
Minimax Theory and its Applications 01 (2016), No. 1, 083109 Copyright Heldermann Verlag 2016 On Resonant (p,2)Equations Giuseppina Barletta DICEAM, Facoltà di Ingegneria, Università di Reggio Calabria, Via Graziella  Loc. Feo di Vito, 89122 Reggio Calabria, Italy giuseppina.barletta@unirc.it Giuseppina D'Aguì Dept. of Engineering and Applied Mathematics, University of Messina, 98166 Messina, Italy, Italy dagui@unime.it Nikolaos S. Papageorgiou Dept. of Mathematics, National Technical University, Zografou Campus, Athens 15780, Greece npapg@math.ntua.gr We consider a nonlinear nonhomogeneous elliptic equation driven by the sum of a pLaplacian and a Laplacian (p,2)equation with a Carathéodory reaction which at ±∞ is resonant with respect to the principal eigenvalue of the negative Dirichlet pLaplacian. Using minimax methods based on the critical point theory, together with truncation techniques and Morse theory, we obtain multiplicity results producing three or four solutions with sign information (constant sign solutions and nodal solutions). Keywords: Minimax characterization, nonlinear regularity, nonlinear maximum principle, nodal solutions, resonant equation. MSC: 35J20, 35J60; 58E05 [ Fulltextpdf (249 KB)] for subscribers only. 