  In the calculation of the $K^+$-nucleus cross sections, the coupling of the
mesons exchanged between the $K^+$ and the target nucleons to the polarization
of the Fermi sea has been taken into account. This polarization has been
calculated in the one-loop approximation but summed up to all orders (RPA-type
calculation). This effect is found to be rather important but does not improve
the agreement with experiment.
