Just a small notation question from this Wikipedia page:
The absolute Galois group of a finite field $K$ is isomorphic to the group $$\hat{\mathbb{Z}}=\lim_{\leftarrow} \mathbb{Z}/n\mathbb{Z}.$$
What does the $\displaystyle\lim_{\leftarrow}$ part mean? Why is it written like that?
It is used to denote the inverse limit as opposed to the notation $\displaystyle\lim_{\to}$ which is used to denote the direct limit.