Curvature of the round unit sphere
= Curvature of the round unit sphere
With outward normal $N(x)=x$, the unit sphere has $A(X,Y)=-\langle X,Y\rangle N$. The <Gauss equation> therefore gives sectional curvature one on every tangent two-plane.
= Curvature of the round unit sphere
With outward normal $N(x)=x$, the unit sphere has $A(X,Y)=-\langle X,Y\rangle N$. The <Gauss equation> therefore gives sectional curvature one on every tangent two-plane.