Results 41 to 50 of about 112 (100)

New Formulae for the Decycling Number of Graphs

Discussiones Mathematicae Graph Theory, 2019
A set S of vertices of a graph G is called a decycling set if G−S is acyclic. The minimum order of a decycling set is called the decycling number of G, and denoted by ∇(G). Our results include: (a) For any graph G,, where T is taken over all the spanning
Yang Chao, Ren Han
doaj   +1 more source

Sombor index of zero-divisor graphs of commutative rings

Analele Stiintifice ale Universitatii Ovidius Constanta: Seria Matematica, 2022
In this paper, we investigate the Sombor index of the zero-divisor graph of ℤn which is denoted by Γ(ℤn) for n ∈ {pα, pq, p2q, pqr} where p, q and r are distinct prime numbers. Moreover, we introduce an algorithm which calculates the Sombor index of Γ(ℤn)
Gürsoy Arif, Ülker Alper, Kircali Gürsoy Necla   +2 more
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On the existence of tripartite graphs and n-partite graphs

Open Mathematics
A sequence α\alpha of nonnegative integers is said to be graphic if it is the degree sequence of a simple graph GG, and such a graph GG is called a realization of α\alpha .
Guo Jiyun, Li Haiyan, Zhang Yuqin, Liu Lingling, Fu Miao   +4 more
doaj   +1 more source

ALTERNATING AND SYMMETRIC GROUPS WITH EULERIAN GENERATING GRAPH

Forum of Mathematics, Sigma, 2017
Given a finite group $G$ , the generating graph $\unicode[STIX]{x1D6E4}(G)$
ANDREA LUCCHINI, CLAUDE MARION
doaj   +1 more source

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
doaj   +1 more source

Properties of uniformly $3$-connected graphs [PDF]

Discrete Mathematics & Theoretical Computer Science
A graph on at least ${{k+1}}$ vertices is uniformly $k$-connected if each pair of its vertices is connected by $k$ and not more than $k$ independent paths.
Frank Göring, Tobias Hofmann
doaj   +1 more source

Computation of Augmented Zagreb Index and their Polynomial of Certain Class of Windmill Graphs

, 2018
The augmented Zagreb index of a graph G=(V, E) is defined by In this paper, we compute the augmented Zagreb index and their polynomials of certain classes of windmill graphs like French windmill graph, Dutch windmill graph, Kulli cycle windmill graph ...
Diwakar, S. A., Chaluvaraju, B.
core  

The Subset-Strong Product of Graphs

Annales Mathematicae Silesianae
In this paper, we introduce the subset-strong product of graphs and give a method for calculating the adjacency spectrum of this product. In addition, exact expressions for the first and second Zagreb indices of the subset-strong products of two graphs ...
Eliasi Mehdi
doaj   +1 more source

On the δ-chromatic numbers of the Cartesian products of graphs

Open Mathematics
In this work, we study the δ\delta -chromatic number of a graph, which is the chromatic number of the δ\delta -complement of a graph. We give a structure of the δ\delta -complements and sharp bounds on the δ\delta -chromatic numbers of the Cartesian ...
Tangjai Wipawee, Pho-on Witsarut, Vichitkunakorn Panupong   +2 more
doaj   +1 more source

On Nordhaus-Gaddum type relations of δ-complement graphs. [PDF]

Heliyon, 2023
Vichitkunakorn P, Maungchang R, Tangjai W.   +2 more
europepmc   +1 more source