Varietà lineare

Dato un insieme $\mathbb{U}$ SSV di $\mathbb{V}$, $$\begin{gathered} \mathbb{U}+\underline{v}=\{\underline{w}\in \mathbb{U}:\underline{w}=\underline{u}+\underline{v}, \\ \underline{u}\in \mathbb{U}\} \end{gathered}$$.