Sheaves, Complexes of Groups, and Developability

In this thesis, we define sheaves over a small category. In Definition 5.1.1, we give the basic definitions of a sheaf and, following Warren Dick’s retelling of Joel Friedman’s proof of the Hanna Neumann Conjecture (2), give our own proof 4.1.1. In Definition 7.2.2, we give the necessary conditions for a sheaf to satisfy to imply that a complex of groups is developable.