A note on borderline Brezis-Nirenberg type problems
Julian Haddad, Marcos Montenegro
TL;DR
This work analyzes borderline Brezis–Nirenberg-type problems for divergence-form elliptic operators concentrating ellipticity at a boundary point. It introduces interior $\alpha$-singular boundary points and a constrained, variational framework with $\Phi_A$ and $\Psi_{a,p}$ on unit Sobolev-type manifolds, using bubbles to obtain strict energy inequalities relative to the Sobolev constants $K(n,2)$ and $K(n,p)$. By constructing boundary-centered bubbles and performing precise scaling estimates, it proves the existence of positive $C^1$ solutions for all $\lambda$ below the first eigenvalue, under specified growth exponents $\gamma$, $\sigma$ and boundary singularity conditions $\alpha$. These results extend the classical Brezis–Nirenberg theory to non-smooth domains with boundary ellipticity concentration and clarify how boundary geometry governs existence thresholds in border-case regimes.
Abstract
We study the effect of ellipticity points on the boundary in the Brezis-Nirenberg problem for elliptic operators in divergence form.
