摘要
M.Kriesell证明了收缩临界5-连通图的平均度不超过24并猜想收缩临界5-连通图的平均度小于10.本文构造了一个反例证明M.Kriesell的猜想不成立并给出了收缩临界5-连通图平均度新的上界.
M. Kriesell shown that any contraction critical 5-connected graph has average degree at most 24 and conjectured that every finite 5-connected graph of average degree at least 10 admitted an 5-contractible edge. We show this Conjecture is not true by giving a counter example. Further we show that any finite contraction critical 5-connected graph has average degree at most 20. This improve the result of M. Kriesell.
出处
《数学研究》
CSCD
2011年第3期243-256,共14页
Journal of Mathematical Study
基金
supported by Doctor Fundation of Guangxi Teachers Education University (2010B001)
关键词
5-连通图
收缩临界
平均度
5-connected graph
contraction critical
average degree
