Endre Boros

1 Introduction A hypergraph is a finite set of finite sets called hyperedges. We consider the following two properties of hypergraphs. A hypergraph is Sperner [1] (also called simple [2, 3] or a clutter [4]) if no hyperedge is contained in another hyperedge. A hypergraph is conformal if for each set U $U$ of vertices, if each pair of vertices in U $U$ is contained in some hyperedge, then U $U$ is contained in some hyperedge (see, e.g., Schrijver [4]).