at <tt class="docutils literal"><span class="pre">vertex(0,</span> <span class="pre">g)</span> <span class="pre">==</span>
<span class="pre">*num_vertices(g).first</span></tt>. This function is only guaranteed to be
accurate when no vertices have been added to or removed from the
graph after its initial construction.</p>
<hr class="docutils" />
<pre class="literal-block">
std::pair&lt;edge_descriptor, bool&gt;
edge(vertex_descriptor u, vertex_descriptor v,
     const adjacency_list&amp; g);
</pre>
<p>Return