Subject: Re: question abt operations Date: Wed, 17 Nov 99 17:12:29 MST From: "Peter D. Zvengrowski" Reply to Pedro Real Dear Pedro, The original paper by Steenrod on the subject should answer your question completely. It's in 1948 Annals Math - Products of Cocycles and Extensions of MAppings. The explicit formulae are really generalizations of the usual formula for cup products of (simplicial) cochains where one has two simplexes such tthat the last vertex of the first simplex equals the first vertex of the second simplex. This is generalized to "cup-i" products, where the last i vertices of the first simplex agree with the first i of the second (we are assuming a vertex order here, or at least a partial order such that ther vertices of any simplex are simply ordered). Saludo, Peter Zvengrowski