Existence of positive solutions for a class of almost critical problems on an annulus
Gabriele Mancini, Giuseppe Mario Rago, Giusi Vaira
TL;DR
This work analyzes the existence of multi-peak (bubble) positive solutions to slightly subcritical or slightly supercritical elliptic problems on an annulus with Dirichlet boundary conditions. The authors perform a finite-dimensional reduction around symmetric k-point configurations, exploiting the Green and Robin functions to derive a reduced energy whose leading term involves the interaction function Λ1(r). They establish a sharp threshold ρ_k for the annulus geometry: when the hole is sufficiently small or sufficiently large (depending on the ε-regime and problem type), stable critical points exist for the reduced functional, yielding k-bubble solutions, while in the opposite regime no such solutions exist. The analysis hinges on precise spectral properties of the circulant interaction matrix and intricate estimates of Gegenbauer polynomials, covering dimensions N=3,4, and N≥5. The results extend and unify previous findings, clarifying how domain geometry governs bubbling phenomena in near-critical elliptic problems on annuli.
Abstract
In this paper we will consider multi-peaks positive solutions for a class of slightly subcritical or slightly supercritical elliptic problems on an annulus with Dirichlet boundary conditions. By using the explicit form of the Green function and of the Robin function on the annulus, we prove that the annulus becomes thinner and thinner when the number of bumps increases for the slightly subcritical case, while the hole of the annulus is very small for the slightly supercritical case.
