  We prove the following statement: Let g be a light-line-complete
pseudo-Riemannian Einstein metric of indefinite signature on a connected
(n>2)-dimensional manifold M. Assume that a conformally equivalent metric is
also Einstein. Then, the metrics are proportional with a constant coefficient.
  If in addition the manifold is closed, the assumption that the manifold is
light-line-complete could be omitted.
