The Lodha–Moore groups and their 𝑛-adic generalizations are not SCY

Abstract A closed symplectic 4-manifold is symplectic Calabi–Yau (SCY) if its canonical class is trivial. Friedl and Vidussi proved that Thompson’s group 𝐹 cannot be the fundamental group of any SCY 4-manifold. In this paper, we show that its generalizations, called the Brown–Thompson groups, and the 𝑛-adic Lodha–Moore groups, also cannot be the fundamental group of any SCY 4-manifold by using their method. From this proof, we also show that there exist infinitely many non-trivial examples which satisfy Geoghegan’s conjecture.

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Publication Details

Journal
Journal of Group Theory
Published
2026-08-24
DOI
https://doi.org/10.1515/jgth-2026-0096
Primary Topic
Geometric and Algebraic Topology
Type
article
Field-Weighted Citation Impact
0.00

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article

The Lodha–Moore groups and their 𝑛-adic generalizations are not SCY

Akihiro Takano, Yuya Kodama
Journal of Group Theory
Geometric and Algebraic Topology
article

The Lodha–Moore groups and their 𝑛-adic generalizations are not SCY

Akihiro Takano, Yuya Kodama
article en

Abstract

Abstract A closed symplectic 4-manifold is symplectic Calabi–Yau (SCY) if its canonical class is trivial. Friedl and Vidussi proved that Thompson’s group 𝐹 cannot be the fundamental group of any SCY 4-manifold. In this paper, we show that its generalizations, called the Brown–Thompson groups, and the 𝑛-adic Lodha–Moore groups, also cannot be the fundamental group of any SCY 4-manifold by using their method. From this proof, we also show that there exist infinitely many non-trivial examples which satisfy Geoghegan’s conjecture.

Journal of Group Theory
Kagoshima University (JP), Toneyama National Hospital (JP), The University of Osaka (JP)
Japan Society for the Promotion of Science
Reduced inequalities
Openalex Percentile: Top 5%
Geometric and Algebraic Topology
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