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

<b>let </b><font color="Maroon">U0</font> be  <a href="unialg_1.html#V3">strict</a> <a href="unialg_2.html#V2">with_const_op</a> <a href="unialg_1.html#NM2">Universal_Algebra</a>;<br/><b>let </b><font color="Maroon">L</font> be   <a href="struct_0.html#NM2">Subset</a> of <span class="p1">(<span class="default"><a href="unialg_2.html#K12">UnSubAlLattice</a> <font color="Maroon">U0</font></span>)</span>; <i><font color="Red">:: according to </font></i><a class="ref" href="vectsp_8.html#D6">VECTSP_8:def 6</a><br/>



<div><a class="txt" onclick="hsNdiv(this)" href="javascript:()" title="32_1"><b>per </b></a><a class="txt" onclick="hs(this)" href="javascript:()"><b>cases </b></a><span class="hide"><a NAME="E1:32_1"/>
( <font color="Maroon">L</font> <a href="hidden.html#R1">=</a>  <a href="xboole_0.html#K1">{}</a>  or <font color="Maroon">L</font> <a href="hidden.html#NR2" target="_self">&lt;&gt;</a>  <a href="xboole_0.html#K1">{}</a>  )
 </span>;<br/><div class="add"><div><a class="txt" onclick="hsNdiv(this)" href="javascript:()" title="32_1_1"><b>suppose </b></a><a NAME="E1:32_1_1"/><i><font color="Green">E26</font></i>: 
<font color="Maroon">L</font> <a href="hidden.html#R1">=</a>  <a href="xboole_0.html#K1">{}</a> 
 ;<br/><div class="add"><b>thus </b><a NAME="E2:32_1_1"/>
 ex <font color="Olive">b<sub>1</sub></font> being   <a href="subset_1.html#M1">Element</a> of the <a href="struct_0.html#U1">carrier</a> of <span class="p1">(<span class="default"><a href="unialg_2.html#K12">UnSubAlLattice</a> <font color="Maroon">U0</font></span>)</span> st <br/>( <font color="Olive">b<sub>1</sub></font> <a href="lattice3.html#R3">is_less_than</a> <font color="Maroon">L</font> &amp; ( for <font color="Olive">b<sub>2</sub></font> being   <a href="subset_1.html#M1">Element</a> of the <a href="struct_0.html#U1">carrier</a> of <span class="p1">(<span class="default"><a href="unialg_2.html#K12">UnSubAlLattice</a> <font color="Maroon">U0</font></span>)</span>  holds <br/>(  not <font color="Olive">b<sub>2</sub></font> <a href="lattice3.html#R3">is_less_than</a> <font color="Maroon">L</font> or <font color="Olive">b<sub>2</sub></font> <a href="lattices.html#R1">[=</a> <font color="Olive">b<sub>1</sub></font> ) ) )
 <div><a class="txt" onclick="hs2(this)" href="javascript:()" title="32_1_1_1"><b>proof </b></a><div class="add">

<b>take </b>
 <a href="lattices.html#K6">Top</a> <span class="p1">(<span class="default"><a href="unialg_2.html#K12">UnSubAlLattice</a> <font color="Maroon">U0</font></span>)</span>
;<br/>

<b>thus </b><a NAME="E1:32_1_1_1"/>
 <a href="lattices.html#K6">Top</a> <span class="p1">(<span class="default"><a href="unialg_2.html#K12">UnSubAlLattice</a> <font color="Maroon">U0</font></span>)</span> <a href="lattice3.html#R3">is_less_than</a> <font color="Maroon">L</font>
 <div><a class="txt" onclick="hs2(this)" href="javascript:()" title="32_1_1_1_1"><b>proof </b></a><div class="add">

<b>let </b><font color="Maroon">l1</font> be   <a href="struct_0.html#NM1">Element</a> of <span class="p1">(<span class="default"><a href="unialg_2.html#K12">UnSubAlLattice</a> <font color="Maroon">U0</font></span>)</span>; <i><font color="Red">:: according to </font></i><a class="ref" href="lattice3.html#D16">LATTICE3:def 16</a><br/>

<b>thus </b><a NAME="E1:32_1_1_1_1"/>
(  not <font color="Maroon">l1</font> <a href="hidden.html#R2">in</a> <font color="Maroon">L</font> or  <a href="lattices.html#K6">Top</a> <span class="p1">(<span class="default"><a href="unialg_2.html#K12">UnSubAlLattice</a> <font color="Maroon">U0</font></span>)</span> <a href="lattices.html#R1">[=</a> <font color="Maroon">l1</font> )
 <b>by </b><i/>;<br/>


