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

<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">F</font> be   <a href="struct_0.html#NM3">Subset-Family</a> of <font color="Maroon">T</font>;<br/>



<b>assume </b><a NAME="E1:115"/><i><font color="Green">E18</font></i>: 
<font color="Maroon">F</font> is <a href="tdlat_2.html#V3" target="_self">open-domains-family</a>
 ;<br/>

<b>let </b><font color="Maroon">X</font> be   <a href="struct_0.html#NM2">Subset</a> of <span class="p1">(<span class="default"><a href="tdlat_1.html#K12">Open_Domains_Lattice</a> <font color="Maroon">T</font></span>)</span>;<br/>

<b>assume </b><a NAME="E2:115"/><i><font color="Green">E19</font></i>: 
<font color="Maroon">X</font> <a href="hidden.html#R1">=</a> <font color="Maroon">F</font>
 ;<br/>

<b>thus </b><a NAME="E3:115"/>
( <font color="Maroon">X</font> <a href="hidden.html#NR2" target="_self">&lt;&gt;</a>  <a href="xboole_0.html#K1">{}</a>  implies  <a href="lattice3.html#K16">"/\"</a> <font color="Maroon">X</font>,<span class="p1">(<span class="default"><a href="tdlat_1.html#K12">Open_Domains_Lattice</a> <font color="Maroon">T</font></span>)</span> <a href="hidden.html#R1">=</a>  <a href="tops_1.html#K1">Int</a> <span class="p1">(<span class="default"><a href="setfam_1.html#K6">meet</a> <font color="Maroon">F</font></span>)</span> )
 <div><a class="txt" onclick="hs2(this)" href="javascript:()" title="115_1"><b>proof </b></a><div class="add">

<b>assume </b><a NAME="E1:115_1"/><i><font color="Green">E22</font></i>: 
<font color="Maroon">X</font> <a href="hidden.html#NR2" target="_self">&lt;&gt;</a>  <a href="xboole_0.html#K1">{}</a> 
 ;<br/>

<b>set </b><font color="Maroon">A</font> =  <a href="tops_1.html#K1">Int</a> <span class="p1">(<span class="default"><a href="setfam_1.html#K6">meet</a> <font color="Maroon">F</font></span>)</span>;<br/>
<a NAME="E2:115_1"/>
 <a href="tops_1.html#K1">Int</a> <span class="p1">(<span class="default"><a href="setfam_1.html#K6">meet</a> <font color="Maroon">F</font></span>)</span> is <a href="tops_1.html#V6">open_condensed</a>
 
<b>by </b><i>, <a class="ref" href="tdlat_2.html#T18" target="_self">Th18</a></i>;<br/>
<a NAME="E3:115_1"/><b>then </b>
 <a href="tops_1.html#K1">Int</a> <span class="p1">(<span class="default"><a href="setfam_1.html#K6">meet</a> <font color="Maroon">F</font></span>)</span> <a href="hidden.html#R2">in</a> <span class="p1">{<span class="default"> <font color="Olive">C</font> where <font color="Olive">C</font> is   <a href="struct_0.html#NM2">Subset</a> of <font color="Maroon">T</font> : <font color="Olive">C</font> is <a href="tops_1.html#V6">open_condensed</a> </span>}</span> 
 
;<br/>
<a NAME="E4:115_1"/><b>then </b><i><font color="Green">E23</font></i>: 
 <a href="tops_1.html#K1">Int</a> <span class="p1">(<span class="default"><a href="setfam_1.html#K6">meet</a> <font color="Maroon">F</font></span>)</span> <a href="hidden.html#R2">in</a>  <a href="tdlat_1.html#K9">Open_Domains_of</a> <font color="Maroon">T</font>
 
<b>by </b><i><a class="ref" href="tdlat_1.html#D9">TDLAT_1:def 9</a></i>;<br/>
<b>then reconsider </b><font color="Maroon">a</font> =  <a href="tops_1.html#K1">Int</a> <span class="p1">(<span class="default"><a href="setfam_1.html#K6">meet</a> <font color="Maroon">F</font></span>)</span> as   <a href="struct_0.html#NM1">Element</a> of <span class="p1">(<span class="default"><a href="tdlat_1.html#K12">Open_Domains_Lattice</a> <font color="Maroon">T</font></span>)</span> <b>by </b><i/>;<br/>
<a NAME="E6:115_1"/><i><font color="Green">E31</font></i>: 
<font color="Maroon">a</font> <a href="lattice3.html#R3">is_less_than</a> <font color="Maroon">X</font>
 
