Multiple solutions for fourth order elliptic problems with p(x)-biharmonic operators

We study the multiplicity of weak solutions to the following fourth order nonlinear elliptic problem with a p(x)-biharmonic operator [formula] where Ω is a smooth bounded domain in RN, [formula] is the p(x)-biharmonic operator, and λ > 0 is a parameter. We establish sufficient conditions under which there exists a positive number λ* such that the above problem has at least two nontrivial weak solutions for each λ > λ*. Our analysis mainly relies on variational arguments based on the mountain pass lemma and some recent theory on the generalized Lebesgue-Sobolev spaces [formula].