G是一个图,g和f是两个定义在V(G)上的非负整数值函数,并且对任意的x∈V(G),满足g(x)≤f(x).称图G是分数(g,f,m)-覆盖图,如果存在图G的分数(g,f)-因子G[F_h]满足对任意的e∈E(H)有h(e)=1,其中H是图G的m条边的子图.证明了一个图是分数(g,f,m)-覆盖图的充要条件,并得到了几个推论.
Let G be a graph, g and f be two nonnegative integer-valued functions defined on V(G) with g(x) ≤ f(x) for every x∈V(G). A graph G is called a fractional (g, f, m)-covered graph if there exists a fractional (g, f)-factor G[Fh] of G with indicator function h such that h(e) = 1 for every e∈E(H), where H is any subgraph of G with m edges. In this paper, a necessary and sufficient condition for graphs to be fractional (g, f, m)-covered is given, and several corollaries are obtained.