“…However, it is more complex when considering the neutral differential system, i.e., all eigenvalues being with negative real parts are not sufficient for the stability of the zero solution [Z], [4], [8]; [9], [lo], [21], and the global hyperbolicity of a corresponding difference system must be taken into account [l], [9], [lo]. In neutral differential system, when characterizing system stability by means of the corresponding characteristic equation, it is usually required that the supremum of the real parts of all eigenvalues is negative [l], [2], [SI, [9], [IO], 1161, [211, which is notably different from retarded differential system. System (1) is said to be delayindependent stable, if V r E (R+)") the supremum of the real part of A satisfying Equation (2) is negative, that is, there exists a 6 > 0 , such that {Rex : G(X, T , A , E ) = In the literature, delay-independent stability is also called all-delay stability, unconditional stability or absolute stability.…”