In
mathematics,
constant curvature is a concept from
differential geometry. Here, curvature refers to the
sectional curvature of a space (more precisely a
manifold) and is a single number determining its local geometry. The sectional curvature is said to be constant if it has the same value at every point and for every two-dimensional tangent plane at that point. For example, a
sphere is a surface of constant positive curvature.