dence matrix</b> which is an
      NE by NV matrix, such that A(I,J) is 0 unless edge I uses node J
      as one of its two endpoints.
    </p>

    <p>
      The <b>adjacency structure</b> of a graph is, ideally, a list of
      NV lists.  For node I, the list contains all nodes joined by an
      edge to node I.  The length of the list for each node may be
      anything from 0 to NV-1; in MATLAB this data structure can be
      represented by a cell array.
    </p>

    <p>
      If the cell array or lis