(2,1)-Total Labeling of the K-sun Graphs

A (2, 1)-total labeling of a graph G is a functionfmapping the vertex set V(G)∪E(G) to integers such that any two adjacent vertices of G receive distinct integers, any two adjacent edges of G receive distinct integers and a vertex and its incident edges receive integers that differ by at least 2 in absolute value. The span of a (2, 1)-total labeling f of a graph G is the maximum difference between two labels. The (2, 1)-total number of a graph G, denoted by λ2^T(G), is the minimum span of a (2, 1)-total labeling of G. In this paper, we find the (2, 1)-total number for each k-sun graph.