Regular Matroids Without Disjoint Circuits

Suohai Fan1, Hong-Jian Lai2,3, Yehong Shao4, Hehui Wu5, Ju Zhou3
1Department of Mathematics, Jinan University Guangzhou 510632, P. R. China
2School of Mathematics, Physics and Software Enginneering, Lanzhou Jiaotong Uni- versity, Lanzhou 730070, P. R. China
3Department of Mathematics, West Virginia University, Morgantown, WV 26506
4Arts and Sciences, Ohio University Southern, Ironton, OH 45638
5Department of Mathematics, University of Illinois at Urbana-Champaign, Urbana, IL, 61801

Abstract

A cosimple regular matroid \(M\) does not have disjoint circuits if and only if \(M \in \{M(K_{3,3}), M^*(K_n) \mid n \geq 3\}\). This extends a former result of Erdős and Pósa on graphs without disjoint circuits.