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<b>let </b><font color="Maroon">x</font> be    <a href="hidden.html#M1">set</a> ;<br/><b>let </b><font color="Maroon">T1</font> be   <a href="trees_2.html#NM4">DecoratedTree</a>;<br/><b>let </b><font color="Maroon">T2</font> be   <a href="trees_2.html#NM4">DecoratedTree</a>;<br/>





<a NAME="E1:8"/>
<font color="Maroon">x</font> <a href="trees_4.html#K6">-tree</a> <font color="Maroon">T1</font>,<font color="Maroon">T2</font> <a href="hidden.html#R1">=</a> <font color="Maroon">x</font> <a href="trees_4.html#K4">-tree</a> <span class="p1"><a href="finseq_1.html#K10">&lt;*</a><span class="default"><font color="Maroon">T1</font>,<font color="Maroon">T2</font></span><a href="finseq_1.html#K10">*&gt;</a></span>
 
<b>by </b><i><a class="ref" href="trees_4.html#D6">TREES_4:def 6</a></i>;<br/>
<b>hence </b><a NAME="E2:8"/>
<span class="p1">(<span class="default"><font color="Maroon">x</font> <a href="trees_4.html#K6">-tree</a> <font color="Maroon">T1</font>,<font color="Maroon">T2</font></span>)</span> <a href="funct_1.html#K1">.</a> <a href="xboole_0.html#K1">{}</a>  <a href="hidden.html#R1">=</a> <font color="Maroon">x</font>
 <b>by </b><i><a class="ref" href="trees_4.html#D4">TREES_4:def 4</a></i>;<br/>


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