摘要
从最大度的角度讨论两个极大外平面图的公共４染色，证明了当Ｇ是以ｒ个顶点的圈Ｑｒ为标定界环的极大外平面图且△（Ｇ）≥ｒ－２，Ｇ’是以Ｑｒ为标定界环的任一极大外平面图时，Ｇ和Ｇ’有公共４染色．从而证明了四色定理的等价命题在给定条件下成立．
The four colourings of maximum outerplanar graphs are studied in the view of maximum degree. It is proved that when G is a maximum outerplanar graphs with a labeled boundary circuit Qr and △(G)≥r - 2 and G' be any maximum outerplanar graphs with la- beled boundary circuit Qr. Then G and G' have common four four colourings.
出处
《东北师大学报（自然科学版）》
CAS
CSCD
2000年第2期23-26,共4页
Journal of Northeast Normal University(Natural Science Edition)
关键词
极大外平面图
染色
最大度
四色定理
maximum outerplanar graph
colouring
maximal degree
four colour conjecture€
