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<b>let </b><font color="Maroon">c<sub>1</sub></font> be   <a href="sub_metr.html#NM1">PseudoMetricSpace</a>;<br/><b>let </b><font color="Maroon">c<sub>2</sub></font> be    <a href="metric_2.html#M1" target="_self">equivalence_class</a> of <font color="Maroon">c<sub>1</sub></font>;<br/>



<a NAME="E1:15"/>
ex <font color="Olive">b<sub>1</sub></font> being  <a href="struct_0.html#NM1">Element</a> of <font color="Maroon">c<sub>1</sub></font> st <font color="Maroon">c<sub>2</sub></font> <a href="hidden.html#R1">=</a> <font color="Olive">b<sub>1</sub></font> <a href="metric_2.html#K1" target="_self">-neighbour</a> 
 
<b>by </b><i><a class="ref" href="metric_2.html#D3" target="_self">Def3</a></i>;<br/>
<b>hence </b><a NAME="E2:15"/>
<font color="Maroon">c<sub>2</sub></font> is  non <a href="xboole_0.html#V1">empty</a>  <a href="hidden.html#M1">set</a> 
 <b>by </b><i><a class="ref" href="metric_2.html#T9" target="_self">Th9</a></i>;<br/>


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