2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/156017We affirmatively answer a conjecture in the preprint ``Essential dimension and algebraic stacks,'' proving that the essential dimension of an abelian variety over a number field is infinite.4 pages. To appear in C. R. Math. Acad. Sci. Paris. Preprint posted earlier to http://www.mathematik.uni-bielefeld.de/LAG/Number Theory11G99text