Equation 12.6.3773FE713DE9E4

\begin{equation} \begin{aligned} g_{\mathscr S}& =m\, \mathrm{d}U^2+\rho (v)\, \mathrm{d}v^2,\\ \rho (v)& =\frac{Q''/Q-2(Q'/Q)^2}{n} =\frac2n\operatorname {Var}_{\nu _ v}(\ell _ v)>0. \end{aligned} \end{equation}