Robustness properties of linear quadratic hereditary differential systems

In this paper we present a derivation of the Kalman frequency domain inequality, and also the corresponding equality, for the linear quadratic hereditary differential (LQHD) system. As a result, robustness properties of the LQHD system can be dealt with in an efficient manner. In particular, it is shown that the LQHD system has the same robustness properties as the finite dimensional LQ system.