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<b>let </b><font color="Maroon">e1</font> be   <a href="struct_0.html#NM1">Element</a> of <font color="Maroon">G</font>, <font color="Maroon">e2</font> be   <a href="struct_0.html#NM1">Element</a> of <font color="Maroon">G</font>;<br/>

<b>assume </b><b>that </b><br/><a NAME="E1:12_1_1"/><i><font color="Green">E46</font></i>: 
for <font color="Olive">h</font> being  <a href="struct_0.html#NM1">Element</a> of <font color="Maroon">G</font> holds <br/> ( <font color="Olive">h</font> <a href="group_1.html#K1" target="_self">*</a> <font color="Maroon">e1</font> <a href="hidden.html#R1">=</a> <font color="Olive">h</font> &amp; <font color="Maroon">e1</font> <a href="group_1.html#K1" target="_self">*</a> <font color="Olive">h</font> <a href="hidden.html#R1">=</a> <font color="Olive">h</font> )
 <b>and </b><br/><a NAME="E2:12_1_1"/><i><font color="Green">E47</font></i>: 
for <font color="Olive">h</font> being  <a href="struct_0.html#NM1">Element</a> of <font color="Maroon">G</font> holds <br/> ( <font color="Olive">h</font> <a href="group_1.html#K1" target="_self">*</a> <font color="Maroon">e2</font> <a href="hidden.html#R1">=</a> <font color="Olive">h</font> &amp; <font color="Maroon">e2</font> <a href="group_1.html#K1" target="_self">*</a> <font color="Olive">h</font> <a href="hidden.html#R1">=</a> <font color="Olive">h</font> )
 ;<br/>

<b>thus </b><font color="Maroon">e1</font> = 
<font color="Maroon">e2</font> <a href="group_1.html#K1" target="_self">*</a> <font color="Maroon">e1</font>
<b>by </b><i/>
<br/>.= 
<font color="Maroon">e2</font>
<b>by </b><i/>
;<br/>


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