Abstract
We consider a non-linear elliptic problem driven by the p-Laplacian and a non-smooth potential (hemivariational inequality). We assume that the non-linearity involves the combined effects of both concave (i.e. p-sublinear) and convex (i.e. p-superlinear) terms. We show the existence of two positive solutions, using non-smooth critical point theory and the Ekeland variational principle.
Acknowledgements
The authors wish to thank the referee for his/her corrections and remarks.