# Doubles of groups and hyperbolic LERF 3-manifolds

### Abstract

We show that the quasiconvex subgroups in doubles of certain negatively curved groups are closed in the profinite topology. This allows us to construct the first known large family of hyperbolic $3$-manifolds usch that any finitely generated subgroup of the fundamental group of any member of the family is closed in the profinite topology.

Rita Gitik