Extreme points for continuous network programs with arc delays

In this paper the problem of finding the least cost flow in a network over a time interval is considered. Each arc of the network has associated with it a timevarying capacity and a constant time delay. Each node of the network has a storage capacity associated with it, and either a demand or a supply, all these quantities varying over the time interval. A characterization of the extreme points of the set of feasible flows is given.