Infinitely many solutions for fourth-order elliptic equations

In this paper, we study a class of fourth-order elliptic equations setting on RNRN. Based on the minimax methods in critical point theory, we obtain the existence of infinitely many large-energy and small-energy solutions, which unifies and improves the recent results of Yin and Wu [Y. Yin, X. Wu, High energy solutions and nontrivial solutions for fourth-order elliptic equations, J. Math. Anal. Appl. 375 (2011) 699–705].