关于图θ（a，b，c，d，e）的色性

Chromaticity of the graph θ(a,b,c,d,e)

在两个顶点之间用五条长分别是ａ，ｂ，ｃ，ｄ，ｅ的内部不交的路连接而形成的图记为θ（ａ，ｂ，ｃ，ｄ，ｅ），其中ａ≤ｂ≤ｃ≤ｄ≤ｅ，本文讨论了它的色性．得出了θ（ａ，ｂ，ｃ，ｄ，ｅ）是色唯一的一个充分条件．

The graph θ(a,b,c,d,e.) is a 2-connected graph consisting of 5 internally disjoint paths between a pair of vertices of degree 5. The lengths of those paths are a,b,c,d, e respectively, where a≤b≤c≤d≤e.The chromaticity of the graph θ(a, b,c,d,e) is discussed in this paper.A sufficient condition of the graph θ(a,b,c,d,e) being chromatically unique is obtained.