On invertible nonnegative Hamiltonian operator matrices

Invertible and regular completions of operator matrices

On the nonnegative inverse eigenvalue problem of traditional matrices

In this paper, at first for a given set of real or complex numbers $sigma$ with nonnegative summation, we introduce some special conditions that with them there is no nonnegative tridiagonal matrix in which $sigma$ is its spectrum. In continue we present some conditions for existence such nonnegative tridiagonal matrices.

On Nonnegative Factorization of Matrices

It is shown that a sufficient condition for a nonnegative real symmetric matrix to be completely positive is that the matrix is diagonally dominant.

Nonnegative Matrices

For a loopless, acyclic, transitive directed graph S, we study the relations between the predecessor property and the well structured property on S. These properties assure the existence of nonnegativ€ Jordan bases for any nonnegative matrix with singular graph S.

Perturbation theory for Hamiltonian operator matrices and Riccati equations