Concavity properties for free boundary elliptic problems

Abstract

We prove some concavity properties connected to nonlinear Bernoulli type free boundary problems. In particular, we prove a Brunn-Minkowski inequality and an Urysohn's type inequality for the Bernoulli Constant and we study the behaviour of the free boundary with respect to the given boundary data. Moreover we prove a uniqueness result regarding the interior non-linear Bernoulli problem.Comment: 12 pages. This is a revised version of the already published paper, which includes the corrections contained in the Corrigendum available online at http://dx.doi.org/10.1016/j.na.2009.11.03