Abstract
Asymptotic stability independent of the delay of linear differential delay systems with commensurate and non-commensurate delays is analysed using 2-D (two-dimensional) and n-D (n-dimensional) state-space models. Sufficient conditions for stability are obtained in terms of the frequency dependent 1-D (one-dimensional) Lyapunov equations. 2-D and n-D Lyapunov equations with constant parameters are derived using the discrete positive real lemma and the continuous bounded real lemma.