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<b>consider </b><font color="Maroon">F</font> being    <a href="cat_1.html#M2">Functor</a> of <font color="Maroon">A</font>,<font color="Maroon">B</font>;<br/>
<b>take </b>
<span class="p1"><a href="tarski.html#K1">{</a><span class="default"><span class="p2"><a href="tarski.html#K4">[</a><span class="default"><span class="p3"><a href="tarski.html#K4">[</a><span class="default"><font color="Maroon">F</font>,<font color="Maroon">F</font></span><a href="tarski.html#K4">]</a></span>,<span class="p3">(<span class="default"><a href="nattra_1.html#K7" target="_self">id</a> <font color="Maroon">F</font></span>)</span></span><a href="tarski.html#K4">]</a></span></span><a href="tarski.html#K1">}</a></span>
;<br/>

<b>let </b><font color="Maroon">x</font> be    <a href="hidden.html#M1">set</a> ;<br/>

<b>assume </b><a NAME="E2:56_1_1"/><i><font color="Green">E7</font></i>: 
<font color="Maroon">x</font> <a href="hidden.html#R2">in</a> <span class="p1"><a href="tarski.html#K1">{</a><span class="default"><span class="p2"><a href="tarski.html#K4">[</a><span class="default"><span class="p3"><a href="tarski.html#K4">[</a><span class="default"><font color="Maroon">F</font>,<font color="Maroon">F</font></span><a href="tarski.html#K4">]</a></span>,<span class="p3">(<span class="default"><a href="nattra_1.html#K7" target="_self">id</a> <font color="Maroon">F</font></span>)</span></span><a href="tarski.html#K4">]</a></span></span><a href="tarski.html#K1">}</a></span>
 ;<br/>

<b>take </b>
<font color="Maroon">F</font>
;<br/>

<b>take </b>
<font color="Maroon">F</font>
;<br/>

<b>take </b>
 <a href="nattra_1.html#K7" target="_self">id</a> <font color="Maroon">F</font>
;<br/>

<b>thus </b><a NAME="E3:56_1_1"/>
( <font color="Maroon">x</font> <a href="hidden.html#R1">=</a> <span class="p1"><a href="tarski.html#K4">[</a><span class="default"><span class="p2"><a href="tarski.html#K4">[</a><span class="default"><font color="Maroon">F</font>,<font color="Maroon">F</font></span><a href="tarski.html#K4">]</a></span>,<span class="p2">(<span class="default"><a href="nattra_1.html#K7" target="_self">id</a> <font color="Maroon">F</font></span>)</span></span><a href="tarski.html#K4">]</a></span> &amp; <font color="Maroon">F</font> <a href="nattra_1.html#R2" target="_self">is_naturally_transformable_to</a> <font color="Maroon">F</font> )
 <b>by </b><i>, <a class="ref" href="tarski.html#D1">TARSKI:def 1</a></i>;<br/>


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