2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/125095I give a new proof, in scheme-theoretic language, of Tate's old result on genus-change over nonperfect fields in characteristic p>0. Namely, for normal geometrically integral curves, the difference between arithmetic and geometric genus over the algebraic closure is divisible by (p-1)/2.4 pagesAlgebraic GeometryNumber Theory14H20text