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<b>let </b><font color="Maroon">X</font> be    <a href="hidden.html#M1">set</a> ;<br/><b>let </b><font color="Maroon">R</font> be   <a href="eqrel_1.html#NM1">Tolerance</a> of <font color="Maroon">X</font>;<br/><b>let </b><font color="Maroon">T</font> be   <a href="eqrel_1.html#NM1">Tolerance</a> of <font color="Maroon">X</font>;<br/>





<b>assume </b><a NAME="E1:57"/><i><font color="Green">E21</font></i>: 
for <font color="Olive">x</font> being   <a href="hidden.html#M1">set</a>   st <font color="Olive">x</font> <a href="hidden.html#R2">in</a> <font color="Maroon">X</font> holds <br/> <a href="toler_1.html#NK4" target="_self">neighbourhood</a> , <a href="tarski.html#R1">c=</a>  <a href="toler_1.html#NK4" target="_self">neighbourhood</a> ,
 ;<br/>

<b>let </b><font color="Maroon">x</font> be    <a href="hidden.html#M1">set</a> ; <i><font color="Red">:: according to </font></i><a class="ref" href="relat_1.html#D3">RELAT_1:def 3</a><br/><b>let </b><font color="Maroon">y</font> be    <a href="hidden.html#M1">set</a> ;<br/>



<b>assume </b><a NAME="E2:57"/><i><font color="Green">E22</font></i>: 
<span class="p1"><a href="tarski.html#K4">[</a><span class="default"><font color="Maroon">x</font>,<font color="Maroon">y</font></span><a href="tarski.html#K4">]</a></span> <a href="hidden.html#R2">in</a> <font color="Maroon">R</font>
 ;<br/>

<a NAME="E3:57"/><b>then </b><i><font color="Green">E27</font></i>: 
<font color="Maroon">y</font> <a href="hidden.html#R2">in</a>  <a href="toler_1.html#NK4" target="_self">neighbourhood</a> ,
 
<b>by </b><i><a class="txt" href="toler_1.html#E1:57"><i><font color="Green">E21</font></i></a></i>;<br/>
<a NAME="E4:57"/>
<font color="Maroon">x</font> <a href="hidden.html#R2">in</a> <font color="Maroon">X</font>
 
<b>by </b><i><a class="ref" href="toler_1.html#T27" target="_self">Th27</a>, <a class="ref" href="zfmisc_1.html#T106">ZFMISC_1:106</a></i>;<br/>
<a NAME="E5:57"/><b>then </b>
 <a href="toler_1.html#NK4" target="_self">neighbourhood</a> , <a href="tarski.html#R1">c=</a>  <a href="toler_1.html#NK4" target="_self">neighbourhood</a> ,
 
<b>by </b><i/>;<br/>
<b>hence </b><a NAME="E6:57"/>
<span class="p1"><a href="tarski.html#K4">[</a><span class="default"><font color="Maroon">x</font>,<font color="Maroon">y</font></span><a href="tarski.html#K4">]</a></span> <a href="hidden.html#R2">in</a> <font color="Maroon">T</font>
 <b>by </b><i><a class="ref" href="toler_1.html#T32" target="_self">Th32</a>, <a class="txt" href="toler_1.html#E1:57"><i><font color="Green">E21</font></i></a></i>;<br/>


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