English

How many units can a commutative ring have?

Commutative Algebra 2017-01-11 v1 Group Theory Rings and Algebras

Abstract

Laszlo Fuchs posed the following problem in 1960, which remains open: classify the abelian groups occurring as the group of all units in a commutative ring. In this note, we provide an elementary solution to a simpler, related problem: find all cardinal numbers occurring as the cardinality of the group of all units in a commutative ring. As a by-product, we obtain a solution to Fuchs' problem for the class of finite abelian pp-groups when pp is an odd prime.

Cite

@article{arxiv.1701.02341,
  title  = {How many units can a commutative ring have?},
  author = {Sunil K. Chebolu and Keir Lockridge},
  journal= {arXiv preprint arXiv:1701.02341},
  year   = {2017}
}

Comments

6 pages, to appear in Amer. Math. Monthly

R2 v1 2026-06-22T17:45:15.863Z