# Algebraically Closed Fields with a Generic Multiplicative Character

## TL;DR

This paper explores the model theory of algebraically closed fields with a generic multiplicative character, providing axiomatization, classification, and stability results for the structure.

## Contribution

It introduces an axiomatization of the structure, classifies models, and proves stability and definability properties, advancing understanding of such algebraic structures.

## Key findings

- Axiomatization of the structure in a suitable language
- Classification of models up to isomorphism
- Proved that the theory is ω-stable and has definability of Morley rank

## Abstract

We study the model theory of the $2$-sorted structure $(\mathbb{F}, \mathbb{C};\chi)$, where $\mathbb{F}$ is an algebraic closure of a finite field of characteristic $p$, $\mathbb{C}$ is the field of complex numbers and $\chi: \mathbb{F} \to \mathbb{C}$ is an injective, multiplication preserving map. We obtain an axiomatization $\mathrm{ACFC}_p$ of $\mathrm{Th}(\mathbb{F},\mathbb{C};\chi)$ in a suitable language $L$, classify the models of $\mathrm{ACFC}_p$ up to isomorphism, prove a modified model companion result, give various descriptions of definable sets inside a model of $\mathrm{ACFC}_p$, and deduce that $\mathrm{ACFC}_p$ is $\omega$-stable and has definability of Morley rank in families.