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<b>defpred </b><font color="Maroon">S<sub>1</sub></font>[   <a href="hidden.html#M1">set</a> ] <b>means </b>( <font color="Maroon">a<sub>1</sub></font> is    <a href="lattice4.html#M3" target="_self">Field</a> of <font color="Maroon">BL</font> &amp; <font color="Maroon">A</font> <a href="tarski.html#R1">c=</a> <font color="Maroon">a<sub>1</sub></font> );<br/>
<b>consider </b><font color="Maroon">X</font> being    <a href="hidden.html#M1">set</a> <b> such that </b><br/><a NAME="E2:47_1_1"/><i><font color="Green">E25</font></i>: 
for <font color="Olive">Z</font> being   <a href="hidden.html#M1">set</a>  holds <br/> ( <font color="Olive">Z</font> <a href="hidden.html#R2">in</a> <font color="Maroon">X</font> iff ( <font color="Olive">Z</font> <a href="hidden.html#R2">in</a>  <a href="zfmisc_1.html#K1">bool</a> the <a href="struct_0.html#U1">carrier</a> of <font color="Maroon">BL</font> &amp; <font color="Maroon">S<sub>1</sub></font>[<font color="Olive">Z</font>] ) )
 <b>from </b><i><a class="ref" href="xboole_0.html#S1">XBOOLE_0:sch 1</a>();<br/></i>
<b>consider </b><font color="Maroon">x</font> being    <a href="subset_1.html#M2">Element</a> of <font color="Maroon">A</font>;<br/>
<a NAME="E4:47_1_1"/><i><font color="Green">E26</font></i>: 
the <a href="struct_0.html#U1">carrier</a> of <font color="Maroon">BL</font> <a href="tarski.html#R1">c=</a> the <a href="struct_0.html#U1">carrier</a> of <font color="Maroon">BL</font>
 
;<br/>
<b>reconsider </b><font color="Maroon">x</font> = <font color="Maroon">x</font> as   <a href="struct_0.html#NM1">Element</a> of <font color="Maroon">BL</font> ;<br/>
<a NAME="E6:47_1_1"/><i><font color="Green">E27</font></i>: 
( <font color="Maroon">A</font> <a href="tarski.html#R1">c=</a> the <a href="struct_0.html#U1">carrier</a> of <font color="Maroon">BL</font> &amp; the <a href="struct_0.html#U1">carrier</a> of <font color="Maroon">BL</font> is    <a href="lattice4.html#M3" target="_self">Field</a> of <font color="Maroon">BL</font> &amp; the <a href="struct_0.html#U1">carrier</a> of <font color="Maroon">BL</font> <a href="hidden.html#R2">in</a>  <a href="zfmisc_1.html#K1">bool</a> the <a href="struct_0.html#U1">carrier</a> of <font color="Maroon">BL</font> )
 
<b>by </b><i><a class="ref" href="lattice4.html#T7" target="_self">Th7</a>, </i>;<br/>
<a NAME="E7:47_1_1"/><b>then </b><i><font color="Green">E57</font></i>: 
the <a href="struct_0.html#U1">carrier</a> of <font color="Maroon">BL</font> <a href="hidden.html#R2">in</a> <font color="Maroon">X</font>
 
<b>by </b><i/>;<br/>
<a NAME="E8:47_1_1"/><i><font color="Green">E59</font></i>: 
<font color="Maroon">X</font> <a href="hidden.html#NR2" target="_self">&lt;&gt;</a>  <a href="xboole_0.html#K1">{}</a> 
 
