Rings whose Nil-Clean and Clean Elements are Uniquely Nil-Clean

TL;DR

This paper characterizes rings where each nil-clean or clean element is uniquely nil-clean, providing a detailed description for abelian rings and exploring their properties and extensions.

Contribution

It offers a comprehensive characterization of rings with uniquely nil-clean or clean elements, especially focusing on abelian rings and their subclasses.

Findings

Abelian rings with uniquely nil-clean elements are fully described.

In such rings, nil-clean and clean elements coincide with specific subclasses.

Extension properties and group rings of these rings are also analyzed.

Abstract

We consider and study those rings in which each nil-clean or clean element is uniquely nil-clean. We establish that, for abelian rings, these rings have a satisfactory description and even it is shown that the classes of abelian rings and the rings in which nil-clean elements are uniquely nil-clean do coincide. Moreover, we prove that the rings in which clean elements are uniquely nil-clean coincide with the subclass of abelian rings consisting of only unipotent units and, in particular, that in the semipotent case we have a complete characterization only in terms of the former ring and its divisions. Likewise, some extension properties and group rings for such kinds of rings are also considered.