Unramified Brauer groups of finite simple groups of Lie type $A

2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/65627We study the subgroup B_0(G) of H^2(G,Q/Z) consisting of all elements which have trivial restrictions to every Abelian subgroup of G. The group B_0(G) serves as the simplest nontrivial obstruction to stable rationality of algebraic varieties V/G where V is a faithful complex linear representation of the group G. We prove that B_0(G) is trivial for finite simple groups of Lie type A_{\ell}.15 pagesAlgebraic GeometryPrimary 14E08, 14L24, 14L30; Secondary 20D06Unramified Brauer groups of finite simple groups of Lie type $A_{\ell}$text