A characterization of Jordan canonical forms which are similar to eventually nonnegative matrices with the properties of nonnegative matrices

In this paper we give necessary and sufficient conditions for a matrix in Jordan canonical form to be similar to an eventually nonnegative matrix whose irreducible diagonal blocks satisfy the conditions identified by Zaslavsky and Tam, and whose subdiagonal blocks (with respect to its Frobenius normal form) are nonnegative. These matrices are referred to as seminonnegative matrices, and we show that they exhibit many of the same combinatorial spectral properties as nonnegative matrices. This paper extends the work on Jordan forms of irreducible eventually nonnegative matrices to the reducible case.