一种构造k—色临界图的方法

One Means of Constructing K-Chromatically Critical Graphs

图G的色数χ(G)是指对图G进行着色并使相邻顶点具有不同颜色的最少颜色数,若对G的任意真子图H有χ(H)<χ(G)=k,则称G是k—色临界的,因此可以给出一种构造k—色临界图的方法。

The chromatic number Х（G） of graph G is the least color number k if its vertices can be colored with k colors so that no two adjacent vertices have the same color. G is said to be k - critical graph if Х（H） 〈 Х（G） = k for every proper subgraph H of G. In this paper, one means of constructing k - chromatically critical graphs is gived.