On the spectra of P- and P0-matrices

Abstract We consider some conjectures of D. Hershkowitz and A. Berman in concerning the localization of eigenvalues of P - and P 0 -matrices. We show that two of these conjectures are false. We improve a classical formula of Routh's to prove our results. Also we reconsider a theorem of Kellogg's with the generalized result.