  We show an O*((l+1)^n)-time algorithm for the channel assignment problem,
where l is the maximum edge weight. This improves on the previous
O*((l+2)^n)-time algorithm by Kral, as well as algorithms for important special
cases, like L(2,1)-labelling. For the latter problem, our algorithm works in
O*(3^n) time. The progress is achieved by applying the fast zeta transform in
combination with the inclusion-exclusion principle.
