On Isolated Singularities for the Stationary Navier–Stokes System

The classical problem of removable singularities is considered for solutions to the stationary Navier–Stokes system in dimension \(n\ge 3\) $n\ge 3$ and an old theorem of Shapiro (TAMS 187:335–363, 1974) is recovered and extended to solutions in a half ball vanishing on the flat boundary. Moreover, for \(n=4\) $n=4$ it is proved that there are not distributional solutions, smooth away from the singularity and such that \(u(x)=O(|x|^{-1})\) $u(x)=O(|x{|}^{-1})$ .