Closed geodesics on certain surfaces Pierre Vidotto (Nantes) January 26, 2016 Let S be a surface with negative curvature. Denote by N (R) the number of closed geodesics on S with length smaller than R. We will investigate an equivalent to N (R) for certain surfaces S whose Bowen-Margulis measure is infinite. We will first define all notions used through the talk and then give ideas of the proof.