Duality for dormant opers

In the present paper, we prove that on a fixed pointed stable curve of characteristic $p>0$, there exists a duality between dormant ${\mathfrak{s}\mathfrak{l}}_n$-opers ($1<n<p-1$) and dormant ${\mathfrak{s}\mathfrak{l}}_{(p-n)}$-opers. Also, we prove that there exists a unique (up to isomorphism) dormant ${\mathfrak{s}\mathfrak{l}}_{(p-1)}$-oper on a fixed pointed stable curve of characteristic $p>0$.