Xiaogang Liu

collaborators

3 papers

math.CO2026

Index perturbation of signed graphs

Linfeng Xie, Xiaogang Liu

Let $I^ = (G, I ¨ )$ be a signed graph and $v$ a non-isolated vertex of $I^$ . Let $I^ - v$ denote the graph obtained by deleting the vertex $v$ together with all signed edges incident t…

math.CO2026

Size and spectral conditions for a graph with given minimum degree to be $k$ - $d$ -critical

Zhenhao Zhang, Xiaogang Liu, Ligong Wang

A $k$ -matching in a graph $G$ is defined as a function $f : E (G) \to {0, 1, \dots, k}$ satisfying $\sum_{e \in E_{G} (v)} f (e)$ $\leq k$ for each vertex $v \in V (G)$ , where $E_G(v…

math.CO2026

Spectral TurÃ¡n problem for $t K_{4}^{-}$ -free unbalanced signed graphs

Linfeng Xie, Xiaogang Liu

Let $t K_{4}$ denote the family of all graphs consisting of $t$ copies of $K_{4}$ that are allowed to share vertices and $t K_{4}^{-}$ be the set of all unbalanced signed graph…

Index perturbation of signed graphs

Size and spectral conditions for a graph with given minimum degree to be k-d-critical

Spectral TurÃ¡n problem for tK4−​-free unbalanced signed graphs

Size and spectral conditions for a graph with given minimum degree to be $k$ - $d$ -critical

Spectral TurÃ¡n problem for $t K_{4}^{-}$ -free unbalanced signed graphs