Calvin Lab Rm 116
Structural Limits, Modelings and Logic
We present an overview of hierarchies of sparse classes of finite structures, and show the robustness of this notion by stating various equivalent formulations (logical, analytic, combinatorial). We then state two very recent formulations: analytic in terms of structural limits, and categorical in terms of universal categories. This is joint work with Patrice Ossona de Mendez (Paris and Prague).