Linfeng Xie

collaborators

4 papers

math.CO2026

Maximum index of unbalanced signed graphs without a positive odd cycle

Li Ma, Linfeng Xie, Xiaogang Liu

Let $C_{r}^{+}$ be the set of all balanced signed graphs with underlying graphs $C_{r}$ . A signed graph is called $C_{r}^{+}$ -free if it contains no subgraph isomorph…

math.CO2026

Index perturbation of signed graphs

Linfeng Xie, Xiaogang Liu

Let $Γ = (G, σ)$ be a signed graph and $v$ a non-isolated vertex of $Γ$ . Let $Γ - v$ denote the graph obtained by deleting the vertex $v$ together with all signed edges incident to it…

math.CO2026

Localization of spectral Turán theorems for signed graphs

Linfeng Xie, Xiaogang Liu

In this paper, we extend localized Turán theorems to signed graphs and study the corresponding spectral Turán problems. Firstly, we establish a vertex-localized Turán-type inequali…

math.CO2025

Bounds for the largest eigenvalue and sum of Laplacian eigenvalues of signed graphs

Linfeng Xie, Xiaogang Liu

In this paper, we consider the bounds for the largest eigenvalue and the sum of the $k$ largest Laplacian eigenvalues of signed graphs. Firstly, we give an upper bound on the large…