New Valid Inequalities and Facets for the Simple Plant Location Problem

The Simple Plant Location Problem is a well-known (andNP-hard) combinatorial optimisation problem, with applications in logistics. We present a new family of valid inequalities for the associated family of polyhedra, and show that it contains an exponentially large number of new facet-defining members. We also present a new procedure, called facility augmentation, which enables one to derive even more valid and facet-defining inequalities.