Results 91 to 100 of about 963 (204)

On the Maximum SC Index of Chemical Unicyclic Graphs

open access: yesJournal of Mathematics, Volume 2025, Issue 1, 2025.
The sum‐connectivity (SC) index of a graph G is defined as SCG=∑μν∈EG1/Θμ+Θν, where Θμ denotes the vertex degree of μ in G. In this paper, the fourth largest value of SC index for the chemical unicyclic graphs of order n ≥ 7 is determined.
Hui-Yan Cheng   +3 more
wiley   +1 more source

Optimal resistor networks

open access: yesMathematika, Volume 70, Issue 4, October 2024.
Abstract Given a graph on n$n$ vertices with m$m$ edges, each of unit resistance, how small can the average resistance between pairs of vertices be? There are two very plausible extremal constructions — graphs like a star, and graphs which are close to regular — with the transition between them occurring when the average degree is 3.
J. Robert Johnson, Mark Walters
wiley   +1 more source

Graphs which have pancyclic complements

open access: yesInternational Journal of Mathematics and Mathematical Sciences, 1978
Let p and q denote the number of vertices and edges of a graph G, respectively. Let Δ(G) denote the maximum degree of G, and G¯ the complement of G. A graph G of order p is said to be pancyclic if G contains a cycle of each length n, 3≤n≤p.
H. Joseph Straight
doaj   +1 more source

A note on the width of sparse random graphs

open access: yesJournal of Graph Theory, Volume 106, Issue 2, Page 273-295, June 2024.
Abstract In this note, we consider the width of a supercritical random graph according to some commonly studied width measures. We give short, direct proofs of results of Lee, Lee and Oum, and of Perarnau and Serra, on the rank‐ and tree‐width of the random graph G(n,p) $G(n,p)$ when p=1+ϵn $p=\frac{1+\epsilon }{n}$ for ϵ>0 $\epsilon \gt 0$ constant ...
Tuan Anh Do, Joshua Erde, Mihyun Kang
wiley   +1 more source

On Critical Unicyclic Graphs with Cutwidth Four

open access: yes, 2022
The cutwidth minimization problem consists of finding an arrangement of the vertices of a graph G on a line Pn with n=|V(G)| vertices in such a way that the maximum number of overlapping edges (i.e., the congestion) is minimized.
Hongjian Lai, Zhenkun Zhang
core   +1 more source

Subtrees and independent subsets in unicyclic graphs and unicyclic graphs with fixed segment sequence

open access: yes, 2020
In the study of topological indices two negative correlations are well known: that between the number of subtrees and the Wiener index (sum of distances), and that between the Merrifield-Simmons index (number of independent vertex subsets) and the Hosoya index (number of independent edge subsets).
Andriantiana, Eric Ould Dadah, Wang, Hua
openaire   +2 more sources

Graph theory‐based synchronization for stochastic uncertain complex dynamical networks via inverse optimal adaptive control

open access: yesIET Control Theory &Applications, Volume 18, Issue 8, Page 977-986, May 2024.
Abstract This paper is concerned with the synchronization of stochastic uncertain complex dynamic networks with time‐varying delays. In contrast to existing synchronization network models, the current study considers both internal time‐varying delays and coupling time‐varying delays. By analyzing the two factors (i.e.
Xuhui Guo   +3 more
wiley   +1 more source

Brooks' theorem with forbidden colors

open access: yesJournal of Graph Theory, Volume 105, Issue 3, Page 373-385, March 2024.
Abstract We consider extensions of Brooks' classic theorem on vertex coloring where some colors cannot be used on certain vertices. In particular we prove that if G $G$ is a connected graph with maximum degree Δ(G)≥4 ${\rm{\Delta }}(G)\ge 4$ that is not a complete graph and P⊆V(G) $P\subseteq V(G)$ is a set of vertices where either (i) at most Δ(G)−2 ${
Carl Johan Casselgren
wiley   +1 more source

On unicyclic graphs of metric dimension 2

open access: yes, 2017
A metric basis S of a graph G is the subset of vertices of minimum cardinality such that all other vertices are uniquely determined by their distances to the vertices in S. The metric dimension of a graph G is the cardinality of the subset S.
Dudenko, M., Oliynyk, B.
core   +2 more sources

Gracefulness of unicyclic graphs

open access: yes, 2015
С использованием конструктивных и аналитических методов решается задача существования грациозной разметки для одноциклических графов. Доказана грациозность некоторых представителей этого класса графов.Із застосуванням конструктивних та аналітичних ...
Семенюта, М.Ф.
core  

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