<div><a class="txt" onclick="hs2(this)" href="javascript:()" title="115_1_1"><b>proof </b></a><div class="add">

<b>let </b><font color="Maroon">b</font> be   <a href="struct_0.html#NM1">Element</a> of <span class="p1">(<span class="default"><a href="tdlat_1.html#K12">Open_Domains_Lattice</a> <font color="Maroon">T</font></span>)</span>; <i><font color="Red">:: according to </font></i><a class="ref" href="lattice3.html#D16">LATTICE3:def 16</a><br/>

<b>reconsider </b><font color="Maroon">B</font> = <font color="Maroon">b</font> as    <a href="subset_1.html#M2">Element</a> of  <a href="tdlat_1.html#K9">Open_Domains_of</a> <font color="Maroon">T</font> <b>by </b><i/>;<br/>
<b>assume </b><a NAME="E2:115_1_1"/>
<font color="Maroon">b</font> <a href="hidden.html#R2">in</a> <font color="Maroon">X</font>
 ;<br/>

<a NAME="E3:115_1_1"/><b>then </b>
 <a href="tops_1.html#K1">Int</a> <span class="p1">(<span class="default"><a href="setfam_1.html#K6">meet</a> <font color="Maroon">F</font></span>)</span> <a href="tarski.html#R1">c=</a> <font color="Maroon">B</font>
 
<b>by </b><i>, </i>;<br/>
<b>hence </b><a NAME="E4:115_1_1"/>
<font color="Maroon">a</font> <a href="lattices.html#R1">[=</a> <font color="Maroon">b</font>
 <b>by </b><i>, </i>;<br/>


</div><b>end;</b></div>
<a NAME="E7:115_1"/><i><font color="Green">E32</font></i>: 
for <font color="Olive">b</font> being  <a href="struct_0.html#NM1">Element</a> of <span class="p1">(<span class="default"><a href="tdlat_1.html#K12">Open_Domains_Lattice</a> <font color="Maroon">T</font></span>)</span>  st <font color="Olive">b</font> <a href="lattice3.html#R3">is_less_than</a> <font color="Maroon">X</font> holds <br/><font color="Olive">b</font> <a href="lattices.html#R1">[=</a> <font color="Maroon">a</font>
 
<div><a class="txt" onclick="hs2(this)" href="javascript:()" title="115_1_2"><b>proof </b></a><div class="add">

<b>let </b><font color="Maroon">b</font> be   <a href="struct_0.html#NM1">Element</a> of <span class="p1">(<span class="default"><a href="tdlat_1.html#K12">Open_Domains_Lattice</a> <font color="Maroon">T</font></span>)</span>;<br/>

<b>reconsider </b><font color="Maroon">B</font> = <font color="Maroon">b</font> as    <a href="subset_1.html#M2">Element</a> of  <a href="tdlat_1.html#K9">Open_Domains_of</a> <font color="Maroon">T</font> <b>by </b><i/>;<br/>
<a NAME="E2:115_1_2"/>
<font color="Maroon">B</font> <a href="hidden.html#R2">in</a>  <a href="tdlat_1.html#K9">Open_Domains_of</a> <font color="Maroon">T</font>
 
;<br/>
<a NAME="E3:115_1_2"/><b>then </b>
<font color="Maroon">B</font> <a href="hidden.html#R2">in</a> <span class="p1">{<span class="default"> <font color="Olive">C</font> where <font color="Olive">C</font> is   <a href="struct_0.html#NM2">Subset</a> of <font color="Maroon">T</font> : <font color="Olive">C</font> is <a href="tops_1.html#V6">open_condensed</a> </span>}</span> 
 
