  We present approximation algorithms for maximum independent set of
pseudo-disks in the plane, both in the weighted and unweighted cases. For the
unweighted case, we prove that a local search algorithm yields a \PTAS. For the
weighted case, we suggest a novel rounding scheme based on an \LP relaxation of
the problem, which leads to a constant-factor approximation. Most previous
algorithms for maximum independent set (in geometric settings) relied on
packing arguments that are not applicable in this case. As such, the analysis
of both algorithms requires some new combinatorial ideas, which we believe to
be of independent interest.
