Boundedness commutator between Sobolev spaces
  In this paper,we will study the boundedness properties of commutator \[ C_{f}=[ f,\Delta] \] acting from $\overset{.}{H}^{1}(\mathbb{R}^{d}) $ to $\overset{.}{H}^{-1}(\mathbb{R}^{d}) .$ 
Sadek Gala