Tensor modules over the Lie algebras of divergence zero vector fields on $\mathbb{C}^n$
Jinxin Hu, Rencai Lü
TL;DR
This work addresses the problem of classifying the simplicity of tensor modules $F(P,M)$ for the Lie algebra of divergence-zero vector fields $S_n$, with $P$ a simple module over the Weyl algebra $D_n$ and $M$ a simple $rak{sl}_n$-module. Using Shen's monomorphism to realize $F(P,M)$ as an $S_n$-module, the authors prove a dichotomy: if $M$ is not isomorphic to any fundamental $rak{sl}_n$-module $V( abla_k)$, then $F(P,M)$ is simple; otherwise, they construct and analyze submodules $L_n(P,r)$ and $ ilde L_n(P,r)$ to describe all simple subquotients, including explicit quotients and special cases for $P riangleleft A_n$ or $A_n^F$. The results yield a detailed lattice of simple subquotients for weight modules, culminating in a concrete classification in terms of the $L_n(P,r)$ family and related quotients, with implications for the broader program of classifying simple Harish-Chandra modules for related algebras. The work broadens understanding of tensor constructions over Cartan-type Lie algebras and provides tools for Harish-Chandra module classifications.
Abstract
Let $n\geq 2$ be an integer, $S_n$ be the Lie algebra of vector fields on $\mathbb{C}^n$ with zero divergence, and $D_n$ be the Weyl algebra over the polynomial algebra $A_n=\mathbb{C}[t_1,t_2,\cdots,t_n]$. In this paper, we study the simplicity of the tensor $S_n$-module $F(P,M)$, where $P$ is a simple $D_n$-module and $M$ is a simple $\mathfrak{sl}_n$-module. We obtain the necessary and sufficient conditions for $F(P,M)$ to be an irreducible module, and determine all simple subquotients of $F(P,M)$ when it is reducible.