<b>by </b><i>, <a class="ref" href="lattice4.html#D2" target="_self">Def2</a></i>;<br/>
<div><a class="txt" onclick="hs2(this)" href="javascript:()" title="47_1_1_1"><b>now </b></a><div class="add"><b>let </b><font color="Maroon">Z</font> be    <a href="hidden.html#M1">set</a> ;<br/><b>assume </b><a NAME="E1:47_1_1_1"/>
<font color="Maroon">Z</font> <a href="hidden.html#R2">in</a> <font color="Maroon">X</font>
 ;<br/><a NAME="E2:47_1_1_1"/><b>then </b>
<font color="Maroon">A</font> <a href="tarski.html#R1">c=</a> <font color="Maroon">Z</font>
 <b>by </b><i/>;<br/><b>hence </b><a NAME="E3:47_1_1_1"/>
<font color="Maroon">x</font> <a href="hidden.html#R2">in</a> <font color="Maroon">Z</font>
 <b>by </b><i><a class="ref" href="tarski.html#D3">TARSKI:def 3</a></i>;<br/></div><b>end;</b></div>
<b>then reconsider </b><font color="Maroon">F1</font> =  <a href="setfam_1.html#K1">meet</a> <font color="Maroon">X</font> as  non <a href="xboole_0.html#V1">empty</a>  <a href="hidden.html#M1">set</a>  <b>by </b><i><a class="ref" href="lattice4.html#T8" target="_self">Th8</a>, <a class="ref" href="setfam_1.html#D1">SETFAM_1:def 1</a></i>;<br/>
<a NAME="E11:47_1_1"/>
<font color="Maroon">F1</font> <a href="tarski.html#R1">c=</a> the <a href="struct_0.html#U1">carrier</a> of <font color="Maroon">BL</font>
 
<div><a class="txt" onclick="hs2(this)" href="javascript:()" title="47_1_1_2"><b>proof </b></a><div class="add">

<b>let </b><font color="Maroon">x</font> be    <a href="hidden.html#M1">set</a> ; <i><font color="Red">:: according to </font></i><a class="ref" href="tarski.html#D3">TARSKI:def 3</a><br/>

<b>thus </b><a NAME="E1:47_1_1_2"/>
(  not <font color="Maroon">x</font> <a href="hidden.html#R2">in</a> <font color="Maroon">F1</font> or <font color="Maroon">x</font> <a href="hidden.html#R2">in</a> the <a href="struct_0.html#U1">carrier</a> of <font color="Maroon">BL</font> )
 <b>by </b><i><a class="ref" href="lattice4.html#D3" target="_self">Def3</a>, <a class="ref" href="setfam_1.html#D1">SETFAM_1:def 1</a></i>;<br/>


</div><b>end;</b></div>
<b>then reconsider </b><font color="Maroon">F1</font> = <font color="Maroon">F1</font> as  non <a href="xboole_0.html#V1">empty</a> <a href="struct_0.html#NM2">Subset</a> of <font color="Maroon">BL</font> ;<br/>
<a NAME="E13:47_1_1"/>
<font color="Maroon">F1</font> is    <a href="lattice4.html#M3" target="_self">Field</a> of <font color="Maroon">BL</font>
 
<div><a class="txt" onclick="hs2(this)" href="javascript:()" title="47_1_1_3"><b>proof </b></a><div class="add">

<b>let </b><font color="Maroon">a</font> be   <a href="struct_0.html#NM1">Element</a> of <font color="Maroon">BL</font>; <i><font color="Red">:: according to </font></i><a class="ref" href="lattice4.html#D14" target="_self">LATTICE4:def 14</a><br/><b>let </b><font color="Maroon">b</font> be   <a href="struct_0.html#NM1">Element</a> of <font color="Maroon">BL</font>;<br/>



<b>assume </b><a NAME="E1:47_1_1_3"/><i><font color="Green">E60</font></i>: 
( <font color="Maroon">a</font> <a href="hidden.html#R2">in</a> <font color="Maroon">F1</font> &amp; <font color="Maroon">b</font> <a href="hidden.html#R2">in</a> <font color="Maroon">F1</font> )
 ;<br/>

<a NAME="E2:47_1_1_3"/><i><font color="Green">E61</font></i>: 
<font color="Maroon">a</font> <a href="lattices.html#K4">"/\"</a> <font color="Maroon">b</font> <a href="hidden.html#R2">in</a> <font color="Maroon">F1</font>
 
<div><a class="txt" onclick="hs2(this)" href="javascript:()" title="47_1_1_3_1"><b>proof </b></a><div class="add">

