Resonances and scattering poles on asymptotically hyperbolic manifolds
  On an asymptotically hyperbolic manifold (X,g), we show that the resolvent resonances coincide, with multiplicities, with the poles of the renormalized scattering operator, except for the special points n/2-k (with k>0 integer) where an additional term appears: this is the dimension of the kernel of the k-conformal Laplacian on the boundary when (X,g) is Einstein. 
Colin Guillarmou