English

Twisting lemma for $\Lambda$-adic modules

Number Theory 2021-01-11 v2

Abstract

A classical twisting lemma says that given a finitely generated torsion module MM over the Iwasawa algebra Zp[[Γ]]\mathbb{Z}_p[[\Gamma ]] with ΓZp, \Gamma \cong \mathbb{Z}_p, \ \exists a continuous character θ:ΓZp×\theta: \Gamma \rightarrow \mathbb{Z}_p^\times such that, the Γn \Gamma^{n}-Euler characteristic of the twist M(θ)M(\theta) is finite for every nn. This twisting lemma has been generalized for the Iwasawa algebra of a general compact pp-adic Lie group GG. In this article, we consider a further generalization of the twisting lemma to T[[G]]\mathcal{T}[[G]] modules, where GG is a compact pp-adic Lie group and T\mathcal{T} is a finite extension of Zp[[X]]\mathbb{Z}_p[[X]]. Such modules naturally occur in Hida theory. We also indicate arithmetic application by considering the twisted Euler Characteristic of the big Selmer (respectively fine Selmer) group of a Λ\Lambda-adic form over a pp-adic Lie extension.

Keywords

Cite

@article{arxiv.2008.09573,
  title  = {Twisting lemma for $\Lambda$-adic modules},
  author = {Sohan Ghosh and Somnath Jha and Sudhanshu Shekhar},
  journal= {arXiv preprint arXiv:2008.09573},
  year   = {2021}
}

Comments

14 pages

R2 v1 2026-06-23T18:01:26.522Z