English

A Note on Lagrange Subsets of Finite Groups

Group Theory 2025-12-30 v1

Abstract

In a finite group, a subset is called a Lagrange subset if its size divides the group order, and a factor if it admits a complementary subset. We provide a new and comparatively direct proof of the classification of groups in which every Lagrange subset is a factor. We show that any nontrivial such group must be a cyclic group of prime order, the cyclic group of order 4, or an elementary abelian group of order 4, 8, or 9.

Keywords

Cite

@article{arxiv.2512.22900,
  title  = {A Note on Lagrange Subsets of Finite Groups},
  author = {Mikhail Kabenyuk},
  journal= {arXiv preprint arXiv:2512.22900},
  year   = {2025}
}

Comments

8 pages

R2 v1 2026-07-01T08:43:22.081Z