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<b>let </b><font color="Maroon" title="c2">A1</font>, <font color="Maroon" title="c3">A2</font> be    <a href="hidden.html#M1" title="HIDDEN:mode.1">set</a> ;<br/>

<b>assume </b><b>that </b><br/><a NAME="E1:52_1_2"/><i><font color="Green" title="E26">D4</font></i>: 
for <font color="Olive" title="b1">x</font> being   <a href="hidden.html#M1" title="HIDDEN:mode.1">set</a>  holds <br/> ( <font color="Olive" title="b1">x</font> <a href="hidden.html#R2" title="HIDDEN:pred.2">in</a> <font color="Maroon" title="c2">A1</font> iff  ex <font color="Olive" title="b2">I</font> being   <a href="bcialg_1.html#M2" title="BCIALG_1:mode.2">Ideal</a> of <font color="Maroon" title="c1">X</font> st <font color="Olive" title="b1">x</font> is    <a href="bcialg_2.html#M4" title="BCIALG_2:mode.4">I-congruence</a> of <font color="Maroon" title="c1">X</font>,<font color="Olive" title="b2">I</font> )
 <b>and </b><br/><a NAME="E2:52_1_2"/><i><font color="Green" title="E27">D5</font></i>: 
for <font color="Olive" title="b1">x</font> being   <a href="hidden.html#M1" title="HIDDEN:mode.1">set</a>  holds <br/> ( <font color="Olive" title="b1">x</font> <a href="hidden.html#R2" title="HIDDEN:pred.2">in</a> <font color="Maroon" title="c3">A2</font> iff  ex <font color="Olive" title="b2">I</font> being   <a href="bcialg_1.html#M2" title="BCIALG_1:mode.2">Ideal</a> of <font color="Maroon" title="c1">X</font> st <font color="Olive" title="b1">x</font> is    <a href="bcialg_2.html#M4" title="BCIALG_2:mode.4">I-congruence</a> of <font color="Maroon" title="c1">X</font>,<font color="Olive" title="b2">I</font> )
 ;<br/>

<b>defpred </b><font color="Maroon">S<sub>1</sub></font>[   <a href="hidden.html#M1" title="HIDDEN:mode.1">set</a> ] <b>means </b> ex <font color="Olive" title="b1">I</font> being   <a href="bcialg_1.html#M2" title="BCIALG_1:mode.2">Ideal</a> of <font color="Maroon" title="c1">X</font> st $1 is    <a href="bcialg_2.html#M4" title="BCIALG_2:mode.4">I-congruence</a> of <font color="Maroon" title="c1">X</font>,<font color="Olive" title="b1">I</font>;<br/>
<a NAME="E3:52_1_2"/><i><font color="Green" title="E28">D6</font></i>: 
for <font color="Olive" title="b1">x</font> being   <a href="hidden.html#M1" title="HIDDEN:mode.1">set</a>  holds <br/> ( <font color="Olive" title="b1">x</font> <a href="hidden.html#R2" title="HIDDEN:pred.2">in</a> <font color="Maroon" title="c2">A1</font> iff <font color="Maroon">S<sub>1</sub></font>[<font color="Olive" title="b1">x</font>] )
 
<b>by </b><i><a class="txt" href="bcialg_2.html#E1:52_1_2"><i><font color="Green" title="E26">D4</font></i></a></i>;<br/>
<a NAME="E4:52_1_2"/><i><font color="Green" title="E29">D7</font></i>: 
for <font color="Olive" title="b1">x</font> being   <a href="hidden.html#M1" title="HIDDEN:mode.1">set</a>  holds <br/> ( <font color="Olive" title="b1">x</font> <a href="hidden.html#R2" title="HIDDEN:pred.2">in</a> <font color="Maroon" title="c3">A2</font> iff <font color="Maroon">S<sub>1</sub></font>[<font color="Olive" title="b1">x</font>] )
 
<b>by </b><i><a class="txt" href="bcialg_2.html#E2:52_1_2"><i><font color="Green" title="E27">D5</font></i></a></i>;<br/>
<a NAME="E5:52_1_2"/>
<font color="Maroon" title="c2">A1</font> <a href="hidden.html#R1" title="HIDDEN:pred.1">=</a> <font color="Maroon" title="c3">A2</font>
 
<b>from </b><i><a class="ref" href="xboole_0.html#S2" title="XBOOLE_0:sch.2">XBOOLE_0:sch 2</a>(<a class="txt" href="bcialg_2.html#E3:52_1_2"><i><font color="Green" title="E28">D6</font></i></a>, <a class="txt" href="bcialg_2.html#E4:52_1_2"><i><font color="Green" title="E29">D7</font></i></a>);<br/></i>
<b>hence </b><a NAME="E6:52_1_2"/>
<font color="Maroon" title="c2">A1</font> <a href="hidden.html#R1" title="HIDDEN:pred.1">=</a> <font color="Maroon" title="c3">A2</font>
 ;<br/>


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