A degree condition for fractional [a, b]-covered graphs

Let G be a graph of order n with delta(G) >= a + 1, and 3 <= a <= b be integers. In this paper, we first show that if G satisfies max{d(G)(X),d(G)(Y)} >= a(n+1)/a+b for each pair of nonadjacent vertices x, y of G, then G is a fractional [a,b]-covered graph. It is a generalization of the known result with a = b = k which is given by Zhou. Furthermore, we show that this result is best possible in some sense. (C) 2018 Elsevier B.V. All rights reserved.