Edge modes of tetrad gravity: Unlike diffeomorphisms, all shifts are integrable

Abstract: We present an improved notion of internal tetrad shifts in 4 dimensions which is always integrable in the presence of corners. This allows us to study the fully extended corner symmetry algebra of gauge charges, which is a deformation of $ISO(1,3)^S$ involving spacetime curvature. We argue this implies corner noncommutativity of the spin connection $\omega$. The latter in particular hints that an extended BF theory might be a better way understand the dynamics of tetrad gravity. This result presents us with an integrable, complete set of edge modes for gravity in 4D, with potential ramifications for asymptotic symmetries and quantisation.