turkmath.org

Covering spaces of topological spaces has an old and deep history. In this talk, we are going to describe a graph theoretical analogue of coverings. After defining what we mean by ''a graph covering another graph,'' we are going to work out details of the corresponding Galois theory. This is a survey talk on known results mainly for graduate students. Our main reference is Friedman, J.; ''Sheaves on graphs, their homological invariants, and a proof of the Hanna Neumann conjecture.'' Mem. Amer. Math. Soc. 233 (2015), no. 1100.