The Turán Density of the Hypergraph {abc, ade, bde, cde}

Let F 3,2 denote the 3-graph ade, bde, cde}. We show that the maximum size of an F 3,2 -free 3-graph on n vertices is ( + o(1)) , proving a conjecture of Mubayi and Rodl [J. Comb. Th. A, 100 (2002), 135--152]