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<b>let </b><font color="Maroon" title="c1">GX</font> be    <a href="pre_topc.html#L1" title="PRE_TOPC:struct.1">TopStruct</a> ;<br/><b>let </b><font color="Maroon" title="c2">R</font>, <font color="Maroon" title="c3">S</font> be   <a href="struct_0.html#NM2" title="STRUCT_0:NM.2">Subset</a> of <font color="Maroon" title="c1">GX</font>;<br/>





<b>assume </b><b>that </b><br/><a NAME="E1:67"/><i><font color="Green" title="E40">A1</font></i>: 
<font color="Maroon" title="c2">R</font> is <a href="tops_1.html#V1" title="TOPS_1:attr.1">dense</a>
 <b>and </b><br/><a NAME="E2:67"/><i><font color="Green" title="E41">A2</font></i>: 
<font color="Maroon" title="c2">R</font> <a href="tarski.html#R1" title="TARSKI:pred.1">c=</a> <font color="Maroon" title="c3">S</font>
 ;<br/>

<a NAME="E3:67"/>
 <a href="pre_topc.html#K2" title="PRE_TOPC:func.2">Cl</a> <font color="Maroon" title="c2">R</font> <a href="hidden.html#R1" title="HIDDEN:pred.1">=</a>  <a href="struct_0.html#K2" title="STRUCT_0:func.2">[#]</a> <font color="Maroon" title="c1">GX</font>
 
<b>by </b><i><a class="txt" href="tops_1.html#E1:67"><i><font color="Green" title="E40">A1</font></i></a>, <a class="ref" href="tops_1.html#D3" target="_self" title="TOPS_1:def.3">Def3</a></i>;<br/>
<a NAME="E4:67"/><b>then </b>
 <a href="struct_0.html#K2" title="STRUCT_0:func.2">[#]</a> <font color="Maroon" title="c1">GX</font> <a href="tarski.html#R1" title="TARSKI:pred.1">c=</a>  <a href="pre_topc.html#K2" title="PRE_TOPC:func.2">Cl</a> <font color="Maroon" title="c3">S</font>
 
<b>by </b><i><a class="txt" href="tops_1.html#E2:67"><i><font color="Green" title="E41">A2</font></i></a>, <a class="ref" href="pre_topc.html#T49" title="PRE_TOPC:th.49">PRE_TOPC:49</a></i>;<br/>
<a NAME="E5:67"/><b>then </b>
 <a href="struct_0.html#K2" title="STRUCT_0:func.2">[#]</a> <font color="Maroon" title="c1">GX</font> <a href="hidden.html#R1" title="HIDDEN:pred.1">=</a>  <a href="pre_topc.html#K2" title="PRE_TOPC:func.2">Cl</a> <font color="Maroon" title="c3">S</font>
 
<b>by </b><i><a class="ref" href="xboole_0.html#D10" title="XBOOLE_0:def.10">XBOOLE_0:def 10</a></i>;<br/>
<b>hence </b><a NAME="E6:67"/>
<font color="Maroon" title="c3">S</font> is <a href="tops_1.html#V1" title="TOPS_1:attr.1">dense</a>
 <b>by </b><i><a class="ref" href="tops_1.html#D3" target="_self" title="TOPS_1:def.3">Def3</a></i>;<br/>


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