Given a real matrix Q,X:,, when is Q in the convex hull of { Y’m’},? In this paper some necessary conditions on Q-the “diagonal inequality”-are formulated and they are proved to generalize the Cohen-Falmagne conditions. A counterexample shows that the diagonal inequality is insufficient (as are hence, perforce, the Cohen-Falmagne conditions). The same example is used to show that Fishburn’s con...
