<?xml version="1.0"?>
<div class="add">

<b>take </b>
 <a href="xboole_0.html#K1">{}</a> 
;<br/>

<b>thus </b><a NAME="E1:85_1_1"/>
 <a href="xboole_0.html#K1">{}</a>  is <a href="xboole_0.html#V1">empty</a>
 ;<br/>


</div>
