A Note on Graphs of Dichromatic Number 2
- Resource Type
- article
- Authors
- Raphael Steiner
- Source
- Discrete Mathematics & Theoretical Computer Science, Vol vol. 22 no. 4, Iss Graph Theory (2021)
- Subject
- directed graphs
acyclic colouring
dichromatic number
planar graphs
k5-minor-free graphs
[math]mathematics [math]
[math.math-co]mathematics [math]/combinatorics [math.co]
Mathematics
QA1-939
- Language
- English
- ISSN
- 1365-8050
Neumann-Lara and Škrekovski conjectured that every planar digraph is 2-colourable. We show that this conjecture is equivalent to the more general statement that all oriented K_5-minor-free graphs are 2-colourable.