Linear algebra and topology
Sylvain E. Cappell, Julius L. Shaneson · Bulletin of the American Mathematical Society · 1979
of A are primitive nth.roots of unity.Results obtained independently on this problem by Dennis Sullivan and Reinhardt Schultz [9], using classifying space methods, showed it for n = p s and n = 2p s , p an odd prime, and perhaps some more cases.We announce the following.