Drazin invertibility for matrices over an arbitrary ring
This paper deals with the Drazin inverse of a matrix \(A\) over an arbitrary ring \(R\). Characterizations for its existence and for the existence of the Drazin inverse of the product \(PAQ\) (where \(P\) and \(Q\) are matrices over \(R\) and there exist \(P'\) and \(Q'\) such that \(P'PA=A=AQQ'\)) are given and expressions for its computation are also presented. In addition, the case of Drazin inverses of companion matrices over general rings is studied by means of lower triangular Toeplitz matrices.
scientific article; zbMATH DE number 2083511