Nuts have no hair

الأصل · EN

We show that the Riemannian Kerr solutions are the only Riemannian, Ricci-flat and asymptotically flat C²-metrics gμν on a 4-dimensional complete manifold M of topology R² × S² which have (at least) a 1-parameter group of periodic isometries with only isolated fixed points ("nuts") and with orbits of bounded length at infinity.