Spectrum analysis of a more general augmentation block preconditioner for generalized saddle point matrices (Q291895)

The authors first analyse and correct two previous results by \textit{O. Axelsson} et al. [J. Comput. Appl. Math. 280, 141--157 (2015; Zbl 1309.65035)]. Then, according to these new results they design and theoretically analyse a class of general augmentation block preconditioners for solving generalised saddle point systems with singular \((1, 1)\) blocks.