Wiedersehen metrics and exotic involutions of Euclidean spheres
Wiedersehen metrics and exotic involutions of Euclidean spheres
We provide explicit, simple, geometric formulas for free involutions ρ of Euclidean spheres that are not conjugate to the antipodal involution. Therefore the quotient Sn/ρ is a manifold that is homotopically equivalent but not diffeomorphic to . We use these formulas for constructing explicit non-trivial elements in π1 Diff(S5) and …