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arXiv · 2106.00529

Maximal Discrete Subgroups of $SO^+(2,n+2)$

Aloys Krieg·Felix Schaps
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Abstract

We characterize the maximal discrete subgroups of $SO^+(2,n+2)$, which contain the discriminant kernel of an even lattice, which contains two hyperbolic planes over $\mathbb{Z}$. They coincide with the normalizers in $SO^+(2,n+2)$ and are given by the group of all integral matrices inside $SO^+(2,n+2)$, whenever the underlying lattice is maximal even. Finally we deal with the irreducible root lattices as examples.

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Aloys Krieg, Felix Schaps. 2021-06-01. Maximal Discrete Subgroups of $SO^+(2,n+2)$. https://arxiv.org/abs/2106.00529

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