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<div class="add">

<b>defpred </b><font color="Maroon">S<sub>1</sub></font>[   <a href="subset_1.html#M1">Element</a> of  <a href="unialg_2.html#K9" target="_self">Sub</a> <font color="Maroon">U0</font>,   <a href="subset_1.html#M1">Element</a> of  <a href="unialg_2.html#K9" target="_self">Sub</a> <font color="Maroon">U0</font>,   <a href="subset_1.html#M1">Element</a> of  <a href="unialg_2.html#K9" target="_self">Sub</a> <font color="Maroon">U0</font>] <b>means </b>for <font color="Olive">U1</font>, <font color="Olive">U2</font> being <a href="unialg_1.html#V3">strict</a>  <a href="unialg_2.html#M3" target="_self">SubAlgebra</a> of <font color="Maroon">U0</font>  st <font color="Maroon">a<sub>1</sub></font> <a href="hidden.html#R1">=</a> <font color="Olive">U1</font> &amp; <font color="Maroon">a<sub>2</sub></font> <a href="hidden.html#R1">=</a> <font color="Olive">U2</font> holds <br/><font color="Maroon">a<sub>3</sub></font> <a href="hidden.html#R1">=</a> <font color="Olive">U1</font> <a href="unialg_2.html#K5" target="_self">/\</a> <font color="Olive">U2</font>;<br/>
<a NAME="E1:48_1_1"/><i><font color="Green">E20</font></i>: 
for <font color="Olive">x</font>, <font color="Olive">y</font> being   <a href="subset_1.html#M1">Element</a> of  <a href="unialg_2.html#K9" target="_self">Sub</a> <font color="Maroon">U0</font>  ex <font color="Olive">z</font> being   <a href="subset_1.html#M1">Element</a> of  <a href="unialg_2.html#K9" target="_self">Sub</a> <font color="Maroon">U0</font> st <font color="Maroon">S<sub>1</sub></font>[<font color="Olive">x</font>,<font color="Olive">y</font>,<font color="Olive">z</font>]
 
<div><a class="txt" onclick="hs2(this)" href="javascript:()" title="48_1_1_1"><b>proof </b></a><div class="add">

<b>let </b><font color="Maroon">x</font> be    <a href="subset_1.html#M1">Element</a> of  <a href="unialg_2.html#K9" target="_self">Sub</a> <font color="Maroon">U0</font>, <font color="Maroon">y</font> be    <a href="subset_1.html#M1">Element</a> of  <a href="unialg_2.html#K9" target="_self">Sub</a> <font color="Maroon">U0</font>;<br/>

<b>reconsider </b><font color="Maroon">U1</font> = <font color="Maroon">x</font>, <font color="Maroon">U2</font> = <font color="Maroon">y</font> as  <a href="unialg_1.html#V3">strict</a>  <a href="unialg_2.html#M3" target="_self">SubAlgebra</a> of <font color="Maroon">U0</font> <b>by </b><i/>;<br/>
<b>reconsider </b><font color="Maroon">z</font> = <font color="Maroon">U1</font> <a href="unialg_2.html#K5" target="_self">/\</a> <font color="Maroon">U2</font> as    <a href="subset_1.html#M1">Element</a> of  <a href="unialg_2.html#K9" target="_self">Sub</a> <font color="Maroon">U0</font> <b>by </b><i/>;<br/>
<b>take </b>
<font color="Maroon">z</font>
;<br/>

<b>thus </b><a NAME="E3:48_1_1_1"/>
<font color="Maroon">S<sub>1</sub></font>[<font color="Maroon">x</font>,<font color="Maroon">y</font>,<font color="Maroon">z</font>]
 ;<br/>


</div><b>end;</b></div>
<b>consider </b><font color="Maroon">o</font> being   <a href="binop_1.html#NM2">BinOp</a> of  <a href="unialg_2.html#K9" target="_self">Sub</a> <font color="Maroon">U0</font><b> such that </b><br/><a NAME="E3:48_1_1"/><i><font color="Green">E26</font></i>: 
for <font color="Olive">a</font>, <font color="Olive">b</font> being   <a href="subset_1.html#M1">Element</a> of  <a href="unialg_2.html#K9" target="_self">Sub</a> <font color="Maroon">U0</font> holds  <font color="Maroon">S<sub>1</sub></font>[<font color="Olive">a</font>,<font color="Olive">b</font>,<font color="Maroon">o</font> <a href="binop_1.html#K2">.</a> <font color="Olive">a</font>,<font color="Olive">b</font>]
 <b>from </b><i><a class="ref" href="binop_1.html#S3">BINOP_1:sch 3</a>();<br/></i>
<b>take </b>
<font color="Maroon">o</font>
;<br/>

<b>thus </b><a NAME="E4:48_1_1"/>
for <font color="Olive">x</font>, <font color="Olive">y</font> being   <a href="subset_1.html#M1">Element</a> of  <a href="unialg_2.html#K9" target="_self">Sub</a> <font color="Maroon">U0</font><br/> for <font color="Olive">U1</font>, <font color="Olive">U2</font> being <a href="unialg_1.html#V3">strict</a>  <a href="unialg_2.html#M3" target="_self">SubAlgebra</a> of <font color="Maroon">U0</font>  st <font color="Olive">x</font> <a href="hidden.html#R1">=</a> <font color="Olive">U1</font> &amp; <font color="Olive">y</font> <a href="hidden.html#R1">=</a> <font color="Olive">U2</font> holds <br/><font color="Maroon">o</font> <a href="binop_1.html#K2">.</a> <font color="Olive">x</font>,<font color="Olive">y</font> <a href="hidden.html#R1">=</a> <font color="Olive">U1</font> <a href="unialg_2.html#K5" target="_self">/\</a> <font color="Olive">U2</font>
 <b>by </b><i/>;<br/>


</div>
