We prove that if the fundamental group of an orientable finite volume hyperbolic 3-manifold has finite index in the reflection group of a right-angled ideal polyhedron in then it has a co-final tower of finite sheeted covers with positive rank gradient. The manifolds we consider are also known to have co-final towers of covers with zero rank gradient.
Cite this article
Darlan Girão, Rank gradient in co-final towers of certain Kleinian groups. Groups Geom. Dyn. 8 (2014), no. 1, pp. 143–155DOI 10.4171/GGD/220