<b>by </b><i><a class="ref" href="tdlat_1.html#D9">TDLAT_1:def 9</a></i>;<br/>
<a NAME="E4:115_1_2"/><b>then </b><i><font color="Green">E33</font></i>: 
 ex <font color="Olive">C</font> being  <a href="struct_0.html#NM2">Subset</a> of <font color="Maroon">T</font> st <br/>( <font color="Olive">C</font> <a href="hidden.html#R1">=</a> <font color="Maroon">B</font> &amp; <font color="Olive">C</font> is <a href="tops_1.html#V6">open_condensed</a> )
 
;<br/>
<b>assume </b><a NAME="E5:115_1_2"/><i><font color="Green">E35</font></i>: 
<font color="Maroon">b</font> <a href="lattice3.html#R3">is_less_than</a> <font color="Maroon">X</font>
 ;<br/>

<a NAME="E6:115_1_2"/>
for <font color="Olive">C</font> being  <a href="struct_0.html#NM2">Subset</a> of <font color="Maroon">T</font>  st <font color="Olive">C</font> <a href="hidden.html#R2">in</a> <font color="Maroon">F</font> holds <br/><font color="Maroon">B</font> <a href="tarski.html#R1">c=</a> <font color="Olive">C</font>
 
<div><a class="txt" onclick="hs2(this)" href="javascript:()" title="115_1_2_1"><b>proof </b></a><div class="add">

<b>let </b><font color="Maroon">C</font> be   <a href="struct_0.html#NM2">Subset</a> of <font color="Maroon">T</font>;<br/>

<b>reconsider </b><font color="Maroon">C1</font> = <font color="Maroon">C</font> as   <a href="struct_0.html#NM2">Subset</a> of <font color="Maroon">T</font> ;<br/>
<b>assume </b><a NAME="E2:115_1_2_1"/><i><font color="Green">E36</font></i>: 
<font color="Maroon">C</font> <a href="hidden.html#R2">in</a> <font color="Maroon">F</font>
 ;<br/>

<a NAME="E3:115_1_2_1"/><b>then </b>
<font color="Maroon">C1</font> is <a href="tops_1.html#V6">open_condensed</a>
 
<b>by </b><i>, <a class="ref" href="tdlat_2.html#T15" target="_self">Th15</a></i>;<br/>
<a NAME="E4:115_1_2_1"/><b>then </b>
<font color="Maroon">C</font> <a href="hidden.html#R2">in</a> <span class="p1">{<span class="default"> <font color="Olive">P</font> where <font color="Olive">P</font> is   <a href="struct_0.html#NM2">Subset</a> of <font color="Maroon">T</font> : <font color="Olive">P</font> is <a href="tops_1.html#V6">open_condensed</a> </span>}</span> 
 
;<br/>
<a NAME="E5:115_1_2_1"/><b>then </b><i><font color="Green">E38</font></i>: 
<font color="Maroon">C</font> <a href="hidden.html#R2">in</a>  <a href="tdlat_1.html#K9">Open_Domains_of</a> <font color="Maroon">T</font>
 
<b>by </b><i><a class="ref" href="tdlat_1.html#D9">TDLAT_1:def 9</a></i>;<br/>
<b>then reconsider </b><font color="Maroon">c</font> = <font color="Maroon">C</font> as   <a href="struct_0.html#NM1">Element</a> of <span class="p1">(<span class="default"><a href="tdlat_1.html#K12">Open_Domains_Lattice</a> <font color="Maroon">T</font></span>)</span> <b>by </b><i/>;<br/>
<a NAME="E7:115_1_2_1"/>
<font color="Maroon">b</font> <a href="lattices.html#R1">[=</a> <font color="Maroon">c</font>
 
<b>by </b><i>, , , <a class="ref" href="lattice3.html#D16">LATTICE3:def 16</a></i>;<br/>
<b>hence </b><a NAME="E8:115_1_2_1"/>
<font color="Maroon">B</font> <a href="tarski.html#R1">c=</a> <font color="Maroon">C</font>
 <b>by </b><i>, </i>;<br/>


</div><b>end;</b></div>
<a NAME="E7:115_1_2"/><b>then </b>
<font color="Maroon">B</font> <a href="tarski.html#R1">c=</a>  <a href="tops_1.html#K1">Int</a> <span class="p1">(<span class="default"><a href="setfam_1.html#K6">meet</a> <font color="Maroon">F</font></span>)</span>
 
