10 papers
Clique supersaturation under a chromatic constraint below the Turán threshold
Benju Wang, Longfei Fang, Jinlong Shu
A central theme in extremal graph theory is the supersaturation problem, which investigates the minimum number of copies of a target subgraph forced by prescribed edge conditions.…
Edge-spectral supersaturation for tripartite color-critical graphs
Longfei Fang, Huiqiu Lin, Mingqing Zhai
We study edge-spectral supersaturation for two families of color-critical graphs with chromatic number three. For an integer , we define the spectral threshold \[ g_r(m):=…
Spectral extremal graphs on closed surfaces of fixed Euler genus
Mingqing Zhai, Longfei Fang, Huiqiu Lin
Graph theory on surfaces extends classical graph structures to topological surfaces, providing a theoretical foundation for characterizing the embedding properties of complex netwo…
On the Turán number of odd-ballooning of -chromatic graphs
Longfei Fang, Xueyi Huang, Huiqiu Lin +1
Given a graph , the Turán number is the maximum number of edges in any -vertex -free graph. The odd-ballooning of , denoted by , is a graph obta…
The spectral Turán problem: Characterizing spectral-consistent graphs
Longfei Fang, Sergey Goryainov, Denis Krotov +2
Let and denote the families of -vertex -free graphs with the maximum size and the maximum spectral radius, respectively. A graph is said…
Extremal eigenvalues with respect to graph minors
Mingqing Zhai, Longfei Fang, Huiqiu Lin
Let denote the maximum spectral radius of -vertex -minor free graphs. The problem on determining this extremal value can be dated back to the early 1990s.…