T</span></code>, there
        is a <span class="bold"><strong>conversion direction</strong></span> denoted: <code class="computeroutput"><span class="identifier">S</span><span class="special">-&gt;</span><span class="identifier">T</span></code>.
      </p>
<p>
        For any two ranges the following <span class="emphasis"><em>range relation</em></span> can
        be defined: A range <code class="computeroutput"><span class="identifier">X</span></code> can
        be <span class="emphasis"><em>entirely co