三次图的结构特征

THE STRUCTURE CHARACTERS OF CUBIC GRAPH

通过对三次图结构的研究给出了两个主要结论：（１）对连通度μ（Ｇ）＝０，１，２，３，分别给出点数Ｐ＝｜Ｖ（Ｇ）｜的可达到的下界；（２）２—连通图Ｇ，存在２—连通三次图Ｇ′，Ｇ′可收缩到Ｇ。

In this paper,we mainly study the structure of cubic graph and give two main results (1)For μ (G)=0,1,2,3,then the minimum of point mumber is 8,10,8,4。 (2)A graph without a bridge may be Contracted by a cubic graph