Special Session 7: Recent developments on nonlinear geometric PDEs

Eigenfunctions in domains with small balls removed
Ying Li
Central China Normal University&Sapienza University of Rome
Peoples Rep of China
Co-Author(s):    Laura Abatangelo, Massimo Grossi
Abstract:
This work concentrates on the eigenvalues and eigenfunctions of the Dirichlet Laplacian in a bounded domain with a small hole $B(P,\varepsilon)$ removed. We derive pointwise estimates of the $u-$capacity potential $V_{\varepsilon}$ associated with $B(P,\varepsilon)$ in dimensions two and higher. Using these estimates, we obtain a uniform estimate for $u_\varepsilon-u-V_{\varepsilon}$ when the eigenvalue is simple. When the eigenvalue is multiple, we also derive the bifurcation of $\lambda_\varepsilon$, which was previously obtained by Abatangelo, L\`ena and Musolino in 2022 and 2024. Finally, in dimension two, we apply the uniform estimate of $u_\varepsilon$ to study the number of intersection points between the nodal line $\mathcal{N}_\varepsilon$ and $\partial B(P,\varepsilon)$.