When n = 1, there is a diffeomorphism S 2 ≅ ≅ C P 1 given by stereographic projection. This leads to the "special" Hopf fibration S → S → S. When the Fubini–Study metric is written in coordinates on CP, its restriction to the real tangent bundle yields an expression of the ordinary "round metric" of radius 1/2 (and Gaussian curvature 4) on S.