English

Two-block paths in oriented graphs of large semidegree

Combinatorics 2025-04-01 v1

Abstract

We study the existence of oriented paths with two blocks in oriented graphs under semidegree conditions. A block of an oriented path is a maximal directed subpath. Given positive integers kk and \ell with k/2<kk/2\le \ell < k, we establish a semidegree function that guarantees the containment of every oriented path with two blocks of sizes \ell and kk-\ell. As a corollary, we show that every oriented graph with all in- and out-degrees at least 3k/43k/4 contains every two-block path with kk arcs. Our results extend previous work on Stein's conjecture and related problems concerning oriented paths.

Keywords

Cite

@article{arxiv.2503.23191,
  title  = {Two-block paths in oriented graphs of large semidegree},
  author = {Irena Penev and S Taruni and Stéphan Thomassé and Ana Trujillo-Negrete and Mykhaylo Tyomkyn},
  journal= {arXiv preprint arXiv:2503.23191},
  year   = {2025}
}
R2 v1 2026-06-28T22:39:09.746Z