Add paragraph about the range of monetary values.

Signed-off-by: Daira Hopwood <daira@jacaranda.org>

protocol/protocol.tex

@@ -3084,6 +3084,12 @@ distinct openings of the \noteCommitment when Condition I or II is violated.
           because the paper did not take into account the need to encode compressed
           $y$-coordinates. The fork of \libsnark used by \Zcash uses a different
           format to upstream \libsnark, in order to follow \cite{IEEE2004}.
+    \item The range of monetary values differs. In \Zcash, this range is
+          $\range{0}{\MAXMONEY}$; in \Zerocash it is $\range{0}{2^{64}-1}$.
+          (The \joinSplitStatement still only directly enforces that the sum
+          of amounts in a given \joinSplitTransfer is in the latter range;
+          this enforcement is technically redundant given that the Balance
+          property holds.)
 \end{itemize}