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Lifting subgroups of PSL2 to SL2 over local fields

  • Naomi Andrew , Matthew J. Conder , Ari Markowitz und Jeroen Schillewaert ORCID logo EMAIL logo
VerĂśffentlicht/Copyright: 27. Februar 2025

Abstract

Let 𝐾 be a non-archimedean local field. We show that discrete subgroups without 2-torsion in PSL 2 ⁢ ( K ) can always be lifted to SL 2 ⁢ ( K ) , and provide examples (when char ⁡ ( K ) ≠ 2 ) which cannot be lifted if either of these conditions is removed. We also briefly discuss lifting representations of groups into PSL 2 ⁢ ( K ) to SL 2 ⁢ ( K ) .

Award Identifier / Grant number: 850930

Funding source: Marsden Fund

Award Identifier / Grant number: 3723563

Award Identifier / Grant number: 3725880

Award Identifier / Grant number: 3726956

Funding statement: This work has received funding from the European Research Council (ERC) under the European Union’s Horizon 2020 research and innovation programme (grant agreement No. 850930). It has also received funding from the New Zealand Marsden Fund (grant numbers 3723563 and 3725880) and the Rutherford Foundation (grant number 3726956).

Acknowledgements

We thank Sam Hughes for cohomological advice. The first author would like to thank the University of Auckland for its hospitality during a visit in September 2023.

  1. Communicated by: Michael Giudici

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Received: 2024-03-16
Revised: 2024-12-03
Published Online: 2025-02-27
Published in Print: 2025-07-01

Š 2025 Walter de Gruyter GmbH, Berlin/Boston

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