<?xml version="1.0"?>
<div><span class="kw">theorem </span><a NAME="T87"><span class="comment"><font color="firebrick">:: QUATERN3:87</font></span><br/></a><div class="add"><span class="p1">(<span class="default"><a href="quaterni.html#K23" title="QUATERNI:func.23">-</a> <a href="quatern2.html#K2" title="QUATERN2:func.2">1q</a></span>)</span> <a href="quatern3.html#K2" title="QUATERN3:func.2">^2</a>  <a href="hidden.html#R1" title="HIDDEN:pred.1">=</a> 1</div></div>
