MINRES-N is a minimal residual algorithm, originally developed by the authors for solving systems of linear equations with normal coefficient matrices whose spectra lie on algebraic curves of low degree. In a previous publication, the authors showed that a variant of MINRES-N, called MINRES-N2, is applicable to nonnormal matrices A satisfying the condition rank (A − A∗) = 1. This fact is extended to nonnormal matrices A such that rank (A − A∗) = k, k ≥ 1.