<a NAME="E1:47_1_1_3_1"/>
for <font color="Olive">Z</font> being   <a href="hidden.html#M1">set</a>   st <font color="Olive">Z</font> <a href="hidden.html#R2">in</a> <font color="Maroon">X</font> holds <br/><font color="Maroon">a</font> <a href="lattices.html#K4">"/\"</a> <font color="Maroon">b</font> <a href="hidden.html#R2">in</a> <font color="Olive">Z</font>
 
<div><a class="txt" onclick="hs2(this)" href="javascript:()" title="47_1_1_3_1_1"><b>proof </b></a><div class="add">

<b>let </b><font color="Maroon">Z</font> be    <a href="hidden.html#M1">set</a> ;<br/>

<b>assume </b><a NAME="E1:47_1_1_3_1_1"/><i><font color="Green">E62</font></i>: 
<font color="Maroon">Z</font> <a href="hidden.html#R2">in</a> <font color="Maroon">X</font>
 ;<br/>

<a NAME="E2:47_1_1_3_1_1"/><b>then </b><i><font color="Green">E63</font></i>: 
<font color="Maroon">Z</font> is    <a href="lattice4.html#M3" target="_self">Field</a> of <font color="Maroon">BL</font>
 
<b>by </b><i/>;<br/>
<a NAME="E3:47_1_1_3_1_1"/>
( <font color="Maroon">a</font> <a href="hidden.html#R2">in</a> <font color="Maroon">Z</font> &amp; <font color="Maroon">b</font> <a href="hidden.html#R2">in</a> <font color="Maroon">Z</font> )
 
<b>by </b><i><a class="ref" href="lattice4.html#T9" target="_self">Th9</a>, <a class="ref" href="lattice4.html#D4" target="_self">Def4</a>, <a class="ref" href="setfam_1.html#D1">SETFAM_1:def 1</a></i>;<br/>
<b>hence </b><a NAME="E4:47_1_1_3_1_1"/>
<font color="Maroon">a</font> <a href="lattices.html#K4">"/\"</a> <font color="Maroon">b</font> <a href="hidden.html#R2">in</a> <font color="Maroon">Z</font>
 <b>by </b><i>, </i>;<br/>


</div><b>end;</b></div>
<b>hence </b><a NAME="E2:47_1_1_3_1"/>
<font color="Maroon">a</font> <a href="lattices.html#K4">"/\"</a> <font color="Maroon">b</font> <a href="hidden.html#R2">in</a> <font color="Maroon">F1</font>
 <b>by </b><i><a class="ref" href="lattice4.html#T8" target="_self">Th8</a>, <a class="ref" href="setfam_1.html#D1">SETFAM_1:def 1</a></i>;<br/>


</div><b>end;</b></div>
<a NAME="E3:47_1_1_3"/>
<font color="Maroon">a</font> <a href="lattices.html#K7">`</a>  <a href="hidden.html#R2">in</a> <font color="Maroon">F1</font>
 
<div><a class="txt" onclick="hs2(this)" href="javascript:()" title="47_1_1_3_2"><b>proof </b></a><div class="add">

<a NAME="E1:47_1_1_3_2"/>
for <font color="Olive">Z</font> being   <a href="hidden.html#M1">set</a>   st <font color="Olive">Z</font> <a href="hidden.html#R2">in</a> <font color="Maroon">X</font> holds <br/><font color="Maroon">a</font> <a href="lattices.html#K7">`</a>  <a href="hidden.html#R2">in</a> <font color="Olive">Z</font>
 
<div><a class="txt" onclick="hs2(this)" href="javascript:()" title="47_1_1_3_2_1"><b>proof </b></a><div class="add">

<b>let </b><font color="Maroon">Z</font> be    <a href="hidden.html#M1">set</a> ;<br/>

<b>assume </b><a NAME="E1:47_1_1_3_2_1"/><i><font color="Green">E64</font></i>: 
<font color="Maroon">Z</font> <a href="hidden.html#R2">in</a> <font color="Maroon">X</font>
 ;<br/>

