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<b>let </b><font color="Maroon">F</font> be  non <a href="realset1.html#V1" target="_self">trivial</a>  <a href="hidden.html#M1">set</a> ;<br/><b>let </b><font color="Maroon">A</font> be    <a href="realset1.html#M4" target="_self">OnePoint</a> of <font color="Maroon">F</font>;<br/>



<a NAME="E1:25"/>
 ex <font color="Olive">x</font> being   <a href="subset_1.html#M1">Element</a> of <font color="Maroon">F</font> st <font color="Maroon">A</font> <a href="hidden.html#R1">=</a> <span class="p1"><a href="tarski.html#K1">{</a><span class="default"><font color="Olive">x</font></span><a href="tarski.html#K1">}</a></span>
 
<b>by </b><i/>;<br/>
<b>hence </b><a NAME="E2:25"/>
<font color="Maroon">F</font> <a href="subset_1.html#K6">\</a> <font color="Maroon">A</font> is  non <a href="xboole_0.html#V1">empty</a>  <a href="hidden.html#M1">set</a> 
 <b>by </b><i/>;<br/>


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