<b>by </b><i>, , , </i>;<br/>
<b>hence </b><a NAME="E8:115_1_2"/>
<font color="Maroon">b</font> <a href="lattices.html#R1">[=</a> <font color="Maroon">a</font>
 <b>by </b><i>, </i>;<br/>


</div><b>end;</b></div>
<a NAME="E8:115_1"/>
 <a href="tdlat_1.html#K12">Open_Domains_Lattice</a> <font color="Maroon">T</font> is <a href="lattice3.html#V4">complete</a>
 
<b>by </b><i/>;<br/>
<b>hence </b><a NAME="E9:115_1"/>
 <a href="lattice3.html#K16">"/\"</a> <font color="Maroon">X</font>,<span class="p1">(<span class="default"><a href="tdlat_1.html#K12">Open_Domains_Lattice</a> <font color="Maroon">T</font></span>)</span> <a href="hidden.html#R1">=</a>  <a href="tops_1.html#K1">Int</a> <span class="p1">(<span class="default"><a href="setfam_1.html#K6">meet</a> <font color="Maroon">F</font></span>)</span>
 <b>by </b><i>, , <a class="ref" href="lattice3.html#T34">LATTICE3:34</a></i>;<br/>


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

<b>thus </b><a NAME="E4:115"/>
( <font color="Maroon">X</font> <a href="hidden.html#R1">=</a>  <a href="xboole_0.html#K1">{}</a>  implies  <a href="lattice3.html#K16">"/\"</a> <font color="Maroon">X</font>,<span class="p1">(<span class="default"><a href="tdlat_1.html#K12">Open_Domains_Lattice</a> <font color="Maroon">T</font></span>)</span> <a href="hidden.html#R1">=</a>  <a href="pre_topc.html#K2">[#]</a> <font color="Maroon">T</font> )
 <div><a class="txt" onclick="hs2(this)" href="javascript:()" title="115_2"><b>proof </b></a><div class="add">

<b>assume </b><a NAME="E1:115_2"/><i><font color="Green">E39</font></i>: 
<font color="Maroon">X</font> <a href="hidden.html#R1">=</a>  <a href="xboole_0.html#K1">{}</a> 
 ;<br/>

<b>set </b><font color="Maroon">A</font> =  <a href="pre_topc.html#K2">[#]</a> <font color="Maroon">T</font>;<br/>
<a NAME="E2:115_2"/>
 <a href="pre_topc.html#K2">[#]</a> <font color="Maroon">T</font> is <a href="tops_1.html#V6">open_condensed</a>
 
<b>by </b><i><a class="ref" href="tdlat_1.html#T21">TDLAT_1:21</a></i>;<br/>
<a NAME="E3:115_2"/><b>then </b>
 <a href="pre_topc.html#K2">[#]</a> <font color="Maroon">T</font> <a href="hidden.html#R2">in</a> <span class="p1">{<span class="default"> <font color="Olive">C</font> where <font color="Olive">C</font> is   <a href="struct_0.html#NM2">Subset</a> of <font color="Maroon">T</font> : <font color="Olive">C</font> is <a href="tops_1.html#V6">open_condensed</a> </span>}</span> 
 
;<br/>
<a NAME="E4:115_2"/><b>then </b><i><font color="Green">E68</font></i>: 
 <a href="pre_topc.html#K2">[#]</a> <font color="Maroon">T</font> <a href="hidden.html#R2">in</a>  <a href="tdlat_1.html#K9">Open_Domains_of</a> <font color="Maroon">T</font>
 
<b>by </b><i><a class="ref" href="tdlat_1.html#D9">TDLAT_1:def 9</a></i>;<br/>
<b>then reconsider </b><font color="Maroon">a</font> =  <a href="pre_topc.html#K2">[#]</a> <font color="Maroon">T</font> as   <a href="struct_0.html#NM1">Element</a> of <span class="p1">(<span class="default"><a href="tdlat_1.html#K12">Open_Domains_Lattice</a> <font color="Maroon">T</font></span>)</span> <b>by </b><i/>;<br/>
<a NAME="E6:115_2"/><i><font color="Green">E70</font></i>: 
<font color="Maroon">a</font> <a href="lattice3.html#R3">is_less_than</a> <font color="Maroon">X</font>
 
