图G=(y,E)的Wiener指数W(G)是一个基于距离的拓扑指数,它是G中所有顶点之间的距离之和.对于任意整数n,证明了存在无限多个圈秩为2平面二部化学图,其Wiener指数与它的线图的Wiener指数之差是n,且其线图也是化学图;部分解决了A.D.Dobrynin和L.S.Mel’nikow提出的一个公开问题.
The Wiener index W(G) of a graph G = (V,E) is a distance-based topological index defined as the sum of distances between all pairs of vertices in G. For any integer n, an infinite family of planar and bipartite chemical graphs with cyclomatic number two are constructed such that their line graphs are also chemical graphs, and the difference of the Wiener indices between the graphs and their line graphs is n. This affirms partly an open problem proposed by A. D. Dobrynin and L. S. Mel'nikov.