“…Theorem 4 (Order reduction of linear switching descriptor systems [1]): Consider a switching descriptor system described by (10) and switching conditions (38),(39) when σ switches from i to j and suppose that (X i ,Y i ) is a decomposition of E i with Y i ∈ R n×r for i = 1, · · · N. Then, there exist matrices T 1 , · · · , T N such that the following holds. A function x(·) is a solution to system (10) with (38),(39) if and only if…”