给出了图的孤立韧度,(G)与分数[a,b]-因子存在性间的关系,证明了若δ(G)≥I(G)≥α-1+(α-1)/b,其中a,b均为整数,2≤a〈b,则图G有分数[a,b]-因子。进一步证明该结论在一定意义下是最好的,并且提出。猜想当a=b时结论仍然成立。
Abstract: The relatiomhips between the isolated toughness I(G) and the exlstenee of fractional [a, b]-factors were given. It was proved that if δ (G) ≥ I(G) ≥ a - 1 + ( a - 1 ) / b, then G has a fractional [ a, b ]-factor where 2 ≤ a 〈 b. The results are best possible in some sense. In addition a conjecture about a = b was given.