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JOURNALS // Funktsional'nyi Analiz i ego Prilozheniya // Archive

Funktsional. Anal. i Prilozhen., 2025 Volume 59, Issue 1, Pages 54–88 (Mi faa4234)

Derived category of equivariant coherent sheaves on a smooth toric variety and Koszul duality

Valery Luntsab

a Indiana University, Department of Mathematics, Bloomington, USA
b National Research University "Higher School of Economics", Moscow, Russia

Abstract: Let $X$ be a smooth toric variety defined by the fan $\Sigma$. We consider $\Sigma$ as a finite set with topology and define a natural sheaf of graded algebras $\mathcal{A}_\Sigma$ on $\Sigma$. The category of modules over $\mathcal{A}_\Sigma$ is studied (together with other related categories). This leads to a certain combinatorial Koszul duality equivalence.
We describe the equivariant category of coherent sheaves $\mathrm{coh}_{X,T}$ and a related (slightly bigger) equivariant category $\mathcal{O}_{X,T}\text{-}\mathrm{mod}$ in terms of sheaves of modules over the sheaf of algebras $\mathcal{A}_\Sigma$. Eventually (for a complete $X$), the combinatorial Koszul duality is interpreted in terms of the Serre functor on $D^b(\mathrm{coh}_{X,T})$.

Keywords: toric varieties, equivariant coherent sheaves, derived category.

MSC: 14M25, 18G80, 57S25

Received: 23.05.2024
Revised: 14.08.2024
Accepted: 19.08.2024

DOI: 10.4213/faa4234


 English version:
Functional Analysis and Its Applications, 2025, 59:1, 38–64

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© Steklov Math. Inst. of RAS, 2025