Eun-Kyung Cho

collaborators

2 papers

math.CO2025

On Alon-Tarsi orientations of sparse graphs

Eun-Kyung Cho, Ilkyoo Choi, Boram Park +1

Assume $G$ is a graph, $(v_{1}, \dots, v_{k})$ is a sequence of distinct vertices of $G$ , and $(a_{1}, \dots, a_{k})$ is an integer sequence with $a_{i} \in {1, 2}$ . We say $G$ is \emph{$(a_1…

math.CO2025

Obstructions for homomorphisms to odd cycles in series-parallel graphs

Eun-Kyung Cho, Ilkyoo Choi, Boram Park +1

For a graph $H$ , an $H$ -colouring of a graph $G$ is a vertex map $I ¨ : V (G) \to V (H)$ such that adjacent vertices are mapped to adjacent vertices. A graph $G$ is $C_{2 k + 1}$ -critical…