JOINS, CORONAS AND THEIR VERTEX-EDGE WIENER POLYNOMIALS

The vertex-edge Wiener index of a simple connected graph G is defined as the sum of distances between vertices and edges of G. The vertex-edge Wiener polynomial of G is a generating function whose first derivative is a q-analog of the vertex-edge Wiener index. Two possible distances D-1(u, e|G) and D-2(u, e|G) between a vertex u and an edge e of G can be considered and corresponding to them, the first and second vertex-edge Wiener indices of G, and the first and second vertex-edge Wiener polynomials of G are introduced. In this paper, we study the behavior of these indices and polynomials under the join and corona product of graphs. Results are applied for some classes of graphs such as suspensions, bottlenecks, and thorny graphs.