Maximal subgroups of the Mathieu group $M_{23}$ and symplectic automorphisms of supersingular K3 surfaces

2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/104883We show that the Mathieu groups $M_{22}$ and $M_{11}$ can act on the supersingular $K3$ surface with Artin invariant 1 in characteristic 11 as symplectic automorphisms. More generally we show that all maximal subgroups of the Mathieu group $M_{23}$ with three orbits on 24 letters act on a supersingular $K3$ surface with Artin invariant 1 in a suitable characteristic.7 pagesAlgebraic Geometry14J28; 20D08Maximal subgroups of the Mathieu group $M_{23}$ and symplectic automorphisms of supersingular K3 surfacestext