dges appear in the edge list, while not specified,
      is often chosen to be ascending order.
    </p>

    <p>
      Another representation of a graph is the <b>adjacency matrix</b>.
      This is an NV by NV matrix A in which A(I,J) is the number of edges
      between nodes I and J.  Ordinarily, this value is either 0 or 1,
      although there are natural extensions to this idea.
    </p>

    <p>
      Given an ordering of the edges as well as the nodes, we can
      represent the graph by an <b>inci