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<b>let </b><font color="Maroon">T</font> be  non <a href="struct_0.html#V3">empty</a> <a href="pre_topc.html#NM1">TopSpace</a>;<br/>

<a NAME="E1:21"/>
for <font color="Olive">x</font>, <font color="Olive">y</font> being  <a href="pre_topc.html#NM2">Point</a> of <span class="p1">(<span class="default"><a href="t_0topsp.html#K3" target="_self">T_0-reflex</a> <font color="Maroon">T</font></span>)</span>  st not <font color="Olive">x</font> <a href="hidden.html#R1">=</a> <font color="Olive">y</font> holds <br/> ex <font color="Olive">A</font> being  <a href="struct_0.html#NM2">Subset</a> of <span class="p1">(<span class="default"><a href="t_0topsp.html#K3" target="_self">T_0-reflex</a> <font color="Maroon">T</font></span>)</span> st <br/>( <font color="Olive">A</font> is <a href="pre_topc.html#V3">open</a> &amp; ( ( <font color="Olive">x</font> <a href="hidden.html#R2">in</a> <font color="Olive">A</font> &amp; not <font color="Olive">y</font> <a href="hidden.html#R2">in</a> <font color="Olive">A</font> ) or ( <font color="Olive">y</font> <a href="hidden.html#R2">in</a> <font color="Olive">A</font> &amp; not <font color="Olive">x</font> <a href="hidden.html#R2">in</a> <font color="Olive">A</font> ) ) )
 
<b>by </b><i/>;<br/>
<b>hence </b><a NAME="E2:21"/>
 <a href="t_0topsp.html#K3" target="_self">T_0-reflex</a> <font color="Maroon">T</font> is   <a href="t_0topsp.html#NM1">T_0-TopSpace</a>
 <b>by </b><i/>;<br/>


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