Degree distance of unicyclic and bicyclic graphs

作者:Ilic Aleksandar*; Stevanovic Dragan; Feng Lihua; Yu Guihai; Dankelmann Peter
来源:Discrete Applied Mathematics, 2011, 159(8): 779-788.
DOI:10.1016/j.dam.2011.01.013

摘要

Let G be a connected graph with vertex set V (G). The degree distance of G is defined as D'(G) = Sigma({u,v}subset of V(G)) (deg(G)(u) + deg(G)(v))d(u, v), where deg(G)(u) is the degree of vertex u, and d(u, u) denotes the distance between u and v. Here we characterize n-vertex unicyclic graphs with girth k, having minimum and maximum degree distance, respectively. Furthermore, we prove that the graph B-n obtained from two triangles linked by a path, is the unique graph having the maximum degree distance among bicyclic graphs, which resolves a recent conjecture of Tomescu.