“…By definition of the mapping vec, we have Sp (XY) = (vec X) T • (vec Y T ) for any X ∈ M p,q (K), Y ∈ M q,p (K). Let us apply this equality in system (25), for every i = 1, n, to the matrix X = C * J i−1 B and to the matrices Y = Q ρ , ρ = 0, θ, and in system (26), for every i = 1, n, to the matrix X = C * J i−1 B and to Y = R(τ). Let us construct the mk × n-matrix P = [vec(C * B), vec(C * JB), .…”