  We propose that N=2 U(2) gauge theories on the A_1 ALE space, with asymptotic
holonomies not in SU(2), correspond to the Ramond sector of super Liouville
theory. As evidence, we show that the instanton partition functions for the
theories with and without a fundamental hypermultiplet, computed with such
holonomies, coincide with the norms or the inner products of the Whittaker
vectors in the Ramond sector. This correspondence suggests that S-duality of
U(2) gauge theories interchanges the sectors with different boundary
conditions.
