# Almost-Schur lemma - Mathematics > Differential Geometry

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Abstract: Schur-s lemma states that every Einstein manifold of dimension $n\geq 3$ hasconstant scalar curvature. Here $M,g$ is defined to be Einstein if itstraceless Ricci tensor $$\Rico:=\Ric-\frac{R}{n}g$$ is identically zero. Inthis short note we ask to what extent the scalar curvature is constant if thetraceless Ricci tensor is assumed to be \emph{small} rather than identicallyzero.

Author: ** Camillo De Lellis, Peter M. Topping**

Source: https://arxiv.org/