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Sibirskii Matematicheskii Zhurnal, 2025, Volume 66, Number 4, Pages 613–620 DOI: https://doi.org/10.33048/smzh.2025.66.405
(Mi smj7966)
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New examples of nonpronormal subgroups of odd index in finite simple linear and unitary groups
J. Guoa, W. Guobc, N. V. Maslovade, D. O. Revinf a School of Mathematics and Statistics, Hainan University, Haikou, P. R. China
b School of Mathematics and Statistics, Nantong University, Nantong, Jiangsu, P. R. China
c Department of Mathematics, University of Science and Technology of China, Hefei, P. R. China
d Krasovskii Institute of Mathematics and Mechanics, Yekaterinburg, Russia
e Ural Federal University, Yekaterinburg, Russia
f Sobolev Institute of Mathematics, Novosibirsk, Russia
DOI:
https://doi.org/10.33048/smzh.2025.66.405
Abstract:
A subgroup $H$ of a group $G$ is said to be pronormal if, for every element $g \in G$, the subgroups $H$ and $H^g$ are conjugate in the subgroup $\langle H, H^g\rangle$. It is known that a substantial portion of finite simple groups possesses property $(*)$: every subgroup of odd index is pronormal in the group. To date, finite simple groups with property $(*)$ have been classified, except for finite simple linear and unitary groups subject to certain restrictions on their natural arithmetic parameters. In 2024, a classification was initiated for finite simple linear and unitary groups in which all subgroups of odd index are pronormal. The plan is to identify all possible sources of nonpronormal subgroups of odd index and then prove that there are no other such examples. In 2024, series of examples of nonpronormal subgroups of odd index were found in finite simple linear and unitary groups over fields of odd characteristic. In the present paper, we construct a new series of examples of nonpronormal subgroups of odd index in finite simple linear and unitary groups over a field of odd characteristic.
Keywords:
finite group, simple group, linear simple group, unitary simple group, pronormal subgroup, odd index.
Received: 27.12.2024 Revised: 02.04.2025 Accepted: 25.04.2025
Citation:
J. Guo, W. Guo, N. V. Maslova, D. O. Revin, “New examples of nonpronormal subgroups of odd index in finite simple linear and unitary groups”, Sibirsk. Mat. Zh., 66:4 (2025), 613–620; Siberian Math. J., 66:4 (2025), 928–934
Linking options:
https://www.mathnet.ru/eng/smj7966 https://www.mathnet.ru/eng/smj/v66/i4/p613
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