<?xml version="1.0"?>
<div>:: <span class="kw">deftheorem </span>   defines <a href="modal_1.html#K1" title="MODAL_1:func.1">Root</a> <a onclick="hs(this)" href="javascript:()">MODAL_1:def 1 : <br/></a><span> for <font color="Olive" title="b1">Z</font> being   <a href="trees_1.html#NM1" title="TREES_1:NM.1">Tree</a> holds   <a href="modal_1.html#K1" title="MODAL_1:func.1">Root</a> <font color="Olive" title="b1">Z</font> <a href="hidden.html#R1" title="HIDDEN:pred.1">=</a>  <a href="xboole_0.html#K1" title="XBOOLE_0:func.1">{}</a> ;<br/></span></div>
