Finite-dimensional pseudofinite groups of small dimension, without CFSG
Confluentes Mathematici, Tome 17 (2025), pp. 55-71

Any simple pseudofinite group $G$ is known to be isomorphic to a (twisted) Chevalley group over a pseudofinite field. This celebrated result mostly follows from the work of Wilson in 1995 and heavily relies on the classification of finite simple groups (CFSG). It easily follows that $G$ is finite-dimensional with additive and fine dimension and, in particular, that if $\dim (G)=3$ then $G$ is isomorphic to $\operatorname{PSL}_2(F)$ for some pseudofinite field $F$. We describe pseudofinite groups of fine and additive dimension $\leqslant 3$ and, in particular, show that the classification $G \cong \operatorname{PSL}_2(F)$ is independent of CFSG.

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DOI : 10.5802/cml.100
Classification : 03C60, 03C45, 20D05
Keywords: pseudofinite groups, finite-dimensional groups, classification of finite simple groups, simple groups of Lie type

Ulla Karhumäki 1 ; Frank O. Wagner 2

1 Institut Camille Jordan, Université Claude Bernan Lyon 1, Lyon, France
2 Institut Camille Jordan, UMR5208, CNRS, Université Claude Bernard Lyon 1, Lyon, France
Licence : CC-BY-NC-ND 4.0
Droits d'auteur : Les auteurs conservent leurs droits
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Ulla Karhumäki; Frank O. Wagner. Finite-dimensional pseudofinite groups of small dimension, without CFSG. Confluentes Mathematici, Tome 17 (2025), pp. 55-71. doi: 10.5802/cml.100

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