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arXiv · 2305.05041

The Chevalley-Bass Theorem

Yuri Bilu
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Abstract

This is an exposition of a theorem due to Chevalley (1951) and Bass (1965). Let $K$ be a finitely generated field. Then there exists a positive integer $Λ$, depending only on $K$, such that for every positive integer $n$ the following holds: if $α\in K$ is a $Λn$th power in the cyclotomic extension $K(ζ_{Λn})$, then $α$ is an $n$th power in $K$. We also give explicit expressions for a suitable $Λ$ of two kinds: one in terms of the degree of the maximal abelian subfield of $K$, the other in terms of the discriminant of this subfield.

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Yuri Bilu. 2023-08-08. The Chevalley-Bass Theorem. https://arxiv.org/abs/2305.05041

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