  The dispersion of the dielectric function for wurtzite InN is analytically
evaluated in the region near the fundamental energy gap. The real part of the
dielectric function has a logarithmic singularity at the absorption edge. This
results in the large contribution into the optical dielectric constant. For
samples with degenerate carriers, the real part of the dielectric function is
divergent at the absorption edge. The divergence is smeared with temperatures
or relaxation rate. The imaginary part of the dielectric function has a plateau
far away from the absorption onset.
