Invariance of stability properties of Hadamard and Szegö product polynomials (Q1349422)

The paper investigates the invariance of integral representations of Hadamard and Szegö product operations of coefficient-wise multiplications for two (Hurwitz and Schur) polynomials. Section 2 shows how the Hadamard product polynomial provides a link between the convolutional description of the input/output behaviour of linear time-invariant discrete-time systems and Parseval's relation. Section 3 points out the invariance of the polynomial Schur property under the operation of composition (Szegö multiplication) of two Schur polynomials. Concluding remarks are drawn in Section 4.