<?xml version="1.0"?>
<div class="add">

<b>reconsider </b><font color="Maroon">A</font> =  <a href="topgen_5.html#K1" target="_self">y=0-line</a>  as   <a href="struct_0.html#NM2">Subset</a> of <a href="topgen_5.html#K3" target="_self">Niemytzki-plane</a>  <b>by </b><i>, </i>;<br/>
<a NAME="E2:51"/>
<font color="Maroon">A</font> is <a href="tops_1.html#V3">nowhere_dense</a>
 
<div><a class="txt" onclick="hs2(this)" href="javascript:()" title="51_1"><b>proof </b></a><div class="add">

<b>thus </b> <a href="tops_1.html#K1">Int</a> <span class="p1">(<span class="default"><a href="pre_topc.html#K4">Cl</a> <font color="Maroon">A</font></span>)</span> = 
 <a href="tops_1.html#K1">Int</a> <font color="Maroon">A</font>
<b>by </b><i><a class="ref" href="pre_topc.html#T52">PRE_TOPC:52</a>, </i>
<br/>.= 
 <a href="xboole_0.html#K1">{}</a> 
<b>by </b><i/>
; <i><font color="Red">:: according to </font></i><a class="ref" href="tops_3.html#D3">TOPS_3:def 3</a><br/>


</div><b>end;</b></div>
<b>hence </b><a NAME="E3:51"/>
 <a href="topgen_5.html#K1" target="_self">y=0-line</a>  is  <a href="tops_1.html#V3">nowhere_dense</a> <a href="struct_0.html#NM2">Subset</a> of <a href="topgen_5.html#K3" target="_self">Niemytzki-plane</a> 
 ;<br/>


</div>
