Convergence of multigrid methods for nonsymmetric, indefinite problems
A convergence theory is developed for multigrid methods for nonsymmetric, indefinite problems in a variational setting. Convergence is proved under discrete analogues of the \(H^{1+\alpha}\) regularity assumption. Special emphasis is put on the verification of the assumptions for various smoothers. \{The lower-order terms of differential equations lead to stencils with coefficients which are O(h) when compared with the coefficients of the main part. Therefore, the lower-order nonsymmetric terms are treated as perturbations. Unfortunately, the reviewer does not see whether the arguments imply that the nonsymmetric terms become arbitrarily small with respect to the discrete norms.\}
scientific article; zbMATH DE number 4080760
scientific article