Network Design Subject to Facility Location

We consider the problem of designing a transportation network to allow the residents of the network to avail service provided by a single facility whose location is predetermined. This problem is known to be NPComplete for general graph. The problem remains NPComplete even when the vertices of the network are required to lie on the boundary of a convex polygon in the Euclidean plane. We present a polynomial time algorithm for computing the median constrained minimum spanning tree when the edges of the required network are not allowed to cross with each other. Our technique is based on the integer programming formulation of the network design problem.