CRPC-TR99799 September 1999 Title: Improved Energy Estimates for Interior Penalty, Constrained and Discontinuous Galerkin Methods for Elliptical Problems Authors: Beatrice Riviere, Mary Wheeler, and Vivette Girault Submitted November 1999 Abstract: Three Galerkin methods using discontinuous approximation spaces are introduced to solve elliptical problems. The underlying bilinear form for all three methods is the same and is nonsymmetric. In one case, a penalty is added to the form and in another, a constraint on jumps on each face of the triangulation. All three methods are locally conservative and the third one is not restricted. Optimal a priori hp error estimates are derived for all three procedures. ------------------------------------------------------------------------------ Beatrice Riviere and Mary Wheeler The Center for Subsurface Modeling The University of Texas Vivette Girault Universite Pierre et Marie Curie, Paris VI Laboratoire Analyse Numerique Paris, France