Counter-example to ‘Sufficient and necessary condition for the asymptotic stability of discrete linear interval systems’

Note on Schur stability of three‐dimensional interval matrices

“…$$ Then $$$ G\left(-17/8\right) $$$ and $$$ G\left(17/8\right) $$$ are Schur stable but $$$ G(0) $$$ is not Schur stable. Other similar counterexamples to Theorems 6 and 7, for $$$ n=4 $$$, were given in References 26‐29. All interval matrices in these examples have the form of a companion matrix of some polynomial.…”

“…All interval matrices in these examples have the form of a companion matrix of some polynomial. Counterexamples to Theorem 7, for $$$ n=2 $$$, have been given in References 25,26,30.…”