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<b>let </b><font color="Maroon">D</font> be  non <a href="xboole_0.html#V1">empty</a>  <a href="hidden.html#M1">set</a> ;<br/><b>let </b><font color="Maroon">f</font> be    <a href="finseq_1.html#M2">FinSequence</a> of <font color="Maroon">D</font>, <font color="Maroon">g</font> be    <a href="finseq_1.html#M2">FinSequence</a> of <font color="Maroon">D</font>;<br/>



<b>assume </b><a NAME="E1:34"/>
<font color="Maroon">g</font> <a href="finseq_8.html#R4" target="_self">is_postposition_of</a> <font color="Maroon">f</font>
 ;<br/>

<a NAME="E2:34"/><b>then </b><i><font color="Green">E17</font></i>: 
 <a href="finseq_5.html#K4">Rev</a> <font color="Maroon">f</font> <a href="finseq_8.html#NR3" target="_self">is_preposition_of</a> 
 
<b>by </b><i><a class="txt" href="finseq_8.html#E2:34"><i><font color="Green">E17</font></i></a></i>;<br/>
<a NAME="E3:34"/><i><font color="Green">E18</font></i>: 
 <a href="finseq_1.html#K3">len</a> <span class="p1">(<span class="default"><a href="finseq_5.html#K4">Rev</a> <font color="Maroon">g</font></span>)</span> <a href="hidden.html#R1">=</a>  <a href="finseq_1.html#K3">len</a> <font color="Maroon">g</font>
 
<b>by </b><i><a class="ref" href="finseq_5.html#D3">FINSEQ_5:def 3</a></i>;<br/>
<a NAME="E4:34"/>
 <a href="finseq_1.html#K3">len</a> <span class="p1">(<span class="default"><a href="finseq_5.html#K4">Rev</a> <font color="Maroon">f</font></span>)</span> <a href="hidden.html#R1">=</a>  <a href="finseq_1.html#K3">len</a> <font color="Maroon">f</font>
 
<b>by </b><i><a class="ref" href="finseq_5.html#D3">FINSEQ_5:def 3</a></i>;<br/>
<b>hence </b><a NAME="E5:34"/>
 <a href="finseq_1.html#K3">len</a> <font color="Maroon">g</font> <a href="xxreal_0.html#R1">&lt;=</a>  <a href="finseq_1.html#K3">len</a> <font color="Maroon">f</font>
 <b>by </b><i><a class="ref" href="finseq_8.html#T2" target="_self">Th2</a>, , <a class="ref" href="finseq_1.html#T84">FINSEQ_1:84</a></i>;<br/>


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