a href="mailto:P.Lamela-Seijas@kent.ac.uk"><tt>P.Lamela-Seijas@kent.ac.uk</tt></a>), Simon Thompson (<a href="mailto:S.J.Thompson@kent.ac.uk"><tt>S.J.Thompson@kent.ac.uk</tt></a>).</p>

<h2><a name="description">Description</a></h2>
   Implements an indexed tree with isolated nodes.
<h2><a name="types">Data Types</a></h2>

<h3 class="typedecl"><a name="type-tree">tree()</a></h3>
<p><b>abstract datatype</b>: <tt>tree()</tt></p>


<h3 class="typedecl"><a name="type-tree_node">tree_node()</a></h3>
<p><b>abstra