On sign symmetric circulant matrices

In the last four decades many researchers have studied and analyzed the study of sign symmetry and positivity of principal minors of matrices, since these issues are related to stability. In this work we extend the theory about sign symmetric basic p-circulant permutation and sifted p-circulant matrices. We present and prove sufficient and necessary conditions for P-matrices and necessary conditions for P2-matrices. Finally we present a class of matrices, where the P2-matrices are stable.