A Minimax Theorem for Directed Graphs
Cláudio Leonardo Lucchesi, Daniel H. Younger · Journal of the London Mathematical Society · 1978
THEOREM. For a finite directed graph G, a minimum transversal of the directed cuts of G is equal in cardinality to a maximum disjoint collection of directed cuts. This minimax equality was conjectured about a decade ago by one of the authors ([7; page 43], [8], [9]) and, independently, by Neil Robertson. It arose in the study