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<b>let </b><font color="Maroon">c<sub>2</sub></font> be   <a href="struct_0.html#NM2">Subset</a> of <font color="Maroon">c<sub>1</sub></font>;<br/>

<b>assume </b><a NAME="E1:73_2_1"/>
<font color="Maroon">c<sub>2</sub></font> is <a href="isomichi.html#V2" target="_self">subcondensed</a>
 ;<br/>

<a NAME="E2:73_2_1"/><b>then </b>
 <a href="isomichi.html#K1" target="_self">Border</a> <font color="Maroon">c<sub>2</sub></font> is <a href="xboole_0.html#V1">empty</a>
 
<b>by </b><i><a class="ref" href="isomichi.html#T26" target="_self">Th26</a></i>;<br/>
<b>hence </b><a NAME="E3:73_2_1"/>
<font color="Maroon">c<sub>2</sub></font> is <a href="isomichi.html#V3" target="_self">1st_class</a>
 <b>by </b><i><a class="ref" href="isomichi.html#T47" target="_self">Th47</a></i>;<br/>


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