Simple superelliptic Lie algebras

Let $m\in N$, $P(t)\in C[t]$. Then we have the Riemann surfaces (commutative algebras) $R_m(P)=C[t^{\pm 1},u\mathrm{\mid }{u}^m=P(t)]$ and $S_m(P)=C[t,u\mathrm{\mid }{u}^m=P(t)]\mathrm{.}$ The Lie algebras ${\mathcal{R}}_m(P)=Der(R_m(P))$ and ${\mathcal{S}}_m(P)=Der(S_m(P))$ are called the $m$-th superelliptic Lie algebras associated to $P(t)$. In this paper we determine the necessary and sufficient conditions for such Lie algebras to be simple, and determine their universal central extensions and their derivation algebras. We also study the isomorphism and automorphism problem for these Lie algebras.