A nilpotent symmetry of quantum gauge theories

For the Becchi-Rouet-Stora-Tyutin invariant extended action for any gauge t heory, there exists another off-shell nilpotent symmetry. For linear gauges , it can be elevated to a symmetry of the quantum theory and used in the co nstruction of the quantum effective action. Generalizations for nonlinear a nd actions with higher-order ghost terms are also possible.