Connectivity of generating graphs of nilpotent groups

Abstract

Let $G$ be $2$-generated group. The generating graph of $\hat{I}“(G)$ is the graph whose vertices are the elements of $G$ and where two vertices $g$ and $h$ are adjacent if $G=⟨g,h⟩$. This graph encodes the combinatorial structure of the distribution of generating pairs across $G$. In this paper we study several natural graph theoretic properties related to the connectedness of $\hat{I}“(G)$ in the case where $G$ is a finite nilpotent group. For example, we prove that if $G$ is nilpotent, then the graph obtained from $\hat{I}“(G)$ by removing its isolated vertices is maximally connected and, if $|G|\ge 3$, also Hamiltonian. We pose several questions.

11 pages; to appear in Algebraic Combinatorics