English

Finiteness and infiniteness of gradings of Noetherian rings

Commutative Algebra 2025-08-11 v2

Abstract

In this paper we show that for a torsion-free abelian group GG, rankZG<\operatorname{rank}_\mathbb{Z}G<\infty if and only if there exists a Noetherian GG-graded ring RR such that the set {Rg0}\{R_g \neq 0\} generates the group GG. For every GG of finite rank, we construct a GG-graded ring RR such that Rg0R_g \neq 0 for all gGg \in G. We prove such rings give examples of PIDs which are not ED. We also use the relations between the graded division ring and the group cohomology to prove some vanishing and nonvanishing results for second group cohomology. Finally, we prove that the Hilbert series of a finitely generated GG-graded RR-module is well-defined when R0R_0 is Artinian, and this Hilbert series times some Laurent polynomial is equal to a Laurent polynomial.

Keywords

Cite

@article{arxiv.2508.01628,
  title  = {Finiteness and infiniteness of gradings of Noetherian rings},
  author = {Cheng Meng},
  journal= {arXiv preprint arXiv:2508.01628},
  year   = {2025}
}

Comments

Fixed some typos