摘要
设 G 为n 阶3连通无爪图,δ= min{d( x)| x ∈ V( G)} ,δ= min{ max(d( x) ,d( y))| x ,y∈ V( G) ,d( x ,y) = 3} ,则 C( G) ≥min{ n ,3 δ+ δ,6 δ}·用反证法,若图 G 的最长圈不满足结论,利用 G 的3连通性和无爪性构造矛盾·
It was proved that if G is a 3 connected claw free graph on n vertices with the minimum degree δ =min{d( x )| x ∈ V(G )}and δ *=min{max(d( x ),d( y ))| x,y∈V(G) ,d( x,y )=3},then the circumference of the graph G is at least min{ n,3δ *+δ,6δ }. The graph G was sorted into several types to be examined. The method of reduction to absurdity was used to get the above result. The properties of 3 Connected claw free of the graph were used to structure the contradiction if the longest cycle of graph G does not satisfy a given condition or does to prove the above conclusion.
出处
《东北大学学报(自然科学版)》
EI
CAS
CSCD
北大核心
1999年第4期434-437,共4页
Journal of Northeastern University(Natural Science)
基金
国家自然科学基金
关键词
3-连通
无爪图
周长
简单图
connected,claw free graph,circumference.