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

<b>let </b><font color="Maroon">c<sub>1</sub></font> be  non <a href="xboole_0.html#V1">empty</a>  <a href="hidden.html#M1">set</a> ;<br/>

<b>consider </b><font color="Maroon">c<sub>2</sub></font> being    <a href="subset_1.html#M1">Element</a> of <font color="Maroon">c<sub>1</sub></font>;<br/>
<a NAME="E2:14"/>
( <span class="p1">(<span class="default"><a href="funcsdom.html#K9" target="_self">RealFuncZero</a> <font color="Maroon">c<sub>1</sub></font></span>)</span> <a href="funct_2.html#K3">.</a> <font color="Maroon">c<sub>2</sub></font> <a href="hidden.html#R1">=</a> 0 &amp; <span class="p1">(<span class="default"><a href="funcsdom.html#K10" target="_self">RealFuncUnit</a> <font color="Maroon">c<sub>1</sub></font></span>)</span> <a href="funct_2.html#K3">.</a> <font color="Maroon">c<sub>2</sub></font> <a href="hidden.html#R1">=</a> 1 )
 
<b>by </b><i><a class="ref" href="funcsdom.html#T12" target="_self">Th12</a>, <a class="ref" href="funcsdom.html#T13" target="_self">Th13</a></i>;<br/>
<b>hence </b><a NAME="E3:14"/>
 <a href="funcsdom.html#K9" target="_self">RealFuncZero</a> <font color="Maroon">c<sub>1</sub></font> <a href="hidden.html#NR2" target="_self">&lt;&gt;</a>  <a href="funcsdom.html#K10" target="_self">RealFuncUnit</a> <font color="Maroon">c<sub>1</sub></font>
 ;<br/>


</div>
