In this paper we relate antiblocker duality between polyhedra, graph theory and the disjunctive procedure. In particular, we analyze the behavior of the disjunctive procedure over the clique relaxation, K(G), of the stable set polytope in a graph G and the one associated to its complementary graph, K(¯ G). We obtain a generalization of the Perfect Graph… (More)
In this paper we define a disjunctive procedure over blocking type polyhedra with vertices in [0, 1] n , study its properties, and analize its behavior under blocker duality. We compare the indices of the procedure over a pair of blocking clutter polyhedra, obtaining that they coincide.
We study the Lovász-Schrijver SDP-operator applied to the fractional stable set polytope of graphs. The problem of obtaining a combinatorial characterization of graphs for which the SDP-operator generates the stable set polytope in one step has been open since 1990. In an earlier publication, we named these graphs N +-perfect. In the current contribution,… (More)