A framework for the stability of a class of neutral type systems in a critical case

Under the proposed framework, a class of existing stability criteria can be extended to determine the stability of a class of neutral type systems in a critical case, i.e., the spectral radius of the principal neutral term (matrix D in this paper) is equal to 1. Furthermore, an interesting property of the extended criteria is given. Illustrative examples are presented to demonstrate the effectiveness of the proposed framework.