  We study the effect of inhomogeneity of the paring interaction or the
background potential on the superconducting transition temperature, T_c. In the
weak coupling BCS regime, we find that inhomogeneity which is incommensurate
with the Fermi surface nesting vectors enhances T_c relative to its value for
the uniform system. For a fixed modulation strength we find that the highest
T_c is reached when the characteristic modulation length scale is of the order
of the superconducting coherence length.
