English

A Generalization of $\Delta$U Rings

Rings and Algebras 2026-05-22 v1 Representation Theory

Abstract

In this paper, we introduce and study a new class of rings calling them {\it weakly ΔU\Delta U-rings}, hereafter abbreviated as {\it WΔUW\Delta U-rings} for short. A ring RR is said to be WΔUW\Delta U if every unit of RR can be expressed as ±1+d\pm 1 + d for some dΔ(R)d \in \Delta(R), where Δ(R)\Delta(R) is the largest Jacobson radical of RR that is closed under multiplication by units. Utilizing the known structure of Δ(R)\Delta(R), we investigate the relationships between WΔUW\Delta U rings and certain classical concepts such as ΔU\Delta U-rings, UJUJ-rings, WUJWUJ-rings, as well as clean and exchange rings. Among the main results, we show that a matrix ring Mn(R)M_n(R) is never WΔUW\Delta U for any n2n \ge 2. We also provide complete characterizations of local, semi-local, semi-simple and semi-regular rings that are WΔUW\Delta U. Furthermore, it is shown for exchange rings that the WΔUW\Delta U property is equivalent to being WUJWUJ. Furthermore, the behavior of WΔUW\Delta U-rings under various ring extensions, including skew polynomial rings, skew power series rings, triangular matrix rings, trivial extensions and group rings, is thoroughly examined. Several examples are given to illustrate that the class of WΔUW\Delta U-rings properly contains the class of ΔU\Delta U-rings. Finally, necessary and sufficient conditions for a group ring RGRG to be WΔUW\Delta U are established too. Resuming all of the presented above, our results expanded those by Karaba\c{c}ak et al. published in J. Algebra \& Appl. (2021).

Keywords

Cite

@article{arxiv.2605.22700,
  title  = {A Generalization of $\Delta$U Rings},
  author = {Peter Danchev and Omid Hasanzadeh and Ahmad Moussavi and Mehrdad Esfandiar},
  journal= {arXiv preprint arXiv:2605.22700},
  year   = {2026}
}

Comments

20 pages

R2 v1 2026-07-22T07:26:40.945Z