Let $M$ be a manifold. Does it admit an elliptic operator on $C^{\infty}(M)$ which satisfy Leibnitz rule? Let $M$ be a symplectic manifold with the standard Poisson structure on $C^{\infty}(M)$. Does it admit an elliptic operator $D$ which satisfy $D(\{f,g\})=\{D(f),g\}+\{f,D(g)\}$?