Abstract:Let G be a connected graph. The connectivity κ(G) of a connected graph G is the least positive integer k such that there is F⊂V,|F|=k, and G-F is disconnected or is a trivial graph. If every minimum vertex cut isolates a vertex of G, a graph G is super connected or super-κ. Define the inverse degree of a graph G with no isolated vertices as R(G)=1/(d(v)). In this paper, we show that let G be a connected graph with order n and minimum degree δ, if R(G)<1+2/(δ+1)+(n-2δ-1)/((n-1)(n-3)), then G is super-κ.
作者简介: 郭利涛(1982-),ORCID:http://orcid.org/0000-0003-1410-8509,male,doctor,associate professor,the field of interest is graph theory,E-mail:ltguo2012@126.com.
引用本文:
郭利涛. 超连通图的充分条件[J]. 浙江大学学报(理学版), 2018, 45(4): 391-393.
GUO Litao. Sufficient conditions for graphs to be super connected. Journal of ZheJIang University(Science Edition), 2018, 45(4): 391-393.
[1] BONDY J,MURTY U.Graph Theory and Its Application[M]. New York:Academic Press, 1976.
[2] KELMANS A. Asymptotic formulas for the probability of k-connectedness of random graphs[J].Theory of Probability and Its Applications,1972,17(2):253-265.
[3] LESNIAK L. Results on the edge-connectivity of graphs[J].Discrete Mathematics, 1974,8(4):351-354.
[4] FIOL M. On super-edge-connected digraphs and bipartite digraphs[J].Journal of Graph Theory, 1992,16(6):545-555.
[5] TIAN Y Z, GUO L T, MENG J X, et al. Inverse degree and super edge-connectivity[J].International Journal of Computer Mathematics, 2012,89(6):752-759.
[6] FAJTLOWICZ S. On conjectures of graffiti Ⅱ[J].Congr Numer, 1987,60:189-197.
[7] DANKELMANNP, SWART H, BERG P V D. Diameter and inverse degree[J].Discrete Mathematics,2008,308(5):670-673.
[8] DANKELMANNP, HELLWIG A, VOLKMANN L. Inverse degree and edge-connectivity[J].Discrete Mathematics, 2009,309(9):2943-2947.
[9] ERDÖS P, PACH J, SPENCER J. On the mean distance between points of a graph[C]//Proceedings of the 250th Anniversary Conference on Graph Theory,Congressus Numerantium 64. Winnipeg:Utilitas Mathematica Publishing Inc,1988:121-124.
[10] MA X L, TIAN Y Z. Inverse degree and connectivity[J].Chinese Quarterly Journal of Mathematics, 2013,28(2):257-260.