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<b>let </b><font color="Maroon">n</font> be   <a href="nat_1.html#NM1">Nat</a>;<br/>

<b>assume </b><a NAME="E1:7"/><i><font color="Green">E31</font></i>: 
<font color="Maroon">n</font> <a href="xxreal_0.html#NR2" target="_self">&gt;=</a> 1
 ;<br/>

<b>hence </b><font color="Maroon">n</font> <a href="power.html#K1" target="_self">-root</a> 0 = 
<font color="Maroon">n</font> <a href="prepower.html#K4">-Root</a> 0
<b>by </b><i/>
<br/>.= 
0
<b>by </b><i>, <a class="ref" href="prepower.html#D3">PREPOWER:def 3</a></i>
;<br/><br/>


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