Kybernetika

In this note sufficient conditions for the stability of continuous- and discrete-time dynamic interval systems are investigated. In particular, we focus our attention on stability conditions based on the extensions of Gershgorin's theorem, i. e. Gershgorin's theorem is applied after some similarity transformation, cf. Argoun(1986), Chen(1992) and Yau(1989). We show that the tests on stability and stability margins of dynamic interval systems suggested in Chen(1992) and in Yau(1989) can be considerably improved.