sults are folded and are displayed upon hovering or clicking.  We can unfold them by default using annotations or directives:</p>
<pre class="alectryon-io highlight"><!-- Generator: Alectryon --><span class="alectryon-sentence"><input checked="checked" class="alectryon-toggle" id="literate-lean3-lean-chk1" style="display: none" type="checkbox"><label class="alectryon-input" for="literate-lean3-lean-chk1"><span class="k">#check</span> nat</label><small class="alectryon-output"><div><div class="alectryon-mess