2021/06/12 by Vladimiro Benedetti, Benedetti, Vladimiro, Jieao Song +1 · 1 citation
Mathematics · #14C30 #14J28 #14J42 #14J45 #Advanced Algebra and Geometry #Algebraic Geometry (math.AG) #Algebraic Geometry and Number Theory #FOS: Mathematics #Geometry and complex manifolds
paper · pdf · doi:10.48550/arxiv.2106.06859
openalex publication_date 2021/06/12 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
Let V10 be a 10-dimensional complex vector space and let σ∈\bigwedge3V10^\vee be a non-zero alternating 3-form. One can define several associated degeneracy loci: the Debarre-Voisin variety X6σ\subsetGr(6,V10), the Peskine variety X1σ\subsetP(V10), and the hyperplane section X3σ⊂ Gr(3,V10). Their interest stems from the fact that the Debarre-Voisin varieties form a locally complete family of projective hyperkähler fourfolds of K3[2]-type. We prove that when smooth, the varieties X6σ, X1σ, and X3σ share one same integral Hodge structure, and that X1σ and X3σ both satisfy the integral Hodge conjecture in all degrees. This is obtained as a consequence of a detailed analysis of the geometry of these varieties along three divisors in the moduli space. On one of the divisors, an associated K3 surface S of degree 6 can be constructed geometrically and the Debarre-Voisin fourfold is shown to be isomorphic to a moduli space of twisted sheaves on S, in analogy with the case of cubic fourfolds containing a plane.