Sub-Riemannian geodesics on nested principal bundles

Abstract: We study the interplay between geodesics on two non-holono-mic systems that are related by the action of a Lie group on them. After some geometric preliminaries, we use the Hamiltonian formalism to write the parametric form of geodesics. We present several geometric examples, including a non-holonomic structure on the Gromoll-Meyer exotic sphere and twistor space.