Gexin Yu

collaborators

3 papers

math.CO2026

Connectivities for k-knitted graphs and for minimal counterexamples to Hadwiger's Conjecture

Ken-ichi Kawarabayashi, Gexin Yu

For a given subset $S \subseteq V (G)$ of a graph $G$ , the pair $(G, S)$ is \emph{knitted} if for every partition of $S$ into non-empty subsets $S_{1}, S_{2}, \dots, S_{t}$ , there exist pa…

math.CO2026

Flexible DP-4-coloring of planar graphs without 4-cycles and intersecting triangles

Shu Fang, Runrun Liu, Gexin Yu

Graph coloring with preferences offers a powerful framework for constraint satisfaction problems in which fulfilling every request is impossible but satisfying a guaranteed positiv…

math.CO2025

Connectivity of contraction-critical graphs

Michael Lafferty, Runrun Liu, Martin Rolek +1

Contraction-critical graphs came from the study of minimal counterexamples to Hadwiger's conjecture. A graph is $k$ -contraction-critical if it is $k$ -chromatic, but any proper mino…