Portland State University. Department of Mathematics and Statistics
Date of Award
Doctor of Philosophy (Ph.D.) in Mathematical Sciences
Mathematics and Statistics
1 online resource (vii, 103 pages)
Galerkin methods, Numerical analysis
This dissertation presents a duality theorem of the Aubin-Nitsche type for discontinuous Petrov Galerkin (DPG) methods. This explains the numerically observed higher convergence rates in weaker norms. Considering the specific example of the mild-weak (or primal) DPG method for the Laplace equation, two further results are obtained. First, for triangular meshes, the DPG method continues to be solvable even when the test space degree is reduced, provided it is odd. Second, a non-conforming method of analysis is developed to explain the numerically observed convergence rates for a test space of reduced degree. Finally, for rectangular meshes, the test space is reduced, yet the convergence is recovered regardless of parity.
Harb, Ammar, "Discrete Stability of DPG Methods" (2016). Dissertations and Theses. Paper 2916.