English

On a $q$-Skew Amitsur's Theorem

Rings and Algebras 2026-05-12 v1

Abstract

Let RR be an algebra over an uncountable field, σ\sigma a locally torsion automorphism and δ\delta a locally nilpotent left σ\sigma-derivation such that qσδ=δσq\sigma\delta = \delta\sigma, where qq is a nonzero scalar. We show that the constant part of the Jacobson radical of the Ore extension R[x;σ,δ]R[x;\sigma,\delta] is nil. This partially answers a question of Greenfeld, Smoktunowicz and Ziembowski posed in 2019. As a corollary, we employ Shin's 2024 result to prove a q-skew Amitsur's theorem whenever the field is additionally assumed to be of characteristic zero. That is, the Jacobson radical of R[x;σ,δ]R[x;\sigma, \delta] is N[x;σ,δ]N[x;\sigma,\delta] for some nil ideal NN of RR.

Cite

@article{arxiv.2605.08100,
  title  = {On a $q$-Skew Amitsur's Theorem},
  author = {Aristide F. J. -C. Launois},
  journal= {arXiv preprint arXiv:2605.08100},
  year   = {2026}
}

Comments

13 pages; comments welcome

R2 v1 2026-07-01T12:58:21.513Z