Derivations for the even part of the Hamiltonian superalgebra in positive characteristic

Abstract

In this paper we consider the derivations for even part of the finite-dimensional Hamiltonian superalgebra $H$ over a field of prime characteristic. We first introduce an ideal $\mathfrak{N}$ of $H_{\bar{0}}$ and show that the derivation space from $H_{\bar{0}}$ into $W_{\bar{0}}$ can be obtained by the derivation space from $\mathfrak{N}$ into $W_{\bar{0}},$ the even part of the generalized Witt superalgebra $W$. For further application we also give the generating set of the ideal $\mathfrak{N}$. Then we describe three series of exceptional derivations from $H_{\bar{0}}$ into $W_{\bar{0}}.$ Finally, we determine all the derivations vanishing on the non-positive $\mathbb{Z}$-graded part of $H_{\bar{0}}$, the odd $\mathbb{Z}$-homogeneous derivations, and negative $\mathbb{Z}$-homogeneous derivations from $H_{\bar{0}}$ into $W_{\bar{0}}.$

21 pages