The study of cohesive subgroups is an important aspect of social network analysis. Cohesive subgroups are studied using different relaxations of the notion of clique in a graph. For instance, given a graph and an integer ...

We describe the adjacency of vertices of the (unbounded version of the) set covering polyhedron, in a similar way to the description given by Chvátal for the stable set polytope. We find a sufficient condition for adjacency, ...

In 1994, Cornuéjols and Novick published a classification of ideal and minimally non-ideal circulant clutters. One of their main results for doing so relates contractions of these clutters, simple directed cycles in an ...

In this paper we study lift-and-project polyhedral operators defined by Lovász and Schrijver and Balas, Ceria and Cornuéjols on the clique relaxation of the stable set polytope of webs. We compute the disjunctive rank of ...

Given a graph G = (V;E), a subset S V is 2-dominating if every vertex in S has at least two neighbors in S. The minimum cardinality of such a set is called the 2-domination number of G. Consider a process in discrete ...

Using polyhedral combinatorics and graph theory results, we study unstable families of coalitions and analyze the effect of adding players or deleting coalitions in order to obtain a stable family. We also generalize the ...