20250228 Differentiable Stacks III

At the end of the last talk, we saw that we can view categories fibered in groupoids as a lax presheaf with values in groupoids. A natural question then to ask is how and when we can glue objects and morphisms defined on some cover, similarly as one does with sheaves. This leads to the concept of descent data and stacks. We will also see that some examples from earlier talks turn out to be stacks.