English

Products in a Category with One Object

Category Theory 2016-08-23 v2 Combinatorics

Abstract

We study monoids equipped with a second binary operation that captures the structure of the endomorphisms of an object XX such that X=X×XX=X\times X. We construct a universal monoid of this type and examine some of its rich combinatorial structure. We show that if XX has a nontrivial endomorphism and X=X×XX=X\times X, then every finite monoid has a faithful action on XX.

Keywords

Cite

@article{arxiv.1604.03999,
  title  = {Products in a Category with One Object},
  author = {Aaron Gray and Keith Pardue},
  journal= {arXiv preprint arXiv:1604.03999},
  year   = {2016}
}

Comments

This is a revised version of the paper first posted in April. We have tightened some arguments and added a new section with a conjecture and some further questions. Please send comments to the second author

R2 v1 2026-06-22T13:31:58.232Z