Subtrees of bipartite digraphs — the minimum degree condition Original Research Article

Let D be a bipartite digraph and let T be an oriented tree of order k. We consider two conditions of the minimum indegree and the minimum outdegree of a digraph D guaranteeing that D contains T. The bounds depend on k and the conditions are sharp. We also include some remarks on the same problem for an arbitrary digraph (not necessarily bipartite).