Proof of a conjecture on the spectral radius condition for [a,b]-factors

For two positive integers a and b with a≤b, an [a,b]-factor of a graph is a spanning subgraph of the graph such that the degree of each vertex in the subgraph is between a and b. Recently, Cho, Hyun, O and Park posed a conjecture for the existence of [a,b]-factors in graphs under a spectral radius condition. We confirm this conjecture in this paper.