Complexity of locally-injective homomorphisms to tournaments
Discrete Mathematics
2023-06-22 v3 Combinatorics
Abstract
For oriented graphs and , a homomorphism is locally-injective if, for every , it is injective when restricted to some combination of the in-neighbourhood and out-neighbourhood of . Two of the possible definitions of local-injectivity are examined. In each case it is shown that the associated homomorphism problem is NP-complete when is a reflexive tournament on three or more vertices with a loop at every vertex, and solvable in polynomial time when is a reflexive tournament on two or fewer vertices.
Cite
@article{arxiv.1710.08825,
title = {Complexity of locally-injective homomorphisms to tournaments},
author = {Stefan Bard and Thomas Bellitto and Christopher Duffy and Gary MacGillivray and Feiran Yang},
journal= {arXiv preprint arXiv:1710.08825},
year = {2023}
}
Comments
22 pages, 16 figures