Ruifang Liu

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math.CO2026

The exact Turán number of the even wheel $W_{2 k + 2}$ among non- $3$ -partite graphs

Qixuan Yuan, Ruifang Liu, Sanming Zhou

Let $ex (n, H)$ denote the Turán number of $H$ . A graph is color-critical if there exists an edge $e \in E (H)$ such that $χ (H - e) < χ (H)$ . For a color-critical graph $H$ with $χ…

math.CO2026

Extremal problems on $[a, b]$ -covered graphs

Qixuan Yuan, Ruifang Liu, Jinjiang Yuan

A graph $G$ is $[a, b]$ -covered if for each edge $e$ of $G$ there is an $[a, b]$ -factor containing it. For $a = b = 1$ , an $[a, b]$ -covered graph is a matching covered graph. The structur…

The exact Turán number of the even wheel W2k+2​ among non-3-partite graphs

Extremal problems on [a,b]-covered graphs

The exact Turán number of the even wheel $W_{2 k + 2}$ among non- $3$ -partite graphs

Extremal problems on $[a, b]$ -covered graphs