The Sombor spectral radius ρ_Sombor of a graph is defined as the largest eigenvalue of the Sombor matrix. Liu et al. (2022) shows that for any tree, ρ_Sombor<=sqrt(n^3 - 3n^2 + 4n - 2), with equality iff the tree is the star graph S_n .

graph eigenvalue | sombor matrix | spectral radius