Results 61 to 70 of about 532 (122)

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
doaj   +1 more source

Bounds for Laplacian-type graph energies

, 2015
Let G be an undirected simple and connected graph with n vertices .n 3/ and m edges. Denote by 1 2 n 1 > n D 0, 1 2 n , and 1 2 n 1 > n D 0 , respectively, the Laplacian, signless Laplacian, and normalized Laplacian eigenvalues of G. The Laplacian energy,
I. Gutman, E. Milovanovic, I. Milovanovic   +2 more
semanticscholar   +1 more source

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

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 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

Complete graphs: the space of simplicial cones, and their path tree representation

, 2017
Let $G$ be a complete graph with $n+1$ vertices. In a recent paper of the authors, it is shown that the path trees of the graph play a special role in the structure of the truncated powers and partition functions that are associated with the graph ...
Ron, Amos, Shengnan, Wang
core  

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

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