===affil2: ===firstname: Meng-Huo (Alan) ===firstname4: ===firstname3: ===lastname2: ===lastname: Chen ===firstname5: ===affil6: ===lastname3: ===email: mchen01@uw.edu ===lastname6: ===affil5: ===otherauths: ===lastname4: ===affil4: ===lastname7: ===affil7: ===firstname7: ===postal: Department of Applied Mathematics, University of Washington, Guggenheim Hall #414, Box 352420, Seattle, WA 98195-2420 USA ===firstname6: ===ABSTRACT: We show that a pairwise aggregation-based algebraic 2-grid method, applied to the linear system $Ax = b$ arising from a 1D model problem for Poisson's equation with Dirichlet boundary conditions, reduces the $A$-norm of the error at each step by at least the factor $\sqrt{5/8}$. We then generalize this result to problems with the same eigenvectors but different eigenvalues from the model problem, and also to problems with different eigenvectors that are especially well-suited to the method. Finally, we discuss the reduction in the A-norm of the error when the 2-grid method is replaced by a multigrid V-cycle and indicate that conjugate gradient acceleration is required in order to improve the degraded performance of multigrid V-cycle. ===affil3: ===lastname5: ===affilother: ===title: Analysis Of an Aggregation-Based Algebraic Multigrid Methods On Matrices Related to a 1D Model Problem ===firstname2: