An Explicit Construction of $\mathbb{S}^1$-Gerbes over the Stack $[G/G]$

Fuente: arXiv
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Autori principali: Ni, Dadi, Qi, Kaichuan
Natura: Preprint
Pubblicazione: 2026
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author Ni, Dadi
Qi, Kaichuan
author_facet Ni, Dadi
Qi, Kaichuan
contents For a compact and connected Lie group $G$, we present an explicit construction of an $\mathbb{S}^1$-gerbe over the differentiable stack $[G/G]$ in the framework of $\mathbb{S}^1$-central extensions of Lie groupoids. This gives a complete proof of the construction outlined earlier by Behrend--Xu--Zhang, together with an explicit proof of the differential-form identity stated there without proof. In particular, when $G$ is compact, simple, and simply connected, the Dixmier--Douady class of the resulting gerbe is the canonical generator of ${\rm H}^3_G(G,\mathbb Z)$.
format Preprint
id arxiv_https___arxiv_org_abs_2601_05183
institution arXiv
publishDate 2026
record_format arxiv
spellingShingle An Explicit Construction of $\mathbb{S}^1$-Gerbes over the Stack $[G/G]$
Ni, Dadi
Qi, Kaichuan
Symplectic Geometry
53D17, 53D20, 22E67
For a compact and connected Lie group $G$, we present an explicit construction of an $\mathbb{S}^1$-gerbe over the differentiable stack $[G/G]$ in the framework of $\mathbb{S}^1$-central extensions of Lie groupoids. This gives a complete proof of the construction outlined earlier by Behrend--Xu--Zhang, together with an explicit proof of the differential-form identity stated there without proof. In particular, when $G$ is compact, simple, and simply connected, the Dixmier--Douady class of the resulting gerbe is the canonical generator of ${\rm H}^3_G(G,\mathbb Z)$.
title An Explicit Construction of $\mathbb{S}^1$-Gerbes over the Stack $[G/G]$
topic Symplectic Geometry
53D17, 53D20, 22E67
url https://arxiv.org/abs/2601.05183