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<b>let </b><font color="Maroon">c<sub>1</sub></font> be  non <a href="struct_0.html#V3">empty</a>  <a href="prelamb.html#L1" target="_self">typealg</a> ;<br/><b>let </b><font color="Maroon">c<sub>2</sub></font> be    <a href="prelamb.html#M1" target="_self">Proof</a> of <font color="Maroon">c<sub>1</sub></font>;<br/><b>let </b><font color="Maroon">c<sub>3</sub></font> be    <a href="trees_1.html#M1">Element</a> of  <a href="relat_1.html#K1">dom</a> <font color="Maroon">c<sub>2</sub></font>;<br/>





<a NAME="E1:28"/>
<font color="Maroon">c<sub>3</sub></font> is <a href="prelamb.html#V2" target="_self">correct</a>
 
<b>by </b><i><a class="ref" href="prelamb.html#D13" target="_self">Def13</a></i>;<br/>
<b>hence </b><a NAME="E2:28"/>
( <span class="p1">(<span class="default"><font color="Maroon">c<sub>2</sub></font> <a href="trees_2.html#K3">.</a> <font color="Maroon">c<sub>3</sub></font></span>)</span> <a href="mcart_1.html#K2">`2</a>  <a href="hidden.html#R1">=</a> 0 or <span class="p1">(<span class="default"><font color="Maroon">c<sub>2</sub></font> <a href="trees_2.html#K3">.</a> <font color="Maroon">c<sub>3</sub></font></span>)</span> <a href="mcart_1.html#K2">`2</a>  <a href="hidden.html#R1">=</a> 1 or <span class="p1">(<span class="default"><font color="Maroon">c<sub>2</sub></font> <a href="trees_2.html#K3">.</a> <font color="Maroon">c<sub>3</sub></font></span>)</span> <a href="mcart_1.html#K2">`2</a>  <a href="hidden.html#R1">=</a> 2 or <span class="p1">(<span class="default"><font color="Maroon">c<sub>2</sub></font> <a href="trees_2.html#K3">.</a> <font color="Maroon">c<sub>3</sub></font></span>)</span> <a href="mcart_1.html#K2">`2</a>  <a href="hidden.html#R1">=</a> 3 or <span class="p1">(<span class="default"><font color="Maroon">c<sub>2</sub></font> <a href="trees_2.html#K3">.</a> <font color="Maroon">c<sub>3</sub></font></span>)</span> <a href="mcart_1.html#K2">`2</a>  <a href="hidden.html#R1">=</a> 4 or <span class="p1">(<span class="default"><font color="Maroon">c<sub>2</sub></font> <a href="trees_2.html#K3">.</a> <font color="Maroon">c<sub>3</sub></font></span>)</span> <a href="mcart_1.html#K2">`2</a>  <a href="hidden.html#R1">=</a> 5 or <span class="p1">(<span class="default"><font color="Maroon">c<sub>2</sub></font> <a href="trees_2.html#K3">.</a> <font color="Maroon">c<sub>3</sub></font></span>)</span> <a href="mcart_1.html#K2">`2</a>  <a href="hidden.html#R1">=</a> 6 or <span class="p1">(<span class="default"><font color="Maroon">c<sub>2</sub></font> <a href="trees_2.html#K3">.</a> <font color="Maroon">c<sub>3</sub></font></span>)</span> <a href="mcart_1.html#K2">`2</a>  <a href="hidden.html#R1">=</a> 7 )
 <b>by </b><i><a class="ref" href="prelamb.html#D5" target="_self">Def5</a></i>;<br/>


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