Let $\mathbb{A}$ be a (non-empty) subset of a compact kähler surface $\mathbb{X}$.
Denote by $\mathcal{N}(\mathbb{A})$ the normal vector bundle of $\mathbb{A}$.
What do they mean by saying "let $\varphi_{\lambda}$ be the fibrewise multiplication by $\lambda \in \mathbb{C}^*$ on $\mathcal{N}(\mathbb{A})$"?