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<b>set </b><font color="Maroon">c<sub>1</sub></font> =  <a href="topgen_3.html#K2">Sorgenfrey-line</a> ;<br/>
<a NAME="E1:69"/><i><font color="Green">E49</font></i>: 
the <a href="struct_0.html#U1">carrier</a> of <a href="topgen_3.html#K2">Sorgenfrey-line</a>  <a href="hidden.html#R1">=</a>  <a href="numbers.html#K1">REAL</a> 
 
<b>by </b><i><a class="ref" href="topgen_3.html#D2">TOPGEN_3:def 2</a></i>;<br/>
<b>let </b><font color="Maroon">c<sub>2</sub></font> be  <a href="xreal_0.html#V1">real</a>  <a href="ordinal1.html#NM1" target="_self">number</a> ;<br/>

<b>reconsider </b><font color="Maroon">c<sub>3</sub></font> =  <a href="limfunc1.html#K4">right_open_halfline</a> <font color="Maroon">c<sub>2</sub></font> as  <a href="pre_topc.html#V3">open</a> <a href="struct_0.html#NM2">Subset</a> of <a href="topgen_3.html#K2">Sorgenfrey-line</a>  <b>by </b><i><a class="ref" href="topgen_3.html#T14">TOPGEN_3:14</a></i>;<br/>
<a NAME="E3:69"/>
<span class="p1">(<span class="default"><span class="p2">(<span class="default"><a href="limfunc1.html#K2">left_closed_halfline</a> <font color="Maroon">c<sub>2</sub></font></span>)</span> <a href="subset_1.html#K3">`</a> </span>)</span> <a href="subset_1.html#K3">`</a>  <a href="hidden.html#R1">=</a> <font color="Maroon">c<sub>3</sub></font> <a href="subset_1.html#K3">`</a> 
 
<b>by </b><i><a class="txt" href="topgen_5.html#E1:69"><i><font color="Green">E49</font></i></a>, <a class="ref" href="borsuk_5.html#T98">BORSUK_5:98</a>, <a class="ref" href="topmetr.html#T24">TOPMETR:24</a></i>;<br/>
<b>hence </b><a NAME="E4:69"/>
 <a href="limfunc1.html#K2">left_closed_halfline</a> <font color="Maroon">c<sub>2</sub></font> is  <a href="pre_topc.html#V4">closed</a> <a href="struct_0.html#NM2">Subset</a> of <a href="topgen_3.html#K2">Sorgenfrey-line</a> 
 ;<br/>


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