li>
</ul></div>
<p>
        For:
      </p>
<div class="variablelist">
<p class="title"><b></b></p>
<dl class="variablelist">
<dt><span class="term">(a) X-&gt;Y:</span></dt>
<dd><p>
              <code class="computeroutput"><span class="identifier">R</span><span class="special">(</span><span class="identifier">X</span><span class="special">)</span> <span class="special">&amp;</span> <span class="identifier">R</span><span class="special">(</span><span class="identifier">Y</span><span class="special">)</span