Star-factors of tournaments

Let S_m denote the m-vertex simple digraph formed by m − 1 edges with a common tail. Let f(m) denote the minimum n such that every n-vertex tournament has a spanning subgraph consisting of n/m disjoint copies of S_m. We prove that m lg m − m lg lg m ≤ f(m) ≤ 4m² − 6m for sufficiently large m. © 1998 John Wiley & Sons, Inc. J. Graph Theory 28: 141–145, 1998