Gradient network
In network science, a gradient network is a directed subnetwork of an undirected "substrate" network where each node has an associated scalar potential and one out-link that points to the node with the smallest (or largest) potential in its neighborhood, defined as the union of itself and its neighbors on the substrate network. == Definition == Transport takes place on a fixed network G = G ( V , E ) {\displaystyle G=G(V,E)} called the substrate graph.