On superlinear Schrödinger equations with periodic potential

Abstract

We obtain ground state solutions for a wide class of superlinear Schrodinger equations with periodic potential. The result improves the recent result of Szulkin and Weth (J Funct Anal 257:3802–3822, 2009). The main ingredient is the observation that even in the strongly indefinite case, all Cerami sequences for the energy functional are bounded.