【摘要】 <正> 以下限于讨论有限简图,并以D(G),ε(G),△(G),X′(G)分别表示G的点数,边数,点的最大次数与边色数. 由定理,X′(G)或等于△(G)或等于△(G)+1,分别称G属于第一类或第二类,并记为 G∈C~1或G∈C~2.更多还原

【Abstract】 In [2,3], E. T. Parker and R. Lasker gave the edge-chromatic number of twospecial kinds of compositions of graphs. Some results are given in this paper concern-ing whether x’(G[H]) can be determined accrording to x’(G) and x’(H). In 1981, M. Planthoit gave a sufficient condition for simple graphs with a spann-ing star to be of class one [4]. This paper gives two sufficient conditions for generalsimple graphs to be of class one.更多还原