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<b>let </b><font color="Maroon">c<sub>1</sub></font>, <font color="Maroon">c<sub>2</sub></font> be   <a href="modal_1.html#NM1">MP-variable</a>;<br/>



<a NAME="E1:54"/><i><font color="Green">E38</font></i>: 
 <a href="xboole_0.html#K1">{}</a>  <a href="hidden.html#R2">in</a>  <a href="trees_1.html#K2">elementary_tree</a> 0
 
<b>by </b><i><a class="ref" href="trees_1.html#T47">TREES_1:47</a></i>;<br/>
<b>assume </b><a NAME="E2:54"/><i><font color="Green">E39</font></i>: 
 <a href="modal_1.html#K16" target="_self">@</a> <font color="Maroon">c<sub>1</sub></font> <a href="hidden.html#R1">=</a>  <a href="modal_1.html#K16" target="_self">@</a> <font color="Maroon">c<sub>2</sub></font>
 ;<br/>

<font color="Maroon">c<sub>1</sub></font> = 
<span class="p1">(<span class="default"><a href="modal_1.html#K16" target="_self">@</a> <font color="Maroon">c<sub>1</sub></font></span>)</span> <a href="funct_1.html#K1">.</a> <a href="xboole_0.html#K1">{}</a> 
<b>by </b><i><a class="txt" href="modal_1.html#E1:54"><i><font color="Green">E38</font></i></a>, <a class="ref" href="funcop_1.html#T13">FUNCOP_1:13</a></i>
<br/>.= 
<font color="Maroon">c<sub>2</sub></font>
<b>by </b><i><a class="txt" href="modal_1.html#E1:54"><i><font color="Green">E38</font></i></a>, <a class="txt" href="modal_1.html#E2:54"><i><font color="Green">E39</font></i></a>, <a class="ref" href="funcop_1.html#T13">FUNCOP_1:13</a></i>
;<br/>
<b>hence </b><a NAME="E4:54"/>
<font color="Maroon">c<sub>1</sub></font> <a href="hidden.html#R1">=</a> <font color="Maroon">c<sub>2</sub></font>
 ;<br/>


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