Descriptor (singular) linear systems have been considered in many papers and books (Bru et al., 2003; 2002; Choundhury, 1972; Campbell et al., 1976; Dai, 1989; Guang-Ren Duan, 2010; Kaczorek, 2013; 2011a; 2014b; 2004; 1992; 2014c; 2011c; 2011d; 2011e; Virnik, 2008). The eigenvalue and invariant assignment by state and output feedbacks was investigated by Kaczorek (2004; 2011d), along with minim...