Equidistribution and counting points on orbits of geometrically finite hyperbolic groups

-
Nimish Shah, Ohio State University
Fine Hall 322

In this joint work with Hee Oh, we consider various sphere packing configurations that are invariant under actions of geometrically finite hyperbolic groups, and estimate the cardinality of spheres of curvature at most T with respect to euclidean, or spherical, or hyperbolic metric. This sphere counting problem is studied by proving "weighted equidistribution" results related to translates of certain co-dimension one submanifolds under the geodesic flow on the unit tangent bundle of M a hyperbolic n-manifold, where the fundamental group of M is a geometrically finite discrete subgroup of the group of isometries of the n dimensional hyperbolic space.