An obstruction for the mean curvature of a conformal immersion S^{n}-> R^{n+1}

Ammann, Bernd; Humbert, Emmanuel; Ahmedou, Mohameden Ould

An obstruction for the mean curvature of a conformal immersion S^{n}-> R^{n+1}

Authors

Ammann, Bernd

Humbert, Emmanuel

Ahmedou, Mohameden Ould

Description

We prove a Pohozaev type identity for non-linear eigenvalue equations of the Dirac operator on Riemannian spin manifolds with boundary. As an application, we obtain that the mean curvature H of a conformal immersion S^{n}-> R^{n+1} satisfies $\int \partial_X H=0$ where X is a conformal vector field on S^{n} and where the integration is carried out with respect to the Euclidean volume measure of the image.<BR> This identity is analogous to the Kazdan-Warner obstruction that appears in the problem of prescribing the scalar curvature on S^{n} inside the standard conformal class.