Description
I will first present a formalism to study symmetries in the context of diffeomorphism-invariant gauge theories. With it, I will show a universal symmetry algebra that contains the gauge symmetry and a covariant version of the diffeomorphisms. Then, I will include nondynamical fields that are supposed to describe effects associated with more fundamental degrees of freedom. Typically, these objects reduce/break the symmetries of the theory, and I will present a method to find the residual symmetries. I will present some results obtained with this method in theories with explicit Lorentz invariance and for the Unimodular Theory of Gravity, which is only invariant under a subgroup of diffeomorphisms.
