“…Compared with state-space models, the study of singular systems is more arduous, since not only stability, but also regularity and impulse elimination (for continuous-time singular systems) and causality (for discrete-time singular systems) should be considered simultaneously, while the latter two do not appear in state-space ones [37]. Recently, much appreciable work has been performed on the design of H ∞ filters for many kinds of singular system in various settings, including systems with or without time delay [11,14,21,36,39,41,43,45], systems with stochastic switching [22,35], and discrete-time switched systems under arbitrary switching signals [13]. However, to the authors' knowledge, the problem of H ∞ filter design for discrete-time switched singular time-delay systems has not been fully studied.…”