Berge's Conjecture and Aharoni-Hartman-Hoffman's Conjecture for locally in-semicomplete digraphs
Abstract
Let be a positive integer and let be a digraph. A path partition of is a set of vertex-disjoint paths which covers . Its -norm is defined as . A path partition is -optimal if its -norm is minimum among all path partitions of . A partial -coloring is a collection of disjoint stable sets. A partial -coloring is orthogonal to a path partition if each path meets distinct sets of . Berge (1982) conjectured that every -optimal path partition of has a partial -coloring orthogonal to it. A (path) -pack of is a collection of at most vertex-disjoint paths in . Its weight is the number of vertices it covers. A -pack is optimal if its weight is maximum among all -packs of . A coloring of is a partition of into stable sets. A -pack is orthogonal to a coloring if each set meets paths of . Aharoni, Hartman and Hoffman (1985) conjectured that every optimal -pack of has a coloring orthogonal to it. A digraph is semicomplete if every pair of distinct vertices of is adjacent. A digraph is locally in-semicomplete if, for every vertex , the in-neighborhood of induces a semicomplete digraph. Locally out-semicomplete digraphs are defined similarly. In this paper, we prove Berge's and Aharoni-Hartman-Hoffman's Conjectures for locally in/out-semicomplete digraphs.
Keywords
Cite
@article{arxiv.1708.06691,
title = {Berge's Conjecture and Aharoni-Hartman-Hoffman's Conjecture for locally in-semicomplete digraphs},
author = {Maycon Sambinelli and Carla Negri Lintzmayer and Cândida Nunes da Silva and Orlando Lee},
journal= {arXiv preprint arXiv:1708.06691},
year = {2017}
}