English

Projective Geometries and Simple Pointed Matroids as $\mathbb{F}_1$-modules

Category Theory 2024-04-09 v1 Combinatorics

Abstract

We describe a fully faithful embedding of projective geometries, given in terms of closure operators, into F1\mathbb{F}_1-modules, in the sense of Connes and Consani. This factors through a faithful functor out of simple pointed matroids. This follows from our construction of a fully faithful embedding of weakly unital, commutative hypermagmas into \fun\fun-modules. This embedding is of independent interest as it generalizes the classical Eilenberg-MacLane embedding for commutative monoids and recovers Segal's nerve construction for commutative partial monoids. For this reason, we spend some time elaborating its structure.

Keywords

Cite

@article{arxiv.2404.04730,
  title  = {Projective Geometries and Simple Pointed Matroids as $\mathbb{F}_1$-modules},
  author = {Jonathan Beardsley and So Nakamura},
  journal= {arXiv preprint arXiv:2404.04730},
  year   = {2024}
}

Comments

31 pages, comments welcome

R2 v1 2026-06-28T15:46:06.245Z