# NonLERFness of groups of certain mixed 3-manifolds and arithmetic hyperbolic $n$-manifolds

 Geometric Structures on 3-manifolds Topic: NonLERFness of groups of certain mixed 3-manifolds and arithmetic hyperbolic $n$-manifolds Speaker: Hongbin Sun Affiliation: University of California, Berkeley Date: Tuesday, May 3 Time/Room: 2:00pm - 3:00pm/S-101 Video Link: https://video.ias.edu/geostruct/2016/0503-Sun

I will show that the groups of mixed 3-manifolds containing arithmetic hyperbolic pieces and the groups of certain noncompact arithmetic hyperbolic $n$-manifolds ($n > 3$) are not LERF. The main ingredient is a study of the set of virtual fibered boundary slopes for cusped hyperbolic 3-manifolds, and some specialty of Bianchi manifolds.