Sublinear elliptic problems under radiality. Harmonic $NA$ groups and Euclidean spaces

Ewa Damek, Zeineb Ghardallou

Let $Ł$ be the Laplace operator on ${\mathbb{R}}^d$, $d\ge 3$ or the Laplace Beltrami operator on the harmonic $NA$ group (in particular on a rank one noncompact symmetric space). For the…