Spaces of nonnegatively curved surfaces

Abstract

We determine the homeomorphism type of the space of smooth complete nonnegatively curved metrics on surfaces of positive Euler characteristic equipped with the topology of $C^{\gamma }$ uniform convergence on compact sets, when $\gamma$ is infinite or is not an integer. If $\gamma =\infty$, the space of metrics is homeomorphic to the separable Hilbert space. If $\gamma$ is finite and not an integer, the space of metrics is homeomorphic to the countable power of the linear span of the Hilbert cube. We also prove similar results for some other spaces of metrics including the space of complete smooth Riemannian metrics on an arbitrary manifold.

28 pages, some corrections, to appear in J. Math. Soc. Japan