0
$\begingroup$

Let $e_{1},e_{2}$ be a frame of $\mathbb{R}^{2}$. $G=(ne_{1}+me_{2} : n,m \in \mathbb{Z})$ be a subgroup acting on $\mathbb{R}^{2}$ by translation.Show that the quotient map $\pi :\mathbb{R}^{2}\to\mathbb{R}^{2}/G$ is locally bijective.

1 Answers 1