The total acquisition number of random geometric graphs

Ewa Infeld ; Dieter Mitsche ; Paweł Prałat¹

¹Department of Mathematics Ryerson University

The electronic journal of combinatorics, Tome 24 (2017) no. 3

Résumé

Let $G$ be a graph in which each vertex initially has weight 1. In each step, the weight from a vertex $u$ to a neighbouring vertex $v$ can be moved, provided that the weight on $v$ is at least as large as the weight on $u$. The total acquisition number of $G$, denoted by $a_t(G)$, is the minimum cardinality of the set of vertices with positive weight at the end of the process. In this paper, we investigate random geometric graphs $\mathcal{G}(n,r)$ with $n$ vertices distributed uniformally at random in $[0,\sqrt{n}]^2$ and two vertices being adjacent if and only if their distance is at most $r$. We show that asymptotically almost surely $a_t(\mathcal{G}(n,r)) = \Theta( n / (r \lg r)^2)$ for the whole range of $r=r_n \ge 1$ such that $r \lg r \le \sqrt{n}$. By monotonicity, asymptotically almost surely $a_t(\mathcal{G}(n,r)) = \Theta(n)$ if $r < 1$, and $a_t(\mathcal{G}(n,r)) = \Theta(1)$ if $r \lg r > \sqrt{n}$.

Détail

DOI : 10.37236/6632

Classification : 05C80, 05C10
Mots-clés : total acquisition number, random geometric graphs