(1) National Laboratory of Industrial Control Technology, Zhejiang University, Hangzhou, Zhejiang, PRC;(2) National Laboratory of Industrial Control Technology, Zhejiang University, Hangzhou, Zhejiang, PRC
Abstract:
A recent paper (Ref. 1) established a new approach to estimate the robust stability radius of a Schur polynomial. This note points out that the approach given in Ref. 1 is not correct and also gives a counterexample to the main result of Ref. 1.