Closure to “Discussion of ‘On Stability of Time-Varying Multidimensional Linear Systems’ ” [ASME J. Vibr. Acoust., 121, No. 4, pp. 509–511 (1999)]

Dr. Shahruz claims that Theorem 2 in 1 is stronger than Theorem 1 in 2. Since Dr. Shahruz proves his claim by showing an example, not a mathematical derivation, I feel his argument is not convincing. Also it indicates clearly in 2, that the main purpose of the Theorem in 2 is to use damping to eliminate the parametric resonance. So there is no need for considering a time-varying damping.