A Brezis--Merle inequality for the biharmonic operator with Dirichlet boundary conditions in four-dimensional balls

Abstract

In this paper, we establish a Brezis-Merle type inequality for very weak solutions of the biharmonic Dirichlet problem in the four-dimensional unit ball. By combining this inequality with moving-plane arguments, we obtain uniform a priori estimates for positive solutions of semilinear biharmonic equations with exponential nonlinearities in both the subcritical and critical regimes. As an application of these estimates, we prove the existence of a positive solution by means of topological methods. We also extend the analysis to a class of non-variational cooperative systems.

arXiv comment33 pages