Dipartimento di Matematica, Universà di Roma ``Tor Vergata', Via della Ricerca Scientifica 00133 Roma, Italy ; Dipartimento di Matematica, Università di Roma ``Tor Vergata', Via della Ricerca Scientifica, 00133 Roma, Italy
Abstract:
We consider weak solutions of the differential inequality of p-Laplacian type
such that on a smooth bounded domain in and either or is a weak solution of the corresponding Dirichlet problem with zero boundary condition. Assuming that on the boundary of the domain we prove that , and assuming that on the boundary of the domain we prove unless . The novelty is that the nonlinearity is allowed to change sign. In particular, the result holds for the model nonlinearity with .