Subtract two TransferFunctions (zp1 - zp2)
function subtract import Modelica; import ZerosAndPoles = Modelica_LinearSystems2.WorkInProgress.DiscreteZerosAndPoles; import Modelica_LinearSystems2.Math.Polynomial; import Complex; input ZerosAndPoles zp1; input ZerosAndPoles zp2; end subtract;