English

Most $q$-matroids are not representable

Combinatorics 2025-11-27 v2

Abstract

A qq-matroid is the analogue of a matroid which arises by replacing the finite ground set of a matroid with a finite-dimensional vector space over a finite field. These qq-matroids are motivated by coding theory as the representable qq-matroids are the ones that stem from rank-metric codes. In this note, we establish a qq-analogue of Nelson's theorem in matroid theory by proving that asymptotically almost all qq-matroids are not representable. This answers a question about representable qq-matroids by Jurrius and Pellikaan strongly in the negative.

Keywords

Cite

@article{arxiv.2408.06795,
  title  = {Most $q$-matroids are not representable},
  author = {Sebastian Degen and Lukas Kühne},
  journal= {arXiv preprint arXiv:2408.06795},
  year   = {2025}
}

Comments

10 pages, To appear in Combinatorial Theory

R2 v1 2026-06-28T18:11:35.596Z