. We study the distributed parameter suboptimal full information H-infinity problem for a stable well-posed linear system with control u, disturbance w, state x, and output y. Here u, w, and y are L2 -signals on (0; 1) with values in the Hilbert spaces U , W , and Y , and the state x is a continuous function of time with values in the Hilbert space H. The problem is to determine if there exists a
... [Show full abstract] (dynamic) gamma-suboptimal feedforward compensator, i.e., a compensator U such that the choice u = Uw makes the norm of the input/output map from w to y less than a given constant gamma. A sufficient condition for the existence of a gamma-suboptimal compensator is that an appropriately extended input/output map of the system has a (J; S)-inner-outer factorization of a special type, and if the control and disturbance spaces are finite-dimensional and the system has an L1 impulse response, then this condition is also necessary. Moreover, in this case there exists a central state feedback/feedforward ...
