Sectional Curvature
The mathematical object kappa which controls the rate of geodesic deviation.
See also
Bishop's Inequality, Cheeger's Finiteness Theorem, GeodesicExplore with Wolfram|Alpha
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Cite this as:
Weisstein, Eric W. "Sectional Curvature." From MathWorld--A Wolfram Resource. https://mathworld.wolfram.com/SectionalCurvature.html