The Blaschke conjecture and great circle fibrations of spheres
arXiv:math/0112027 · doi:10.1353/ajm.2004.0039
Abstract
We construct an explicit diffeomorphism taking any fibration of a sphere by great circles into the Hopf fibration, using elementary geometry--indeed the diffeomorphism is a local (differential) invariant, algebraic in derivatives.
arXiv comment61 pages, 8 figures, corrected errors in the published version