English

One-sided inverses in noncommutative infinitary semigroups

Group Theory 2026-05-28 v1 Rings and Algebras

Abstract

In a former paper we introduced partial infinitary noncommutative semigroups and showed, among other, that significant differences arise in comparison with the commutative case, previously studied in the literature. For example, in the commutative case we cannot have an infinitary identity ee together with two elements aea \not= e, beb \not= e such that ab=eab= e, just under the assumption that the countable product abababaabababa\dots is defined. Here we show that this is possible in the noncommutative case, actually, we can have an infinitary semigroup on a countable set with a complete identity and such that the operation is defined for every indexed linearly ordered set.

Keywords

Cite

@article{arxiv.2605.28416,
  title  = {One-sided inverses in noncommutative infinitary semigroups},
  author = {Paolo Lipparini},
  journal= {arXiv preprint arXiv:2605.28416},
  year   = {2026}
}

Comments

18 pages

R2 v1 2026-07-22T07:37:06.979Z