“…Positive linear systems with different fractional orders were addressed by Kaczorek (2011b;2012), along with descriptor positive discrete-time and continuous-time nonlinear systems (Kaczorek, 2014a), the positivity and linearization of nonlinear discrete-time systems by state feedbacks (Kaczorek, 2014b), or new * Corresponding author stability tests of positive standard and fractional linear systems (Kaczorek, 2011a). The stability and robust stabilization of discrete-time switched systems were analyzed by Zhang et al (2014a;2014b), while the controllability of dynamical systems was investigated by Klamka (2013).…”