Higher spin representations of maximal compact subalgebras of simply-laced Kac-Moody-algebras

Fuente: arXiv
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Hauptverfasser: Lautenbacher, Robin, Köhl, Ralf
Format: Preprint
Veröffentlicht: 2024
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author Lautenbacher, Robin
Köhl, Ralf
author_facet Lautenbacher, Robin
Köhl, Ralf
contents Given the maximal compact subalgebra $\mathfrak{k}(A)$ of a split-real Kac-Moody algebra $\mathfrak{g}(A)$ of type $A$, we study certain finite-dimensional representations of $\mathfrak{k}(A)$, that do not lift to the maximal compact subgroup $K(A)$ of the minimal Kac-Moody group $G(A)$ associated to $\mathfrak{g}(A)$ but only to its spin cover $Spin(A)$. Currently, four elementary of these so-called spin representations are known. We study their (ir-)reducibility, semi-simplicity, and lift to the group level. The interaction of these representations with the spin-extended Weyl-group is used to derive a partial parametrization result of the representation matrices by the real roots of $\mathfrak{g}(A)$.
format Preprint
id arxiv_https___arxiv_org_abs_2409_07247
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Higher spin representations of maximal compact subalgebras of simply-laced Kac-Moody-algebras
Lautenbacher, Robin
Köhl, Ralf
Representation Theory
17B67, 81R10
Given the maximal compact subalgebra $\mathfrak{k}(A)$ of a split-real Kac-Moody algebra $\mathfrak{g}(A)$ of type $A$, we study certain finite-dimensional representations of $\mathfrak{k}(A)$, that do not lift to the maximal compact subgroup $K(A)$ of the minimal Kac-Moody group $G(A)$ associated to $\mathfrak{g}(A)$ but only to its spin cover $Spin(A)$. Currently, four elementary of these so-called spin representations are known. We study their (ir-)reducibility, semi-simplicity, and lift to the group level. The interaction of these representations with the spin-extended Weyl-group is used to derive a partial parametrization result of the representation matrices by the real roots of $\mathfrak{g}(A)$.
title Higher spin representations of maximal compact subalgebras of simply-laced Kac-Moody-algebras
topic Representation Theory
17B67, 81R10
url https://arxiv.org/abs/2409.07247