Youngho Yoo

activity

20242026

collaborators

3 papers

math.CO2026

Homomorphism counting for immersion-closed classes is not isomorphism

Andrea Jiménez, Benjamin Moore, Daniel A. Quiroz +1

Lovász proved that two graphs $G$ and $H$ are isomorphic if $hom (K, G) = hom (K, H)$ for all graphs $K$ , where $hom (G_{1}, G_{2})$ denotes the number of homomorphisms from $G_{1}$ to $G_2…

math.CO2025

Tree-width of a graph excluding an apex-forest or a wheel as a minor

Chun-Hung Liu, Youngho Yoo

The Grid Minor Theorem states that for every planar graph $H$ , there exists a smallest integer $f (H)$ such that every graph with tree-width at least $f (H)$ contains $H$ as a minor.…

math.CO2024

Erdős-Pósa property of $A$ -paths in unoriented group-labelled graphs

O-joung Kwon, Youngho Yoo

We characterize the obstructions to the Erdős-Pósa property of $A$ -paths in unoriented group-labelled graphs. As a result, we prove that for every finite abelian group $Γ$ and for…

Homomorphism counting for immersion-closed classes is not isomorphism

Tree-width of a graph excluding an apex-forest or a wheel as a minor

Erdős-Pósa property of A-paths in unoriented group-labelled graphs

Erdős-Pósa property of $A$ -paths in unoriented group-labelled graphs