Spectral extrema of graphs with fixed size: forbidden a fan graph, friendship graph or theta graph

Shuchao Li, Sishu Zhao, Lantao Zou

It is well-known that the Brualdi-Hoffman-Turán-type problem inquiries about the maximum spectral radius \( λ(G) \) of an \( F \)-free graph \( G \) with \( m \) edges. Let \( θ…