QI Wu

collaborators

6 papers

cs.DS2026

Unlocking Fractional Moments in Delphic Set Streams

Aranya Kumar Bal, Sourav Chakraborty, Arijit Ghosh +1

We consider estimation of non-integer frequency moments $F_{k}$ and related Bernstein-type statistics in the Delphic set stream model under a bounded-frequency assumption: every univ…

math.CO2026

Hamiltonian cycles in 7-tough $(P_{4} \cup P_{1})$ -free graphs

Yong Lu, Qi Wu, Qiannan Zhou

Shan~[J. Graph Theory (2026)] proved that every 23-tough $(P_{4} \cup P_{1})$ -free graph on at least three vertices is Hamiltonian. We improve this bound to 7 by replacing the final cut…

math.CO2026

Exact generalized TurÃ¡n number of vertex-disjoint paths of length two

Qi Wu, Long-Tu Yuan

We determine the generalized TurÃ¡n number of vertex-disjoint paths of length two and characterize all corresponding extremal graphs. Our proof combines the LovÃ¡sz form of the Kru…

math.CO2026

Local TurÃ¡n inequalities for walks and the spectral radius

Feng Liu, Shuang Sun, Yan Wang +1

Nikiforov's well-known spectral TurÃ¡n inequality for walks states that, for every graph $G$ with clique number $I ¨ (G)$ , $I^»^{r} (G) \leq w_{r} (G) (1 - 1/ I ¨ (G))$ , where $I^» (G)$ is the larges…

math.CO2026

Triangles in graphs without the expansion of $4$ -cycle

Jialei Song, Qi Wu, Long-Tu Yuan

The expansion $F^{△}$ of a graph $F$ is the graph obtained from $F$ by replacing each edge with a triangle. Lv \etal proposed a conjecture on the maximum number of triangle…

math.CO2025

Improved bounds on the $H$ -rank of a mixed graph in terms of the matching number and fractional matching number

Qi Wu, Yong Lu

A mixed graph $G$ is obtained by orienting some edges of a graph $G$ , where $G$ is the underlying graph of $G$ . Let $r (G)$ be the $H$ -rank of $\…

Unlocking Fractional Moments in Delphic Set Streams

Hamiltonian cycles in 7-tough (P4​∪P1​)-free graphs

Exact generalized TurÃ¡n number of vertex-disjoint paths of length two

Local TurÃ¡n inequalities for walks and the spectral radius

Triangles in graphs without the expansion of 4-cycle

Improved bounds on the H-rank of a mixed graph in terms of the matching number and fractional matching number

Hamiltonian cycles in 7-tough $(P_{4} \cup P_{1})$ -free graphs

Triangles in graphs without the expansion of $4$ -cycle

Improved bounds on the $H$ -rank of a mixed graph in terms of the matching number and fractional matching number