Comments on 'Frequency-domain conditions for the robust stability of linear and nonlinear dynamical systems' by S. Dasgupta et al

摘要

A number of comments on and corrections of the above-titled paper by S. Dasgupta et al. (see ibid., vol.38, p.389-397, 1991) are given. They concern the class of functions admitted in the paper, the degree of smoothness in assumption 2.1, the assumption on the parameter region Gamma , the assumptions on the region D and its boundary delta D, theorem 2.1 in the case of unbounded regions D, the role of the decomposition of the functions f(s, A), and the region for damping ratios, as well as some minor and general points.