Linear third-order discrete system stability under parameter variations

Note on Schur stability of three‐dimensional interval matrices

“…Similar examples can be given for larger $$$ n $$$ (see, e.g., Reference 19 for $$$ n=5,6 $$$). However, the discrete counterpart of Theorem 1 is true if $$$ n\le 3 $$$ (see References 20,21), namely, the following theorem is true.…”