M. Babillot et M. Peigne, CLOSED GEODESICS IN HOMOLOGY CLASSES ON HYPERBOLIC MANIFOLDS WITH CUSPS, Comptes rendus de l'Academie des sciences. Serie 1, Mathematique, 324(8), 1997, pp. 901-906
On a class of hyperbolic manifolds with infinite volume, we give an as
ymptotic estimate for the number of closed geodesics in a given homolo
gy class. We show that, in certain cases, the existence of parabolic t
ransformations in the fundamental group Gamma of these manifolds has a
n effect on this estimate. This happens when the Hausdorff dimension o
f the limit set of Gamma is less than 3/2. The geometrical meaning of
this critical value remains to be understood.