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arXiv · 2211.06673

Level lowering for GU(1,2)

Hao Fu
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Abstract

Mazur's principle gives a criterion under which an irreducible mod $\ell$ Galois representation arising from a modular form of level $Np$ (with $p$ prime to $N$) can also arise from a modular form of level $N.$ We prove an analogous result showing that a mod $\ell$ Galois representation arising from a stable cuspidal automorphic representation of the unitary similitude group $G=\mathrm{GU}(1,2)$ which is Steinberg at an inert prime $p$ can also arise from an automorphic representation of $G$ that is unramified at $p$.

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Hao Fu. 2022-11-12. Level lowering for GU(1,2). https://arxiv.org/abs/2211.06673

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