English

$3$-anti-circulant digraphs are $\alpha$-diperfect and BE-diperfect

Combinatorics 2023-03-01 v3

Abstract

Let DD be a digraph. A subset SS of V(D)V(D) is a stable set if every pair of vertices in SS is non-adjacent in DD. A collection of disjoint paths P\mathcal{P} of DD is a path partition of V(D)V(D), if every vertex in V(D)V(D) is exactly on a path of P\mathcal{P}. We say that a stable set SS and a path partition P\mathcal{P} are orthogonal if each path of PP contains exactly one vertex of SS. A digraph DD satisfies the α\alpha-property if for every maximum stable set SS of DD, there exists a path partition P\mathcal{P} such that SS and P\mathcal{P} are orthogonal. A digraph DD is α\alpha-diperfect if every induced subdigraph of DD satisfies the α\alpha-property. In 1982, Claude Berge proposed a characterization for α\alpha-diperfect digraphs in terms of forbidden anti-directed odd cycles. In 2018, Sambinelli, Silva and Lee proposed a similar conjecture. A digraph DD satisfies the Begin-End-property or BE-property if for every maximum stable set SS of DD, there exists a path partition P\mathcal{P} such that (i) SS and P\mathcal{P} are orthogonal and (ii) for each path PPP \in \mathcal{P}, either the start or the end of PP belongs to SS. A digraph DD is BE-diperfect if every induced subdigraph of DD satisfies the BE-property. Sambinelli, Silva and Lee proposed a characterization for BE-diperfect digraphs in terms of forbidden blocking odd cycles. In this paper, we verified both conjectures for 33-anti-circulant digraphs. We also present some structural results for α\alpha-diperfect and BE-diperfect digraphs.

Keywords

Cite

@article{arxiv.2203.05024,
  title  = {$3$-anti-circulant digraphs are $\alpha$-diperfect and BE-diperfect},
  author = {Lucas Ismaily Bezerra Freitas and Orlando Lee},
  journal= {arXiv preprint arXiv:2203.05024},
  year   = {2023}
}

Comments

arXiv admin note: substantial text overlap with arXiv:2111.12168

R2 v1 2026-06-24T10:07:56.218Z