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<b>let </b><font color="Maroon">L</font> be  non <a href="struct_0.html#V3">empty</a> <a href="oposet_1.html#V14">PartialOrdered</a>  <a href="oposet_1.html#L1">OrthoRelStr</a> ;<br/>

<b>assume </b><a NAME="E1:10_1_1"/>
<font color="Maroon">L</font> is <a href="oposet_1.html#V19">OrderInvolutive</a>
 ;<br/>

<b>then consider </b><font color="Maroon">f</font> being   <a href="struct_0.html#NM6">Function</a> of <font color="Maroon">L</font>,<font color="Maroon">L</font><b> such that </b><br/><a NAME="E3:10_1_1"/><i><font color="Green">E22</font></i>: 
( <font color="Maroon">f</font> <a href="funct_2.html#R2">=</a> the <a href="robbins1.html#U1">Compl</a> of <font color="Maroon">L</font> &amp; <font color="Maroon">f</font> is <a href="oposet_1.html#V18">Orderinvolutive</a> )
 <b>by </b><i><a class="ref" href="oposet_1.html#D33">OPOSET_1:def 33</a></i>;<br/>
<b>consider </b><font color="Maroon">g</font> being   <a href="struct_0.html#NM6">Function</a> of <font color="Maroon">L</font>,<font color="Maroon">L</font><b> such that </b><br/><a NAME="E5:10_1_1"/><i><font color="Green">E23</font></i>: 
( <font color="Maroon">g</font> <a href="funct_2.html#R2">=</a> <font color="Maroon">f</font> &amp; <font color="Maroon">g</font> is <a href="oposet_1.html#V2">dneg</a> &amp; <font color="Maroon">g</font> is <a href="waybel_0.html#V5">antitone</a> )
 <b>by </b><i>, <a class="ref" href="oposet_1.html#D32">OPOSET_1:def 32</a></i>;<br/>
<b>thus </b><a NAME="E6:10_1_1"/>
<font color="Maroon">L</font> is <a href="oposet_1.html#V3">Dneg</a>
 <b>by </b><i>, , <a class="ref" href="oposet_1.html#D6">OPOSET_1:def 6</a></i>;<br/>


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