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<b>let </b><font color="Maroon">X1</font> be   <a href="subset_1.html#NM2">Subset</a> of <a href="cqc_lang.html#K7">CQC-WFF</a> ;<br/><b>let </b><font color="Maroon">X2</font> be   <a href="subset_1.html#NM2">Subset</a> of <a href="cqc_lang.html#K7">CQC-WFF</a> ;<br/><b>let </b><font color="Maroon">Y</font> be   <a href="subset_1.html#NM2">Subset</a> of <a href="cqc_lang.html#K7">CQC-WFF</a> ;<br/>





<b>assume </b><a NAME="E1:28"/>
<font color="Maroon">X1</font> <a href="cqc_the3.html#R4" target="_self">|-|</a> <font color="Maroon">X2</font>
 ;<br/>

<a NAME="E2:28"/><b>then </b>
 <a href="cqc_the1.html#K1">Cn</a> <font color="Maroon">X1</font> <a href="hidden.html#R1">=</a>  <a href="cqc_the1.html#K1">Cn</a> <font color="Maroon">X2</font>
 
<b>by </b><i/>;<br/>
<b>then </b> <a href="cqc_the1.html#K1">Cn</a> <span class="p1">(<span class="default"><font color="Maroon">X1</font> <a href="subset_1.html#K4">\/</a> <font color="Maroon">Y</font></span>)</span> = 
 <a href="cqc_the1.html#K1">Cn</a> <span class="p1">(<span class="default"><span class="p2">(<span class="default"><a href="cqc_the1.html#K1">Cn</a> <font color="Maroon">X2</font></span>)</span> <a href="subset_1.html#K4">\/</a> <span class="p2">(<span class="default"><a href="cqc_the1.html#K1">Cn</a> <font color="Maroon">Y</font></span>)</span></span>)</span>
<b>by </b><i/>
<br/>.= 
 <a href="cqc_the1.html#K1">Cn</a> <span class="p1">(<span class="default"><font color="Maroon">X2</font> <a href="subset_1.html#K4">\/</a> <font color="Maroon">Y</font></span>)</span>
<b>by </b><i/>
;<br/>
<b>hence </b><a NAME="E4:28"/>
<font color="Maroon">X1</font> <a href="subset_1.html#K4">\/</a> <font color="Maroon">Y</font> <a href="cqc_the3.html#R4" target="_self">|-|</a> <font color="Maroon">X2</font> <a href="subset_1.html#K4">\/</a> <font color="Maroon">Y</font>
 <b>by </b><i/>;<br/>


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