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<b>consider </b><font color="Maroon">S</font> being    <a href="hidden.html#M1">set</a> ;<br/>
<b>take </b><font color="Maroon">f</font> = <span class="p1"><a href="tarski.html#K1">{</a><span class="default"><a href="xboole_0.html#K1">{}</a> </span><a href="tarski.html#K1">}</a></span> <a href="pre_circ.html#K2">--&gt;</a> <font color="Maroon">S</font>;<br/>

<b>thus </b><a NAME="E2:2_1_1"/>
not <font color="Maroon">f</font> is <a href="xboole_0.html#V1">empty</a>
 ;<br/>

<b>thus </b><a NAME="E3:2_1_1"/>
<font color="Maroon">f</font> is <a href="funct_1.html#V3">constant</a>
 ;<br/>


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