Abstract
In this paper, we state and prove two Fraïssé-style results that cover existence and uniqueness properties for twelve of the eighteen different notions of homomorphism-homogeneity as introduced by Lockett and Truss, and provide forward directions and implications for the remaining six cases. Following these results, we completely determine the extent to which the countable homogeneous undirected graphs (as classified by Lachlan and Woodrow) are homomorphism-homogeneous; we also provide some insight into the directed graph case.
Original language | English |
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Article number | 111674 |
Journal | Discrete Mathematics |
Volume | 343 |
Issue number | 2 |
Early online date | 3 Oct 2019 |
DOIs | |
Publication status | Published - Feb 2020 |
Keywords
- Homomorphism-homogeneous
- Relational structures
- Fraïssé theory
- Infinite graph theory