  The K-partitioning problem consists of partitioning the vertices of a graph
in K sets so as to minimize a function of the edge weights. We introduce a
linear mixed integer formulation with edge variables and representative
variables. We consider the corresponding polyhedron and show which inequalities
are facet-defining. We study several families of facet-defining inequalities
and provide experimental results showing that they improve significantly the
linear relaxation of our formulation.
