Seminars & Colloquia Calendar
On Makkai's Strong Conceptual Completeness Theorem
Jacob Lurie (IAS)
Location: Hill 705
Date & time: Friday, 20 September 2019 at 4:00PM - 5:00PM
Abstract: One of the most fundamental results of mathematical logic is the celebrated Godel completeness theorem, which asserts that every consistent first-order theory T admits a model. In the 1980s, Makkai proved a much sharper result: any first-order theory T can be recovered, up to a suitable notion of equivalence, from its category of models Mod(T) together with some additional structure (supplied by the theory of ultraproducts). In this talk, I'll explain the statement of Makkai's theorem and sketch a new proof of it, inspired by the theory of "pro-etale sheaves" studied by Scholze and Bhatt - Scholze.