English

Matroids with an infinite circuit-cocircuit intersection

Combinatorics 2012-02-29 v2

Abstract

We construct some matroids that have a circuit and a cocircuit with infinite intersection. This answers a question of Bruhn, Diestel, Kriesell, Pendavingh and Wollan. It further shows that the axiom system for matroids proposed by Dress does not axiomatize all infinite matroids. We show that one of the matroids we define is a thin sums matroid whose dual isn't a thin sums matroid.

Keywords

Cite

@article{arxiv.1202.3406,
  title  = {Matroids with an infinite circuit-cocircuit intersection},
  author = {Johannes Carmesin and Nathan Bowler},
  journal= {arXiv preprint arXiv:1202.3406},
  year   = {2012}
}
R2 v1 2026-06-21T20:19:58.962Z