Cappell-Shaneson homotopy spheres are standard
arXiv:0907.0136
Abstract
We show that an infinite sequence of homotopy 4-spheres constructed by Cappell-Shaneson are all diffeomorphic to S^4. This generalizes previous results of Akbulut-Kirby and Gompf.
5 pages, 4 figures. A minor correction, a reference and a remark added, to appear in Annals of Mathematics