定向图的Hamilton有向圈

An oriented graph is a directed graph without loop and with at most one are be-tween each pair of vertices. Let D be an oriented graph of order n such that the in-degree and outdegree of each vertex is at least k. Jackson proved that if n≤2k 2, andk≥2, D contains a Hamiltonian cycle. In this paper, we show that if n≤2k 3, andk≥3, D contains a Hamiltonian cycle.