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arXiv · 2603.17273

Tangent spaces of spherical Schubert varieties and counterexamples to the reducedness conjecture

Marc Besson·Jiuzu Hong·Huanhuan Yu
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Abstract

Given a simply-connected simple algebraic group $G$, we determine the tangent space of any Finkelberg-Mirkovi\'c Schubert scheme at the base point of the affine Grassmannian of $G$. As a consequence, we exhibit non-reduced Finkelberg-Mirkovi\'c Schubert schemes when $G$ is of type $E_6,E_7$ and $E_8$.

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Marc Besson, Jiuzu Hong, Huanhuan Yu. 2026-03-18. Tangent spaces of spherical Schubert varieties and counterexamples to the reducedness conjecture. https://arxiv.org/abs/2603.17273

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