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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/><b>let </b><font color="Maroon">x</font> be   <a href="struct_0.html#NM1">Element</a> of <span class="p1">(<span class="default"><a href="yellow_1.html#K2">InclPoset</a> the <a href="pre_topc.html#U1">topology</a> of <font color="Maroon">T</font></span>)</span>;<br/><b>let </b><font color="Maroon">X</font> be   <a href="struct_0.html#NM2">Subset</a> of <font color="Maroon">T</font>;<br/>





<b>assume </b><a NAME="E1:65"/><i><font color="Green">E34</font></i>: 
<font color="Maroon">x</font> <a href="hidden.html#R1">=</a> <font color="Maroon">X</font>
 ;<br/>

<div><b>hereby </b>
<div class="add"><b>assume </b><a NAME="E1:65_1"/>
<font color="Maroon">x</font> is <a href="waybel_3.html#V1" target="_self">compact</a>
 ;<br/><a NAME="E2:65_1"/><b>then </b><i><font color="Green">E35</font></i>: 
<font color="Maroon">x</font> <a href="waybel_3.html#NR2" target="_self">&lt;&lt;</a> <font color="Maroon">x</font>
 <b>by </b><i/>;<br/><b>thus </b><a NAME="E3:65_1"/>
<font color="Maroon">X</font> is <a href="compts_1.html#V6">compact</a>
 <div><a class="txt" onclick="hs2(this)" href="javascript:()" title="65_1_1"><b>proof </b></a><div class="add">

<b>let </b><font color="Maroon">F</font> be   <a href="struct_0.html#NM3">Subset-Family</a> of <font color="Maroon">T</font>; <i><font color="Red">:: according to </font></i><a class="ref" href="compts_1.html#D7">COMPTS_1:def 7</a><br/>

<b>assume </b><b>that </b><br/><a NAME="E1:65_1_1"/><i><font color="Green">E39</font></i>: 
<font color="Maroon">X</font> <a href="tarski.html#R1">c=</a>  <a href="tarski.html#K3">union</a> <font color="Maroon">F</font>
 <b>and </b><br/><a NAME="E2:65_1_1"/><i><font color="Green">E40</font></i>: 
<font color="Maroon">F</font> is <a href="tops_2.html#V1">open</a>
 ; <i><font color="Red">:: according to </font></i><a class="ref" href="compts_1.html#D1">COMPTS_1:def 1</a><br/>

<b>consider </b><font color="Maroon">G</font> being  <a href="finset_1.html#V1">finite</a> <a href="subset_1.html#NM2">Subset</a> of <font color="Maroon">F</font><b> such that </b><br/><a NAME="E4:65_1_1"/><i><font color="Green">E42</font></i>: 
<font color="Maroon">x</font> <a href="tarski.html#R1">c=</a>  <a href="tarski.html#K3">union</a> <font color="Maroon">G</font>
 <b>by </b><i><a class="ref" href="waybel_3.html#D1" target="_self">Def1</a>, , , <a class="ref" href="waybel_3.html#D2" target="_self">Def2</a>, </i>;<br/>
<a NAME="E5:65_1_1"/>
<font color="Maroon">G</font> is   <a href="struct_0.html#NM3">Subset-Family</a> of <font color="Maroon">T</font>
 
<b>by </b><i><a class="ref" href="xboole_1.html#T1">XBOOLE_1:1</a></i>;<br/>
<b>then reconsider </b><font color="Maroon">G</font> = <font color="Maroon">G</font> as   <a href="struct_0.html#NM3">Subset-Family</a> of <font color="Maroon">T</font> ;<br/>
<b>take </b>
<font color="Maroon">G</font>
;<br/>

<b>thus </b><a NAME="E7:65_1_1"/>
( <font color="Maroon">G</font> <a href="tarski.html#R1">c=</a> <font color="Maroon">F</font> &amp; <font color="Maroon">X</font> <a href="tarski.html#R1">c=</a>  <a href="tarski.html#K3">union</a> <font color="Maroon">G</font> &amp; <font color="Maroon">G</font> is <a href="finset_1.html#V1">finite</a> )
 <b>by </b><i><a class="ref" href="waybel_3.html#D1" target="_self">Def1</a>, <a class="ref" href="waybel_3.html#T1" target="_self">Th1</a></i>; <i><font color="Red">:: according to </font></i><a class="ref" href="compts_1.html#D1">COMPTS_1:def 1</a><br/>


