Duplication and Switching of Divisor Cordial Graphs

A divisor cordial labeling of a graph G with vertex set V is a bijection f from V to {1, 2, 3, . . .,|V|} such that if an edge uv is assigned the label 1 if f(u) divides f(v) or f(v) divides f(u) and 0 otherwise, then the number of edges labeled with 0 and the number of edges labeled with 1 differ by at most 1. If a graph has a divisor cordial labeling, then it is called divisor cordial graph. In this paper, we prove that fan graph, switching of a pendant vertex of a helm graph, switching of a vertex of flower graph, switching of closed helm graph, and also duplication of an arbitrary vertex by an edge of a fan graph are divisor cordial.