Re: query,deformations

The identification of Hoch(A,k) with Ext_A(k,k) is pretty thoroughly aired in Cartan-Eilenberg, but you must know that already. As for the cup product coming from the diagonal, that may be in one of Murray's original deformation papers. I think Eilenberg mentioned it in passing in his homological algebra course (which all instructors at Columbia were expected to sit in on, at least if they were in algebra or topology). But if I had to search the literature, I think I would start with the work of Steenrod. As for categories, I must admit to total ignorance. Michael ===========================