【摘要】 刘儒英介绍了图的特征标R(G),并分别给出当R(G)=0和R(G)=1时图类所具有的性质并对图类进行描述,本文推广此结果,讨论了R(G)=-1和R(G)=-2时的情形,并证明了两类具备一定性质的图并的补图的色唯一性.更多还原

【Abstract】 R(G) was introduced by Liu, and he gave the properties of the classes of graphs and described them respectively when R(G)=0 and R(G)=1. Here, we extend this result to the cases of R(G)=-1 and R(G)=-2, then we prove that the union of two classes of graphs are chromatically unique under the certain conditions.更多还原