%0 Journal Article %T Vanishing geodesic distance on spaces of submanifolds and diffeomorphisms %A Peter W. Michor %A David Mumford %J Mathematics %D 2004 %I arXiv %X The $L^2$-metric or Fubini-Study metric on the non-linear Grassmannian of all submanifolds of type $M$ in a Riemannian manifold $(N,g)$ induces geodesic distance 0. We discuss another metric which involves the mean curvature and shows that its geodesic distance is a good topological metric. The vanishing phenomenon for the geodesic distance holds also for all diffeomorphism groups for the $L^2$-metric. %U http://arxiv.org/abs/math/0409303v2