By Currently Included, $D \isin L$.
-By Tip Own Contents for $R^+$, $D \isin R^+ \equiv D \le R^+$, but by
+By Tip Own Contents for $R^+$, $D \isin R^+ \equiv D \le R^+$, but
by Unique Tip, $D \le R^+ \equiv D \le L$.
So $D \isin R^+$.
$\qed$
+\subsection{Unique Tips:}
+
+Single Parent Unique Tips applies. $\qed$
+
\subsection{Foreign Inclusion}
Consider some $D$ s.t. $\patchof{D} = \bot$. $D \neq C$.