Sixfolds of generalized Kummer type and K3 surfaces

TL;DR

This paper establishes a new geometric relationship between hyper-Kähler sixfolds of generalized Kummer type and K3 surfaces, revealing their deep connections and implications for the Kuga-Satake Hodge conjecture.

Contribution

It constructs a natural association between hyper-Kähler sixfolds of generalized Kummer type and K3^{[3]}-type manifolds, and proves the algebraicity of the Kuga-Satake correspondence for related K3 surfaces.

Findings

Construction of a manifold $Y_K$ associated to each hyper-Kähler sixfold $K$

Demonstration that $Y_K$ is birational to a moduli space of stable sheaves on a K3 surface

Proof that the Kuga-Satake correspondence is algebraic for these K3 surfaces

Abstract

We prove that any hyper-K\"{a}hler sixfold $K$ of generalized Kummer type has a naturally associated manifold $Y_K$ of $\mathrm{K}3^{[3]}$-type. It is obtained as crepant resolution of the quotient of $K$ by a group of symplectic involutions acting trivially on its second cohomology. When $K$ is projective, the variety $Y_K$ is birational to a moduli space of stable sheaves on a uniquely determined projective~$\mathrm{K}3$ surface~$S_K$. As application of this construction we show that the Kuga-Satake correspondence is algebraic for the K3 surfaces $S_K$, producing infinitely many new families of $\mathrm{K}3$ surfaces of general Picard rank $16$ satisfying the Kuga-Satake Hodge conjecture.