研究3-正则图的一个有意义的问题是它是否存在k个没有共边的完美匹配.关于这个问题有一个著名的Fan-Raspaud猜想:每一个无割边的3-正则图都有3个没有共边的完美匹配.但这个猜想至今仍未解决.设dim(P(G))表示图G的完美匹配多面体的维数.本文证明了对于无割边的3-正则图G,如果dim(P(G))≤14,那么k≤4:如果dim(P(G))≤20,那么k≤5.
An interesting problem involving cubic graphs concerns that the existence of k perfect matchings whose intersection is empty. Fan and Raspaud conjectured that k = 3 for every bridgeless cubic graph, but it is still open. Let dim(P(G)) denote the dimension of the perfect matching polytope P(G) of the graph G. In this paper we prove that for a bridgeless cubic graph G, k ≤ 4 if dim(P(G)) ≤ 14; and k ≤ 5 if dim(P(G)) ≤ 20.