Generalized Kummer surfaces over finite fields
Sergey Rybakov
TL;DR
This work refines Katsura’s insights on finite groups acting on abelian surfaces whose quotients are birational to K3 surfaces, focusing on generalized Kummer surfaces over finite fields. It develops a rigid-action framework via the rigid quotient Q[G]^{rig}, classifies possible group actions on abelian surfaces, and analyzes the resulting singularities and Néron–Severi lattices of the resolutions. The paper then connects these geometric data to arithmetic, deriving zeta functions and explicit Frobenius traces for supersingular generalized Kummer surfaces, and provides conditions for the existence of rigid and symplectic actions in various characteristics. The results yield concrete, nonnegative, even Frobenius traces and a detailed catalog of group-field combinations that yield supersingular generalized Kummer surfaces, advancing the arithmetic-geometric classification of these objects.
Abstract
In this paper, we prove a refinement of the Katsura theorem on finite groups acting on abelian surfaces such that the quotient is birational to a $K3$ surface. As an application, we compute traces of Frobenius on the Neron--Severi groups of supersingular generalized Kummer surfaces over finite fields.
