Monotonicity of positive solutions to quasilinear elliptic equations in half-spaces with a changing-sign nonlinearity
Résumé
In this paper we prove themonotonicity of positive solutions to -Delta(p)u = f (u) in half-spaces under zero Dirichlet boundary conditions, for (2N + 2)/(N + 2) < p < 2 and for a general class of regular changing-sign nonlinearities f. The techniques used in the proof of the main result are based on a fine use of comparison and maximum principles and on an adaptation of the celebrated moving plane method to quasilinear elliptic equations in unbounded domains.