On pairs of closed geodesics on hyperbolic surfaces
In this article we prove a trace formula for double sums over totally hyperbolic Fuchsian groups . This links the intersection angles and common perpendiculars of pairs of closed geodesics on with the inner products of squares of absolute values of eigenfunctions of the hyperbolic laplacian . We then extract quantitative results about the intersection angles and common perpendiculars of these geodesics both on average and individually.