The spectral radius of graphs with no K2,t minor
Let t≥3 and G be a graph of order n, with no K2,t minor. If n>400t6, then the spectral radius μ(G) satisfies μ(G)≤[Formula presented]+n+[Formula presented] with equality if and only if n≡1 (modt) and G=K1∨⌊n/t⌋Kt. For t=3 the maximum μ(G) is found exactly for any n>40000.
Linear Algebra and Its Applications
Nikiforov, V. (2017). The spectral radius of graphs with no K2,t minor. Linear Algebra and Its Applications, 531, 510-515. https://doi.org/10.1016/j.laa.2017.06.014