Sign-changing bubble tower solutions for a Paneitz-type problem

This paper is concerned with the following biharmonic problem {Delta(2)u = vertical bar u vertical bar(8/N-4) u in Omega\B(xi(0), epsilon) u = Delta u = 0 on partial derivative(Omega\B(xi(0), epsilon)), (0.1) where Omega is an open bounded domain in R-N, N >= 5, and B(xi(0), epsilon) is a ball centered at xi(0) with radius epsilon, epsilon is a small positive parameter. We obtain the existence of solutions for problem (0.1), which is an arbitrary large number of sign-changing solutions whose profile is a superposition of bubbles with alternate sign which concentrate at the centre of the hole.