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<b>let </b><font color="Maroon">C</font> be  non <a href="struct_0.html#V3">empty</a> <a href="altcat_1.html#V2">transitive</a>  <a href="altcat_1.html#L2">AltCatStr</a> ;<br/><b>let </b><font color="Maroon">D1</font> be  non <a href="struct_0.html#V3">empty</a> <a href="altcat_2.html#V2" target="_self">full</a>  <a href="altcat_2.html#M1" target="_self">SubCatStr</a> of <font color="Maroon">C</font>, <font color="Maroon">D2</font> be  non <a href="struct_0.html#V3">empty</a> <a href="altcat_2.html#V2" target="_self">full</a>  <a href="altcat_2.html#M1" target="_self">SubCatStr</a> of <font color="Maroon">C</font>;<br/>



<b>assume </b><a NAME="E1:68"/><i><font color="Green">E16</font></i>: 
the <a href="struct_0.html#U1">carrier</a> of <font color="Maroon">D1</font> <a href="hidden.html#R1">=</a> the <a href="struct_0.html#U1">carrier</a> of <font color="Maroon">D2</font>
 ;<br/>

<b>then </b>the <a href="altcat_1.html#U1">Arrows</a> of <font color="Maroon">D1</font> = 
the <a href="altcat_1.html#U1">Arrows</a> of <font color="Maroon">C</font> <a href="realset1.html#K1">||</a> the <a href="struct_0.html#U1">carrier</a> of <font color="Maroon">D2</font>
<b>by </b><i/>
<br/>.= 
the <a href="altcat_1.html#U1">Arrows</a> of <font color="Maroon">D2</font>
<b>by </b><i/>
;<br/>
<b>hence </b><a NAME="E3:68"/>
 <a href="altcat_1.html#G2">AltCatStr</a>(# the <a href="struct_0.html#U1">carrier</a> of <font color="Maroon">D1</font>,the <a href="altcat_1.html#U1">Arrows</a> of <font color="Maroon">D1</font>,the <a href="altcat_1.html#U2">Comp</a> of <font color="Maroon">D1</font> #) <a href="hidden.html#R1">=</a>  <a href="altcat_1.html#G2">AltCatStr</a>(# the <a href="struct_0.html#U1">carrier</a> of <font color="Maroon">D2</font>,the <a href="altcat_1.html#U1">Arrows</a> of <font color="Maroon">D2</font>,the <a href="altcat_1.html#U2">Comp</a> of <font color="Maroon">D2</font> #)
 <b>by </b><i>, </i>;<br/>


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