Riemannian submersion
= Riemannian submersion
{c}
{title2=$d\pi|_{(\ker d\pi)^\perp}$}
{wiki}
A surjective <submersion> between <Riemannian manifolds> is Riemannian when its derivative is a <linear isometry> from the orthogonal complement of its kernel onto the target <tangent space>. Its vertical space is the kernel and its horizontal space is the orthogonal complement.