<a NAME="E2:47_1_1_3_2_1"/><b>then </b><i><font color="Green">E65</font></i>: 
<font color="Maroon">Z</font> is    <a href="lattice4.html#M3" target="_self">Field</a> of <font color="Maroon">BL</font>
 
<b>by </b><i/>;<br/>
<a NAME="E3:47_1_1_3_2_1"/>
<font color="Maroon">a</font> <a href="hidden.html#R2">in</a> <font color="Maroon">Z</font>
 
<b>by </b><i><a class="ref" href="lattice4.html#T9" target="_self">Th9</a>, <a class="ref" href="lattice4.html#D4" target="_self">Def4</a>, <a class="ref" href="setfam_1.html#D1">SETFAM_1:def 1</a></i>;<br/>
<b>hence </b><a NAME="E4:47_1_1_3_2_1"/>
<font color="Maroon">a</font> <a href="lattices.html#K7">`</a>  <a href="hidden.html#R2">in</a> <font color="Maroon">Z</font>
 <b>by </b><i>, </i>;<br/>


</div><b>end;</b></div>
<b>hence </b><a NAME="E2:47_1_1_3_2"/>
<font color="Maroon">a</font> <a href="lattices.html#K7">`</a>  <a href="hidden.html#R2">in</a> <font color="Maroon">F1</font>
 <b>by </b><i><a class="ref" href="lattice4.html#T8" target="_self">Th8</a>, <a class="ref" href="setfam_1.html#D1">SETFAM_1:def 1</a></i>;<br/>


</div><b>end;</b></div>
<b>hence </b><a NAME="E4:47_1_1_3"/>
( <font color="Maroon">a</font> <a href="lattices.html#K4">"/\"</a> <font color="Maroon">b</font> <a href="hidden.html#R2">in</a> <font color="Maroon">F1</font> &amp; <font color="Maroon">a</font> <a href="lattices.html#K7">`</a>  <a href="hidden.html#R2">in</a> <font color="Maroon">F1</font> )
 <b>by </b><i/>;<br/>


</div><b>end;</b></div>
<b>then reconsider </b><font color="Maroon">F</font> = <font color="Maroon">F1</font> as    <a href="lattice4.html#M3" target="_self">Field</a> of <font color="Maroon">BL</font> ;<br/>
<b>take </b>
<font color="Maroon">F</font>
;<br/>

<a NAME="E15:47_1_1"/>
for <font color="Olive">Z</font> being   <a href="hidden.html#M1">set</a>   st <font color="Olive">Z</font> <a href="hidden.html#R2">in</a> <font color="Maroon">X</font> holds <br/><font color="Maroon">A</font> <a href="tarski.html#R1">c=</a> <font color="Olive">Z</font>
 
<b>by </b><i/>;<br/>
<b>hence </b><a NAME="E16:47_1_1"/>
<font color="Maroon">A</font> <a href="tarski.html#R1">c=</a> <font color="Maroon">F</font>
 <b>by </b><i><a class="ref" href="lattice4.html#D3" target="_self">Def3</a>, <a class="ref" href="setfam_1.html#T6">SETFAM_1:6</a></i>;<br/>

<b>let </b><font color="Maroon">H</font> be    <a href="lattice4.html#M3" target="_self">Field</a> of <font color="Maroon">BL</font>;<br/>

<b>assume </b><a NAME="E17:47_1_1"/>
<font color="Maroon">A</font> <a href="tarski.html#R1">c=</a> <font color="Maroon">H</font>
 ;<br/>

<a NAME="E18:47_1_1"/><b>then </b>
<font color="Maroon">H</font> <a href="hidden.html#R2">in</a> <font color="Maroon">X</font>
 
<b>by </b><i/>;<br/>
<b>hence </b><a NAME="E19:47_1_1"/>
<font color="Maroon">F</font> <a href="tarski.html#R1">c=</a> <font color="Maroon">H</font>
 <b>by </b><i><a class="ref" href="setfam_1.html#T4">SETFAM_1:4</a></i>;<br/>


</div>
