The minima of a flow named for one form of this quantity solve the isoperimetric problem. The local form of one theorem relates the sum of exterior angles of a simple surface to the sum of integrals of two forms of this quantity, and the global form relates those integrals to the Euler characteristic. As the Hessian's eigen
The minima of a flow named for one form of this quantity solve the isoperimetric problem. The local form of one theorem relates the sum of exterior angles of a simple surface to the sum of integrals of two forms of this quantity, and the global form relates those integrals to the Euler characteristic. As the Hessian's eigenvalues give a form of this quantity, the Hessian's determinant at extrema determines a function's concavity. Under an arc length parametrization, this quantity is the magnitude of the derivative of the tangent vector. For 10 points, name this measure of a surface's bending.