### A topological proof of the vanishing of the product of K_3(Z) with K_1(Z), by Dominique Arlettaz

This paper gives a short and purely homotopical proof of the triviality of
the product of K_3 with K_1 in K_4, for the ring of integers Z. The argument
is based on the study of the external product for the homotopy groups of the
K-theory spectrum and the fact that the 4-dimensional Hurewicz homomorphism
in the algebraic K-theory of Z is an isomorphism.

This paper will appear in the Proceedings of the Poznan conference on
algebraic K-theory (September 4 - 8, 1995).

Dominique Arlettaz <dominique.arlettaz@ima.unil.ch>