Let $C$ be an open convex set in $N_{\mathbb{R}}$ and $f\in{\mathcal{C}}^{2}(C)$ a concave function. Then

$${\mathcal{M}}_{\mu}(f)=(-1)^{n}\det(\operatorname{Hess}(f))\,\text{\rm d}u_{1}\land\dots\land\,\text{\rm d}u_{n},$$

where the Hessian matrix is calculated with respect to the coordinates $(u_{1},\dots,u_{n})$.