>Refinement
          of</a>
        </h6>
<p>
          <a class="link" href="bidirectional_sequence.html" title="Bidirectional Sequence">Bidirectional
          Sequence</a>
        </p>
<div class="variablelist">
<p class="title"><b>Notation</b></p>
<dl class="variablelist">
<dt><span class="term"><code class="computeroutput"><span class="identifier">s</span></code></span></dt>
<dd><p>
                A Random Access Sequence
              </p></dd>
<dt><span class="term"><code class="computeroutput"><sp