\[{(-1)}^{n}\frac{{\mathrm{d}}^{n}}{{\mathrm{d}s}^{n}}\mathscr{L}\mskip-3.0muf%
\mskip 3.0mu\left(s\right)=\mathscr{L}\mskip-3.0muf_{n}\mskip 3.0mu\left(s%
\right),\]