“…While the theory of DAEs, the continuous-time counterpart of (1.1), has been almost well established, qualitative results in the theory of singular difference equations, particularly those for non-autonomous systems, are very few. Though the first result on LSDEs with variable coefficients was given a long time ago in [3], interesting results on the existence and the stability of solutions have been published only recently, see [7][8][9][10][11][12][13]. Most of the stability and robust stability results for singular difference equations are obtained for autonomous systems, e.g.…”