<div><a class="txt" onclick="hs2(this)" href="javascript:()" title="115_2_1"><b>proof </b></a><div class="add">

<b>let </b><font color="Maroon">b</font> be   <a href="struct_0.html#NM1">Element</a> of <span class="p1">(<span class="default"><a href="tdlat_1.html#K12">Open_Domains_Lattice</a> <font color="Maroon">T</font></span>)</span>; <i><font color="Red">:: according to </font></i><a class="ref" href="lattice3.html#D16">LATTICE3:def 16</a><br/>

<b>assume </b><a NAME="E1:115_2_1"/>
<font color="Maroon">b</font> <a href="hidden.html#R2">in</a> <font color="Maroon">X</font>
 ;<br/>

<b>hence </b><a NAME="E2:115_2_1"/>
<font color="Maroon">a</font> <a href="lattices.html#R1">[=</a> <font color="Maroon">b</font>
 <b>by </b><i/>;<br/>


</div><b>end;</b></div>
<a NAME="E7:115_2"/><i><font color="Green">E71</font></i>: 
for <font color="Olive">b</font> being  <a href="struct_0.html#NM1">Element</a> of <span class="p1">(<span class="default"><a href="tdlat_1.html#K12">Open_Domains_Lattice</a> <font color="Maroon">T</font></span>)</span>  st <font color="Olive">b</font> <a href="lattice3.html#R3">is_less_than</a> <font color="Maroon">X</font> holds <br/><font color="Olive">b</font> <a href="lattices.html#R1">[=</a> <font color="Maroon">a</font>
 
<div><a class="txt" onclick="hs2(this)" href="javascript:()" title="115_2_2"><b>proof </b></a><div class="add">

<b>let </b><font color="Maroon">b</font> be   <a href="struct_0.html#NM1">Element</a> of <span class="p1">(<span class="default"><a href="tdlat_1.html#K12">Open_Domains_Lattice</a> <font color="Maroon">T</font></span>)</span>;<br/>

<b>reconsider </b><font color="Maroon">B</font> = <font color="Maroon">b</font> as    <a href="subset_1.html#M2">Element</a> of  <a href="tdlat_1.html#K9">Open_Domains_of</a> <font color="Maroon">T</font> <b>by </b><i/>;<br/>
<b>assume </b><a NAME="E2:115_2_2"/>
<font color="Maroon">b</font> <a href="lattice3.html#R3">is_less_than</a> <font color="Maroon">X</font>
 ;<br/>

<a NAME="E3:115_2_2"/>
<font color="Maroon">B</font> <a href="tarski.html#R1">c=</a>  <a href="pre_topc.html#K2">[#]</a> <font color="Maroon">T</font>
 
<b>by </b><i><a class="ref" href="pre_topc.html#T14">PRE_TOPC:14</a></i>;<br/>
<b>hence </b><a NAME="E4:115_2_2"/>
<font color="Maroon">b</font> <a href="lattices.html#R1">[=</a> <font color="Maroon">a</font>
 <b>by </b><i>, <a class="txt" href="tdlat_2.html#E4:115_2"><i><font color="Green">E68</font></i></a></i>;<br/>


</div><b>end;</b></div>
<a NAME="E8:115_2"/>
 <a href="tdlat_1.html#K12">Open_Domains_Lattice</a> <font color="Maroon">T</font> is <a href="lattice3.html#V4">complete</a>
 
<b>by </b><i><a class="txt" href="tdlat_2.html#E6:115_2"><i><font color="Green">E70</font></i></a></i>;<br/>
<b>hence </b><a NAME="E9:115_2"/>
 <a href="lattice3.html#K16">"/\"</a> <font color="Maroon">X</font>,<span class="p1">(<span class="default"><a href="tdlat_1.html#K12">Open_Domains_Lattice</a> <font color="Maroon">T</font></span>)</span> <a href="hidden.html#R1">=</a>  <a href="pre_topc.html#K2">[#]</a> <font color="Maroon">T</font>
 <b>by </b><i>, , <a class="ref" href="lattice3.html#T34">LATTICE3:34</a></i>;<br/>


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


</div>
