2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/216681Friedrich Knop has given an example of a polynomial algebra A in characteristic two with an unusual SL_2 action. We exhibit a nontrivial class in H^1(SL_2,A), not detected by Frobenius kernels.3 pagesRepresentation Theory20G10; 20G40Rational cohomology of an algebra need not be detected by Frobenius kernelstext