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

<b>let </b><font color="Maroon">l2</font> be   <a href="struct_0.html#NM1">Element</a> of <span class="p1">(<span class="default"><a href="unialg_2.html#K12">UnSubAlLattice</a> <font color="Maroon">U0</font></span>)</span>;<br/>

<b>assume </b><a NAME="E2:32_1_1_1"/>
<font color="Maroon">l2</font> <a href="lattice3.html#R3">is_less_than</a> <font color="Maroon">L</font>
 ;<br/>

<b>thus </b><a NAME="E3:32_1_1_1"/>
<font color="Maroon">l2</font> <a href="lattices.html#R1">[=</a>  <a href="lattices.html#K6">Top</a> <span class="p1">(<span class="default"><a href="unialg_2.html#K12">UnSubAlLattice</a> <font color="Maroon">U0</font></span>)</span>
 <b>by </b><i><a class="ref" href="lattices.html#T45">LATTICES:45</a></i>;<br/>


</div><b>end;</b></div></div><b>end;</b></div><div><a class="txt" onclick="hsNdiv(this)" href="javascript:()" title="32_1_2"><b>suppose </b></a><a NAME="E1:32_1_2"/>
<font color="Maroon">L</font> <a href="hidden.html#NR2" target="_self">&lt;&gt;</a>  <a href="xboole_0.html#K1">{}</a> 
 ;<br/><div class="add"><b>then reconsider </b><font color="Maroon">H</font> = <font color="Maroon">L</font> as  non <a href="xboole_0.html#V1">empty</a> <a href="subset_1.html#NM2">Subset</a> of <span class="p1">(<span class="default"><a href="unialg_3.html#K1" target="_self">Sub</a> <font color="Maroon">U0</font></span>)</span> ;<br/><b>reconsider </b><font color="Maroon">l1</font> =  <a href="unialg_3.html#K7" target="_self">meet</a> <font color="Maroon">H</font> as   <a href="struct_0.html#NM1">Element</a> of <span class="p1">(<span class="default"><a href="unialg_2.html#K12">UnSubAlLattice</a> <font color="Maroon">U0</font></span>)</span> <b>by </b><i><a class="ref" href="unialg_2.html#D15">UNIALG_2:def 15</a></i>;<br/><b>take </b>
<font color="Maroon">l1</font>
;<br/><b>thus </b><a NAME="E4:32_1_2"/>
<font color="Maroon">l1</font> <a href="lattice3.html#R3">is_less_than</a> <font color="Maroon">L</font>
 <div><a class="txt" onclick="hs2(this)" href="javascript:()" title="32_1_2_1"><b>proof </b></a><div class="add">

<b>let </b><font color="Maroon">l2</font> be   <a href="struct_0.html#NM1">Element</a> of <span class="p1">(<span class="default"><a href="unialg_2.html#K12">UnSubAlLattice</a> <font color="Maroon">U0</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">U1</font> = <font color="Maroon">l2</font> as  <a href="unialg_1.html#V3">strict</a>  <a href="unialg_2.html#M3">SubAlgebra</a> of <font color="Maroon">U0</font> <b>by </b><i><a class="ref" href="unialg_2.html#D15">UNIALG_2:def 15</a></i>;<br/>
<b>reconsider </b><font color="Maroon">u</font> = <font color="Maroon">l2</font> as    <a href="unialg_3.html#M2" target="_self">Element</a> of  <a href="unialg_3.html#K1" target="_self">Sub</a> <font color="Maroon">U0</font> ;<br/>
<a NAME="E3:32_1_2_1"/><i><font color="Green">E35</font></i>: 
<span class="p1">(<span class="default"><a href="unialg_3.html#K6" target="_self">Carr</a> <font color="Maroon">U0</font></span>)</span> <a href="funct_2.html#K3">.</a> <font color="Maroon">u</font> <a href="hidden.html#R1">=</a> the <a href="struct_0.html#U1">carrier</a> of <font color="Maroon">U1</font>
 
<b>by </b><i/>;<br/>
<b>assume </b><a NAME="E4:32_1_2_1"/>
<font color="Maroon">l2</font> <a href="hidden.html#R2">in</a> <font color="Maroon">L</font>
 ;<br/>

