On the minimum cut-sets of the power graph of a finite cyclic group, II

Abstract

The power graph $\mathcal{P}(G)$ of a finite group $G$ is the simple graph with vertex set $G$ and two distinct vertices are adjacent if one of them is a power of the other. Let $n=p_1^{n_1}{p}_2^{n_2}\cdots p_r^{n_r},$ where $p_1,p_2,\dots ,p_r$ are primes with $p_1<p_2<\cdots <p_r$ and $n_1,n_2,\dots ,n_r$ are positive integers. For the cyclic group $C_n$ of order $n$, the minimum cut-sets of $\mathcal{P}(C_n)$ are characterized in \cite{cps} for $r\le 3$. Recently, in \cite{MPS}, certain cut-sets of $\mathcal{P}(C_n)$ are identified such that any minimum cut-set of $\mathcal{P}(C_n)$ must be one of them. In this paper, for $r\ge 4$, we explicitly determine the minimum cut-sets, in particular, the vertex connectivity of $\mathcal{P}(C_n)$ when: (i) $n_r\ge 2$, (ii) $r=4$ and $n_r=1$, and (iii) $r=5$, $n_r=1$, $p_1\ge 3$.