Fraisse's Construction from a Topos-Theoretic Perspective (joint with Maths Dept, Different time and place)

Olivia Caramello ( University of Cambridge )

We present a topos-theoretic interpretation of (a categorical generalization of) Fraïssé's construction in Model Theory, with applications to countably categorical theories. The proof of our main theorem represents an instance of exploiting the interplay of syntactic, semantic and geometric ideas in the foundations of Topos Theory.