  The paper shows an inf-sup stability property for several well-known 2D and
3D Stokes elements on triangulations which are not fitted to a given smooth or
polygonal domain. The property implies stability and optimal error estimates
for a class of unfitted finite element methods for the Stokes and Stokes
interface problems, such as Nitsche-XFEM or cutFEM. The error analysis is
presented for the Stokes problem. All assumptions made in the paper are
satisfied once the background mesh is shape-regular and fine enough.
