关于2—连通图的最长圈

On Longest Cycles in 2—connected Graphs

若G是2-连通图,如对G中任何两个距离为2的点υ,ν都有d(υ)+d(ν)≥λ-1(5≤λ≤|V(G)|),则除了两类图外,G的最长圈的长至少为λ。

Any 2-connected graph on n vertices such that the degree sum of any two vertices at distance 2 is at least λ—1 contains a cycle of length at least λ. (for≤5λ≤n) except for two families of graphs which are entirely described.