Multibubble blow-up analysis for the Brezis-Nirenberg problem in three dimensions
Tobias König, Paul Laurain
TL;DR
This work provides a complete multibubble blow-up analysis for the Brezis–Nirenberg-type problem in dimension three, establishing precise global and local asymptotics for sequences of blowing-up positive solutions and revealing how multiple concentration points interact through the Green's function and the interaction matrix M_a. The authors derive a sharp blow-up rate under nondegeneracy or analyticity assumptions on the Robin function, and they construct higher-order corrections to the bubble profile to obtain refined expansions. A key innovation is treating the vanishing Robin function scenario (ρ_a(x0)=0) for multiple bubbles, yielding an explicit blow-up formula that generalizes prior single-bubble results. The work also clarifies regularity requirements for φ_a and ρ_a, providing conditions under which the analytic structure of the concentration set can be leveraged in the asymptotic analysis.
Abstract
For a smooth bounded domain $Ω\subset \mathbb R^3$ and smooth functions $a$ and $V$, we consider the asymptotic behavior of a sequence of positive solutions $u_ε$ to $-Δu_ε+ (a+εV) u_ε= u_ε^5$ on $Ω$ with zero Dirichlet boundary conditions, which blow up as $ε\to 0$. We derive the sharp blow-up rate and characterize the location of concentration points in the general case of multiple blow-up, thereby obtaining a complete picture of blow-up phenomena in the framework of the Brezis-Peletier conjecture in dimension $N=3$.
