Sequences of open Riemannian manifolds with boundary

Abstract

We consider sequences of open Riemannian manifolds with boundary that have no regularity conditions on the boundary. To define a reasonable notion of a limit of such a sequence, we examine "$\delta$ inner regions" which avoid the boundary by a distance $\delta$. We prove Gromov-Hausdorff compactness theorems for sequences of these "$\delta$ inner regions". We then build "glued limit spaces" out of the Gromov-Hausdorff limits of these $\delta$ interior regions and study the properties of these glued limit spaces. Our main applications assume the sequence is noncollapsing and has nonnegative Ricci curvature. We include open questions.