<a NAME="E5:32_1_2_1"/><b>then </b>
the <a href="struct_0.html#U1">carrier</a> of <font color="Maroon">U1</font> <a href="hidden.html#R2">in</a> <span class="p1">(<span class="default"><a href="unialg_3.html#K6" target="_self">Carr</a> <font color="Maroon">U0</font></span>)</span> <a href="relset_1.html#K10">.:</a> <font color="Maroon">H</font>
 
<b>by </b><i>, <a class="ref" href="funct_2.html#T43">FUNCT_2:43</a></i>;<br/>
<a NAME="E6:32_1_2_1"/><b>then </b>
 <a href="setfam_1.html#K6">meet</a> <span class="p1">(<span class="default"><span class="p2">(<span class="default"><a href="unialg_3.html#K6" target="_self">Carr</a> <font color="Maroon">U0</font></span>)</span> <a href="relset_1.html#K10">.:</a> <font color="Maroon">H</font></span>)</span> <a href="tarski.html#R1">c=</a> the <a href="struct_0.html#U1">carrier</a> of <font color="Maroon">U1</font>
 
<b>by </b><i><a class="ref" href="setfam_1.html#T4">SETFAM_1:4</a></i>;<br/>
<a NAME="E7:32_1_2_1"/><b>then </b>
the <a href="struct_0.html#U1">carrier</a> of <span class="p1">(<span class="default"><a href="unialg_3.html#K7" target="_self">meet</a> <font color="Maroon">H</font></span>)</span> <a href="tarski.html#R1">c=</a> the <a href="struct_0.html#U1">carrier</a> of <font color="Maroon">U1</font>
 
<b>by </b><i/>;<br/>
<b>hence </b><a NAME="E8:32_1_2_1"/>
<font color="Maroon">l1</font> <a href="lattices.html#R3">[=</a> <font color="Maroon">l2</font>
 <b>by </b><i/>;<br/>


</div><b>end;</b></div><b>let </b><font color="Maroon">l3</font> be   <a href="struct_0.html#NM1">Element</a> of <span class="p1">(<span class="default"><a href="unialg_2.html#K12">UnSubAlLattice</a> <font color="Maroon">U0</font></span>)</span>;<br/><b>assume </b><a NAME="E5:32_1_2"/><i><font color="Green">E37</font></i>: 
<font color="Maroon">l3</font> <a href="lattice3.html#R3">is_less_than</a> <font color="Maroon">L</font>
 ;<br/><b>reconsider </b><font color="Maroon">U1</font> = <font color="Maroon">l3</font> as  <a href="unialg_1.html#V3">strict</a>  <a href="unialg_2.html#M3">SubAlgebra</a> of <font color="Maroon">U0</font> <b>by </b><i><a class="ref" href="unialg_2.html#D15">UNIALG_2:def 15</a></i>;<br/><b>consider </b><font color="Maroon">x</font> being    <a href="subset_1.html#M2">Element</a> of <font color="Maroon">H</font>;<br/><a NAME="E8:32_1_2"/><i><font color="Green">E46</font></i>: 
<span class="p1">(<span class="default"><a href="unialg_3.html#K6" target="_self">Carr</a> <font color="Maroon">U0</font></span>)</span> <a href="funct_2.html#K3">.</a> <font color="Maroon">x</font> <a href="hidden.html#R2">in</a> <span class="p1">(<span class="default"><a href="unialg_3.html#K6" target="_self">Carr</a> <font color="Maroon">U0</font></span>)</span> <a href="relset_1.html#K10">.:</a> <font color="Maroon">L</font>
 <b>by </b><i><a class="ref" href="funct_2.html#T43">FUNCT_2:43</a></i>;<br/><a NAME="E9:32_1_2"/>
for <font color="Olive">A</font> being   <a href="hidden.html#M1">set</a>   st <font color="Olive">A</font> <a href="hidden.html#R2">in</a> <span class="p1">(<span class="default"><a href="unialg_3.html#K6" target="_self">Carr</a> <font color="Maroon">U0</font></span>)</span> <a href="relset_1.html#K10">.:</a> <font color="Maroon">H</font> holds <br/>the <a href="struct_0.html#U1">carrier</a> of <font color="Maroon">U1</font> <a href="tarski.html#R1">c=</a> <font color="Olive">A</font>
 <div><a class="txt" onclick="hs2(this)" href="javascript:()" title="32_1_2_2"><b>proof </b></a><div class="add">

