Title: Multigrid preconditioning in H(div) on non-convex polygons Authors: D. N. Arnold, R. S. Falk, and R. Winther Source: Comput. Appl. Math., 17(3):303-315, 1998 Abstract: In an earlier paper we constructed and analyzed a multigrid preconditioner for the system of linear algebraic equations arising from the finite element discretization of boundary value problems associated to the differential operator I - grad div. In this paper we analyze the procedure without assuming that the underlying domain is convex and show that, also in this case, the preconditioner is spectrally equivalent to the inverse of the discrete operator. Keywords: preconditioner, finite element, multigrid, nonconvex domain URL: http://www.math.rutgers.edu/~falk/papers/hdivn.pdf