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<b>let </b><font color="Maroon">E</font> be    <a href="algspec1.html#M2" target="_self">Extension</a> of <font color="Maroon">S</font>;<br/>

<b>consider </b><font color="Maroon">x</font> being   <a href="msualg_1.html#NM2">OperSymbol</a> of <font color="Maroon">S</font>;<br/>
<a NAME="E2:58_1_1"/>
<font color="Maroon">S</font> is    <a href="instalg1.html#M1">Subsignature</a> of <font color="Maroon">E</font>
 
<b>by </b><i/>;<br/>
<a NAME="E3:58_1_1"/><b>then </b>
( <font color="Maroon">x</font> <a href="hidden.html#R2">in</a> the <a href="msualg_1.html#U1">OperSymbols</a> of <font color="Maroon">S</font> &amp; the <a href="msualg_1.html#U1">OperSymbols</a> of <font color="Maroon">S</font> <a href="tarski.html#R1">c=</a> the <a href="msualg_1.html#U1">OperSymbols</a> of <font color="Maroon">E</font> )
 
<b>by </b><i><a class="ref" href="instalg1.html#T11">INSTALG1:11</a></i>;<br/>
<b>hence </b><a NAME="E4:58_1_1"/>
the <a href="msualg_1.html#U1">OperSymbols</a> of <font color="Maroon">E</font> <a href="hidden.html#NR2" target="_self">&lt;&gt;</a>  <a href="xboole_0.html#K1">{}</a> 
 ; <i><font color="Red">:: according to </font></i><a class="ref" href="msualg_1.html#D5">MSUALG_1:def 5</a><br/>


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