A collection of nodes, V, sometimes called vertices, plus a collection of arcs, A, which are directed from one node to another. The two sets form a network, denoted As such, it can be considered a directed graph (see other terms, like special graphs).
- Here are associated functions and data values:
- tail of k-th arc is node we sometimes write
- head of k-th arc is node we sometimes write
- in-degree of node is
- out-degree of node is
- arc capacity limits the total flow across the arc at any one time.
- node capacity limits the total flow through a node at any one time.
- supply or demand at a node provides external input or an output requirement.