\subsection{Tip Contents}
-We will consider some $D$ and prove the Exclusive Tip Contents form.
-We need worry only about $C \in \py$. And $\patchof{C} = \patchof{L}$
+xxx up to here
+
+We need worry only about $C \in \py$.
+And $\patchof{C} = \patchof{L}$
so $L \in \py$ so $L \haspatch \p$. We will use the coherence and
patch inclusion of $C$ as just proved.
Firstly we prove $C \haspatch \p$: If $R \in \py$, this is true by
-coherence/inclusion $C \haspatch \p$. So by definition of
+coherence/inclusion $C \haspatch \p$. If $R \not\in \py$ then
+by Tip Merge
+
+
+We will consider some $D$ and prove the Exclusive Tip Contents form.
+
+
+So by definition of
$\haspatch$, $D \isin C \equiv D \le C$. OK.
\subsubsection{For $L \in \py, D \in \py, $:}