English

Combinatorial Cremona automorphisms and Coxeter arrangement matroids

Algebraic Geometry 2025-09-19 v2

Abstract

We explore birational geometry of matroids by investigating automorphisms of their coarse Bergman fans. Combinatorial Cremona maps provide such automorphisms of Bergman fans which are not induced by matroid automorphisms. We investigate the structure of matroids allowing combinatorial Cremona maps and prove a realizability criterion in the presence of two different Cremonas. We also prove that for all matroids associated to Coxeter arrangements the group of coarse automorphisms of the Bergman fan is generated by the matroid automorphisms and at most one combinatorial Cremona map.

Keywords

Cite

@article{arxiv.2411.09987,
  title  = {Combinatorial Cremona automorphisms and Coxeter arrangement matroids},
  author = {Stefan Rettenmayr and Annette Werner},
  journal= {arXiv preprint arXiv:2411.09987},
  year   = {2025}
}

Comments

19 pages, comments welcome

R2 v1 2026-06-28T20:00:52.148Z