Results 61 to 70 of about 504 (100)

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

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

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

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

An extremal problem on potentially $K_{m}-P_{k}$-graphic sequences

, 2005
A sequence $S$ is potentially $K_{m}-P_{k}$ graphical if it has a realization containing a $K_{m}-P_{k}$ as a subgraph. Let $\sigma(K_{m}-P_{k}, n)$ denote the smallest degree sum such that every $n$-term graphical sequence $S$ with $\sigma(S)\geq \sigma(
Lai, Chunhui
core   +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

On the maximum atom-bond sum-connectivity index of graphs

Open Mathematics
The atom-bond sum-connectivity (ABS) index of a graph GG with edges e1,…,em{e}_{1},\ldots ,{e}_{m} is the sum of the numbers 1−2(dei+2)−1\sqrt{1-2{\left({d}_{{e}_{i}}+2)}^{-1}} over 1≤i≤m1\le i\le m, where dei{d}_{{e}_{i}} is the number of edges adjacent
Alraqad Tariq, Saber Hicham, Ali Akbar, Albalahi Abeer M.   +3 more
doaj   +1 more source

Steiner Degree Distance of Two Graph Products

Analele Stiintifice ale Universitatii Ovidius Constanta: Seria Matematica, 2019
The degree distance DD(G) of a connected graph G was invented by Dobrynin and Kochetova in 1994. Recently, one of the present authors introduced the concept of k-center Steiner degree distance defined as SDDk(G)=∑S⊆V(G)|S|=k[∑v∈Sdeg⁡G(v)]dG(S),SDD_k (G)
Mao Yaping, Wang Zhao, Das Kinkar Ch.
doaj   +1 more source

Social network analysis by Turiyam graphs. [PDF]

BMC Res Notes, 2023
Ganati GA, Repalle VNSR, Ashebo MA.
europepmc   +1 more source

Random independent sets in triangle-free graphs

Forum of Mathematics, Sigma
We establish several new results on the existence of probability distributions on the independent sets in triangle-free graphs where each vertex is present with a given probability.
Anders Martinsson, Raphael Steiner
doaj   +1 more source