Results 41 to 50 of about 132 (84)
On the vv-degree based first Zagreb index of graphs
AKCE International Journal of Graphs and CombinatoricsA topological index is a graph invariant applicable in chemistry. The first Zagreb index is a topological index based on the vertex degrees of molecular graphs. For any graph G, the first Zagreb index [Formula: see text] is equal to the sum of squares of
L. Anusha +2 more
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New bounds on Zagreb connection indices for trees with fixed domination number
AKCE International Journal of Graphs and CombinatoricsA set D of vertices in a graph G is a dominating set of G if every vertex not in D is adjacent to a vertex in D. The domination number, [Formula: see text], is the minimum cardinality among all dominating sets of G.
H. Rahbani +2 more
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New bounds for variable topological indices and applications [PDF]
One of the most important information related to molecular graphs is given by the determination (when possible) of upper and lower bounds for their corresponding topological indices. Such bounds allow to establish the approximate range of the topological
Granados, Ana +3 more
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Wiener index of an ideal-based zero-divisor graph of commutative ring with unity
AKCE International Journal of Graphs and CombinatoricsThe Wiener index of a connected graph G is [Formula: see text]. In this paper, we obtain the Wiener index of H-generalized join of graphs [Formula: see text]. As a consequence, we obtain some earlier known results in [Alaeiyan et al. in Aust. J.
Balamoorthy S. +2 more
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On spectra of Hermitian Randic matrix of second kind
, 2023 We propose the Hermitian Randi\'c matrix $R^\omega(X)=(R^\omega_{ij})$, where $\omega=\frac{1+i \sqrt{3}}{2}$ and $R^\omega_{ij}={1}/{\sqrt{d_id_j}}$ if $v_iv_j$ is an unoriented edge, ${\omega}/{\sqrt{d_id_j}}$ if $v_i\rightarrow v_j$, ${\overline ...
Bharali, A +3 more
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, 2023 Let $R$ be a commutative ring with unity. The essential ideal graph $\mathcal{E}_{R}$ of $R$, is a graph with a vertex set consisting of all nonzero proper ideals of \textit{R} and two vertices $I$ and $K$ are adjacent if and only if $I+ K$ is an ...
Banerjee, Subarsha +2 more
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Extremal trees, unicyclic and bicyclic graphs with respect to $p$-Sombor spectral radii
, 2023 For a graph $G=(V,E)$ and $v_{i}\in V$, denote by $d_{v_{i}}$ (or $d_{i}$ for short) the degree of vertex $v_{i}$. The $p$-Sombor matrix $\textbf{S}_{\textbf{p}}(G)$ ($p\neq0$) of a graph $G$ is a square matrix, where the $(i,j)$-entry is equal to ...
Jin, Xian'an +2 more
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Bounds on Kemeny's constant of a graph and the Nordhaus-Gaddum problem
, 2023 We study Nordhaus-Gaddum problems for Kemeny's constant $\mathcal{K}(G)$ of a connected graph $G$. We prove bounds on $\min\{\mathcal{K}(G),\mathcal{K}(\overline{G})\}$ and the product $\mathcal{K}(G)\mathcal{K}(\overline{G})$ for various families of ...
Chan, Ada +5 more
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Trees maximizing the number of almost-perfect matchings
, 2022 We characterize the extremal trees that maximize the number of almost-perfect matchings, which are matchings covering all but one or two vertices, and those that maximize the number of strong almost-perfect matchings, which are matchings missing only one
Cambie, Stijn +4 more
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