关于图的染色问题

On the characterization of graphs

主要得到如下结论:若图G不含有长至少为5的奇圈和H作为子图,则x(P3(G))≤3;若图G不含有长至少为5的奇圈,则x′(G)=Δ;若图G不含有长至少为4的圈,则t(G)=Δ+1;等.

The following results are obtained:if graph G doesn′t contain odd circle of lenth at least five and H * as subgraph,then x(P 3(G))≤3; if graph G contains no odd circle of lenth at least five,then x′(G)= Δ ; if graph G contains no circle of lenth at least four,then t(G)= Δ (G)+1 ;etc.