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arXiv · 2507.13500

Cohomology of $p$-adic Chevalley groups

Andrea Dotto·Bao V. Le Hung
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Abstract

Let $G$ be a split connected reductive group over the ring of integers of a finite unramified extension $K$ of $\mathbf{Q}_p$. Under a standard assumption on the Coxeter number of $G$, we compute the cohomology algebra of $G(\mathcal{O}_K)$ and its Iwahori subgroups, with coefficients in the residue field of $K$. Our methods involve a new presentation of some graded Lie algebras appearing in Lazard's theory of saturated $p$-valued groups, and a reduction to coherent cohomology of the flag variety in positive characteristic. We also consider the case of those inner forms of $\mathrm{GL}_n(K)$ that give rise to the Morava stabilizer groups in stable homotopy theory.

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BibTeXRIS

Andrea Dotto, Bao V. Le Hung. 2025-07-17. Cohomology of $p$-adic Chevalley groups. https://arxiv.org/abs/2507.13500

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