【摘要】 <正> 1964年,V.G.Vizing[2]证明了简单图 G 的边色数 x′(G)满足△(G)≤x′(G)≤△(G)+1.其中△(G)为图 G 的最大度.若x′(G)=△(G),则称 G 为第一类图,并简记为 G∈C~1;若 x′(G)=△(G)+1 则称 G 为第二类图,并简记为 G∈C~2.更多还原

【Abstract】 The key content of this paper is to show some sufficient conditions on thegraph G which belongs to the FIRST SET.The key theorems are(?)Theorem Suppose none of the odd circles in the graph G contain the pointswhose valencies are equal to △(G),then G∈C~1.Theorem Let F={v|d_G(v)=△(G)}.Suppose G〔F〕is a forest.ThenG∈C~I.更多还原