Boundary Vanishing Orders and Asymptotic Expansions for Planar Harmonic Functions with a Sublinear Robin Condition

Hairong Liu, Long Tian, Xiaoping Yang

We study boundary vanishing orders and asymptotic expansions of planar harmonic functions satisfying the sublinear Robin condition ${\partial }_{\nu }u=\lambda u-|u{|}^{p-1}u,$ with $\lambda \ge 0$ and $0…