ns, then the <tt>subgraph</tt> will also support
fewer functions and some of the functions listed below will not be
implemented.


<hr>
<pre>
std::pair&lt;vertex_iterator, vertex_iterator&gt;
vertices(const subgraph&amp; g)
</pre>
    Returns an iterator range providing access to the vertex set of subgraph <i>g</i>.
    (Required by <a href="VertexListGraph.html">VertexListGraph</a>.)

<hr>
<pre>
std::pair&lt;edge_iterator, edge_iterator&gt;
edges(const subgraph&amp; g)
</pre>
    Returns an iterator range 