This paper gives a new proof of a result of Geoghegan and Mihalik which
states that whenever a contractible open n-manifold W which is not
homeomorphic to Rn is a covering space of an n-manifold M and
either n≥4 or n=3 and W is irreducible, then the group of covering
translations injects into the homeotopy group of W.Comment: 4 pages, LaTeX, amsart styl