Ideals in enveloping algebras of affine Kac-Moody algebras

Fuente: arXiv
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Main Authors: Biswal, Rekha, Sierra, Susan J.
Format: Preprint
Published: 2021
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author Biswal, Rekha
Sierra, Susan J.
author_facet Biswal, Rekha
Sierra, Susan J.
contents Let $L$ be an affine Kac-Moody algebra, with central element $c$, and let $λ\in \mathbb C$. We study two-sided ideals in the central quotient $U_λ(L):= U(L)/(c-λ)$ of the universal enveloping algebra of $L$, and prove: Theorem 1. If $λ\neq 0$ then $U_λ(L)$ is simple. Theorem 2. The algebra $U_0(L)$ has just-infinite growth, in the sense that any proper quotient has polynomial growth. As an immediate corollary, we show that the annihilator of any nontrivial integrable highest weight representation of $L$ is centrally generated, extending a result of Chari for Verma modules. We also show that universal enveloping algebras of loop algebras and current algebras of finite-dimensional simple Lie algebras have just-infinite growth, and prove similar results to Theorems 1 and 2 for quotients of symmetric algebras of these Lie algebras by Poisson ideals.
format Preprint
id arxiv_https___arxiv_org_abs_2112_08334
institution arXiv
publishDate 2021
record_format arxiv
spellingShingle Ideals in enveloping algebras of affine Kac-Moody algebras
Biswal, Rekha
Sierra, Susan J.
Rings and Algebras
Representation Theory
Primary: 16S30, 17B67, 16P90, 17B10, Secondary 17B65, 16D30
Let $L$ be an affine Kac-Moody algebra, with central element $c$, and let $λ\in \mathbb C$. We study two-sided ideals in the central quotient $U_λ(L):= U(L)/(c-λ)$ of the universal enveloping algebra of $L$, and prove: Theorem 1. If $λ\neq 0$ then $U_λ(L)$ is simple. Theorem 2. The algebra $U_0(L)$ has just-infinite growth, in the sense that any proper quotient has polynomial growth. As an immediate corollary, we show that the annihilator of any nontrivial integrable highest weight representation of $L$ is centrally generated, extending a result of Chari for Verma modules. We also show that universal enveloping algebras of loop algebras and current algebras of finite-dimensional simple Lie algebras have just-infinite growth, and prove similar results to Theorems 1 and 2 for quotients of symmetric algebras of these Lie algebras by Poisson ideals.
title Ideals in enveloping algebras of affine Kac-Moody algebras
topic Rings and Algebras
Representation Theory
Primary: 16S30, 17B67, 16P90, 17B10, Secondary 17B65, 16D30
url https://arxiv.org/abs/2112.08334