Nilmanifold

In mathematics, a nilmanifold is a differentiable manifold which has a transitive nilpotent group of diffeomorphisms acting on it. As such, a nilmanifold is an example of a homogeneous space and is diffeomorphic to the quotient space, the quotient of a nilpotent Lie group N modulo a closed subgroup H. This notion was introduced by A. Mal'cev in 1951.