Invariants for the Weil representation and Modular Units for Orthogonal Groups of Signature (2,2)

Patrick Bieker

doi:10.1016/j.jnt.2023.03.002

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arXiv · 2108.08107

Invariants for the Weil representation and Modular Units for Orthogonal Groups of Signature (2,2)

Patrick Bieker

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Abstract

We show that the space of invariants for the Weil representation for discriminant groups which contain self-dual isotropic subgroups is spanned by the characteristic functions of the self-dual isotropic subgroups. As an application, we construct modular units for orthogonal groups in signature (2,2) using Borcherds products.

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Patrick Bieker. 2021-08-18. Invariants for the Weil representation and Modular Units for Orthogonal Groups of Signature (2,2). https://doi.org/10.1016/j.jnt.2023.03.002

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