ical intervals, from Guillaume 
    Melquiond, Hervé Brönnimann and Sylvain Pion.</li>
    <li><a href="math/doc/common_factor.html">math/common_factor</a> - Greatest 
    common divisor and least common multiple, from Daryle Walker.</li>
    <li><a href="math/octonion/index.html">math/octonion</a> -
      Octonions, from Hubert Holin.</li>
    <li><a href="math/quaternion/index.html">math/quaternion</a> -
      Quaternions, from Hubert Holin.</li>
    <li><a href="math/special_functions/index.html">math/