Now for my question about abelian groups, which was asked by a student in my algebraic topology class. If G and G' are abelian groups such that for all abelian groups H there is an isomorphism of abelian groups Hom(G,H) iso Hom(G',H), can one conclude that G and G' are isomorphic? No naturality conditions are assumed about the isomorphisms of Hom-groups. Perhaps it follows from Pontryagin duality, but the hypothesis does not assert an isomorphism of topological groups. Don Davis dmd1@lehigh.edu