Corollary 2

*Let $X$ be a paracompact manifold of class $C^r$ ($r \geq 2$) and $\xi$ a vector field of class $C^{r-1}$ on $X$. There exists a law chunk of operation $\psi$ of class $C^{r-1}$ of $K$ on $X$ such that for all $x \in X$, $\xi(x)$ is the image under $t \mapsto (t, x)$ of the tangent vector 1 to $K$ at 0. Two law chunks of operation with the above property coincide on a neighbourhood of $\{0\} \times X$.

This is a special case of Corollary 1.*

§ 5.1