2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/196360Starting from a characterization of admissible Cheataev and vakonomic variations in a field theory with constraints we show how the so called parametrized variational calculus can help to derive the vakonomic and the non-holonomic field equations. We present an example in field theory where the non-holonomic method proved to be unphysical.Mathematical Physics70S05; 70F25; 58A20text