The Embedded Eigenvalue Problem for Classical Groups (This paper is dedicated to Freydoon Shahidi on the occasion of his sixtieth birthday)

By “eigenvalue”, we mean the family of unramified Hecke eigenvalues of an automorphic representation. The question is whether there are any eigenvaluesfor the discrete spectrum that are also eigenvalues for the continuous spectrum.The answer for classical groups has to be part of any general classification of theirautomorphic representations.