Edmonds' Branching Theorem in Digraphs without Forward-infinite Paths
Combinatorics
2017-05-02 v1
Abstract
Let be a finite digraph, and let be nonempty subsets of . The (strong form of) Edmonds' branching theorem states thatthere are pairwise edge-disjoint spanning branchings in such that the root set of is if and only if for all the number of ingoing edges of is greater than or equal to the number of sets disjoint from . As was shown by R. Aharoni and C. Thomassen in \cite{aharoni1989infinite}, this theorem does not remain true for infinite digraphs. Thomassen also proved that for the class of digraphs without backward-infinite paths, the above theorem of Edmonds remains true. Our main result is that for digraphs without forward-infinite paths, Edmonds' branching theorem remains true as well.
Cite
@article{arxiv.1705.00471,
title = {Edmonds' Branching Theorem in Digraphs without Forward-infinite Paths},
author = {Attila Joó},
journal= {arXiv preprint arXiv:1705.00471},
year = {2017}
}