English

The Projectivization Matroid of a $q$-Matroid

Combinatorics 2022-05-06 v2 Information Theory math.IT

Abstract

In this paper, we investigate the relation between a qq-matroid and its associated matroid called the projectivization matroid. The latter arises by projectivizing the groundspace of the qq-matroid and considering the projective space as the groundset of the associated matroid on which is defined a rank function compatible with that of the qq-matroid. We show that the projectivization map is a functor from categories of qq-matroids to categories of matroids, which allows to prove new results about maps of qq-matroids. We furthermore show the characteristic polynomial of a qq-matroid is equal to that of the projectivization matroid. We use this relation to establish a recursive formula for the characteristic polynomial of a qq-matroid in terms of the characteristic polynomial of its minors. Finally we use the projectivization matroid to prove a qq-analogue of the critical theorem in terms of Fqm\mathbb{F}_{q^m}-linear rank metric codes and qq-matroids.

Keywords

Cite

@article{arxiv.2204.01232,
  title  = {The Projectivization Matroid of a $q$-Matroid},
  author = {Benjamin Jany},
  journal= {arXiv preprint arXiv:2204.01232},
  year   = {2022}
}
R2 v1 2026-06-24T10:36:25.291Z