Frequency-distance constraints with large distances

Given a set V of points in the plane, and a vector of distances d = (d0,d1,...,dk-1), an assignment f : V → {1,2,...,t} is called d-feasible if |f(u) - f(v)| > i whenever the distance between the points u and v is less than di. We think of the points in V as sites to which we are to assign ra...