A decomposition theorem for $\mathbb{Q}$-Fano Kähler–Einstein varieties

Let $X$ be a $\mathbb{Q}$-Fano variety admitting a Kähler–Einstein metric. We prove that up to a finite quasi-étale cover, $X$ splits isometrically as a product of Kähler–Einstein $\mathbb{Q}$-Fano varieties whose tangent sheaf is stable with respect to the anticanonical polarization. This relies am...

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Bibliographic Details
Main Authors: Druel, Stéphane, Guenancia, Henri, Păun, Mihai
Format: Article
Language:English
Published: Académie des sciences 2024-06-01
Series:Comptes Rendus. Mathématique
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Online Access:https://comptes-rendus.academie-sciences.fr/mathematique/articles/10.5802/crmath.612/
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Summary:Let $X$ be a $\mathbb{Q}$-Fano variety admitting a Kähler–Einstein metric. We prove that up to a finite quasi-étale cover, $X$ splits isometrically as a product of Kähler–Einstein $\mathbb{Q}$-Fano varieties whose tangent sheaf is stable with respect to the anticanonical polarization. This relies among other things on a very general splitting theorem for algebraically integrable foliations. We also prove that the canonical extension of $T_X$ by $\mathscr{O}_X$ is polystable with respect to the anticanonical polarization.
ISSN:1778-3569