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

<b>assume </b><a NAME="E1:32_1_2_2"/><i><font color="Green">E47</font></i>: 
<font color="Maroon">A</font> <a href="hidden.html#R2">in</a> <span class="p1">(<span class="default"><a href="unialg_3.html#K6" target="_self">Carr</a> <font color="Maroon">U0</font></span>)</span> <a href="relset_1.html#K10">.:</a> <font color="Maroon">H</font>
 ;<br/>

<b>then reconsider </b><font color="Maroon">H1</font> = <font color="Maroon">A</font> as   <a href="struct_0.html#NM2">Subset</a> of <font color="Maroon">U0</font> ;<br/>
<b>consider </b><font color="Maroon">l4</font> being    <a href="unialg_3.html#M2" target="_self">Element</a> of  <a href="unialg_3.html#K1" target="_self">Sub</a> <font color="Maroon">U0</font><b> such that </b><br/><a NAME="E4:32_1_2_2"/><i><font color="Green">E48</font></i>: 
( <font color="Maroon">l4</font> <a href="hidden.html#R2">in</a> <font color="Maroon">H</font> &amp; <font color="Maroon">H1</font> <a href="hidden.html#R1">=</a> <span class="p1">(<span class="default"><a href="unialg_3.html#K6" target="_self">Carr</a> <font color="Maroon">U0</font></span>)</span> <a href="funct_2.html#K3">.</a> <font color="Maroon">l4</font> )
 <b>by </b><i><a class="ref" href="unialg_3.html#D1" target="_self">Def1</a>, <a class="ref" href="funct_2.html#T116">FUNCT_2:116</a></i>;<br/>
<b>reconsider </b><font color="Maroon">l4</font> = <font color="Maroon">l4</font> as   <a href="struct_0.html#NM1">Element</a> of <span class="p1">(<span class="default"><a href="unialg_2.html#K12">UnSubAlLattice</a> <font color="Maroon">U0</font></span>)</span> ;<br/>
<b>reconsider </b><font color="Maroon">U2</font> = <font color="Maroon">l4</font> as  <a href="unialg_1.html#V3">strict</a>  <a href="unialg_2.html#M3">SubAlgebra</a> of <font color="Maroon">U0</font> <b>by </b><i><a class="ref" href="unialg_2.html#D15">UNIALG_2:def 15</a></i>;<br/>
<a NAME="E7:32_1_2_2"/><i><font color="Green">E51</font></i>: 
<font color="Maroon">A</font> <a href="hidden.html#R1">=</a> the <a href="struct_0.html#U1">carrier</a> of <font color="Maroon">U2</font>
 
<b>by </b><i>, </i>;<br/>
<a NAME="E8:32_1_2_2"/>
<font color="Maroon">l3</font> <a href="lattices.html#R3">[=</a> <font color="Maroon">l4</font>
 
<b>by </b><i>, , <a class="ref" href="lattice3.html#D16">LATTICE3:def 16</a></i>;<br/>
<b>hence </b><a NAME="E9:32_1_2_2"/>
the <a href="struct_0.html#U1">carrier</a> of <font color="Maroon">U1</font> <a href="tarski.html#R1">c=</a> <font color="Maroon">A</font>
 <b>by </b><i>, </i>;<br/>


</div><b>end;</b></div><a NAME="E10:32_1_2"/><b>then </b>
the <a href="struct_0.html#U1">carrier</a> of <font color="Maroon">U1</font> <a href="tarski.html#R1">c=</a>  <a href="setfam_1.html#K6">meet</a> <span class="p1">(<span class="default"><span class="p2">(<span class="default"><a href="unialg_3.html#K6" target="_self">Carr</a> <font color="Maroon">U0</font></span>)</span> <a href="relset_1.html#K10">.:</a> <font color="Maroon">H</font></span>)</span>
 <b>by </b><i>, <a class="ref" href="setfam_1.html#T6">SETFAM_1:6</a></i>;<br/><a NAME="E11:32_1_2"/><b>then </b>
the <a href="struct_0.html#U1">carrier</a> of <font color="Maroon">U1</font> <a href="tarski.html#R1">c=</a> the <a href="struct_0.html#U1">carrier</a> of <span class="p1">(<span class="default"><a href="unialg_3.html#K7" target="_self">meet</a> <font color="Maroon">H</font></span>)</span>
 <b>by </b><i/>;<br/><b>hence </b><a NAME="E12:32_1_2"/>
<font color="Maroon">l3</font> <a href="lattices.html#R3">[=</a> <font color="Maroon">l1</font>
 <b>by </b><i/>;<br/></div><b>end;</b></div></div><b>end;</b></div>

</div>
