Lang-Weil type bounds in finite difference fields

Basic data for this talk

Type of talkscientific Talk
Name der VortragendenHils, Martin
Date of talk15/02/2023
Talk languageEnglish

Information about the event

Name of the eventDonau-Rhein-Modelltheorie-Seminar
Event period14/02/2023 - 15/02/2023
Event locationUniversität Passau
Event websitehttps://www.fim.uni-passau.de/professur-reine-mathematik/donau-rhein-modelltheorie-seminar

Abstract

We establish Lang-Weil type bounds for the number of rational points of difference varieties over finite difference fields, in terms of the transformal dimension of the variety and assuming the existence of a smooth rational point. It follows that, working in any non-principle ultraproduct K of finite difference fields, the normalized pseudofinite dimension of a quantifier free partial type p is equal to its transformal dimension, i.e., to the maximal transformal transcendence degree over K of a realization of p. The proof uses a strong form of the Lang-Weil estimates (due to Cafure and Matera) and, as key ingredient to obtain equidimensional Frobenius specializations, the recent work of Dor and Hrushovski on the non-standard Frobenius acting on an algebraically closed non-trivially valued field, in particular the pure stable embeddedness of the residue difference field in this context. This is joint work with Ehud Hrushovski, Jinhe Ye and Tingxiang Zou.
KeywordsLang-Weil estimates; finite difference field; non-standard counting

Speakers from the University of Münster

Hils, Martin

Projects the talk is about

Duration: 01/01/2020 - 31/12/2024
Funded by: DFG - Individual Grants Programme
Type of project: Individual project
Duration: 01/01/2019 - 31/12/2025 | 1st Funding period
Funded by: DFG - Cluster of Excellence
Type of project: Subproject in DFG-joint project hosted at University of Münster