■图的色唯一性

Chromatic Uniqueness of ■ Graphs

设G是简单图,用P(G,λ)表示图G的色多项式,若P(G,λ)=P(H,λ),则称G与H是色等价的,简单的表示为H^G.记[G]={H|H^G}.若[G]={G},称G是色唯一的.本文给出了(∪iCi)∪(∪jDj))图色唯一的相对于文献[1]、[2]中的结论更为一般的结论.

Let G be a simple graph. We denote by P（ G ,λ ） the chromatic polynomial. Two graphs G and H are said to be chromatic equivalent, simply denoted by G - H, if P （ G,λ ） = P （ H, λ ） . Let [ G ] = { H ／ H - G } . For a graph G, G is called to be chromatically unique if [ G ] = { G } . In this artical, We give a conclusion which is more generalize than that from references [1land [2].