NETWORKS
N = {1,2,3,4,5,6,7} A = {(1,2), (2,3), (1,5),(2,5),(3,4), (3,7),(4,5),(4,7),(5,6), (6,7)} A graph consists of a set of N nodes and a set of arcs whose elements are ordered pairs of nodes.
GRAPH + FLOW OF ENTITY LIKE CARS, PEOPLE, ELECTRICITY = NETWORK
A network is a graph whose nodes and/or arcs have associated numerical values (costs, capacities, supplies/demands). We wish to move some entity(electricity, person, vehicle) from one point to another in an underlying network and to do so as effectively as possible.