2009/10/01 by Abdollahi, Alireza, Zarrin, Mohammad · 2 citations
#05C25 #20D60 #FOS: Mathematics #Group Theory (math.GR)
paper · doi:10.48550/arxiv.0910.0098
We associate a graph NG with a group G (called the non-nilpotent graph of G) as follows: take G as the vertex set and two vertices are adjacent if they generate a non-nilpotent subgroup. In this paper we study the graph theoretical properties of NG and its induced subgraph on G\backslash nil(G), where nil(G)=\x∈ G | < x,y> is nilpotent for all y∈ G\. For any finite group G, we prove that NG has either |Z^*(G)| or |Z^*(G)|+1 connected components, where Z^*(G) is the hypercenter of G. We give a new characterization for finite nilpotent groups in terms of the non-nilpotent graph. In fact we prove that a finite group G is nilpotent if and only if the set of vertex degrees of NG has at most two elements.