Existence and Location of Nodal Solutions for Quasilinear Convection–Absorption Neumann Problems

Existence of nodal (i.e., sign changing) solutions and constant-sign solutions for quasilinear elliptic equations involving convection–absorption terms are presented. A location principle for nodal solutions is obtained by means of constant-sign solutions whose existence is also derived. The proof is chiefly based on sub-supersolutions technique together with monotone operator theory.