A short survey of $Z$-matrices and new results on the subclass of $F_0$-matrices

Abstract

A real square matrix $A$ of order $n \times n~ (n \geq 3)$ is called an $F_0$-matrix, if it is a $Z$-matrix (off-diagonal entries nonpositive), all of whose principal submatrices of orders at most $n-2$ are $M$-matrices while there is at least one principal submatrix of order $n-1$, which is an $N_0$-matrix. An $M$-matrix is a $Z$-matrix with the property that the real parts of all its eigenvalues are nonnegative. An $N_0$-matrix, in turn, is characterized by the fact that it is an invertible $Z$-matrix whose inverse is (entrywise) nonpositive. The first aim of this article is to present a short survey of some subclasses of $Z$-matrices, pertinent to the second objective, where new results concerning $F_0$-matrices are presented.