Beautiful pairs in unstable theories and spaces of definable types

Basic data for this talk

Type of talkscientific talk
Name der VortragendenHils, Martin
Date of talk08/03/2023
Talk languageEnglish

Information about the event

Name of the eventResearch Seminar in Model Theory
Event period08/03/2023
Event locationUniversität Wien
Event websitehttps://mathematik.univie.ac.at/en/eventsnews/full-news-display/news/beautiful-pairs-in-unstable-theories-and-spaces-of-definable-types/?no_cache
Organised byKurt Gödel Research Center, Universität Wien

Abstract

By classical results of Poizat, the theory of beautiful pairs of models of a stable theory T is "meaningful" precisely when the set of all definable types in T is strict pro-definable, which is the case if and only if T is nfcp. We transfer the notion of beautiful pairs to unstable theories and study them in particular in henselian valued fields, establishing Ax-Kochen-Ershov principles for various questions in this context. Using this, we show that the theory of beautiful pairs of models of ACVF is "meaningful" and infer the strict pro-definability of various spaces of definable types in ACVF, e.g., the model theoretic analogue of the Huber analytification of an algebraic variety. This is joint work with Pablo Cubides Kovacsics and Jinhe Ye.
Keywordsbeautiful pairs; valued fields; definable types

Speakers from the University of Münster

Hils, Martin
Professorship for Mathematical Logic (Prof. Hils)