The Frechet Differential of a Primary Matrix Function
David L. Powers · Canadian Journal of Mathematics · 1973
LetXbe a given complex matrix of ordern.Iff(z)is analytic at the eigenvalues ofX,one may define the primary matrix functionf(X)with stem functionf(z)by using any of several well-known methods: for instance, canonical forms, power series, or interpolating polynomials [9].