A minimum cost flow problem have both arcs (ij) and (ij) for nodes i and j. Transform this problem to a problem in which the network contains either arc (ij) or arc (i, j), but not both. Assume that a minimum cost flow code is such that its input data should not be l, = u for arc(i, j) (where l is lower bound and u is the capacity of arc (i, j)). How can this arc be eliminated