On SDD1 Matrices

摘要

The paper continues the study of the recently introduced class of SDD1 matrices. The class of general SDD1 matrices and its three subclasses are considered. In particular, it is shown that SDD1 matrices are nonsingular ?-matrices. Also parameter-free upper bounds for the l∞-norm of the inverses to SDD1 matrices are derived. The block triangular form to which any SDD1 matrix can be brought by a symmetric permutation of its rows and columns is described.