Derivation

Statements

Definition. Let $v$ be a tangent vector at a point $p\in {\mathbb{R}}^n$, the mapping $D_v:{\mathcal{C}}^{\infty }(p)\to \mathbb{R}$ defined by the directional derivative at $p$ is said to be a derivation at $p$. The set of all derivations at $p$ is denoted as ${\mathcal{D}}_p({\mathbb{R}}^n)$.

References

@Tu11 pp. 13