Curvature of an exotic 7-sphere

David S. Berman, Martin Cederwall, Tancredi Schettini Gherardini

We study the geometry of the Gromoll-Meyer sphere, one of Milnor's exotic $7$-spheres. We focus on a Kaluza-Klein Ansatz, with a round $S^4$ as base space, unit $S^3$ as fibre, and…