Yuejian Peng

activity

20242026

collaborators

9 papers

math.CO2026

Saturation numbers of some joins of graphs

Xinying Hua, Yuejian Peng

Let $H$ be a graph. A graph $G$ is $H$ -saturated if $G$ is $H$ -free, but adding any edge between two non-adjacent vertices of $G$ yields an $H$ -copy as a subgraph. The saturation n…

math.CO2026

Saturation numbers for joins of graphs and characterization of extremal graphs

Xinying Hua, Yuejian Peng

A graph $G$ is $H$ -saturated if $G$ contains no $H$ -copy as a subgraph, but adding any edge between two non-adjacent vertices in $G$ creates a copy of $H$ . The saturation number $\…

math.CO2026

A spectral LovÃ¡sz-Simonovits theorem

Yongtao Li, Lihua Feng, Yuejian Peng

A fundamental result in extremal graph theory is attributed to Mantel's theorem, which states that every graph on $n$ vertices with more than $⌊ n^{2} /4 ⌋$ edges must con…

math.CO2025

A note on degree conditions for Ramsey goodness of trees

Zhidan Luo, Yuejian Peng

For given graphs $G_{1}, G_{2}$ and $G$ , let $G \to (G_{1}, G_{2})$ denote that each red-blue-coloring of $E (G)$ yields a red copy of $G_{1}$ or a blue copy of $G_{2}$ . Arag…

math.CO2025

Spectral extremal graphs for $F_{6}$ -free graphs with even size

Loujun Yu, Yuejian Peng

Let $F_{l}$ be the fan graph obtained by joining a vertex with a path on $l - 1$ vertices. Yu, Li and Peng [Discrete Math. 346 (2023)] conjectured that if the number of edges of $G$ is…

math.CO2025

Strong spectral stabilities for $C_{2 k + 1}$ -free graphs

Lantao Zou, Yongtao Li, Yuejian Peng

A stability result due to Ren, Wang, Wang and Yang [SIAM J. Discrete Math. 38 (2024)] shows that if $3 \leq r \leq 2 k$ and $n \geq 318 (r - 2)^{2} k$ , and $G$ is a $C_{2 k + 1}$ -free graph on $…

Saturation numbers of some joins of graphs

Saturation numbers for joins of graphs and characterization of extremal graphs

A spectral LovÃ¡sz-Simonovits theorem

A note on degree conditions for Ramsey goodness of trees

Spectral extremal graphs for F6​-free graphs with even size

Strong spectral stabilities for C2k+1​-free graphs

Spectral extremal graphs for $F_{6}$ -free graphs with even size

Strong spectral stabilities for $C_{2 k + 1}$ -free graphs