The scalar curvature, also called the "curvature scalar" (e.g., Weinberg 1972, p. 135; Misner et al. 1973, p. 222) or "Ricci scalar," is given by
where is the metric tensor and is the Ricci curvature tensor.
The scalar curvature, also called the "curvature scalar" (e.g., Weinberg 1972, p. 135; Misner et al. 1973, p. 222) or "Ricci scalar," is given by
where is the metric tensor and is the Ricci curvature tensor.
Weisstein, Eric W. "Scalar Curvature." From MathWorld--A Wolfram Web Resource. https://mathworld.wolfram.com/ScalarCurvature.html