## 77.1 Introduction

This chapter is devoted to generalities concerning groupoids in algebraic spaces. We recommend reading the beautiful paper [K-M] by Keel and Mori.

A lot of what we say here is a repeat of what we said in the chapter on groupoid schemes, see Groupoids, Section 39.1. The discussion of quotient stacks is new here.

In your comment you can use Markdown and LaTeX style mathematics (enclose it like $\pi$). A preview option is available if you wish to see how it works out (just click on the eye in the toolbar).

Unfortunately JavaScript is disabled in your browser, so the comment preview function will not work.

In order to prevent bots from posting comments, we would like you to prove that you are human. You can do this by filling in the name of the current tag in the following input field. As a reminder, this is tag 0438. Beware of the difference between the letter 'O' and the digit '0'.