  We report on Monte Carlo results of diffusion coefficients of lattice star
polymers trapped inside a fixed network (de Gennes model). It is found that our
data are in agreement with the Helfand-Pearson exponential factor \alpha=0.29.
For the pre-exponential power law exponent we find \beta=2. In contrast to
existing theoretical predictions, we find that the number of arms f leads to a
pre-exponential factor of the form exp(-0.75 f).
