English

Four Blocks Cycles C(k,1,1,1) in Digraphs

Combinatorics 2022-01-10 v1

Abstract

A four blocks cycle C(k1,k2,k3,k4) is an oriented cycle formed by the union of four internally disjoint directed paths of lengths k1,k2,k3 and k4 respectively. El Mniny proved that if D is a digraph having a spanning out-tree T with no subdivisions of C(k, 1, 1, 1), then the chromatic number of D is at most 8^{3}k. In this paper, we will improve this bound to 18k.

Keywords

Cite

@article{arxiv.2201.02520,
  title  = {Four Blocks Cycles C(k,1,1,1) in Digraphs},
  author = {Zahraa Mohsen},
  journal= {arXiv preprint arXiv:2201.02520},
  year   = {2022}
}
R2 v1 2026-06-24T08:42:57.667Z