4 papers
A Min-Max Relation on Dicuts and Dijoins in Weighted Chordal Digraphs
Gérard Cornuéjols, Siyue Liu, R. Ravi
In a digraph, a dicut is a cut where all the arcs cross in one direction. A dijoin is a subset of arcs that intersects every dicut. Edmonds and Giles conjectured that in a weighted…
Lower bounds for cube-ideal set-systems
Ahmad Abdi, Gérard Cornuéjols, Daniel Dadush +1
A set-system is cube-ideal if its convex hull can be described by capacity and generalized set covering inequalities. In this paper, we use combinatorics, co…
Strongly connected orientations and integer lattices
Ahmad Abdi, Gérard Cornuéjols, Siyue Liu +1
Let be a digraph whose underlying undirected graph is -edge-connected, and let be the polytope whose vertices are the incidence vectors of arc sets whose reversal…
The rainbow covering number of clean tangled clutters
Ahmad Abdi, Gérard Cornuéjols
In this brief note, we prove a min-min equality for a clean tangled clutter, that the rainbow covering number is equal to the connectivity of its setcore.