On ve-degree and ev-degree of graphs

Abstract Let G = ( V , E ) be a graph with vertex set V and edge set E . The v e -degree of a vertex v ∈ V equals the number of edges v e -dominated by v and the e v -degree of an edge e ∈ E equals the number of vertices e v -dominated by e . Recently, Chellali et al. studied the properties of v e -degree and e v -degree of graphs (Chellali et al., 2017). Also they focused on the regularity and irregularity of these types of degrees and proposed several open problems. In this paper, we solve one of them and obtain some results on the regularity and irregularity of v e - and e v -degrees in graphs.