PreprintCC BY 4.0arXiv
Automorphisms of Twisted Chevalley Groups of type 2 Dℓ (ℓ ≥ 4) over Local Rings
Abstract
We prove that all automorphisms of twisted Chevalley groups of type 2Dℓ, ℓ≥4, and their elementary subgroups over commutative local rings with 1/2 are standard. More precisely, for elementary groups, every automorphism is a composition of strictly inner, diagonal, and ring automorphisms; for full groups, a central factor may also occur. In the adjoint case, diagonal automorphisms are strictly inner and the centre is trivial, so only strictly inner and ring factors are needed for both the elementary and full groups.
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BibTeX
@misc{bunina2026automorphisms,
title = {{Automorphisms of Twisted Chevalley Groups of type $^2 D_\ell \ (\ell \geq 4)$ over Local Rings}},
author = {Elena I. Bunina and Deep H. Makadiya},
howpublished = {arXiv},
year = {2026},
month = oct,
doi = {10.48550/arxiv.2608.02312},
eprint = {2608.02312},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2608.02312},
note = {CC BY 4.0},
}
RIS
TY - UNPB
TI - Automorphisms of Twisted Chevalley Groups of type ^2 D_ℓ (ℓ ≥ 4) over Local Rings
AU - Elena I. Bunina
AU - Deep H. Makadiya
PY - 2026
DA - 2026/10/14
PB - arXiv
DO - 10.48550/arxiv.2608.02312
UR - https://arxiv.org/abs/2608.02312
AB - We prove that all automorphisms of twisted Chevalley groups of type ^2D_ℓ, ℓ≥4, and their elementary subgroups over commutative local rings with 1/2 are standard. More precisely, for elementary groups, every automorphism is a composition of strictly inner, diagonal, and ring automorphisms; for full groups, a central factor may also occur. In the adjoint case, diagonal automorphisms are strictly inner and the centre is trivial, so only strictly inner and ring factors are needed for both the elementary and full groups.
ER -