Eigenvalue location for nonnegative and Z-matrices (Q1307534)

This paper determines bounds for the number of eigenvalues with positive real parts of an \(n\times n\) \(Z\)-matrix \(A=tI-B\) with \(B\geq 0\) and \(t \in [\rho_k(B), \rho_{k+1} (B))\), \([n/2]\leq k\leq n-1\), of \(k\times k\) principal submatrices of \(B\). For \(k=n-1\), \(n-2\) the paper identifies wedges that contain only the unique negative eigenvalues of \(A\).