Diffeomorphism type of the Berger space
arXiv:math/0204352
Abstract
We compute the Eells-Kuiper invariant of the Berger manifold SO(5)/SO(3) and determine that it is diffeomorphic to the total space of an S^3-bundle over S^4. This answers a question raised by K. Grove and W. Ziller.
LaTeX, 17 pages. v2: proofs of corollaries added