# duality breaking

06 Dec 2023The Bianchi-identity in electrodynamics can be written in the form of a field equation for the field dual \(\tilde{F}_{\mu\nu}\) with a vanishing source, and introducing a non-vanishing source at this point is related to phenomena in relation to magnetic charges, which Nature is not using. Could one carry out a similar construction for a field dual of the Riemann-curvature, and would there an argument why the source term is zero?