Shuyan Chen

collaborators

5 papers

math.CO2026

Improved Sidorenko bound for hypergraph Turan densities

Shuyan Chen, Xinmin Hou, Xizhi Liu

For every fixed integer $r \geq 3$ , we prove that the Turán density of every $r$ -uniform hypergraph $F$ with $m \geq 1$ edges satisfies $π (F) \leq 1 - c_{r} m^{- (r - 1) / r}$ , where $c_{r} > 0$ depends…

math.CO2026

Sparse chromatic graphs and the complete-graph triangle bound

Shuyan Chen

We prove that there is an absolute constant $c > 0$ such that every graph of chromatic number at least $r$ and at most $c r^{3} lo g^{2} r$ edges contains at least $(3 r)$ triangles. T…

math.CO2026

Hypergraph Universality and Erdos-Posa Failure for Chromatically Rich Odd Cycles

Shuyan Chen

For every fixed $k \geq 3$ , every finite nonempty clutter $H$ can be realized exactly as the family of inclusion-minimal terminal traces of the $k$ -bad odd cycles, namely t…

math.CO2026

Cyclic Sources of Strong Domination in Graph Norms

Shuyan Chen

Conlon and Lee asked for strongly dominating graphs beyond norming graphs and even paths. We construct a two-parameter family of pairwise non-isomorphic $2$ -connected strongly domi…

math.CO2026

Odd-Cycle Span Defect: A Polynomial Lower Bound and a Square-Root Upper Bound

Shuyan Chen

For a graph $G$ , let $ψ (G) = max {χ (G [V (C)]) : C$ is an odd cycle of $G}$ , with $ψ (G) = 0$ when $G$ is bipartite. For positive integers $N$ , set $F (N) = max {χ (G) - ψ (G) : ∣ V (G) ∣ \leq N}$ . T…