Published online by Cambridge University Press: 04 April 2009
Many well-known combinatorial optimization problems can be stated over the set of acyclic orientationsof an undirected graph. For example, acyclic orientations with certain diameter constraints areclosely related to the optimal solutions of the vertex coloring and frequency assignment problems. In this paper we introduce a linear programming formulation of acyclic orientationswith path constraints, and discuss its use in the solution of the vertex coloring problem andsome versions of the frequency assignment problem. A study of the polytope associated with the formulation is presented, including proofs of which constraints of the formulation are facet-definingand the introduction of new classes of valid inequalities.