The exceptional representations are certain infinite-dimensional projective
representations of the general linear group over a local field, somewhat a
nalogous to the Weil representations of the symplectic group. We examine th
e decomposition of the tensor product of two exceptional representations. O
ur main results concern the multiplicity with which a given representation
may occur in this product and the restrictions imposed upon a representatio
n of the principal series by the assumption that it does occur. (C) 2001 Ed
itions scientifiques et medicales Elsevier SAS.