Type: Article
Publication Date: 2007-10-25
Citations: 26
DOI: https://doi.org/10.1112/jtopol/jtm010
We show that any finitely generated non-elementary Kleinian group has a co-final family of finite index normal subgroups with respect to which it has Property τ. As a consequence, any closed hyperbolic 3-manifold has a co-final family of finite index normal subgroups for which the infimal Heegaard gradient is positive.