<br />

    3.  ${\forall\,x,y\;\;} {Country}(x) \land {Country}(y) \land {Borders}(x,y) \land {}$\
        $\lnot ({MapColor}(x) = {MapColor}(y))$.<br />

    4.  ${\forall\,x,y\;\;} ({Country}(x) \land {Country}(y) \land {Borders}(x,y) ) {\:\;{\Rightarrow}\:\;}{MapColor}(x\neq y)$.
<br />
</p>
    </div>
</div>

<p><br /></p>

<div class="card">
    <div class="card-header p-2">
        <a href="ex_11/" class="p-2">Exercise 11 </a>
        <button type="button" class="btn btn-dark float-right" title="Book