Equation 9.11.110C6FD486D0E4

\begin{equation} \pi ^*\mathrm{d}V_ D=C_ D|s|^{-1}\, \mathrm{d}A_ s\, \mathrm{d}A_ t, \qquad \pi ^*\mathrm{d}V_0=C_0\, \mathrm{d}A_ s\, \mathrm{d}A_ t, \end{equation}