We study Riemannian
manifolds (Mn,g) equipped with a smooth measure m. We show that the
construction of conformally covariant operators of Graham–Jenne–Mason–Sparling
can be adapted to this setting. As a byproduct, we define a family of scalar
curvatures, one of which corresponds to Perelman’s scalar-curvature function. We
also study the variational problem naturally associated to these curvature/operator
pairs.