Vertex adjacencies in the set covering polyhedron
  We describe the adjacency of vertices of the (unbounded version of the) set covering polyhedron, in a similar way to the description given by Chvatal for the stable set polytope. We find a sufficient condition for adjacency, and characterize it with similar conditions in the case where the underlying matrix is row circular. We apply our findings to show a new infinite family of minimally nonideal matrices. 
N\'estor E. Aguilera, Ricardo D. Katz and Paola B. Tolomei
math.CO