Strong lower bounds for a survivable network design problem

We consider a generalization of the Prize Collecting Steiner Tree Problem on a graph with special redundancy requirements on a subset of the customer nodes suitable to model a real world problem occurring in the extension of fiber optic communication networks. We strengthen an existing connection-based mixed integer programming formulation involving exponentially many variables using a recent result with respect to the orientability of two-node connected graphs. The linear programming relaxation of this model is then solved by means of column generation. We show that our new model is theoretically stronger than a previously described one and present promising preliminary computational results.