Shipeng Wang

collaborators

2 papers

math.CO2025

Extremal triangle-free graphs with chromatic number at least four

Sijie Ren, Jian Wang, Shipeng Wang +1

Let $G$ be an $n$ -vertex triangle-free graph. The celebrated Mantel's theorem showed that $e (G) \leq ⌊ \frac{n ^{2}}{4} ⌋$ . In 1962, ErdÅs (together with Gallai), and indepe…

math.CO2025

Longest odd cycles in non-bipartite $C_{2 k + 1}$ -free graphs

Rui Wang, Shipeng Wang

In strengthening a result of AndrÃ¡sfai, ErdÅs and SÃ³s in 1974, HÃ¤ggkvist proved that if $G$ is an $n$ -vertex $C_{2 k + 1}$ -free graph with minimum degree $I^´ (G) > \frac{2 n}{2 k + 3}$ a…

Extremal triangle-free graphs with chromatic number at least four

Longest odd cycles in non-bipartite C2k+1​-free graphs

Longest odd cycles in non-bipartite $C_{2 k + 1}$ -free graphs