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<b>consider </b><font color="Maroon">x</font> being   <a href="struct_0.html#NM1">Element</a> of <font color="Maroon">L</font>;<br/>
<b>take </b>
 <a href="waybel_0.html#K6" target="_self">uparrow</a> <font color="Maroon">x</font>
;<br/>

<b>thus </b><a NAME="E2:65_2_1"/>
( not  <a href="waybel_0.html#K6" target="_self">uparrow</a> <font color="Maroon">x</font> is <a href="xboole_0.html#V1">empty</a> &amp;  <a href="waybel_0.html#K6" target="_self">uparrow</a> <font color="Maroon">x</font> is <a href="waybel_0.html#V13" target="_self">upper</a> &amp;  <a href="waybel_0.html#K6" target="_self">uparrow</a> <font color="Maroon">x</font> is <a href="waybel_0.html#V2" target="_self">filtered</a> )
 ;<br/>


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