Strongly clean ring elements that are one-sided inverses
Abstract
A longstanding open question is whether every strongly clean ring (ring in which every element is strongly clean, i.e., is the sum of an idempotent and a unit which commute with each other) is Dedekind-finite (has the property that every element with a one-sided inverse is invertible). We give an example of a ring with two strongly clean elements that are one-sided, but not two-sided, inverses of one another, suggesting that the answer to that question may be negative. We then discuss possible ways of strengthening this result to give a full negative answer. We end with some brief observations on related topics, in particular, uniquely strongly clean rings.
Keywords
Cite
@article{arxiv.2508.14396,
title = {Strongly clean ring elements that are one-sided inverses},
author = {George M. Bergman},
journal= {arXiv preprint arXiv:2508.14396},
year = {2025}
}
Comments
4 pages. Copy at http://math.berkeley.edu/~gbergman/papers may be updated more frequently than arXiv copy