A catalog of steiner tree formulations

We present some existing and some new formulations for the Steiner tree and Steiner arborescence problems. We show the equivalence of many of these formulations. In particular, we establish the equivalence between the classical bidirected dicut relaxation and two vertex weighted undirected relaxations. The motivation behind this study is a characterization of the feasible region of the dicut relaxation in the natural space corresponding to the Steiner tree problem. *Supported by Air Force contract AFOSR-89-0271 and DARPA contract DARPA-89-5-1988. tOn leave at the Operations Research Center, MIT. Partial Support from the Yonam Foundation.