【摘要】 设G=(V,E)是一个无向简单图,a和b是两个非负整数,若函数f:E→[0,1]对所有的x∈V均满足a≤∑e∈xf(e)≤b,则称f为G的一个分数[a,b]-因子。此时,若还有a=b=k,则称f为G的一个分数k-因子,文章给出了偶图有分数k-因子的一个充分必要条件,并给出一个相关结论。更多还原

【Abstract】 Let G =（V,E） be a graph,a and b be two nonnegative integers,and f: E→ be a function.If a≤∑_e瘙綍xf（e）≤b for all x∈V,f is called as a fractional -factor of G.A fractional k-factor f is a fractional -factor with a = b = k.A necessary and sufficient condition for the fractional k-factors in the bipartite graphs is deduced.In addition,a concerning result is given.更多还原