2025/08/12 by David Zhiyuan Bai, Bai, David Zhiyuan
Mathematics · #Algebraic Geometry (math.AG) #Algebraic Geometry and Number Theory #Algebraic structures and combinatorial models #FOS: Mathematics #Homotopy and Cohomology in Algebraic Topology
paper · pdf · doi:10.48550/arxiv.2508.09065
openalex publication_date 2025/08/12 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
Let X→ C be an elliptic surface with integral fibers and a section. The Hilbert scheme X[n] fibers over C[n]. We construct a commutative group scheme over the entire base C[n] that embeds as an open subscheme of the Hilbert scheme, such that its action on itself extends to the entirety of X[n]. We show that the action is δ-regular in the sense of Ngô. Using the derived McKay correspondence, we construct an exact autoequivalence of DbCoh(X[n]) whose kernel is a maximal Cohen-Macaulay sheaf on the fiber product. We show that this Fourier-Mukai transform intertwines with our group action, i.e. theorem of the square holds. We also discuss the case without a section using the theory of Tate-Shafarevich twists.