Neighborhood union conditions for fractional [a, b]-covered graphs

Let G be a graph of order n. The binding number bind(G) of G is min{vertical bar N-G(X)vertical bar vertical bar X vertical bar vertical bar empty set not equal X subset of V(G) and N-G(X) not equal V(G)}. Throughout this article, some sufficient conditions about neighborhood union and bind(G) for a graph G to be fractional covered are obtained. Moreover, some graphs to verify that the results are best possible in a certain sense are gotten.