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Arithmetic equivalence for non-geometric extensions of global function fields

Authors :
Battistoni, Francesco
Oukhaba, Hassan
Publication Year :
2021

Abstract

In this paper we study couples of finite separable extensions of the function field $\mathbb{F}_q(T)$ which are arithmetically equivalent, i.e. such that prime ideals of $\mathbb{F}_q[T]$ decompose with the same inertia degrees in the two fields, up to finitely many exceptions. In the first part of this work, we extend previous results by Cornelissen, Kontogeorgis and Van der Zalm to the case of non-geometric extensions of $\mathbb{F}_q(T)$, which are fields such that their field of constants may be bigger than $\mathbb{F}_q$. In the second part, we explicitly produce examples of non-geometric extensions of $\mathbb{F}_2(T)$ which are equivalent and non-isomorphic over $\mathbb{F}_2(T)$ and non-equivalent over $\mathbb{F}_4(T)$, solving a particular Inverse Galois Problem.<br />Comment: 18 pages. Comments are welcome

Subjects

Subjects :
Mathematics - Number Theory

Details

Database :
arXiv
Publication Type :
Report
Accession number :
edsarx.2107.01911
Document Type :
Working Paper