English

Matroids with at least two regular elements

Combinatorics 2015-09-15 v1

Abstract

For a matroid MM, an element ee such that both M\eM\backslash e and M/eM/e are regular is called a regular element of MM. We determine completely the structure of non-regular matroids with at least two regular elements. Besides four small size matroids, all 3-connected matroids in the class can be pieced together from F7F_7 or S8S_8 and a regular matroid using 3-sums. This result takes a step toward solving a problem posed by Paul Seymour: Find all 3-connected non-regular matroids with at least one regular element [5, 14.8.8].

Keywords

Cite

@article{arxiv.1103.2959,
  title  = {Matroids with at least two regular elements},
  author = {Sandra Kingan and Manoel Lemos},
  journal= {arXiv preprint arXiv:1103.2959},
  year   = {2015}
}
R2 v1 2026-06-21T17:39:48.369Z