### Lerman on Orbifolds

#### Posted by David Corfield

Eugene Lerman gave us his views on orbifolds in a discussion beginning here. Now you can read a whole paper of his on the subject Orbifolds as Stacks?:

Posted at June 30, 2008 10:40 AM UTCAbstract. The goal of this survey paper is to argue that if orbifolds are groupoids, then the collection of orbifolds and their maps need to be thought of as a 2-category. This 2-category may be either taken to be the weak 2-category of groupoids, bibundles and equivariant maps between bibundles or the strict 2-category of geometric stacks represented by proper étale Lie groupoids. While nothing in this paper is strictly speaking new, it is hoped that differential geometers unfamiliar with groupoids, bibundles and stacks would find it a useful introduction to the subject.

## Re: Lerman on Orbifolds

Hi David,

The link you provided points to this very page instead of the article itself.