t of the vertices of another facet. This is
called a <em>redundant facet</em>. </li>
</ul>
<ul>
<li><b>A facet with fewer than three neighbors. </b>Facet
merging may leave a facet with one or two
neighbors. This is called a <em>degenerate facet</em>.
</li>
</ul>
<ul>
<li><b>A facet with flipped orientation. </b>A
facet's hyperplane may define a halfspace that
does not include the interior point.This is
called a <em>flipped facet</em>. </li>
</ul>
<ul>
<li><strong>A coplanar horizon facet.</strong> A
newly p