s="sectionRef" title="" href="#">Peano-section</a> as a single axiom that defines
${NatNum}(x)$ so as to exclude the possibility of natural numbers
except for those generated by the successor function.
</p>
    </div>
</div>

<p><br /></p>

<div class="card">
    <div class="card-header p-2">
        <a href="ex_16/" class="p-2">Exercise 16 (wumpus-diagnostic-exercise) </a>
        <button type="button" class="btn btn-dark float-right" title="Bookmark Exercise" onclick="bookmark('ch8ex16');" href="#"><i id=