mily: Courier New,Courier,monospace;">bool
            <span style="font-weight: bold;">is_finite</span>() const </td>
            <td>Returns true if the both
end points of the edge are finite, else false. </td>
          </tr>
          <tr>
            <td style="font-family: Courier New,Courier,monospace;">bool
            <span style="font-weight: bold;">is_infinite</span>() const</td>
            <td>Returns true if one of the
end points of the edge is infinite, else false.</td>
          </tr>
      