## Logic Seminar

Recall that if $E/K$ is an infinite Galois extension, then the Galois group $G = \mathrm{Gal}(E/K)$ comes endowed with a canonical topology which in turn makes $G$ a profinite topological group. Observing that $E$ can be written as a union of finite Galois orbits over $K$, we consider $E$ to be a finitary structure. Generalizing this situation using definability leads to a model-theoretic reformulation of Galois groups for schemes. As such, we develop a category of interpretations to detect differences in automorphism groups of multi-sorted structures. This yields a restriction functor from the category of finitary structures to the category of profinite groups, and we show that this functor is an almost equivalence of categories.