In this paper, we are concerned with the existence and nonexistence of
nontrivial solutions for nonlinear elliptic equations involving a biharmonic operator.
Concerning the second order equations, a complementary result was obtained for the
problem of interior, exterior and whole space. The main purpose of this paper is
to discuss whether the complementary result mentioned above is still valid for the
nonlinear fourth order equations. We introduce "Kelvin type transformation" for
a biharmonic operator to convert an exterior problem to an interior problem. The
existence results in case of super-critical exterior problem are shown by introducing
a weighted version of Sobolev-Poincaré type inequality, and the nonexistence results
are shown by giving a Pohozaev-type identity for fourth order equations.