Some results on the complement of the dot product graph of a commutative ring

Abstract

Let [Formula: see text] be a nonzero commutative ring with identity. Let [Formula: see text] be a positive integer. Let [Formula: see text] ([Formula: see text] times). The total dot product graph of [Formula: see text] denoted by [Formula: see text] is an undirected graph with vertex set which equals [Formula: see text] and distinct vertices [Formula: see text] and [Formula: see text] are adjacent if and only if [Formula: see text], where [Formula: see text] is the normal dot product of [Formula: see text] and [Formula: see text]. Let [Formula: see text] denote the set of all zero-divisors of [Formula: see text] and let us denote [Formula: see text] by [Formula: see text]. The zero-divisor dot product graph of [Formula: see text], denoted by [Formula: see text] is the subgraph of [Formula: see text] induced by [Formula: see text]. The graph [Formula: see text] (respectively, [Formula: see text]) was introduced and investigated by Badawi [Commun. Algebra 43(1) (2015) 43–50]. In this paper, we characterize [Formula: see text] such that [Formula: see text] (respectively, [Formula: see text]) is connected and determine the diameter and the radius of [Formula: see text] (respectively, [Formula: see text]) whenever it is connected. Moreover, if [Formula: see text] (respectively, [Formula: see text]) is connected, then we characterize [Formula: see text] such that [Formula: see text] (respectively, [Formula: see text]) admits a cut vertex.