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    33-anti-circulant digraphs are α\alpha-diperfect and BE-diperfect

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    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 P∈PP \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.Comment: arXiv admin note: substantial text overlap with arXiv:2111.1216
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