The Wiener index W(G) of a connected graph G, introduced by Wiener in 1947, is defined as W(G) = Σu,v∈V (G) dG(u, v) where dG(u, v) is the distance (length a shortest path) between the vertices u and v in G. For S ? V (G), the Steiner distance d(S) of the vertices of S, introduced by Chartrand et al. in 1989, is the minimum size of a connected subgraph of G whose vertex set contains S. The k-th Steiner Wiener index SWk(G) of G is defined as SWk(G) = ΣS?V (G),|S|=k d(S). We investigate the following problem: For any positive integer n, one can find a tree T with Steiner Wiener index SWk(T)(2 ≤ k ≤ n) or linear array Steiner Wiener index aSWk1(T)+bSWk2(T) (a, b is a integer) such that coverage n. In this paper, we give some solutions to this problem.
展开▼
机译:由维纳在1947年引入的连接图G的维纳指数W(g)被定义为W(g)=σ U,V∈v(g) sub> d g 子>(u,v)其中d g sub>(u,v)是顶点u和g中的顶点u和v之间的距离(长度是最短路径)。 V(g),由Chartrand等人介绍的S顶点的Steiner距离d(s)。在1989年,是G的连接子图的最小尺寸,其顶点组含有S. k-Th Steiner Wiener指标SWK(g)为G定义为SW K sub>(g)=σ< Sub> S?V(g),| s | = k sub> d(s)。我们调查以下问题:对于任何正整数n,可以找到带有Steiner Wiener指数SW k sub>(t)(2≤k≤n)或线性阵列Steiner Wiener指数的树t sub> sw k1 sub>(t)+ bsw k2 sub>(t)(a,b是整数),使得覆盖n。在本文中,我们对此问题提供了一些解决方案。
展开▼