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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_1.html#V2">transitive</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_1.html#V2">transitive</a>  <a href="altcat_2.html#M1" target="_self">SubCatStr</a> of <font color="Maroon">C</font>;<br/>



<b>assume </b><b>that </b><br/><a NAME="E1:63"/><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>
 <b>and </b><br/><a NAME="E2:63"/><i><font color="Green">E17</font></i>: 
the <a href="altcat_1.html#U1">Arrows</a> of <font color="Maroon">D1</font> <a href="hidden.html#R1">=</a> the <a href="altcat_1.html#U1">Arrows</a> of <font color="Maroon">D2</font>
 ;<br/>

<a NAME="E3:63"/><i><font color="Green">E20</font></i>: 
<font color="Maroon">D1</font> is    <a href="altcat_2.html#M1" target="_self">SubCatStr</a> of <font color="Maroon">D2</font>
 
<b>by </b><i>, , </i>;<br/>
<a NAME="E4:63"/>
<font color="Maroon">D2</font> is    <a href="altcat_2.html#M1" target="_self">SubCatStr</a> of <font color="Maroon">D1</font>
 
<b>by </b><i>, , </i>;<br/>
<b>hence </b><a NAME="E5:63"/>
 <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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