Conformal Scattering of Maxwell Fields on Reissner-Nordstr{\o}m-de Sitter Black Hole Spacetimes

We construct a complete conformal scattering theory for Maxwell fields in the static exterior region of a Reissner-Nordstr{\o}m-de Sitter black bole spacetime. This is done using uniform energy decay results that we obtain in a separate paper, to show that the trace operators are injective and have closed ranges. We then solve the Goursat problem (characteristic Cauchy problem) for Maxwell fields on the null boundaries showing that the trace operators are also surjective.