%0 Journal Article %T On Selberg's small eigenvalue conjecture and residual eigenvalues %A Morten S. Risager %J Mathematics %D 2007 %I arXiv %X We show that Selberg's eigenvalue conjecture concerning small eigenvalues of the automorphic Laplacian for congruence groups is equivalent to a conjecture about the non-existence of residual eigenvalues for a perturbed system. We prove this using a combination of methods from asymptotic perturbation theory and number theory. %U http://arxiv.org/abs/0707.2332v3