulat modulo

Majalah Ilmiah Matematika dan Statistika
Graph theory, introduced by the Swiss mathematician Leonhard Euler in 1736, has played a pivotal role in solving real-world problems since its inception, notably exemplified by Euler's solution to the Konigsberg Bridge problem. Its applications extend to
Lalu Hasan Ghoffari, I Gede Adhitya Wisnu Wardhana, Abdurahim Abdurahim   +2 more
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The sufficient conditions for $k$-leaf-connected graphs in terms of several topological indices

, 2023
Let $G=(V(G), E(G))$ be a graph with vertex set $V(G)$ and edge set $E(G)$. For $k\geq2$ and given any subset $S\subseteq|V(G)|$ with $|S|=k$, if a graph $G$ of order $|V(G)|\geq k+1$ always has a spanning tree $T$ such that $S$ is precisely the set of ...
Hu, Yang, Ma, Tingyan, Wang, Ligong
core  

The minimum exponential atom-bond connectivity energy of trees

Special Matrices
Let G=(V(G),E(G))G=\left(V\left(G),E\left(G)) be a graph of order nn. The exponential atom-bond connectivity matrix AeABC(G){A}_{{e}^{{\rm{ABC}}}}\left(G) of GG is an n×nn\times n matrix whose (i,j)\left(i,j)-entry is equal to ed(vi)+d(vj)−2d(vi)d(vj){e}^
Gao Wei
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Magnetic separation in graphs

Mathematical and Computer Modelling of Dynamical Systems
Vertex and edge operations are very popular tools in studying several properties of graphs, as they help us to calculate complex statements by means of easier or well-known ones. Deletion is probably the most important graph operation.
Hacer Ozden Ayna, Ismail Naci Cangul
doaj   +1 more source

A new method for computing the vertex PI index with applications to special classes of graphs

AKCE International Journal of Graphs and Combinatorics
The Padmakar-Ivan (PI) index of a graph G is given by [Formula: see text], where [Formula: see text] is the number of equidistant vertices for the edge e.
S. C. Manju, K. Somasundaram, Yilun Shang   +2 more
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