Codice QDD208 Titolo A variational characterization of flat spaces in dimension three Data 2015-04-20 Autore/i Catino, G.; Mastrolia, P.; Monticelli, D.D. Link Download full text Abstract In this short note we prove that, in dimension three, flat metrics are the only complete metrics with non-negative scalar curvature which are critical for the sigma_2-curvature functional.