English

Subdivisions of Oriented Cycles in Digraphs with Hamiltonian directed path

Combinatorics 2024-09-19 v1

Abstract

Cohen et al. conjectured that for every oriented cycle CC there exist an integer f(C)f(C) such that every strong f(C)f(C)-chromatic digraph contains a subdivision of CC. El Joubbeh confirmed this conjecture for Hamiltonian digraphs. Indeed, he showed that every 3n3n-chromatic Hamiltonian digraph contains a subdivision of every oriented cycle of order nn. In this article, we improve this bound to 2n2n. Furthermore, we show that, if DD is a digraph containing a Hamiltonian directed path with chromatic number at least 12n512n-5, then DD contains a subdivision of every oriented cycle of order nn. Note that a digraph containing a Hamiltonian directed path need not be strongly connected. Thus, our current result provides a deeper understanding of the condition that may be needed to fully solve the conjecture.

Keywords

Cite

@article{arxiv.2409.11421,
  title  = {Subdivisions of Oriented Cycles in Digraphs with Hamiltonian directed path},
  author = {Abbas Alhakim and Mouhamad El Joubbeh},
  journal= {arXiv preprint arXiv:2409.11421},
  year   = {2024}
}