Separating Partition Inequalities
Mourad Baı̈ou, Francisco Barahona, Ali Ridha Mahjoub · 2000
Given a graph G = (V,E) with nonnegative weights x(e) for each edge e, a partition inequality is of the form x({delta}(S1,...,Sp))≥ap+b. Here {delta}(S1,...,Sp) denotes the multicut defined by a partition S1,...,Sp of V. Partition inequalities arise as valid inequalities for optimization problems related to k-connectivity. We give a polynomial algorithm for the associated separation problem. This is based on an algorithm for finding the minimum of x({delta}(S1,...,Sp))–p that reduces to minimizing a symmetric submodular function. This is handled with the recent algorithm of Queyranne. We also survey some applications of partition inequalities.