English

Complementary cycles of any length in regular bipartite tournaments

Combinatorics 2021-02-10 v1 Discrete Mathematics

Abstract

Let DD be a kk-regular bipartite tournament on nn vertices. We show that, for every pp with 2pn/222 \le p \le n/2-2, DD has a cycle CC of length 2p2p such that DCD \setminus C is hamiltonian unless DD is isomorphic to the special digraph F4kF_{4k}. This statement was conjectured by Manoussakis, Song and Zhang [K. Zhang, Y. Manoussakis, and Z. Song. Complementary cycles containing a fixed arc in diregular bipartite tournaments. Discrete Mathematics, 133(1-3):325--328,1994]. In the same paper, the conjecture was proved for p=2p=2 and more recently Bai, Li and He gave a proof for p=3p=3 [Y. Bai, H. Li, and W. He. Complementary cycles in regular bipartite tournaments. Discrete Mathematics, 333:14--27, 2014].

Keywords

Cite

@article{arxiv.2102.04514,
  title  = {Complementary cycles of any length in regular bipartite tournaments},
  author = {Stéphane Bessy and Jocelyn Thiebaut},
  journal= {arXiv preprint arXiv:2102.04514},
  year   = {2021}
}

Comments

22 pages, 5 figures