Polyhedral studies of vertex coloring problems: The asymmetric representatives formulation

Despite the fact that some vertex coloring problems are polynomially solvable on certain graph classes, most of these problems are not “under control” from a polyhedral point of view. The equivalence between optimization and polyhedral separation suggests that, for these problems, there must exist formulations admitting some elegant characterization for the polytopes associated to them. Therefore, it is interesting to study known formulations for vertex coloring with the goal of finding such characterizations. In this work we study the asymmetric representatives formulation and we show that the corresponding coloring polytope, for a given graph G, can be interpreted as the stable set polytope of another graph RG, obtained from G. This result allows us to derive complete characterizations for the corresponding coloring polytope for some families of graphs, based on known complete characterizations for the stable set polytope.