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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="hidden.html#M1">set</a> ;<br/><b>let </b><font color="Maroon">c<sub>3</sub></font> be   <a href="finseq_1.html#NM1">FinSequence</a>;<br/>





<b>assume </b><a NAME="E1:28"/><i><font color="Green">E15</font></i>: 
(  <a href="trees_4.html#K1" target="_self">root-tree</a> <font color="Maroon">c<sub>1</sub></font> <a href="hidden.html#R1">=</a> <font color="Maroon">c<sub>2</sub></font> <a href="trees_4.html#K4" target="_self">-tree</a> <font color="Maroon">c<sub>3</sub></font> &amp; <font color="Maroon">c<sub>3</sub></font> is <a href="trees_3.html#V6">DTree-yielding</a> )
 ;<br/>

<b>then reconsider </b><font color="Maroon">c<sub>4</sub></font> = <font color="Maroon">c<sub>3</sub></font> as  <a href="trees_3.html#V6">DTree-yielding</a> <a href="finseq_1.html#NM1">FinSequence</a> ;<br/>
<b>thus </b><font color="Maroon">c<sub>1</sub></font> = 
<span class="p1">(<span class="default"><a href="trees_4.html#K1" target="_self">root-tree</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="ref" href="trees_4.html#T3" target="_self">Th3</a></i>
<br/>.= 
<font color="Maroon">c<sub>2</sub></font>
<b>by </b><i><a class="txt" href="trees_4.html#E1:28"><i><font color="Green">E15</font></i></a>, <a class="ref" href="trees_4.html#D4" target="_self">Def4</a></i>
;<br/>

<a NAME="E4:28"/>
(  <a href="relat_1.html#K1">dom</a> <span class="p1">(<span class="default"><font color="Maroon">c<sub>2</sub></font> <a href="trees_4.html#K4" target="_self">-tree</a> <font color="Maroon">c<sub>3</sub></font></span>)</span> <a href="hidden.html#R1">=</a>  <a href="trees_3.html#K13">tree</a> <span class="p1">(<span class="default"><a href="funct_6.html#K2">doms</a> <font color="Maroon">c<sub>4</sub></font></span>)</span> &amp;  <a href="relat_1.html#K1">dom</a> <span class="p1">(<span class="default"><a href="trees_4.html#K1" target="_self">root-tree</a> <font color="Maroon">c<sub>1</sub></font></span>)</span> <a href="hidden.html#R1">=</a>  <a href="trees_1.html#K2">elementary_tree</a> 0 )
 
<b>by </b><i><a class="ref" href="trees_4.html#T3" target="_self">Th3</a>, <a class="ref" href="trees_4.html#T10" target="_self">Th10</a></i>;<br/>
<a NAME="E5:28"/><b>then </b>
(  <a href="funct_6.html#K2">doms</a> <font color="Maroon">c<sub>3</sub></font> <a href="hidden.html#R1">=</a>  <a href="xboole_0.html#K1">{}</a>  &amp;  <a href="relat_1.html#K1">dom</a> <span class="p1">(<span class="default"><a href="funct_6.html#K2">doms</a> <font color="Maroon">c<sub>3</sub></font></span>)</span> <a href="hidden.html#R1">=</a>  <a href="finseq_1.html#K4">dom</a> <font color="Maroon">c<sub>3</sub></font> &amp;  <a href="finseq_1.html#K4">dom</a> <a href="xboole_0.html#K1">{}</a>  <a href="hidden.html#R1">=</a>  <a href="xboole_0.html#K1">{}</a>  )
 
<b>by </b><i><a class="txt" href="trees_4.html#E1:28"><i><font color="Green">E15</font></i></a>, <a class="ref" href="finseq_1.html#T26">FINSEQ_1:26</a>, <a class="ref" href="trees_3.html#T23">TREES_3:23</a>, <a class="ref" href="trees_3.html#T39">TREES_3:39</a>, <a class="ref" href="trees_3.html#T53">TREES_3:53</a>, <a class="ref" href="trees_3.html#T55">TREES_3:55</a></i>;<br/>
<b>hence </b><a NAME="E6:28"/>
<font color="Maroon">c<sub>3</sub></font> <a href="hidden.html#R1">=</a>  <a href="xboole_0.html#K1">{}</a> 
 <b>by </b><i><a class="ref" href="finseq_1.html#T26">FINSEQ_1:26</a></i>;<br/>


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