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arXiv · 0710.0705

Hopf Algebras and Congruence Subgroups

Yorck Sommerhaeuser·Yongchang Zhu
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Abstract

We prove that the kernel of the natural action of the modular group on the center of the Drinfel'd double of a semisimple Hopf algebra is a congruence subgroup. To do this, we introduce a class of generalized Frobenius-Schur indicators and endow it with an action of the modular group that is compatible with the original one.

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Yorck Sommerhaeuser, Yongchang Zhu. 2008-02-06. Hopf Algebras and Congruence Subgroups. https://arxiv.org/abs/0710.0705

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