</div><b>end;</b></div></div>
<b>end;</b></div>

<b>assume </b><a NAME="E3:65"/><i><font color="Green">E43</font></i>: 
for <font color="Olive">F</font> being  <a href="struct_0.html#NM3">Subset-Family</a> of <font color="Maroon">T</font>  st <font color="Olive">F</font> <a href="compts_1.html#R1">is_a_cover_of</a> <font color="Maroon">X</font> &amp; <font color="Olive">F</font> is <a href="tops_2.html#V1">open</a> holds <br/> ex <font color="Olive">G</font> being  <a href="struct_0.html#NM3">Subset-Family</a> of <font color="Maroon">T</font> st <br/>( <font color="Olive">G</font> <a href="tarski.html#R1">c=</a> <font color="Olive">F</font> &amp; <font color="Olive">G</font> <a href="compts_1.html#R1">is_a_cover_of</a> <font color="Maroon">X</font> &amp; <font color="Olive">G</font> is <a href="finset_1.html#V1">finite</a> )
 ; <i><font color="Red">:: according to </font></i><a class="ref" href="compts_1.html#D7">COMPTS_1:def 7</a><br/>

<div><a class="txt" onclick="hs2(this)" href="javascript:()" title="65_2"><b>now </b></a><div class="add"><b>let </b><font color="Maroon">F</font> be   <a href="struct_0.html#NM3">Subset-Family</a> of <font color="Maroon">T</font>;<br/><b>assume </b><a NAME="E1:65_2"/><i><font color="Green">E44</font></i>: 
( <font color="Maroon">F</font> is <a href="tops_2.html#V1">open</a> &amp; <font color="Maroon">x</font> <a href="tarski.html#R1">c=</a>  <a href="tarski.html#K3">union</a> <font color="Maroon">F</font> )
 ;<br/><a NAME="E2:65_2"/>
<font color="Maroon">F</font> <a href="compts_1.html#R1">is_a_cover_of</a> <font color="Maroon">X</font>
 <div><a class="txt" onclick="hs2(this)" href="javascript:()" title="65_2_1"><b>proof </b></a><div class="add">

<b>thus </b><a NAME="E1:65_2_1"/>
<font color="Maroon">X</font> <a href="tarski.html#R1">c=</a>  <a href="tarski.html#K3">union</a> <font color="Maroon">F</font>
 <b>by </b><i><a class="ref" href="waybel_3.html#D1" target="_self">Def1</a>, </i>; <i><font color="Red">:: according to </font></i><a class="ref" href="compts_1.html#D1">COMPTS_1:def 1</a><br/>


</div><b>end;</b></div><b>then consider </b><font color="Maroon">G</font> being   <a href="struct_0.html#NM3">Subset-Family</a> of <font color="Maroon">T</font><b> such that </b><br/><a NAME="E4:65_2"/><i><font color="Green">E48</font></i>: 
( <font color="Maroon">G</font> <a href="tarski.html#R1">c=</a> <font color="Maroon">F</font> &amp; <font color="Maroon">G</font> <a href="compts_1.html#R1">is_a_cover_of</a> <font color="Maroon">X</font> &amp; <font color="Maroon">G</font> is <a href="finset_1.html#V1">finite</a> )
 <b>by </b><i>, </i>;<br/><a NAME="E5:65_2"/>
<font color="Maroon">x</font> <a href="tarski.html#R1">c=</a>  <a href="tarski.html#K3">union</a> <font color="Maroon">G</font>
 <b>by </b><i><a class="ref" href="waybel_3.html#D1" target="_self">Def1</a>, <a class="ref" href="waybel_3.html#D2" target="_self">Def2</a>, <a class="ref" href="compts_1.html#D1">COMPTS_1:def 1</a></i>;<br/><b>hence </b><a NAME="E6:65_2"/>
 ex <font color="Olive">G</font> being <a href="finset_1.html#V1">finite</a> <a href="subset_1.html#NM2">Subset</a> of <font color="Maroon">F</font> st <font color="Maroon">x</font> <a href="tarski.html#R1">c=</a>  <a href="tarski.html#K3">union</a> <font color="Olive">G</font>
 <b>by </b><i><a class="ref" href="waybel_3.html#D2" target="_self">Def2</a></i>;<br/></div><b>end;</b></div>
<b>hence </b><a NAME="E5:65"/>
<font color="Maroon">x</font> <a href="waybel_3.html#NR2" target="_self">&lt;&lt;</a> <font color="Maroon">x</font>
 <b>by </b><i/>; <i><font color="Red">:: according to </font></i><a class="ref" href="waybel_3.html#D2" target="_self">WAYBEL_3:def 2</a><br/>


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