Classification of positive solutions to a nonlinear biharmonic equation with critical exponent

Rupert L. Frank, Tobias König

For $n\ge 5$, we consider positive solutions $u$ of the biharmonic equation \[ Δ^2 u = u^\frac{n+4}{n-4} \qquad \text{on}\ \mathbb R^n \setminus \{0\} \] with a non-removable sin…