Some results about inverse-positive matrices

A nonsingular real matrix A is said to be inverse-positive if all the elements of its inverse are nonnegative. This class of matrices contains the M-matrices, from which inherit some of their properties and applications, especially in economy and in the description of iterative methods for solving nonlinear systems. In this paper we present some new characterizations for inverse-positive matrices and we analyze when this concept is preserved by the sub-direct sum of matrices.