A simple preconditioner for a discontinuous Galerkin method for the   Stokes problem
  In this paper we construct Discontinuous Galerkin approximations of the Stokes problem where the velocity field is H(div)-conforming. This implies that the velocity solution is divergence-free in the whole domain. This property can be exploited to design a simple and effective preconditioner for the final linear system. 
Blanca Ayuso de Dios and Franco Brezzi and L. Donatella Marini and   Jinchao Xu and Ludmil Zikatanov
math.NA