English

On the Root of Unity Ambiguity in a Formula for the Brumer--Stark Units

Number Theory 2025-12-18 v3

Abstract

We prove a conjectural formula for the Brumer--Stark units. Dasgupta--Kakde have shown the formula is correct up to a bounded root of unity. In this paper we resolve the ambiguity in their result. We also remove an assumption from Dasgupta--Kakde's result on the formula.

Keywords

Cite

@article{arxiv.2302.12332,
  title  = {On the Root of Unity Ambiguity in a Formula for the Brumer--Stark Units},
  author = {Matthew H. L. Honnor},
  journal= {arXiv preprint arXiv:2302.12332},
  year   = {2025}
}

Comments

12 pages. This version proves a stronger result, dealing with the ambiguity at 2