a href = "p04_f.m">p04_f.m</a>, 
          returns the objective function value for problem 4.
        </li>
        <li>
          <a href = "p04_m.m">p04_m.m</a>, 
          returns the spatial dimension for problem 4.
        </li>
        <li>
          <a href = "p04_sol.m">p04_sol.m</a>, 
          returns known solutions for problem 4.
        </li>
        <li>
          <a href = "p04_title.m">p04_title.m</a>, 
          returns a title for problem 4.
        </li>
        <li>
          <a href = 