On the number of ends of rank one locally symmetric spaces

Abstract

Let Y be a noncompact rank one locally symmetric space of finite volume. Then Y has a finite number e(Y) > 0 of topological ends. In this paper, we show that for any n ∈ N, the Y with e(Y) ≥ n that are arithmetic fall into finitely many commensurability classes. In particular, there is a constant cn such that n-cusped arithmetic orbifolds do not exist in dimension greater than cn. We make this explicit for one-cusped arithmetic hyperbolic n-orbifolds and prove that none exist for n ≥ 30.