The automorphism group of the $p^n$-torsion points of an elliptic curve over a field of characteristic $p\ge 5$

Bo-Hae Im, Hansol Kim

For a field $K$ of characteristic $p\ge 5$ and the elliptic curve $E_{s,t}:y^2=x^3+sx+t$ defined over the function field $K\left(s,t\right)$ of two variables $s$ and $t$,…