“…The theory of stability, optimal control and H 2 /H ∞ control, as well as important applications of such systems, can be found in several papers in the current literature, for instance in [5,6,7,8,10,12,13,14,15,18,19] for continuous-time case, and [9] for the discrete-time case. Fault tolerant control issues were also considered in the same framework, for instance in [1,2,3,22,24,25,26].…”