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<b>let </b><font color="Maroon">c<sub>1</sub></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">c<sub>2</sub></font>, <font color="Maroon">c<sub>3</sub></font>, <font color="Maroon">c<sub>4</sub></font> be    <a href="filerec1.html#NM1" target="_self">File</a> of <font color="Maroon">c<sub>1</sub></font>;<br/>



<b>assume </b><a NAME="E1:45"/>
<font color="Maroon">c<sub>4</sub></font> <a href="filerec1.html#R1" target="_self">is_a_record_of</a> <font color="Maroon">c<sub>2</sub></font>,<font color="Maroon">c<sub>3</sub></font>
 ;<br/>

<a NAME="E2:45"/><b>then </b>
( <font color="Maroon">c<sub>4</sub></font> <a href="finseq_8.html#NR3" target="_self">is_preposition_of</a>  &amp; <font color="Maroon">c<sub>4</sub></font> <a href="finseq_8.html#R5">is_terminated_by</a> <font color="Maroon">c<sub>3</sub></font> )
 
<b>by </b><i><a class="ref" href="filerec1.html#D1" target="_self">Def1</a></i>;<br/>
<a NAME="E3:45"/><b>then </b>
(  <a href="finseq_8.html#K8">addcr</a> <font color="Maroon">c<sub>4</sub></font>,<font color="Maroon">c<sub>3</sub></font> <a href="finseq_8.html#NR3" target="_self">is_preposition_of</a>  &amp; <font color="Maroon">c<sub>4</sub></font> <a href="finseq_8.html#R5">is_terminated_by</a> <font color="Maroon">c<sub>3</sub></font> )
 
<b>by </b><i><a class="ref" href="filerec1.html#T29" target="_self">Th29</a></i>;<br/>
<b>hence </b><a NAME="E4:45"/>
<font color="Maroon">c<sub>4</sub></font> <a href="filerec1.html#R1" target="_self">is_a_record_of</a> <font color="Maroon">c<sub>4</sub></font>,<font color="Maroon">c<sub>3</sub></font>
 <b>by </b><i><a class="ref" href="filerec1.html#D1" target="_self">Def1</a></i>;<br/>


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