English

Chern Numbers of Matroids

Combinatorics 2023-10-18 v3 Algebraic Geometry

Abstract

We define Chern numbers of a matroid. These numbers are obtained when intersecting appropriate matroid Chern-Schwartz-MacPherson cycles defined by L\'opez de Medrano, Rinc\'on, and Shaw. We prove that when a matroid arises from a complex hyperplane arrangement the Chern numbers of the matroid correspond to the Chern numbers of the log cotangent bundle. A matroid of rank 3 has two Chern numbers. We prove that they are positive and that their ratio is bounded by 3, which is analogous to the Bogomolov-Miyaoka-Yau inequality. If the matroid is orientable, we generalize a result of Eterovi\'c, Figuera, and Urz\'ua to prove that the ratio is bounded above by 5/2. Finally, we give a formula for the Chern numbers of the uniform matroid of any rank.

Keywords

Cite

@article{arxiv.2310.01956,
  title  = {Chern Numbers of Matroids},
  author = {Eline Mannino},
  journal= {arXiv preprint arXiv:2310.01956},
  year   = {2023}
}
R2 v1 2026-06-28T12:39:18.751Z