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<b>let </b><font color="Maroon">X</font> be  non <a href="struct_0.html#V3">empty</a> <a href="pre_topc.html#NM1">TopSpace</a>;<br/><b>let </b><font color="Maroon">x</font> be   <a href="pre_topc.html#NM2">Point</a> of <font color="Maroon">X</font>;<br/>



<b>consider </b><font color="Maroon">F</font> being   <a href="struct_0.html#NM3">Subset-Family</a> of <font color="Maroon">X</font><b> such that </b><br/><a NAME="E2:33"/><i><font color="Green">E16</font></i>: 
for <font color="Olive">A</font> being  <a href="struct_0.html#NM2">Subset</a> of <font color="Maroon">X</font> holds <br/> ( <font color="Olive">A</font> <a href="hidden.html#R2">in</a> <font color="Maroon">F</font> iff ( <font color="Olive">A</font> is <a href="pre_topc.html#V3">open</a> &amp; <font color="Olive">A</font> is <a href="pre_topc.html#V4">closed</a> &amp; <font color="Maroon">x</font> <a href="hidden.html#R2">in</a> <font color="Olive">A</font> ) )
 <b>and </b><br/><a NAME="E3:33"/><i><font color="Green">E22</font></i>: 
 <a href="connsp_2.html#K1" target="_self">qComponent_of</a> <font color="Maroon">x</font> <a href="hidden.html#R1">=</a>  <a href="setfam_1.html#K6">meet</a> <font color="Maroon">F</font>
 <b>by </b><i/>;<br/>
<a NAME="E4:33"/>
for <font color="Olive">A</font> being  <a href="struct_0.html#NM2">Subset</a> of <font color="Maroon">X</font>  st <font color="Olive">A</font> <a href="hidden.html#R2">in</a> <font color="Maroon">F</font> holds <br/><font color="Olive">A</font> is <a href="pre_topc.html#V4">closed</a>
 
<b>by </b><i><a class="ref" href="connsp_2.html#T8" target="_self">Th8</a></i>;<br/>
<b>hence </b><a NAME="E5:33"/>
 <a href="connsp_2.html#K1" target="_self">qComponent_of</a> <font color="Maroon">x</font> is <a href="pre_topc.html#V4">closed</a>
 <b>by </b><i>, <a class="ref" href="pre_topc.html#T44">PRE_TOPC:44</a></i>;<br/>


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