Comments on: “Delay-dependent robust H∞ control for discrete-time uncertain singular systems with interval time-varying delays in state and control input” [Journal of the Franklin Institute 347 (2010) 1704-1722]

A error of the paper “Delay-dependent robust H∞ control for discrete-time uncertain singular systems with interval time-varying delays in state and control input” [Journal of the Franklin Institute 347 (2010) 1704-1722] is pointed out, which indicates that the robust H∞ state feedback control problem mentioned above is yet an open problem. Furthermore, based on the so-called cone complementarity linearization technique, an approach is proposed to solve the open problem.