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<b>let </b><font color="Maroon">X</font> be    <a href="hidden.html#M1">set</a> ;<br/><b>let </b><font color="Maroon">p</font> be   <a href="armstrng.html#NM3">Dependency</a> of <font color="Maroon">X</font>, <font color="Maroon">q</font> be   <a href="armstrng.html#NM3">Dependency</a> of <font color="Maroon">X</font>, <font color="Maroon">r</font> be   <a href="armstrng.html#NM3">Dependency</a> of <font color="Maroon">X</font>;<br/>



<b>assume </b><a NAME="E1:38"/>
( <font color="Maroon">p</font> <a href="armstrng.html#NR6" target="_self">&lt;=</a> <font color="Maroon">q</font> &amp; <font color="Maroon">q</font> <a href="armstrng.html#NR6" target="_self">&lt;=</a> <font color="Maroon">r</font> )
 ;<br/>

<a NAME="E2:38"/><b>then </b>
( <font color="Maroon">q</font> <a href="mcart_1.html#K1">`1</a>  <a href="tarski.html#R1">c=</a> <font color="Maroon">p</font> <a href="mcart_1.html#K1">`1</a>  &amp; <font color="Maroon">p</font> <a href="mcart_1.html#K2">`2</a>  <a href="tarski.html#R1">c=</a> <font color="Maroon">q</font> <a href="mcart_1.html#K2">`2</a>  &amp; <font color="Maroon">r</font> <a href="mcart_1.html#K1">`1</a>  <a href="tarski.html#R1">c=</a> <font color="Maroon">q</font> <a href="mcart_1.html#K1">`1</a>  &amp; <font color="Maroon">q</font> <a href="mcart_1.html#K2">`2</a>  <a href="tarski.html#R1">c=</a> <font color="Maroon">r</font> <a href="mcart_1.html#K2">`2</a>  )
 
<b>by </b><i/>;<br/>
<a NAME="E3:38"/><b>then </b>
( <font color="Maroon">r</font> <a href="mcart_1.html#K1">`1</a>  <a href="tarski.html#R1">c=</a> <font color="Maroon">p</font> <a href="mcart_1.html#K1">`1</a>  &amp; <font color="Maroon">p</font> <a href="mcart_1.html#K2">`2</a>  <a href="tarski.html#R1">c=</a> <font color="Maroon">r</font> <a href="mcart_1.html#K2">`2</a>  )
 
<b>by </b><i><a class="ref" href="xboole_1.html#T1">XBOOLE_1:1</a></i>;<br/>
<b>hence </b><a NAME="E4:38"/>
<font color="Maroon">p</font> <a href="armstrng.html#NR6" target="_self">&lt;=</a> <font color="Maroon">r</font>
 <b>by </b><i/>;<br/>


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